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Life cycle environmental and economic analyses of a hydrogen station with wind energy
international journal of hydrogen energy 35 (2010) 2213–2225
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Life cycle environmental and economic analyses of a hydrogen station with wind energy Ji-Yong Lee a, Sanghyuk An b, Kyounghoon Cha b, Tak Hur b,* a b
Eco Strategy Team, LG Electronics, 16 Woomyeon-Dong, Seocho-Gu, Seoul, South Korea Dept. of Chemical and Biological Engineering, Konkuk University, 1, Hwayang-dong, Gwangjin-gu, Seoul, South Korea
article info
abstract
Article history:
This study aimed to identify the environmental and economic aspects of the wind-hydrogen
Received 8 October 2009
system using life cycle assessment (LCA) and life cycle costing (LCC) methodologies. The target
Received in revised form
H2 pathways are the H2 pathway of water electrolysis (WE) with wind power (WE[Wind]) and
17 December 2009
the H2 pathway of WE by Korean electricity mix (WE[KEM]). Conventional fuels (gasoline and
Accepted 17 December 2009
diesel) are also included as target fuel pathways to identify the fuel pathways with economic
Available online 27 January 2010
and environmental advantages over conventional fuels. The key environmental issues in the transportation sector are analyzed in terms of fossil fuel consumption (FFC), regulated air
Keywords:
pollutants (RAPs), abiotic resource depletion (ARD), and global warming (GW). The life cycle
Wind energy
costs of the target fuel pathways consist of the well-to-tank (WTT) costs and the tank-to-wheel
Hydrogen
(TTW) costs. Moreover, two scenarios are analyzed to predict potential economic and envi-
LCA (life cycle assessment)
ronmental improvements offered by wind energy-powered hydrogen stations.
LCC (life cycle costing)
In LCA results, WE[Wind] is superior to the other pathways in all environmental categories. The LCC results show that the projected WTT cost savings of WE[Wind] and WE[KEM] compared to gasoline are US $ 0.050 and US $ 0.036 per MJ, respectively, because hydrogen will not be subjected to any fuel tax according to the Korean Energy Policy in 2015. Although WE[KEM] and WE[Wind] incur high capital costs owing to the required capital investment in fuel cell vehicles (FCVs), they have lower well-to-wheel (WTW) costs than those of conventional fuels due to the high FCV efficiency in fuel utilization stage. WTW costs for gasoline are higher than those of WE[KEM] and WE[Wind] by US $ 12,600 and US $ 10,200, respectively. This study demonstrated the future competitiveness of the WE[Wind] pathway in both environmental and economic aspects. In the WTT stage, the point-of-sale of the electricity produced by the wind power plant (WPP) cannot be controlled because the wind-powered electricity production fluctuates considerably depending on the wind. However, the use of a wind-powered H2 station in the future enables stable wind power plant management and provides greater economic profit than the present system since the wind-powered electricity can be used for the hydrogen production in the H2 station and any residual electricity is sold to Korea electric power corporation (KEPCO). If 5% of conventional vehicles in Korea are substituted with FCVs using H2 via WE[Wind] in 2015, CO2 emission will be reduced by 2,876,000 tons/year and annual LCC costs by US $ 8559 million. Thus, the operation of windpowered hydrogen stations will encourage the introduction of hydrogen into the transportation fuel market. ª 2009 Published by Elsevier Ltd on behalf of Professor T. Nejat Veziroglu.
* Corresponding author. E-mail addresses: [email protected] (J.-Y. Lee), [email protected] (S. An), [email protected] (K. Cha), takhur@ konkuk.ac.kr (T. Hur). 0360-3199/$ – see front matter ª 2009 Published by Elsevier Ltd on behalf of Professor T. Nejat Veziroglu. doi:10.1016/j.ijhydene.2009.12.082
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international journal of hydrogen energy 35 (2010) 2213–2225
Introduction
Worldwide insecurity of energy supply, high oil prices and increasing levels of greenhouse gas (GHG) emissions have prompted researchers to look for alternative energy sources to replace existing non-renewable energy sources such as fossil fuels. Korea has a high dependence on fossil fuels and is under pressure to do its part to reduce global warming, as agreed upon under the Kyoto-protocol. Korea emits 591.1 million tons of CO2 annually, which ranks as the tenth country in the world for greenhouse gas emissions [1]. The Korean government also has a 5% target for new and renewable energy as a proportion of total energy consumption. Among the various renewable energy sources such as wind, solar and biomass, the wind energy is one source of renewable energy which has recently undergone rapid worldwide commercialization owing to improvements in technology and greater economic efficiency. Korea has invested heavily in the harnessing of wind energy for electricity production due to the absence of air pollution. Recently, the amount spent on research and development spending on wind energy in Korea has increased by US $ 51.5 million between 1988 and 2005 [2]. The clean development mechanism (CDM) scheme in the Kyoto Protocol is further motivation to encourage the establishment of a wind power plant (WPP). With its long coastline, Korea has a great deal of wind. Four coastal wind power stations are currently operating: Saemanguem (4500 kW), Pohang-youngdeuk (40,500 kW), Taebaek Mountains (35,000 kW), and Jeju Island (15,800 kW). [3] However, the fluctuation of wind-powered electricity, depending on the strength of the wind, causes problems in matching electricity supply and demand. This problem necessitates further improvements in energy efficiency of wind power stations and the development of other applications for the use of excess wind-powered electricity other than merely feeding into the main electricity grid. As an alternative energy to fossil-based resources, hydrogen offers the potential to enhance energy security and reduce energy imports, due to the variety of possible sources such as fossil resources, solar, wind, hydro, geothermal, and nuclear energies. In addition, hydrogen fuel cell vehicles (H2 FCVs) have zero exhaust emissions and are very efficient since hydrogen is used as a transportation fuel [4]. Hydrogen is also a possible solution to the problem of the fluctuating levels of wind-powered electricity. The production of hydrogen by WE pathways with the residue electricity generated from wind power will reduce greenhouse gas emissions. Despite these ecological advantages, an economic barrier has prevented the penetration of wind power plant and hydrogen use into the energy market. Therefore, this study analyses the environmental and economic feasibility of applying wind power plants to hydrogen generation as an alternative energy source. The environmental and economic impacts of wind-powered H2 generation via water electrolysis in Korea are evaluated and compared with those of conventional fuels (gasoline and diesel). It is assumed that hydrogen is used as a fuel in the transportation sector which is a dominant sector in total fossil fuel consumption (FFC), regulated air pollutants (RAPs), and global warming potential (GWP). The environmental and economic impacts are calculated based on the standard life cycle assessment (LCA)
and life cycle costing (LCC) methods that allow compilation and evaluation of the inputs, outputs, the potential environmental impacts, and total costs of a product system throughout its entire life cycle. In addition, two scenario analyses are conducted: Scenario (1), cost benefit analysis (CBA) of the future operation of a hydrogen station with Wind power plant system; and Scenario (2), the effect of the substitution of FCVs for ICEVs.
2.
Methodology
2.1.
Life cycle assessment (LCA)
LCA is a systematic tool to analyze the environmental impact of a product throughout all stages of its life cycle - from the extraction of resources, through the production of materials, parts and the product itself, and its use to the management after it is discarded, either by reuse, recycling or final disposal. LCA compiles and evaluates the inputs and outputs and the potential environmental impacts of a product system throughout its life cycle [5,6]. The environmental impacts between existing products and the development of new products can be compared, including comparisons with new prototypes [7]. In the present study, the environmental impacts were evaluated based on the international standards for LCA, ISO 14040-44. In this study, Fossil fuel consumption and Regulated air pollutants are chosen as inventory parameters for life cycle inventory analysis (LCI) to identify the significant environmental issues related to the target systems. From life cycle impact assessment (LCIA), the impacts on global warming (GW) and abiotic resource depletion (ARD) of the target fuel pathways were assessed by using the eco-indicators developed by the Ministry of Knowledge Economy (MKE), as shown in Table 1.
2.2.
Life cycle costing (LCC)
Fuller defined ‘LCC is an economic method of project evaluation in which all costs arising from owning, operating, maintaining, and ultimately disposing of a project are considered to be potentially important to that decision’ [8]. This study attempts to estimate the life cycle costs of target systems by integrating the various cost-categories such as capital costs, operational costs, and maintenance costs. The cost-categories in Table 2 were applied to the target pathways consistently. In performing LCC, this study defined the total life cycle costs of the target systems as consisting of the well-to-tank (WTT) and tank-to-wheel (TTW) costs, where the former is the sum of the costs incurred from raw material extraction to the station and the latter the costs incurred from the driving of the vehicle such as vehicle purchasing costs, and fuel costs.
3.
Target system
The target systems examined in this study are shown in Fig. 1. The WE pathways extend from water extraction and treatment to H2 FCV. H2 is produced by an electrolyzer and stored in its gaseous state (350 bar) in a fuelling system for dispensing to the H2 FCV. Gasoline and diesel are also included
international journal of hydrogen energy 35 (2010) 2213–2225
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Table 1 – Environmental impact category. Impact category
Category indicator
Key parameter
Abiotic Resource Depletion (ARD)a Global Warming (GW)
1/year
Coal, Crude oil, Natural gas CO2, CH4 etc
g CO2 eq/g
Reference for the characterization EIA, International Energy Annual 2000, 2002, U.S. Geological Survey (SUGS) 2001–2002 IPCC 1996, Global warming potential 100 years
a Abiotic resources are natural resources (including energy resources) such as iron ore, crude oil and wind energy, which are regarded as non-living.
in the target systems to enable comparative diagnosis of the environmental and economic feasibility of the WE pathways.
[Cathode] 2OH / H2O þ 1/2O2 þ 2e [Anode] 2H2O þ 2e– / (1) H2 þ 2OH–
3.1.
When coupled with a renewable energy source, hydrogen may thereby be produced by electrolysis without emitting any air emissions. Nevertheless, at present, few WE plants are operating in Korea, owing to the high production costs. The National New & Renewable Energy Technology R&D program of the Ministry of Knowledge Economy has been developing a WE station on Jeju Island since 2007, in order to monitor its technical, environmental and economic performance. This study compared WE[Wind], which is H2 made by water electrolysis using electricity from a wind power plant, with WE[KEM], which is H2 made by WE using electricity from the Korean electricity grid. Table 3 shows the composition of the Korean electricity grid.
Wind power
Most Korean wind power plants are located on the eastern coast and Jeju Island. This study evaluated two plants on Jeju Island: the Hangwon wind power plant located 35 km northeast of Jeju city and the Hangyung wind power plant located 45 km southwest of Jeju city, which commenced electricity generation into the grid in April 2003 and February 2006, respectively.
3.1.1.
Hangwon wind power plant
15 wind turbines installed in the Hangwon wind power plant consist of seven 660 kW turbines, two 600 kW turbines and one 225 kW turbine manufactured by Vestas and five 750 kW turbines manufactured by NEG-MICON, giving a total capacity of 9795 kW. The Hangwon wind power plant generated 20,125 MW h/year in 2005 with a production efficiency of 25.50%, equating to 1% of the total electricity consumption of Jeju Island [9].
3.1.2.
Hangyung wind power plant
The Hangyung wind power plant, comprising four 1.5 MW NEG-MICON wind turbines, generated 18,683 MW h/year in 2005 with a production efficiency of 34.88%, higher than that of the Hangwon wind power plant [10].
3.2.
3.3.
Gasoline and diesel
Gasoline and diesel, the most conventional fuels in the world, are included in this study in order to stand as a comparison for H2 via water electrolysis as transportation fuel. Crude oil, raw material for gasoline and diesel, is mainly imported from the Middle East to the petrochemical complexes in Ulsan and Yeosu in the southern part of Korea. Later on, gasoline and diesel are produced at refineries there. Gasoline and diesel are then distributed to gas stations and dispensed to Internal Combustion Engine Vehicles (ICEV) as shown in Fig. 1.
H2 via water electrolysis (WE)
Electrolysis is a process in which hydrogen is produced by an electrochemical reaction between electricity and water. By passing an electric current between two metal electrodes in water, a very pure hydrogen gas is formed at the anode electrode and oxygen at the cathode electrode, as shown below.
Table 2 – Cost categories for LCC. Cost-categories Capital costs
Operational and maintenance costs
Other costs
Sub cost-categories Preparation costs Construction costs Purchase costs for equipment Material costs, Energy costs (Fuels & Electricity), Labor costs etc. Vehicle purchasing, fuel distribution, tax, insurance, regular testing cost etc.
3.4.
Vehicles (ICEV and FCVs)
The target vehicles are the ‘Tucson’ ICEV and H2 FCV which are a sport utility vehicle (SUV) with internal combustion engine and fuel cell drive train, respectively. Table 4 shows the target vehicle systems.
4.
Life cycle analysis
The environmental and economic aspects of the windhydrogen system are examined by using LCA and LCC, respectively and compared with conventional fuel systems. The primary data (site-specific data) were obtained from the related companies or institutes operating the target systems, prior to the secondary data collection. The data on cost-categories and environmental impacts associated with the entire life cycles of the target systems were collected at the companies and institutes with large market shares in their industrial area, in relation to each life cycle stage.
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Fig. 1 – Target systems.
In principle, the site-specific data on the commercial processes and systems were collected. In addition, the simulation or pilot-plant data was also used for the analysis because most processes or systems related to hydrogen infrastructure remain in the R&D stage or at the pilot-plant scale. All the studied companies either have participated in the National New & Renewable Energy Technology R&D program of the Ministry of Knowledge Economy or have a significant market share in their industrial sector. For data validation, the following approaches were applied: Material and energy balance Cause and effect relationship - Treatment of missing data -
4.1.
Analysis model
The main goal of this study is to compare the environmental and economic aspect of water electrolysis pathways to gasoline and diesel. The system boundary includes six life cycle stages as shown in Fig. 1. The environmental impacts associated with vehicle manufacturing and infrastructure are excluded in this study. For comprehensive comparison of the LCA and LCC results of the target fuel pathways, the comparisons between fuel pathways shall be made on the basis of the same function(s), quantified by the same functional unit(s) in LCA, LCC methodology [6,11]. As shown in Table 5, the function of target system was selected as the transportation fuel for the vehicle
driving. A functional unit is quantified performance of a product system for use as a reference unit. Thus, in order to comprehensively compare the LCA and LCC results of the fuel pathways with different fuels and vehicle types, the functional unit (f.u.) is defined as 160,000 km of driving. The reference flow, which is the amount of fuel required to drive 160,000 km, is determined for each fuel pathway, considering the fuel efficiency. Then, the environmental and economic aspects with the entire life cycle of the reference flow for each fuel pathway are analyzed and compared each other. The LCA and LCC results of each target system were calculated based on the reference flow of each fuel pathway and the point of time for H2 to be used as a transportation fuel. However, the present status alone is not enough to estimate the effects of the H2 and FCV, since H2 and FCV aren’t fully developed and commercialized yet. Therefore, this study carries out the future status analysis with some considerations regarding market launch time of H2 FCV and the advancement of technology on H2 production and vehicles (FCV & ICEV) [12,13]. The target time for market launch of H2 FCV is set as 2015. The improvements in the H2 production efficiency and vehicle technologies expected by 2015 are then considered as shown in Table 6. The reduction of the life cycle costs of the target fuel pathways in the future (2015) was calculated, reflecting the mass production and up-scaling of the H2 production capacity of the H2 station using the up-scaling factor found in the U.C DAVIS study and California fuel cell program, as shown in the Eq. (2) [14,15].
Table 3 – Composition of Korean electricity grid, 2007. Energy source Hydro Nuclear Coal Crude oil LNG Others (Renewable etc)
Generation amounts (GWh)
Component ratio(%)
5042 142,937 154,674 21,216 78,427 829
1.25% 35.46% 38.37% 5.26% 19.45% 0.21%
Source: Electric Power Statistics Information System, http://epsis.kpx. or.kr/
Scaling factor
Costf ¼ Costi
Reformer PSA Storage Compressor Dispenser Electrolyzer
Sizef
Sizei
(2)
Scaling factor 0.6 0.5 0.8 0.7 0 0.46
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Table 4 – Target vehicle system. Classifications Brand Engine Fuel Fuel Efficiency
4.2.
Table 6 – Analytical model for the commercial time.
Sport utility vehicle (SUV)
Present
Tucson ICEV FCV Gasoline Diesel H2 9.8 km/L 12.6 km/L 22.0 km/L (gasoline equiv.)
Environmental analysis
An LCI analysis was conducted in accordance with the procedure addressed in ISO 14044.
4.2.1.
Raw material extraction and transportation
The LCI databases for most materials and energies have already been made by the Ministry of Knowledge Economy and the Ministry of Environment (MOE). The national LCI databases were used in the material extraction stage, as shown in Table 7. In the material transportation stage, fuel consumptions and transportation distances for the raw materials were collected. Table 8 presents the collected data in the raw material transportation stage. The environmental impacts in the raw material transportation stage were calculated with the collected data according to the following equation. Environmental exchanges ¼
XFEi;t Dist EFi;k DWT i;j
Fuel processing
The national LCI databases for gasoline and diesel, established by the Ministry of Knowledge Economy were used [16]. The environmental impacts of the electricity generated from wind power were assessed considering the environmental aspects of the construction, as well as the operation and maintenance of the wind power plants. The environmental impacts resulting from the construction of wind power were calculated using the NREL 2001 study [17]. The environmental impacts due to the operation and maintenance of the wind power were collected from the Hangwon and Hangyung wind
Table 5 – Function, functional unit, and reference flow. Fuel pathway Gasoline Diesel WE[KEM] WE[Wind]
65–69 30
75 400
6
100
State of the arts
Price considered Up Scaling, Mass Production 75.0a
H2 production efficiency 60.8 (%) Station capacity 14EA FCV fueling 190EA FCV fueling a day a dayb Vehicle type Sport utility vehicle (TUCSON made by Hyundai Motors) Engine type Fuel cell engine (A/T) Vehicle purchasing costs US $600,000/ea US $47,619/eac Fuel efficiency (km/kg) 82.0 km/kg H2 111.8 km/kg H2 Reference flow 1952 kg H2 1431 kg H2 (kg fuel) a The energy efficiency of hydrogen production in the future scenario was assumed to be the same as that of commercialized SR plants at present [18]. b The present capacity of the average gas station in Korea. c The FCV price and the fuel efficiency of vehicles in 2015 were estimated from the data given by Hyundai Motors.
(3)
EFi,k emission factor (g emitted/ton fuel k consumption) FEi,t fuel efficiency(ton fuel consumption/km driving by vehicle t) DWT: Dead-Weight-Tons Dist: Transportation distance (km)
4.2.2.
Efficiency (%) H2 production capacity (Nm3/hr) Number of stations (units) Cost
Commercial time (future, 2015)
Function
Functional unit
Reference flowa
Transportation fuel
160,000 km drivingfor 10 years
10,400 kg of gasoline 10,083 kg of diesel 1431 kg of hydrogen
a Reference flow was set as the amount of fuel consumption for 160,000 km driving.
power plants, as shown in Table 9. The environmental impacts caused by the hydrogen production were based on the operational data collected from the water electrolyzer made by Teledyne, with a hydrogen capacity of 11.2 Nm3/h max. Flow rate and a H2 delivery pressure of 8.3 kg/cm2 gauge, as shown in Table 10.
4.2.3.
Fuel distribution and storage
The conventional fuels are produced in the refinery complex, distributed via a pipeline from the production site to an oil reservoir distributed by tank lorry to gas stations, and finally stored in the storage tank until used for refueling. It is not necessary for WE[Wind] and WE[KEM] to distribute H2 from the production site to the H2 station because hydrogen is produced at the hydrogen fuelling station and then supplied to the FCV. However, a H2 pressure of 350 bar is needed in the WE pathways for dispensing H2 to the FCV. The H2 compression
Table 7 – LCI databases on raw material extraction. Raw material Natural gas
Crude oil
Water
Source National LCI DB made by Ministry of Environment (2003) [19]. The status of Indonesian energy industry, 2005 [20] Crude oil bj–Source: Van den Bergh en Jurgens. Pre consultant, 1997 National LCI DB made by Ministry of Environment (2003) [19]
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Table 8 – Data collected for raw material transportation. Oil tanker Source Route DWT(kg) Transportation distance (km) Fuel type Fuel consumption (Ton) Fuel efficiency (kg/km)
Hanjin shipping, SK shipping, HMM, 2007 Fujairah / Korea Mina al Ahmadi / Korea 317,614 277,798 10,286 11,401 BUNKER C (MF380) 1616.93 1351.02 157.20 118.50
The emission factor of IMO-SETAC & IPCC [21] Unit CO2 SOx NOx CH4 N 2O CO NMVOC
Fuel utilization
The environmental impacts of the target fuel pathways in the fuel utilization stage were calculated by using the driving data of the target vehicles based on the driving program, which consisted of a 55% urban dynamometer driving schedule and 45% highway driving schedule. Table 12 presents the environmental impacts and fuel efficiencies of the target vehicles. The total driving distance was calculated with the average daily driving distance and the vehicle’s lifetime, according to the statistics of various types of vehicle published by Ministry of Environment in 2005 [22].
4.3.
Economic analysis
4.3.1.
Well-to-tank costs
Bintulu / Korea 72,021 3782 HFO380 CST/MDO 543.56 147.33
Ras Laffin / Korea 76,065 10,138 3279.16 324.00
kg emitted/ton fuel consumption 3.11E þ 03 9.00E þ 01 8.70E þ 01 3.25E 02 8.00E 02 1.90E þ 00 8.72E þ 00
data were collected from the H2 station of Hyundai Motors and from Deokyang Energy which has H2 compressors and a large market share in the H2 distribution market. Table 11 shows the collected data on the fuel distribution and storage.
4.2.4.
LNG ship
4.3.1.1. Gasoline and diesel. The WTT costs of gasoline and diesel were collected from the energy department of the Ministry of Knowledge Economy, which published the cost breakdowns of the conventional fuels in 2007. Such data were not available from the major energy companies as they do not
publish fuel production costs, which are regarded as confidential data.
4.3.1.2. WE pathways. The WTT costs of the WE pathways consist of the costs related to the wind power plant and to the H2 station. The capital costs, operational and maintenance (O&M) costs of the wind power plant were collected from the Jeju Special Self-Governing Province in 2007. In order to calculate the WTT costs per kW electricity produced by the wind power plant, the lifetime of the wind turbines was assumed to be 20 years and the discount rate to be 7% [23]. The cost categories of H2 stations were classified into the capital costs and O&M costs. The former include the capital costs for the equipment in the H2 station. The lifetime of the overall equipment was assumed to be 15 years. The discount rate was 8%, which is the social discount rate of the public investments [23]. The O&M costs of the H2 station were calculated with the LCA input/output data. Table 13 shows the cost parameters considered in the WTT stage of the target systems and they were applied to all target systems consistently. 4.3.2.
Tank-to-wheel (TTW) costs
The TTW costs consisted of the vehicle purchasing cost, O&M costs, and registration costs such as the registration and acquisition taxes, as shown in Table 14. However, the insurance and maintenance costs of the vehicles were not
Table 9 – Environmental impacts from the construction of the Wind power plants. Regulated air emissions Air emission CO NOx VOC Dust SOx
Fossil fuel consumptions
g/kg of H2
g/160,000 km driving
0.72 2.16 2.75 27.04 3.77
1034.18 3087.10 3935.25 38,687.66 5394.58
Resource
g/kg of H2
g/160,000 km driving
Coal 145.14 207,691.33 Natural gas 11.66 16,691.18 Crude oil 36.80 52,667.38 Global warming potential (g CO2 equiv.) g/kg of H2 g/160,000 km driving 756.60 1,082,694.60
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Table 10 – Data collection for H2 via WE. Parameter
Amount
Unit
Target system
Input Water Electricity KOH N2
11.00E þ 00 62.72E þ 00 7.14E 03 6.85E 04
kg kWh kg kg
Output H2 O2 H 2O KOH N2
1.00E þ 00 8.00E þ 00 2.00E þ 00 7.14E 03 6.85E 04
kg kg kg kg kg
considered based on the assumption that they were the same for ICEV and FCV [24]. Table 15 shows the key cost parameters applied to both WTT and TTW stages in the whole life cycle stage.
5.
Results and discussion
5.1.
Environmental aspects
5.1.1.
Global warming potential (GWP)
Fig. 2 shows the Global warming Potential results of the target fuel pathways over the course of the entire life cycles. The key difference between the conventional fuels and WEs was the greenhouse gas emissions of the fuel utilization stage because the H2 FCV does not emit any CO2 during fuel utilization. The WE[Wind] pathway yielded the lowest Global warming Potential (52,824 g CO2 equiv.) among the target fuel pathways due to its use of wind energy for the H2 production and the absence of any fossil fuel consumption in the H2 production. Although the WE[KEM] had lower Global warming Potential than those of the conventional fuels, it also caused significant greenhouse gas emissions owing to the high portion of thermal power generation in the Korean electricity mix and the low WE energy efficiency [25].
5.1.2.
Table 12 – Environmental impacts and fuel efficiencies of the target vehicles.
Abiotic resource depletion (ARD)
The consumptions of crude oil, coal, and natural gas throughout the life cycle were calculated. The Fossil Fuel
ICEV
Fuel type Fuel efficiency (kg/km) CO2 (g/km) CO (g/km) NOx (g/km) SOx (g/km) HC (g/km) PM (g/km)
Gasoline 6.50E 02 1.92E þ 02 2.27E 01 1.08E 02 1.30E 03 3.23E 02 2.40E 03
FCV
Diesel 6.30E 02 1.88E þ 02 1.61E 01 8.00E 02 1.26E 03 4.48E 02 5.00E 03
H2[KEM, Wind] 8.95E 03 – – – – – – – – – – – –
Consumption results are expressed MJ to allow comparison among the target fuels as shown in Eq. (4). In addition, Abiotic resource depletion was calculated from the depletion of the ultimate reserve in relation to the annual use by using Eq. (5). FFCi
X
Cj LHVj
(4)
FFCi: Fossil fuel consumption (MJ, i/160,000 km driving) of the fuel pathway, i (gasoline, diesel, WE[KEM], WE[Wind]) LHVj: LHV (low heating value) (MJ/kg, fossil fuel j ) of fossil fuel, j (crude oil, natural gas, coal) Cj: The consumption (kg, fossil fuel j ) of each fossil fuel, j Abiotic Resource depletion ¼
X
ADPi mi
ADPi: Abiotic depletion potential of resource i mi: The quantity of resource i (kg) As shown in Fig. 3, the WE[KEM] and the WE[Wind] showed lower Fossil Fuel Consumption and Abiotic resource depletion than the conventional fuels due to the higher fuel efficiency of FCV than that of the ICEVs. Throughout the life cycle, the conventional fuels were more fossil fuel intensive than WE[Wind] with levels of 293,518 MJ (gasoline)–271,673 MJ (diesel). The Abiotic resource depletion of WE[KEM] was greatly reduced compared to that of gasoline because of crude oil’s high sensitivity to resource depletion. The Abiotic resource depletion of WE[Wind] was less than 1% of that of conventional fuels, which demonstrates its competitiveness as a transportation fuel given the increasing concern for nonrenewable resource exhaustion.
Table 11 – Data collected for fuel distribution and storage. Gasoline and diesel distribution Route The refinery (Yeosu) / [Pipeline] / The oil reservoir (Sungnam) / [Tank lorry] / The gas station Fuel Distribution Pipeline (468 km) 9.26 kWh/ton fuel distribution Tank lorry (58 km) Diesel: 1.78 km/liter EFa of Ministry of Environment Fuel storage Dispensing 4.75E 04 kWh/kg gasoline 1.90E 04 kWh/kg diesel H2 via WE Stage Fuel storage
Sub stage Compression (0–350 bar) Dispensing
(5)
i
Input Electricity Electricity
a EF: Emission factor for automobiles made in the Ministry of Environment [22].
Amount 3.17 0.01
Unit kWh/kg H2
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Table 13 – Cost categories in the WTT stage. Pathways
Cost-category
Sub cost-category
Gasoline & Diesel Raw material costs O&M costs
H2 via WE
5.1.3.
Material extraction & transportation costs Labor costs, Replacement costs, Energy costs, Processing material costs, Regular maintenance costs Fuel distribution Operational & maintenance costs costs for tank lorry & pipeline Fuel tax Educational tax, Transportation tax, Value added tax, Driving tax Capital costs Construction costs for the office and facilities in H2 station, H2 equipment costs O&M costs Labor costs, Replacement costs, Regular maintenance costs. Water, Energy costs, Processing material costs Raw material Material & transportation costs costs
Regulated air pollutants (RAPs)
Fig. 4 shows the Regulated air pollutants results of the conventional fuels and WE pathways. The Regulated air pollutants results were derived for dust, VOC, NOx, SOx, and CO, the levels of which are regulated in Korea. Although the WE[KEM] does not emit any of these five Regulated air pollutants directly, many Regulated air pollutants are released in the electricity generation for producing H2. Approximately, 63% of the electricity mix is produced by the combustion of fossil fuels in Korea. In the case of dust, SOx, and NOx emissions, the WE[KEM] pathway had more emissions than the conventional fuels due to its requirement for a great amount of electricity in order to produce the hydrogen in the station. However, the WE[Wind] pathway effectively reduced the levels of dust, SOx, and NOx. Gasoline had the highest VOC emissions because of the high leakage for volatile aromatic hydrocarbons in the
distribution stage and the storage tank of the gas station. As for CO emissions, the conventional fuels had much higher emissions than the WE[KEM] and the WE[Wind] due to the incomplete combustion of ICEV in the fuel utilization stage. The serious problems arising from urban air emissions support the environmental competitiveness of using H2 via the WE[Wind] as a transportation fuel.
5.2.
The WTT costs of the target pathways were calculated in the energy unit (US $/MJ) for comparison among the energy sources, as shown in Fig. 5(a). The conventional fuels maintained a cost competitiveness of US $ 0.0094 (gasoline) and US $ 0.0070 (diesel) per MJ over the WE[Wind] in the WTT stage, when the fuel taxes for the conventional fuels were excluded. However, with the increasing prices of the conventional fuels and fuel taxes due to fossil fuel resource depletion, the WE pathways are expected to have greater cost competitiveness in the future. Therefore, the WE[Wind] and the WE[KEM] demonstrated cost savings of US $ 0.050 and $ 0.036 per MJ over gasoline, respectively, because the WTT costs of the WE pathways will not incur any fuel tax according to the Korean Energy Policy in 2015 [12]. Fig. 5(b) indicates the well-to-wheel (WTW) costs for the 160,000 km driven by the FCV utilizing H2 and the ICEV using conventional fuels for their life time. Despite the high capital costs of the WE[KEM] and the WE[Wind] with the FCV purchase, they incurred lower WTW costs than those of the conventional fuels due to the lower fuel costs of the highly fuel efficient FCV. The WTW costs for gasoline were higher than those of the WE[KEM] and the WE[Wind] by US $ 12,600 and US $ 10,200, respectively, over 160,000 km of driving. In addition, the cost competitiveness of the WE[KEM] and the WE[Wind] over the conventional fuels will be further enhanced by cost savings associated with the mass production and localization for equipment of hydrogen stations and FCVs in the near future.
5.3.
Table 14 – Cost categories in the TTW stage. Module FCV
Cost-category Vehicle costs O&M costs
Registration costs
Gasoline & Diesel
Vehicle costs O&M costs
Registration costs
Sub cost-category Purchasing costs for the target vehicle Insurance costs, Maintenance costs, Fuel (hydrogen) costs Registration tax, Acquisition tax, and other costs for the registration Selling costs for the target vehicle Insurance costs, Maintenance costs, Fuel (gasoline & diesel) costs Registration tax, Acquisition tax, and other costs for the registration
Economic aspects
Interpretation
Two scenarios are investigated in order to examine the economic competitiveness of the hydrogen station with Wind power plant and the effect of the replacement of the conventional ICEV with H2 FCV in the future. In Scenario (1), cost benefit analysis (CBA) is conducted for the future operation of the hydrogen station with Wind power plant. In Scenario (2), the effect of the substitution of FCVs for ICEVs is examined.
5.3.1. Scenario (1): Cost benefit analysis of the future operation of a hydrogen station with wind power plant At present, all the electricity produced by Wind power plant is sold to Korea electric power corporation in Korea. This scenario is to compare the Cost benefit analysis results of the present Wind power plant system with those of the alternative system which produces hydrogen via water electrolysis using wind-powered electricity and sells any residual electricity to Korea electric power corporation.
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Table 15 – Summary of the key cost parameters. Key-cost parameter
Present costs, 2007 Natural gas (US $/m3) Industrial water Electricity (US ¢/kWh)
Materials Water Energy
General cost parameters (Labor, waste treatment cost) Gasoline (US $/liter) Diesel (US $/liter)
0.46 1.30 US $/ton Spring Summer Autumn Winter Applying each market price
Annual price escalation ratio CIF
5.74% 6.87% 2.34% 2.48% 2.34% 2.36% 3%a
4.61 6.10 4.61 4.94
6.61%a 85% of gasoline priceb
1.42 1.17
a Average price escalation ratio (2003–2007) in Korea published by the Ministry of Finance and Economy and the Ministry of Knowledge and Economy. b Korean Energy Policy, 2007.
For this purpose, Scenario (1) estimated the optimum hydrogen price assuming that the hydrogen station was operated with a Wind power plant in the near future. Moreover, the return on investment (ROI) was calculated as the present value which converted the value of money in the future into the present value based on a single present value (SPV) in order to calculate the net savings. [8] The time scope of this scenario was 20 years from March, 2005 to March, 2025, considering the durability of Wind power plant. In this study, it is assumed that H2 station with Wind power plant will be introduced from 2015. Table 16 shows the data collection and calculation for this scenario analysis.
5.3.1.1. Present system: sell all the wind-powered electricity to Korea electric power corporation.
5.3.1.2. Alternative system: operate the WE H2 station with the wind-powered electricity and then sell any residual electricity to Korea electric power corporation. Costs: þ [ 10 year (2005–2014)] þ (2015–2025)] Revenues: [ (2015–2025)]
10 year (2005–2014)] þ [ 10 year
Present and alternative systems include the future investment costs and revenues, as analyzed in the future. Therefore, Table 17 was converted to present value using equation (6) for comparison between the present and alternative systems under the equal situation. Single Present ValueðSPVÞ ¼ Ft
Costs:
þ [ 20 year (2005–2025)]
Revenues:
20 year (2005–2025)
þ [ 10 year
1 t ð1 þ dÞ
(6)
Ft: Future cash amount d: Discount rate t: The number of years from 2005 until 2025 The net saving is derived from calculation using Eq. (7). Net saving ðPresent valueÞ ¼
t X ðPb Pc Þ
(7)
0
Pb: Present value for revenues Pc: Present value for costs t: The number of years from 2005 until 2025 Then, ROI is calculated by equation (8) to indicate the investment returns on the present and alternative systems. ROI ¼
Fig. 2 – Global warming Potential results of each fuel pathway in the entire life cycle.
Pb Pc
Pb: Present value for revenues Pc: Present value for costs
(8)
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Fig. 3 – Fossil fuel consumption (FFC) and abiotic resource depletion (ARD) results of each fuel pathway in the entire life cycle.
Fig. 4 – Regulated air pollutants (RAPs) results of each fuel pathway in the entire life cycle.
Fig. 5 – WTT costs and WTW costs of target fuel pathways.
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Table 16 – Data collection and calculation for scenario analysis. Contents
Data description
Annual electricity generation Annual H2 production Electricity consumption for 1 kg H2 production Annual electricity consumption for H2 production Residual electricity after H2 production Selling price of 1 kWh of electricity The construction costs of H2 station Selling price for H2 (Assumed) Annual revenues of alternative system The unit cost for construction of Korea electric power corporation per kW The electricity production capacity of Wind power plant The construction costs for Wind power plant (9795 kW) Annual O&M costs for Wind power plant per kW Annual O&M costs for Wind power plant Annual O&M costs for H2 station Annual O&M costs for the alternative case
Amount
Unit
Primary data Primary data
19,734,966 315,360
kWh/year kg
Primary data
44.44
kWh/kg H2
14,014,598
kWh/year
Primary data Primary data Fluctuation for the calculation þ
5,720,368 0.102 2,422,541 Ref. Fig. 6 Ref. Fig. 6
kWh/year US $/kWh US $ US $/kg H2 US $/year
Primary data
1619
US $/kW
Primary data
9795
kW
15,858,571
US $
35.64
US $/kW /year
349,121
US $/year
89,576
US $/year
438,698
US $/year
Primary data Primary data þ
Source: Hangwon Wind power plant in Jeju Island, Korea.
Fig. 6 shows the Cost benefit analysis and return on investment results of the present and alternative systems according to the changes in the selling price of hydrogen. The break-even point of the alternative system was about 3.46 US $/kg H2 (9.40 US $/kg gasoline equiv.), indicating that the alternative system became profitable with a hydrogen selling price of over the break-even point. Furthermore, the alternative system exhibited a greater cost competitiveness over the present system with a hydrogen selling price of over 6.17 US $/kg H2 (16.76 US $/kg gasoline equiv.). The alternative system clearly demonstrated greater, long-term cost efficiency than the present system with the increase of a hydrogen price. In addition, if the hydrogen selling price is the same as the future gasoline price estimated considering the annual price escalation rate for the last decade (1997–2006), the alternative system could produce net savings of about 11 million US $ per each Wind power plant H2 station from equation (7).
5.3.2. ICEVs
Scenario (2): the effect of the substitution of FCVs for
This scenario analysis was conducted to estimate the reduction of greenhouse gas emissions and cost savings as a function of the substitution rate of FCVs for ICEVs, considering the Korean Energy Policy. Fig. 7 shows the effects of annual global warming reduction and life cycle cost savings according to the substitution percentage of FCVs, using hydrogen by the WE[Wind] and the WE[KEM], for ICEVs. The replacement to FCV using H2 via the WE[Wind] is the most effective alternative because the greenhouse gas emission of the WE[Wind] is much smaller than those of the WE[KEM]. If 5% of conventional vehicles are replaced by FCV using H2 via the WE[Wind] and the WE[KEM], CO2 emissions will be reduced by 2,876,000 ton/year, 242,900 ton/year and annual cost savings will be gained by 8559 million US $/year, 10,585 million US $/year, respectively. This means that the substitution of FCVs via the WE[Wind] is more effective in the
Table 17 – Costs and revenues for present and alternative systems, derived from Table 16. Year
Present system Costs
2005 2006–2014 2015 2016–2025
þ for each year
Alternative system Revenues
for each year
Costs þ for each year þ for each year
Revenues for each year for each year
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Fig. 6 – Cost benefit analysis results for the present and alternative systems.
Fig. 7 – Greenhouse gas reductions and cost savings according to the substitution of FCVs for ICEVs. environmental aspects, while FCVs via the WE[KEM] is effective in the economic aspects.
6.
Conclusions
The present study has examined the competitiveness of a hydrogen station with wind energy in both environmental and economic aspects by analyzing future conditions under two scenarios. In the LCA results, the WE[Wind] exhibited Abiotic resource depletion of 0.32%, Global warming Potential of 0.15%, and much smaller Regulated air pollutants (0.34% CO, 0.01% VOC, 0.38% SOx, 2.56% NOx, 0.02% dust) in comparison with gasoline. Therefore, the WE[Wind] demonstrated its environmental competitiveness as a transportation fuel. Despite the lower
degree of environmental improvement offered by the WE[KEM] over gasoline, compared to the WE[Wind], the WE[KEM] nevertheless also exhibited Abiotic resource depletion of under 43.89%, Global warming Potential of 90.93%, CO of 8.22%, VOC of 35.77% in comparison with the conventional fuels. Therefore, the WE[KEM] also showed its environmental competitiveness as a transportation fuel. However, the WE[KEM] had higher emissions than the conventional fuels for some Regulated air pollutants (298.36% SOx, 378.20% NOx, 398.53% dust) owing to the combustion of fossil fuels for the electricity production. Approximately, 63% of the Korean electricity mix is produced by the combustion of fossil fuels. [25] In the LCC results, the water electrolysis pathways exhibited cost competitiveness compared to the conventional fuels although the high O&M costs significantly impacted the WTT results for the water electrolysis pathways. In the WTT
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stage, it is quite difficult to manage the selling point of the electricity produced by the Wind power plant because the electricity production in the Wind power plant fluctuates widely depending on the wind. On the other hand, a Wind power plant-powered H2 station can provide stable Wind power plant management and greater economic profit than the present system, as shown in the results of Scenario (1), if the Wind power plant-powered electricity is used for the hydrogen production in the H2 station and any residual electricity is sold to Korea electric power corporation in the future. Despite the water electrolysis pathways had high initial FCV purchasing costs, they remained cost competitive over gasoline by US$ 12,600 (WE[KEM]), and US$ 10,200 (WE[Wind]) for the WTW stage because of the high efficiency of FCV compared with ICEV. In addition, the analysis of Scenario (2) showed that the replacement of ICEVs with FCVs would result in the significant annual cost savings as well as the reduction of greenhouse gas emission. Therefore, it is expected that the introduction of H2 stations with the Wind power plants encourage the development of H2 FCV into the Korean market.
Acknowledgement This study is supported by New & Renewable Energy Technology R&D program of the Ministry of Knowledge Economy.
Acyronyms
ARD Abiotic resource depletion CBA Cost benefit analysis FCV Fuel cell vehicle FFC Fossil fuel consumption G.H2 Gaseous hydrogen GHGs Greenhouse gases GWP Global warming potential ICEV Internal combustion engine vehicle LCA Life cycle assessment LCC Life cycle costing LCI Life cycle inventory MOE Ministry of Environment MKE Ministry of Knowledge Economy RAPs Regulated air pollutants TTW Tank to wheel WE Water electrolysis WE[KEM] Water electrolysis with the Korean electricity mix WE[Wind] Water electrolysis with wind power WPP Wind power plant WTT Well-to-tank WTW Well-to-wheel
references
[1] Korea Energy Management Corporation, The annual statistics of greenhouse gases in Korea; 2006 [in Korean].
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[2] Korea energy management corporation, New & Renewable energy policy and R&D status; 2006 [in Korean]. [3] The status of new & renewable energy policy and R&D, Korea: Korea energy management corporation; 2006 [in Korean]. [4] Joan O. The transition to hydrogen; 2005. Access No 27: 10–16. [5] International Organization for Standardization (ISO). ISO 14040: environmental management – life cycle assessment – principles and framework: Switzerland; 2004. [6] International Organization for Standardization (ISO). ISO 14044: environmental management – life cycle assessment – requirement and guidelines: Switzerland; 2006. [7] Guinee JB, Bruijn HD, Duin RV. Life cycle assessment – an operational guide to the ISO standards: CML; 2001. [8] Fuller SK, Petersen SR. Life-cycle costing manual for the Federal energy management program, LCC manual: US.DOE; 1996. [9] The status of the wind power plant at Hangwon Ri in Jeju island, Korea: Jeju special self-Govering province; 2006 [in Korean]. [10] Sim YS. The status of electricity generation by wind power plant at Hangyung-Ri in Jeju island. Korea: Southern Power Co., Ltd.; 2006 [in Korean]. [11] Hunkeler D, Lichtenvort K, Rebitzer G. Environmental life cycle costing. SETAC; 2008. [12] Master plan for the Environmental friendly Hydrogen economy: Korean Ministry of Knowledge Economy; 2005 [in Korean]. [13] Robert R, William V. Fuel Cell Vehicle World Survey 2003. Breakthrough Technologies Institute; 2004. [14] Jonathan X.W, Lipman T.E. An Assessment of the Near-Term Costs of Hydrogen Refueling Stations and Station Components: U.C DAVIS; 2006. [15] Weinert J.A. Near-term economic analysis of hydrogen fueling stations: U.C DAVIS; 2005. [16] Environmental national standard database: The Korean Ministry of Knowledge Economy; 2003 [in Korean]. [17] Spath PL, Mann MK. Life cycle assessment of renewable hydrogen production via wind/electrolysis. National Renewable Energy Laboratory; 2004. [18] Dongquan H, Anthony F. Well-to-tank energy use and greenhouse gas emissions of transportation fuels-North American analysis: GM, Argonne National Lab; 2001. [19] Life cycle inventory of products – water, industrial water, raw materials and chemical components: domestic area. The Korean Ministry of Environment (Ministry of Environment); 2002 [in Korean]. [20] The status of Indonesian energy industry, Korea. The Exportimport bank of Korea; 2005 [in Korean]. [21] Houghton JT. Greenhouse gases inventory reporting instructions: intergovernmental panel on climate change; 1997. [22] Notification 2005-41 – the special law for the improvement of the metropolitan area – the method for estimating total pollutants of vehicles. Korea: The ministry of Environment; 2005. [23] Lee CH, Kim CS. The study on the improvement of the feedin tariffs for new & renewable energy and connection with the RPS, Korea; 2006 [in Korean]. [24] An economic analysis of various hydrogen fuelling pathways from a Canadian perspective, a report for nature: tax policy services group of Ernst & Young; 2003. [25] The contribution of each energy source on the domestic electricity-grid: Korea energy economics institute; 2007 [in Korean].
Available at www.sciencedirect.com
journal homepage: www.elsevier.com/locate/he
Life cycle environmental and economic analyses of a hydrogen station with wind energy Ji-Yong Lee a, Sanghyuk An b, Kyounghoon Cha b, Tak Hur b,* a b
Eco Strategy Team, LG Electronics, 16 Woomyeon-Dong, Seocho-Gu, Seoul, South Korea Dept. of Chemical and Biological Engineering, Konkuk University, 1, Hwayang-dong, Gwangjin-gu, Seoul, South Korea
article info
abstract
Article history:
This study aimed to identify the environmental and economic aspects of the wind-hydrogen
Received 8 October 2009
system using life cycle assessment (LCA) and life cycle costing (LCC) methodologies. The target
Received in revised form
H2 pathways are the H2 pathway of water electrolysis (WE) with wind power (WE[Wind]) and
17 December 2009
the H2 pathway of WE by Korean electricity mix (WE[KEM]). Conventional fuels (gasoline and
Accepted 17 December 2009
diesel) are also included as target fuel pathways to identify the fuel pathways with economic
Available online 27 January 2010
and environmental advantages over conventional fuels. The key environmental issues in the transportation sector are analyzed in terms of fossil fuel consumption (FFC), regulated air
Keywords:
pollutants (RAPs), abiotic resource depletion (ARD), and global warming (GW). The life cycle
Wind energy
costs of the target fuel pathways consist of the well-to-tank (WTT) costs and the tank-to-wheel
Hydrogen
(TTW) costs. Moreover, two scenarios are analyzed to predict potential economic and envi-
LCA (life cycle assessment)
ronmental improvements offered by wind energy-powered hydrogen stations.
LCC (life cycle costing)
In LCA results, WE[Wind] is superior to the other pathways in all environmental categories. The LCC results show that the projected WTT cost savings of WE[Wind] and WE[KEM] compared to gasoline are US $ 0.050 and US $ 0.036 per MJ, respectively, because hydrogen will not be subjected to any fuel tax according to the Korean Energy Policy in 2015. Although WE[KEM] and WE[Wind] incur high capital costs owing to the required capital investment in fuel cell vehicles (FCVs), they have lower well-to-wheel (WTW) costs than those of conventional fuels due to the high FCV efficiency in fuel utilization stage. WTW costs for gasoline are higher than those of WE[KEM] and WE[Wind] by US $ 12,600 and US $ 10,200, respectively. This study demonstrated the future competitiveness of the WE[Wind] pathway in both environmental and economic aspects. In the WTT stage, the point-of-sale of the electricity produced by the wind power plant (WPP) cannot be controlled because the wind-powered electricity production fluctuates considerably depending on the wind. However, the use of a wind-powered H2 station in the future enables stable wind power plant management and provides greater economic profit than the present system since the wind-powered electricity can be used for the hydrogen production in the H2 station and any residual electricity is sold to Korea electric power corporation (KEPCO). If 5% of conventional vehicles in Korea are substituted with FCVs using H2 via WE[Wind] in 2015, CO2 emission will be reduced by 2,876,000 tons/year and annual LCC costs by US $ 8559 million. Thus, the operation of windpowered hydrogen stations will encourage the introduction of hydrogen into the transportation fuel market. ª 2009 Published by Elsevier Ltd on behalf of Professor T. Nejat Veziroglu.
* Corresponding author. E-mail addresses: [email protected] (J.-Y. Lee), [email protected] (S. An), [email protected] (K. Cha), takhur@ konkuk.ac.kr (T. Hur). 0360-3199/$ – see front matter ª 2009 Published by Elsevier Ltd on behalf of Professor T. Nejat Veziroglu. doi:10.1016/j.ijhydene.2009.12.082
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international journal of hydrogen energy 35 (2010) 2213–2225
Introduction
Worldwide insecurity of energy supply, high oil prices and increasing levels of greenhouse gas (GHG) emissions have prompted researchers to look for alternative energy sources to replace existing non-renewable energy sources such as fossil fuels. Korea has a high dependence on fossil fuels and is under pressure to do its part to reduce global warming, as agreed upon under the Kyoto-protocol. Korea emits 591.1 million tons of CO2 annually, which ranks as the tenth country in the world for greenhouse gas emissions [1]. The Korean government also has a 5% target for new and renewable energy as a proportion of total energy consumption. Among the various renewable energy sources such as wind, solar and biomass, the wind energy is one source of renewable energy which has recently undergone rapid worldwide commercialization owing to improvements in technology and greater economic efficiency. Korea has invested heavily in the harnessing of wind energy for electricity production due to the absence of air pollution. Recently, the amount spent on research and development spending on wind energy in Korea has increased by US $ 51.5 million between 1988 and 2005 [2]. The clean development mechanism (CDM) scheme in the Kyoto Protocol is further motivation to encourage the establishment of a wind power plant (WPP). With its long coastline, Korea has a great deal of wind. Four coastal wind power stations are currently operating: Saemanguem (4500 kW), Pohang-youngdeuk (40,500 kW), Taebaek Mountains (35,000 kW), and Jeju Island (15,800 kW). [3] However, the fluctuation of wind-powered electricity, depending on the strength of the wind, causes problems in matching electricity supply and demand. This problem necessitates further improvements in energy efficiency of wind power stations and the development of other applications for the use of excess wind-powered electricity other than merely feeding into the main electricity grid. As an alternative energy to fossil-based resources, hydrogen offers the potential to enhance energy security and reduce energy imports, due to the variety of possible sources such as fossil resources, solar, wind, hydro, geothermal, and nuclear energies. In addition, hydrogen fuel cell vehicles (H2 FCVs) have zero exhaust emissions and are very efficient since hydrogen is used as a transportation fuel [4]. Hydrogen is also a possible solution to the problem of the fluctuating levels of wind-powered electricity. The production of hydrogen by WE pathways with the residue electricity generated from wind power will reduce greenhouse gas emissions. Despite these ecological advantages, an economic barrier has prevented the penetration of wind power plant and hydrogen use into the energy market. Therefore, this study analyses the environmental and economic feasibility of applying wind power plants to hydrogen generation as an alternative energy source. The environmental and economic impacts of wind-powered H2 generation via water electrolysis in Korea are evaluated and compared with those of conventional fuels (gasoline and diesel). It is assumed that hydrogen is used as a fuel in the transportation sector which is a dominant sector in total fossil fuel consumption (FFC), regulated air pollutants (RAPs), and global warming potential (GWP). The environmental and economic impacts are calculated based on the standard life cycle assessment (LCA)
and life cycle costing (LCC) methods that allow compilation and evaluation of the inputs, outputs, the potential environmental impacts, and total costs of a product system throughout its entire life cycle. In addition, two scenario analyses are conducted: Scenario (1), cost benefit analysis (CBA) of the future operation of a hydrogen station with Wind power plant system; and Scenario (2), the effect of the substitution of FCVs for ICEVs.
2.
Methodology
2.1.
Life cycle assessment (LCA)
LCA is a systematic tool to analyze the environmental impact of a product throughout all stages of its life cycle - from the extraction of resources, through the production of materials, parts and the product itself, and its use to the management after it is discarded, either by reuse, recycling or final disposal. LCA compiles and evaluates the inputs and outputs and the potential environmental impacts of a product system throughout its life cycle [5,6]. The environmental impacts between existing products and the development of new products can be compared, including comparisons with new prototypes [7]. In the present study, the environmental impacts were evaluated based on the international standards for LCA, ISO 14040-44. In this study, Fossil fuel consumption and Regulated air pollutants are chosen as inventory parameters for life cycle inventory analysis (LCI) to identify the significant environmental issues related to the target systems. From life cycle impact assessment (LCIA), the impacts on global warming (GW) and abiotic resource depletion (ARD) of the target fuel pathways were assessed by using the eco-indicators developed by the Ministry of Knowledge Economy (MKE), as shown in Table 1.
2.2.
Life cycle costing (LCC)
Fuller defined ‘LCC is an economic method of project evaluation in which all costs arising from owning, operating, maintaining, and ultimately disposing of a project are considered to be potentially important to that decision’ [8]. This study attempts to estimate the life cycle costs of target systems by integrating the various cost-categories such as capital costs, operational costs, and maintenance costs. The cost-categories in Table 2 were applied to the target pathways consistently. In performing LCC, this study defined the total life cycle costs of the target systems as consisting of the well-to-tank (WTT) and tank-to-wheel (TTW) costs, where the former is the sum of the costs incurred from raw material extraction to the station and the latter the costs incurred from the driving of the vehicle such as vehicle purchasing costs, and fuel costs.
3.
Target system
The target systems examined in this study are shown in Fig. 1. The WE pathways extend from water extraction and treatment to H2 FCV. H2 is produced by an electrolyzer and stored in its gaseous state (350 bar) in a fuelling system for dispensing to the H2 FCV. Gasoline and diesel are also included
international journal of hydrogen energy 35 (2010) 2213–2225
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Table 1 – Environmental impact category. Impact category
Category indicator
Key parameter
Abiotic Resource Depletion (ARD)a Global Warming (GW)
1/year
Coal, Crude oil, Natural gas CO2, CH4 etc
g CO2 eq/g
Reference for the characterization EIA, International Energy Annual 2000, 2002, U.S. Geological Survey (SUGS) 2001–2002 IPCC 1996, Global warming potential 100 years
a Abiotic resources are natural resources (including energy resources) such as iron ore, crude oil and wind energy, which are regarded as non-living.
in the target systems to enable comparative diagnosis of the environmental and economic feasibility of the WE pathways.
[Cathode] 2OH / H2O þ 1/2O2 þ 2e [Anode] 2H2O þ 2e– / (1) H2 þ 2OH–
3.1.
When coupled with a renewable energy source, hydrogen may thereby be produced by electrolysis without emitting any air emissions. Nevertheless, at present, few WE plants are operating in Korea, owing to the high production costs. The National New & Renewable Energy Technology R&D program of the Ministry of Knowledge Economy has been developing a WE station on Jeju Island since 2007, in order to monitor its technical, environmental and economic performance. This study compared WE[Wind], which is H2 made by water electrolysis using electricity from a wind power plant, with WE[KEM], which is H2 made by WE using electricity from the Korean electricity grid. Table 3 shows the composition of the Korean electricity grid.
Wind power
Most Korean wind power plants are located on the eastern coast and Jeju Island. This study evaluated two plants on Jeju Island: the Hangwon wind power plant located 35 km northeast of Jeju city and the Hangyung wind power plant located 45 km southwest of Jeju city, which commenced electricity generation into the grid in April 2003 and February 2006, respectively.
3.1.1.
Hangwon wind power plant
15 wind turbines installed in the Hangwon wind power plant consist of seven 660 kW turbines, two 600 kW turbines and one 225 kW turbine manufactured by Vestas and five 750 kW turbines manufactured by NEG-MICON, giving a total capacity of 9795 kW. The Hangwon wind power plant generated 20,125 MW h/year in 2005 with a production efficiency of 25.50%, equating to 1% of the total electricity consumption of Jeju Island [9].
3.1.2.
Hangyung wind power plant
The Hangyung wind power plant, comprising four 1.5 MW NEG-MICON wind turbines, generated 18,683 MW h/year in 2005 with a production efficiency of 34.88%, higher than that of the Hangwon wind power plant [10].
3.2.
3.3.
Gasoline and diesel
Gasoline and diesel, the most conventional fuels in the world, are included in this study in order to stand as a comparison for H2 via water electrolysis as transportation fuel. Crude oil, raw material for gasoline and diesel, is mainly imported from the Middle East to the petrochemical complexes in Ulsan and Yeosu in the southern part of Korea. Later on, gasoline and diesel are produced at refineries there. Gasoline and diesel are then distributed to gas stations and dispensed to Internal Combustion Engine Vehicles (ICEV) as shown in Fig. 1.
H2 via water electrolysis (WE)
Electrolysis is a process in which hydrogen is produced by an electrochemical reaction between electricity and water. By passing an electric current between two metal electrodes in water, a very pure hydrogen gas is formed at the anode electrode and oxygen at the cathode electrode, as shown below.
Table 2 – Cost categories for LCC. Cost-categories Capital costs
Operational and maintenance costs
Other costs
Sub cost-categories Preparation costs Construction costs Purchase costs for equipment Material costs, Energy costs (Fuels & Electricity), Labor costs etc. Vehicle purchasing, fuel distribution, tax, insurance, regular testing cost etc.
3.4.
Vehicles (ICEV and FCVs)
The target vehicles are the ‘Tucson’ ICEV and H2 FCV which are a sport utility vehicle (SUV) with internal combustion engine and fuel cell drive train, respectively. Table 4 shows the target vehicle systems.
4.
Life cycle analysis
The environmental and economic aspects of the windhydrogen system are examined by using LCA and LCC, respectively and compared with conventional fuel systems. The primary data (site-specific data) were obtained from the related companies or institutes operating the target systems, prior to the secondary data collection. The data on cost-categories and environmental impacts associated with the entire life cycles of the target systems were collected at the companies and institutes with large market shares in their industrial area, in relation to each life cycle stage.
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Fig. 1 – Target systems.
In principle, the site-specific data on the commercial processes and systems were collected. In addition, the simulation or pilot-plant data was also used for the analysis because most processes or systems related to hydrogen infrastructure remain in the R&D stage or at the pilot-plant scale. All the studied companies either have participated in the National New & Renewable Energy Technology R&D program of the Ministry of Knowledge Economy or have a significant market share in their industrial sector. For data validation, the following approaches were applied: Material and energy balance Cause and effect relationship - Treatment of missing data -
4.1.
Analysis model
The main goal of this study is to compare the environmental and economic aspect of water electrolysis pathways to gasoline and diesel. The system boundary includes six life cycle stages as shown in Fig. 1. The environmental impacts associated with vehicle manufacturing and infrastructure are excluded in this study. For comprehensive comparison of the LCA and LCC results of the target fuel pathways, the comparisons between fuel pathways shall be made on the basis of the same function(s), quantified by the same functional unit(s) in LCA, LCC methodology [6,11]. As shown in Table 5, the function of target system was selected as the transportation fuel for the vehicle
driving. A functional unit is quantified performance of a product system for use as a reference unit. Thus, in order to comprehensively compare the LCA and LCC results of the fuel pathways with different fuels and vehicle types, the functional unit (f.u.) is defined as 160,000 km of driving. The reference flow, which is the amount of fuel required to drive 160,000 km, is determined for each fuel pathway, considering the fuel efficiency. Then, the environmental and economic aspects with the entire life cycle of the reference flow for each fuel pathway are analyzed and compared each other. The LCA and LCC results of each target system were calculated based on the reference flow of each fuel pathway and the point of time for H2 to be used as a transportation fuel. However, the present status alone is not enough to estimate the effects of the H2 and FCV, since H2 and FCV aren’t fully developed and commercialized yet. Therefore, this study carries out the future status analysis with some considerations regarding market launch time of H2 FCV and the advancement of technology on H2 production and vehicles (FCV & ICEV) [12,13]. The target time for market launch of H2 FCV is set as 2015. The improvements in the H2 production efficiency and vehicle technologies expected by 2015 are then considered as shown in Table 6. The reduction of the life cycle costs of the target fuel pathways in the future (2015) was calculated, reflecting the mass production and up-scaling of the H2 production capacity of the H2 station using the up-scaling factor found in the U.C DAVIS study and California fuel cell program, as shown in the Eq. (2) [14,15].
Table 3 – Composition of Korean electricity grid, 2007. Energy source Hydro Nuclear Coal Crude oil LNG Others (Renewable etc)
Generation amounts (GWh)
Component ratio(%)
5042 142,937 154,674 21,216 78,427 829
1.25% 35.46% 38.37% 5.26% 19.45% 0.21%
Source: Electric Power Statistics Information System, http://epsis.kpx. or.kr/
Scaling factor
Costf ¼ Costi
Reformer PSA Storage Compressor Dispenser Electrolyzer
Sizef
Sizei
(2)
Scaling factor 0.6 0.5 0.8 0.7 0 0.46
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Table 4 – Target vehicle system. Classifications Brand Engine Fuel Fuel Efficiency
4.2.
Table 6 – Analytical model for the commercial time.
Sport utility vehicle (SUV)
Present
Tucson ICEV FCV Gasoline Diesel H2 9.8 km/L 12.6 km/L 22.0 km/L (gasoline equiv.)
Environmental analysis
An LCI analysis was conducted in accordance with the procedure addressed in ISO 14044.
4.2.1.
Raw material extraction and transportation
The LCI databases for most materials and energies have already been made by the Ministry of Knowledge Economy and the Ministry of Environment (MOE). The national LCI databases were used in the material extraction stage, as shown in Table 7. In the material transportation stage, fuel consumptions and transportation distances for the raw materials were collected. Table 8 presents the collected data in the raw material transportation stage. The environmental impacts in the raw material transportation stage were calculated with the collected data according to the following equation. Environmental exchanges ¼
XFEi;t Dist EFi;k DWT i;j
Fuel processing
The national LCI databases for gasoline and diesel, established by the Ministry of Knowledge Economy were used [16]. The environmental impacts of the electricity generated from wind power were assessed considering the environmental aspects of the construction, as well as the operation and maintenance of the wind power plants. The environmental impacts resulting from the construction of wind power were calculated using the NREL 2001 study [17]. The environmental impacts due to the operation and maintenance of the wind power were collected from the Hangwon and Hangyung wind
Table 5 – Function, functional unit, and reference flow. Fuel pathway Gasoline Diesel WE[KEM] WE[Wind]
65–69 30
75 400
6
100
State of the arts
Price considered Up Scaling, Mass Production 75.0a
H2 production efficiency 60.8 (%) Station capacity 14EA FCV fueling 190EA FCV fueling a day a dayb Vehicle type Sport utility vehicle (TUCSON made by Hyundai Motors) Engine type Fuel cell engine (A/T) Vehicle purchasing costs US $600,000/ea US $47,619/eac Fuel efficiency (km/kg) 82.0 km/kg H2 111.8 km/kg H2 Reference flow 1952 kg H2 1431 kg H2 (kg fuel) a The energy efficiency of hydrogen production in the future scenario was assumed to be the same as that of commercialized SR plants at present [18]. b The present capacity of the average gas station in Korea. c The FCV price and the fuel efficiency of vehicles in 2015 were estimated from the data given by Hyundai Motors.
(3)
EFi,k emission factor (g emitted/ton fuel k consumption) FEi,t fuel efficiency(ton fuel consumption/km driving by vehicle t) DWT: Dead-Weight-Tons Dist: Transportation distance (km)
4.2.2.
Efficiency (%) H2 production capacity (Nm3/hr) Number of stations (units) Cost
Commercial time (future, 2015)
Function
Functional unit
Reference flowa
Transportation fuel
160,000 km drivingfor 10 years
10,400 kg of gasoline 10,083 kg of diesel 1431 kg of hydrogen
a Reference flow was set as the amount of fuel consumption for 160,000 km driving.
power plants, as shown in Table 9. The environmental impacts caused by the hydrogen production were based on the operational data collected from the water electrolyzer made by Teledyne, with a hydrogen capacity of 11.2 Nm3/h max. Flow rate and a H2 delivery pressure of 8.3 kg/cm2 gauge, as shown in Table 10.
4.2.3.
Fuel distribution and storage
The conventional fuels are produced in the refinery complex, distributed via a pipeline from the production site to an oil reservoir distributed by tank lorry to gas stations, and finally stored in the storage tank until used for refueling. It is not necessary for WE[Wind] and WE[KEM] to distribute H2 from the production site to the H2 station because hydrogen is produced at the hydrogen fuelling station and then supplied to the FCV. However, a H2 pressure of 350 bar is needed in the WE pathways for dispensing H2 to the FCV. The H2 compression
Table 7 – LCI databases on raw material extraction. Raw material Natural gas
Crude oil
Water
Source National LCI DB made by Ministry of Environment (2003) [19]. The status of Indonesian energy industry, 2005 [20] Crude oil bj–Source: Van den Bergh en Jurgens. Pre consultant, 1997 National LCI DB made by Ministry of Environment (2003) [19]
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Table 8 – Data collected for raw material transportation. Oil tanker Source Route DWT(kg) Transportation distance (km) Fuel type Fuel consumption (Ton) Fuel efficiency (kg/km)
Hanjin shipping, SK shipping, HMM, 2007 Fujairah / Korea Mina al Ahmadi / Korea 317,614 277,798 10,286 11,401 BUNKER C (MF380) 1616.93 1351.02 157.20 118.50
The emission factor of IMO-SETAC & IPCC [21] Unit CO2 SOx NOx CH4 N 2O CO NMVOC
Fuel utilization
The environmental impacts of the target fuel pathways in the fuel utilization stage were calculated by using the driving data of the target vehicles based on the driving program, which consisted of a 55% urban dynamometer driving schedule and 45% highway driving schedule. Table 12 presents the environmental impacts and fuel efficiencies of the target vehicles. The total driving distance was calculated with the average daily driving distance and the vehicle’s lifetime, according to the statistics of various types of vehicle published by Ministry of Environment in 2005 [22].
4.3.
Economic analysis
4.3.1.
Well-to-tank costs
Bintulu / Korea 72,021 3782 HFO380 CST/MDO 543.56 147.33
Ras Laffin / Korea 76,065 10,138 3279.16 324.00
kg emitted/ton fuel consumption 3.11E þ 03 9.00E þ 01 8.70E þ 01 3.25E 02 8.00E 02 1.90E þ 00 8.72E þ 00
data were collected from the H2 station of Hyundai Motors and from Deokyang Energy which has H2 compressors and a large market share in the H2 distribution market. Table 11 shows the collected data on the fuel distribution and storage.
4.2.4.
LNG ship
4.3.1.1. Gasoline and diesel. The WTT costs of gasoline and diesel were collected from the energy department of the Ministry of Knowledge Economy, which published the cost breakdowns of the conventional fuels in 2007. Such data were not available from the major energy companies as they do not
publish fuel production costs, which are regarded as confidential data.
4.3.1.2. WE pathways. The WTT costs of the WE pathways consist of the costs related to the wind power plant and to the H2 station. The capital costs, operational and maintenance (O&M) costs of the wind power plant were collected from the Jeju Special Self-Governing Province in 2007. In order to calculate the WTT costs per kW electricity produced by the wind power plant, the lifetime of the wind turbines was assumed to be 20 years and the discount rate to be 7% [23]. The cost categories of H2 stations were classified into the capital costs and O&M costs. The former include the capital costs for the equipment in the H2 station. The lifetime of the overall equipment was assumed to be 15 years. The discount rate was 8%, which is the social discount rate of the public investments [23]. The O&M costs of the H2 station were calculated with the LCA input/output data. Table 13 shows the cost parameters considered in the WTT stage of the target systems and they were applied to all target systems consistently. 4.3.2.
Tank-to-wheel (TTW) costs
The TTW costs consisted of the vehicle purchasing cost, O&M costs, and registration costs such as the registration and acquisition taxes, as shown in Table 14. However, the insurance and maintenance costs of the vehicles were not
Table 9 – Environmental impacts from the construction of the Wind power plants. Regulated air emissions Air emission CO NOx VOC Dust SOx
Fossil fuel consumptions
g/kg of H2
g/160,000 km driving
0.72 2.16 2.75 27.04 3.77
1034.18 3087.10 3935.25 38,687.66 5394.58
Resource
g/kg of H2
g/160,000 km driving
Coal 145.14 207,691.33 Natural gas 11.66 16,691.18 Crude oil 36.80 52,667.38 Global warming potential (g CO2 equiv.) g/kg of H2 g/160,000 km driving 756.60 1,082,694.60
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Table 10 – Data collection for H2 via WE. Parameter
Amount
Unit
Target system
Input Water Electricity KOH N2
11.00E þ 00 62.72E þ 00 7.14E 03 6.85E 04
kg kWh kg kg
Output H2 O2 H 2O KOH N2
1.00E þ 00 8.00E þ 00 2.00E þ 00 7.14E 03 6.85E 04
kg kg kg kg kg
considered based on the assumption that they were the same for ICEV and FCV [24]. Table 15 shows the key cost parameters applied to both WTT and TTW stages in the whole life cycle stage.
5.
Results and discussion
5.1.
Environmental aspects
5.1.1.
Global warming potential (GWP)
Fig. 2 shows the Global warming Potential results of the target fuel pathways over the course of the entire life cycles. The key difference between the conventional fuels and WEs was the greenhouse gas emissions of the fuel utilization stage because the H2 FCV does not emit any CO2 during fuel utilization. The WE[Wind] pathway yielded the lowest Global warming Potential (52,824 g CO2 equiv.) among the target fuel pathways due to its use of wind energy for the H2 production and the absence of any fossil fuel consumption in the H2 production. Although the WE[KEM] had lower Global warming Potential than those of the conventional fuels, it also caused significant greenhouse gas emissions owing to the high portion of thermal power generation in the Korean electricity mix and the low WE energy efficiency [25].
5.1.2.
Table 12 – Environmental impacts and fuel efficiencies of the target vehicles.
Abiotic resource depletion (ARD)
The consumptions of crude oil, coal, and natural gas throughout the life cycle were calculated. The Fossil Fuel
ICEV
Fuel type Fuel efficiency (kg/km) CO2 (g/km) CO (g/km) NOx (g/km) SOx (g/km) HC (g/km) PM (g/km)
Gasoline 6.50E 02 1.92E þ 02 2.27E 01 1.08E 02 1.30E 03 3.23E 02 2.40E 03
FCV
Diesel 6.30E 02 1.88E þ 02 1.61E 01 8.00E 02 1.26E 03 4.48E 02 5.00E 03
H2[KEM, Wind] 8.95E 03 – – – – – – – – – – – –
Consumption results are expressed MJ to allow comparison among the target fuels as shown in Eq. (4). In addition, Abiotic resource depletion was calculated from the depletion of the ultimate reserve in relation to the annual use by using Eq. (5). FFCi
X
Cj LHVj
(4)
FFCi: Fossil fuel consumption (MJ, i/160,000 km driving) of the fuel pathway, i (gasoline, diesel, WE[KEM], WE[Wind]) LHVj: LHV (low heating value) (MJ/kg, fossil fuel j ) of fossil fuel, j (crude oil, natural gas, coal) Cj: The consumption (kg, fossil fuel j ) of each fossil fuel, j Abiotic Resource depletion ¼
X
ADPi mi
ADPi: Abiotic depletion potential of resource i mi: The quantity of resource i (kg) As shown in Fig. 3, the WE[KEM] and the WE[Wind] showed lower Fossil Fuel Consumption and Abiotic resource depletion than the conventional fuels due to the higher fuel efficiency of FCV than that of the ICEVs. Throughout the life cycle, the conventional fuels were more fossil fuel intensive than WE[Wind] with levels of 293,518 MJ (gasoline)–271,673 MJ (diesel). The Abiotic resource depletion of WE[KEM] was greatly reduced compared to that of gasoline because of crude oil’s high sensitivity to resource depletion. The Abiotic resource depletion of WE[Wind] was less than 1% of that of conventional fuels, which demonstrates its competitiveness as a transportation fuel given the increasing concern for nonrenewable resource exhaustion.
Table 11 – Data collected for fuel distribution and storage. Gasoline and diesel distribution Route The refinery (Yeosu) / [Pipeline] / The oil reservoir (Sungnam) / [Tank lorry] / The gas station Fuel Distribution Pipeline (468 km) 9.26 kWh/ton fuel distribution Tank lorry (58 km) Diesel: 1.78 km/liter EFa of Ministry of Environment Fuel storage Dispensing 4.75E 04 kWh/kg gasoline 1.90E 04 kWh/kg diesel H2 via WE Stage Fuel storage
Sub stage Compression (0–350 bar) Dispensing
(5)
i
Input Electricity Electricity
a EF: Emission factor for automobiles made in the Ministry of Environment [22].
Amount 3.17 0.01
Unit kWh/kg H2
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Table 13 – Cost categories in the WTT stage. Pathways
Cost-category
Sub cost-category
Gasoline & Diesel Raw material costs O&M costs
H2 via WE
5.1.3.
Material extraction & transportation costs Labor costs, Replacement costs, Energy costs, Processing material costs, Regular maintenance costs Fuel distribution Operational & maintenance costs costs for tank lorry & pipeline Fuel tax Educational tax, Transportation tax, Value added tax, Driving tax Capital costs Construction costs for the office and facilities in H2 station, H2 equipment costs O&M costs Labor costs, Replacement costs, Regular maintenance costs. Water, Energy costs, Processing material costs Raw material Material & transportation costs costs
Regulated air pollutants (RAPs)
Fig. 4 shows the Regulated air pollutants results of the conventional fuels and WE pathways. The Regulated air pollutants results were derived for dust, VOC, NOx, SOx, and CO, the levels of which are regulated in Korea. Although the WE[KEM] does not emit any of these five Regulated air pollutants directly, many Regulated air pollutants are released in the electricity generation for producing H2. Approximately, 63% of the electricity mix is produced by the combustion of fossil fuels in Korea. In the case of dust, SOx, and NOx emissions, the WE[KEM] pathway had more emissions than the conventional fuels due to its requirement for a great amount of electricity in order to produce the hydrogen in the station. However, the WE[Wind] pathway effectively reduced the levels of dust, SOx, and NOx. Gasoline had the highest VOC emissions because of the high leakage for volatile aromatic hydrocarbons in the
distribution stage and the storage tank of the gas station. As for CO emissions, the conventional fuels had much higher emissions than the WE[KEM] and the WE[Wind] due to the incomplete combustion of ICEV in the fuel utilization stage. The serious problems arising from urban air emissions support the environmental competitiveness of using H2 via the WE[Wind] as a transportation fuel.
5.2.
The WTT costs of the target pathways were calculated in the energy unit (US $/MJ) for comparison among the energy sources, as shown in Fig. 5(a). The conventional fuels maintained a cost competitiveness of US $ 0.0094 (gasoline) and US $ 0.0070 (diesel) per MJ over the WE[Wind] in the WTT stage, when the fuel taxes for the conventional fuels were excluded. However, with the increasing prices of the conventional fuels and fuel taxes due to fossil fuel resource depletion, the WE pathways are expected to have greater cost competitiveness in the future. Therefore, the WE[Wind] and the WE[KEM] demonstrated cost savings of US $ 0.050 and $ 0.036 per MJ over gasoline, respectively, because the WTT costs of the WE pathways will not incur any fuel tax according to the Korean Energy Policy in 2015 [12]. Fig. 5(b) indicates the well-to-wheel (WTW) costs for the 160,000 km driven by the FCV utilizing H2 and the ICEV using conventional fuels for their life time. Despite the high capital costs of the WE[KEM] and the WE[Wind] with the FCV purchase, they incurred lower WTW costs than those of the conventional fuels due to the lower fuel costs of the highly fuel efficient FCV. The WTW costs for gasoline were higher than those of the WE[KEM] and the WE[Wind] by US $ 12,600 and US $ 10,200, respectively, over 160,000 km of driving. In addition, the cost competitiveness of the WE[KEM] and the WE[Wind] over the conventional fuels will be further enhanced by cost savings associated with the mass production and localization for equipment of hydrogen stations and FCVs in the near future.
5.3.
Table 14 – Cost categories in the TTW stage. Module FCV
Cost-category Vehicle costs O&M costs
Registration costs
Gasoline & Diesel
Vehicle costs O&M costs
Registration costs
Sub cost-category Purchasing costs for the target vehicle Insurance costs, Maintenance costs, Fuel (hydrogen) costs Registration tax, Acquisition tax, and other costs for the registration Selling costs for the target vehicle Insurance costs, Maintenance costs, Fuel (gasoline & diesel) costs Registration tax, Acquisition tax, and other costs for the registration
Economic aspects
Interpretation
Two scenarios are investigated in order to examine the economic competitiveness of the hydrogen station with Wind power plant and the effect of the replacement of the conventional ICEV with H2 FCV in the future. In Scenario (1), cost benefit analysis (CBA) is conducted for the future operation of the hydrogen station with Wind power plant. In Scenario (2), the effect of the substitution of FCVs for ICEVs is examined.
5.3.1. Scenario (1): Cost benefit analysis of the future operation of a hydrogen station with wind power plant At present, all the electricity produced by Wind power plant is sold to Korea electric power corporation in Korea. This scenario is to compare the Cost benefit analysis results of the present Wind power plant system with those of the alternative system which produces hydrogen via water electrolysis using wind-powered electricity and sells any residual electricity to Korea electric power corporation.
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Table 15 – Summary of the key cost parameters. Key-cost parameter
Present costs, 2007 Natural gas (US $/m3) Industrial water Electricity (US ¢/kWh)
Materials Water Energy
General cost parameters (Labor, waste treatment cost) Gasoline (US $/liter) Diesel (US $/liter)
0.46 1.30 US $/ton Spring Summer Autumn Winter Applying each market price
Annual price escalation ratio CIF
5.74% 6.87% 2.34% 2.48% 2.34% 2.36% 3%a
4.61 6.10 4.61 4.94
6.61%a 85% of gasoline priceb
1.42 1.17
a Average price escalation ratio (2003–2007) in Korea published by the Ministry of Finance and Economy and the Ministry of Knowledge and Economy. b Korean Energy Policy, 2007.
For this purpose, Scenario (1) estimated the optimum hydrogen price assuming that the hydrogen station was operated with a Wind power plant in the near future. Moreover, the return on investment (ROI) was calculated as the present value which converted the value of money in the future into the present value based on a single present value (SPV) in order to calculate the net savings. [8] The time scope of this scenario was 20 years from March, 2005 to March, 2025, considering the durability of Wind power plant. In this study, it is assumed that H2 station with Wind power plant will be introduced from 2015. Table 16 shows the data collection and calculation for this scenario analysis.
5.3.1.1. Present system: sell all the wind-powered electricity to Korea electric power corporation.
5.3.1.2. Alternative system: operate the WE H2 station with the wind-powered electricity and then sell any residual electricity to Korea electric power corporation. Costs: þ [ 10 year (2005–2014)] þ (2015–2025)] Revenues: [ (2015–2025)]
10 year (2005–2014)] þ [ 10 year
Present and alternative systems include the future investment costs and revenues, as analyzed in the future. Therefore, Table 17 was converted to present value using equation (6) for comparison between the present and alternative systems under the equal situation. Single Present ValueðSPVÞ ¼ Ft
Costs:
þ [ 20 year (2005–2025)]
Revenues:
20 year (2005–2025)
þ [ 10 year
1 t ð1 þ dÞ
(6)
Ft: Future cash amount d: Discount rate t: The number of years from 2005 until 2025 The net saving is derived from calculation using Eq. (7). Net saving ðPresent valueÞ ¼
t X ðPb Pc Þ
(7)
0
Pb: Present value for revenues Pc: Present value for costs t: The number of years from 2005 until 2025 Then, ROI is calculated by equation (8) to indicate the investment returns on the present and alternative systems. ROI ¼
Fig. 2 – Global warming Potential results of each fuel pathway in the entire life cycle.
Pb Pc
Pb: Present value for revenues Pc: Present value for costs
(8)
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Fig. 3 – Fossil fuel consumption (FFC) and abiotic resource depletion (ARD) results of each fuel pathway in the entire life cycle.
Fig. 4 – Regulated air pollutants (RAPs) results of each fuel pathway in the entire life cycle.
Fig. 5 – WTT costs and WTW costs of target fuel pathways.
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Table 16 – Data collection and calculation for scenario analysis. Contents
Data description
Annual electricity generation Annual H2 production Electricity consumption for 1 kg H2 production Annual electricity consumption for H2 production Residual electricity after H2 production Selling price of 1 kWh of electricity The construction costs of H2 station Selling price for H2 (Assumed) Annual revenues of alternative system The unit cost for construction of Korea electric power corporation per kW The electricity production capacity of Wind power plant The construction costs for Wind power plant (9795 kW) Annual O&M costs for Wind power plant per kW Annual O&M costs for Wind power plant Annual O&M costs for H2 station Annual O&M costs for the alternative case
Amount
Unit
Primary data Primary data
19,734,966 315,360
kWh/year kg
Primary data
44.44
kWh/kg H2
14,014,598
kWh/year
Primary data Primary data Fluctuation for the calculation þ
5,720,368 0.102 2,422,541 Ref. Fig. 6 Ref. Fig. 6
kWh/year US $/kWh US $ US $/kg H2 US $/year
Primary data
1619
US $/kW
Primary data
9795
kW
15,858,571
US $
35.64
US $/kW /year
349,121
US $/year
89,576
US $/year
438,698
US $/year
Primary data Primary data þ
Source: Hangwon Wind power plant in Jeju Island, Korea.
Fig. 6 shows the Cost benefit analysis and return on investment results of the present and alternative systems according to the changes in the selling price of hydrogen. The break-even point of the alternative system was about 3.46 US $/kg H2 (9.40 US $/kg gasoline equiv.), indicating that the alternative system became profitable with a hydrogen selling price of over the break-even point. Furthermore, the alternative system exhibited a greater cost competitiveness over the present system with a hydrogen selling price of over 6.17 US $/kg H2 (16.76 US $/kg gasoline equiv.). The alternative system clearly demonstrated greater, long-term cost efficiency than the present system with the increase of a hydrogen price. In addition, if the hydrogen selling price is the same as the future gasoline price estimated considering the annual price escalation rate for the last decade (1997–2006), the alternative system could produce net savings of about 11 million US $ per each Wind power plant H2 station from equation (7).
5.3.2. ICEVs
Scenario (2): the effect of the substitution of FCVs for
This scenario analysis was conducted to estimate the reduction of greenhouse gas emissions and cost savings as a function of the substitution rate of FCVs for ICEVs, considering the Korean Energy Policy. Fig. 7 shows the effects of annual global warming reduction and life cycle cost savings according to the substitution percentage of FCVs, using hydrogen by the WE[Wind] and the WE[KEM], for ICEVs. The replacement to FCV using H2 via the WE[Wind] is the most effective alternative because the greenhouse gas emission of the WE[Wind] is much smaller than those of the WE[KEM]. If 5% of conventional vehicles are replaced by FCV using H2 via the WE[Wind] and the WE[KEM], CO2 emissions will be reduced by 2,876,000 ton/year, 242,900 ton/year and annual cost savings will be gained by 8559 million US $/year, 10,585 million US $/year, respectively. This means that the substitution of FCVs via the WE[Wind] is more effective in the
Table 17 – Costs and revenues for present and alternative systems, derived from Table 16. Year
Present system Costs
2005 2006–2014 2015 2016–2025
þ for each year
Alternative system Revenues
for each year
Costs þ for each year þ for each year
Revenues for each year for each year
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Fig. 6 – Cost benefit analysis results for the present and alternative systems.
Fig. 7 – Greenhouse gas reductions and cost savings according to the substitution of FCVs for ICEVs. environmental aspects, while FCVs via the WE[KEM] is effective in the economic aspects.
6.
Conclusions
The present study has examined the competitiveness of a hydrogen station with wind energy in both environmental and economic aspects by analyzing future conditions under two scenarios. In the LCA results, the WE[Wind] exhibited Abiotic resource depletion of 0.32%, Global warming Potential of 0.15%, and much smaller Regulated air pollutants (0.34% CO, 0.01% VOC, 0.38% SOx, 2.56% NOx, 0.02% dust) in comparison with gasoline. Therefore, the WE[Wind] demonstrated its environmental competitiveness as a transportation fuel. Despite the lower
degree of environmental improvement offered by the WE[KEM] over gasoline, compared to the WE[Wind], the WE[KEM] nevertheless also exhibited Abiotic resource depletion of under 43.89%, Global warming Potential of 90.93%, CO of 8.22%, VOC of 35.77% in comparison with the conventional fuels. Therefore, the WE[KEM] also showed its environmental competitiveness as a transportation fuel. However, the WE[KEM] had higher emissions than the conventional fuels for some Regulated air pollutants (298.36% SOx, 378.20% NOx, 398.53% dust) owing to the combustion of fossil fuels for the electricity production. Approximately, 63% of the Korean electricity mix is produced by the combustion of fossil fuels. [25] In the LCC results, the water electrolysis pathways exhibited cost competitiveness compared to the conventional fuels although the high O&M costs significantly impacted the WTT results for the water electrolysis pathways. In the WTT
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stage, it is quite difficult to manage the selling point of the electricity produced by the Wind power plant because the electricity production in the Wind power plant fluctuates widely depending on the wind. On the other hand, a Wind power plant-powered H2 station can provide stable Wind power plant management and greater economic profit than the present system, as shown in the results of Scenario (1), if the Wind power plant-powered electricity is used for the hydrogen production in the H2 station and any residual electricity is sold to Korea electric power corporation in the future. Despite the water electrolysis pathways had high initial FCV purchasing costs, they remained cost competitive over gasoline by US$ 12,600 (WE[KEM]), and US$ 10,200 (WE[Wind]) for the WTW stage because of the high efficiency of FCV compared with ICEV. In addition, the analysis of Scenario (2) showed that the replacement of ICEVs with FCVs would result in the significant annual cost savings as well as the reduction of greenhouse gas emission. Therefore, it is expected that the introduction of H2 stations with the Wind power plants encourage the development of H2 FCV into the Korean market.
Acknowledgement This study is supported by New & Renewable Energy Technology R&D program of the Ministry of Knowledge Economy.
Acyronyms
ARD Abiotic resource depletion CBA Cost benefit analysis FCV Fuel cell vehicle FFC Fossil fuel consumption G.H2 Gaseous hydrogen GHGs Greenhouse gases GWP Global warming potential ICEV Internal combustion engine vehicle LCA Life cycle assessment LCC Life cycle costing LCI Life cycle inventory MOE Ministry of Environment MKE Ministry of Knowledge Economy RAPs Regulated air pollutants TTW Tank to wheel WE Water electrolysis WE[KEM] Water electrolysis with the Korean electricity mix WE[Wind] Water electrolysis with wind power WPP Wind power plant WTT Well-to-tank WTW Well-to-wheel
references
[1] Korea Energy Management Corporation, The annual statistics of greenhouse gases in Korea; 2006 [in Korean].
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