Approaches to polymer electrolyte membrane fuel cells (PEMFCs) and their cost

Renewable and Sustainable Energy Reviews 52 (2015) 897–906

Contents lists available at ScienceDirect

Renewable and Sustainable Energy Reviews journal homepage: www.elsevier.com/locate/rser

Approaches to polymer electrolyte membrane fuel cells (PEMFCs) and their cost Nayibe Guerrero Moreno a,n, Myriam Cisneros Molina b, Dominic Gervasio c, Juan Francisco Pérez Robles a a

CINVESTAV-Unidad Querétaro, Libramiento Norponiente 2000, Real de Juriquilla, C.P. 76230 Querétaro, Mexico Comisin Nacional de Vivienda CONAVI, Mexico c University of Arizona, The Department of Chemical and Environmental Engineering, Harshbager 108, 1133 E. James Rogers Way, Tucson 85721-0011, Az, USA b

art ic l e i nf o

a b s t r a c t

Article history: Received 11 November 2014 Received in revised form 22 May 2015 Accepted 29 July 2015

Cost analyses developed for fuel cells are reviewed, focusing mainly on polymer electrolyte membrane fuel cell (PEMFC) technology, because the solid polymer membrane electrolyte is robust and operates under conditions needed for most pressing applications, especially for the automotive application. Presently, PEMFC cost is still too high for large scale commercialization. The cost of electrodes and membranes contributes substantially to the total PEMFC cost which is driving research to reduce the costs of these components so the PEMFC can be introduced into large scale power markets. A scenario analysis for PEMFC costs for an automotive application illustrates that reducing the MEA cost up to 27% makes achievable the $40/kW cost target by 2020, which corresponds to a reduction in the cost of the catalyst by $3.55/kW and the membrane by $0.8/kW. The ultimate cost target for the PEMFC of 30/kW is obtained when the MEA cost is reduced by 45%, which corresponds to a projected cost reduction for catalyst cost by $6.41/kW and membrane by $1.44/kW. If these costs are met, the PEMFC would reach a price which is cost competitive to Internal Combustion Engine Vehicles which would allow the use of PEMFCs for power generation in a significant number of sectors. & 2015 Elsevier Ltd. All rights reserved.

Keywords: Cost analysis Fuel cell PEMFC MEA DFMA Bottom up

Contents 1.

2.

3.

n

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.1. PEMFC outline . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.2. Fuel cell market . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.3. PEMFC challenges towards commercialization. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.4. PEMFCs cost generalities . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Types of cost analyses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.1. Learning curves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.2. Benefit-cost analysis (BCA) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.3. Scenario analysis . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.4. Cost minimization analysis (CMA) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.5. Cost effectiveness analysis. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.6. Design for manufacture and assembly cost estimation (DMFA) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.7. Bottom up cost estimating . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.8. Market penetration model (MPM) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.9. Cost of PEMFC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . The importance of the reduction of membranes and catalyst costs over the PEMFC cost. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.1. Costs and production volume . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.2. Scenario analysis: reducing the cost of MEA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Corresponding author. Tel.: þ 52 442 211 99 17; fax: þ52 442 2119938. E-mail address: [email protected] (N. Guerrero Moreno).

http://dx.doi.org/10.1016/j.rser.2015.07.157 1364-0321/& 2015 Elsevier Ltd. All rights reserved.

898 898 898 898 899 899 899 900 900 900 900 900 900 901 901 902 903 904

898

N. Guerrero Moreno et al. / Renewable and Sustainable Energy Reviews 52 (2015) 897–906

4. Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 904 Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 904 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 904

1. Introduction 1.1. PEMFC outline Polymer electrolyte membrane fuel cells (PEMFCs) have several physicochemical advantages over the rest of the fuel cell types. They can continuously operate at low temperature and high current densities. PEMFCs are the smallest, lightest, and most durable, tolerant to shock and vibration. PEMFCs have long stack life due to solid electrolyte, fast start-ups due to thin structures, high energy efficiency and capability for discontinuous operation (tolerant to many starts and stops) [1–5]. Furthermore, PEMFC does not emit pollutants like NOx or CO, and when hydrogen is used as fuel, the only chemical byproduct is pure water. This is why many consider PEMFC an ideal power source for a ZeroEmission Vehicle (ZEV). All these characteristics make PEMFCs a valuable option for a series of power applications, ranging from watt levels for portable micropower to kilowatt levels for transportation to megawatts for large-scale stationary power systems in residential and distributed generation [5–8]. 1.2. Fuel cell market Commercialization of fuel cell systems began in 2007 and became more pronounced in 2011, especially for the stationary market. PEMFCs dominated the global sales for stationary and mobile applications, however during this time there was low demand for transportation power [9]. The last years have seen important developments in the economy of fuel cell technology. The market of the Fuel Cell Electric Vehicles (FCEVs) has been driving towards FCEV commercialization. As a consequence, PEMFCs production has increased and a number of agreements were established between companies in the automotive industry, fuel cell producers and also governments.1 These agreements are expected to boost use of fuel cell technology and expand the range of applications. Regarding manufacturing, Japan increased the units shipped from 1.000 units in 2008 to more than 20.000 units in 2012; this extraordinary increase is related to the Japan's residential fuel cell program (stationary power), which in 2013 continued growing. The US also increased production from about 1.000 units in 2008 to roughly 5.000 units in 2012. The tendency in Europe was different with a reduction in the fuel cell shipments going from about 5.000 units in 2008 to roughly 2.200 units in 2012. This was mainly attributed to the drop in the sale of luxury recreational vehicles. In 2012 Asia led the worldwide system shipments with 61% of the global market, overcoming North America shipments. However, regarding total megawatts, US had greater shipments, due to the sale of large stationary fuel cells with nearly 60 MW while Japan had about 20 MW, since Japan's focus was small the stationary market [9]. According to the DOE 1 Japan increased the RD&D budget for fuel cells and hydrogen, In Europe projects like the UK H2Mobility, the Fuel Cells and Hydrogen Joint Undertaking (FCH JU), In US the H2USA, the Advanced Clean Cars Program in California. In the side of car manufacturers, Toyota joined efforts with BMW, in the same way Daimler, Renault-Nissan with Ford, and General Motors (GM) with Honda to develop enhanced fuel cell systems for their hydrogen cars. Ballard signed a collaboration with Azure Hydrogen from China for the production of fuel cells buses. Fuel Cell Energy started a marketing partnership with NRG Energy to sell fuel cell power to their customers [9–13].

forecast, in 2013 about 150 MW of stationary fuel cells were shipped around the world [10]. Many companies in US in diverse sectors, from high tech industries (BMW, Verizon, Coca Cola, Sysco, P&G, etc.) to grocery/home stores (Walmart, Safeway, Kroger, IKEA, Lowe's, etc.), included fuel cells in their energy systems to reduce energy costs while being eco-friendly. Recently, Norway's largest grocery distributor partnered with Power Cell from Swedish to reduce diesel consumption by up to 90% duringelectricity generation using fuel cells. These fuel cell customers represent an important growing market. Regarding profitability in the fuel cells business, although 2012 and 2013 were important years with sales and shipments increase, fuel cell companies still reported considerable losses. However, companies like Bloom Energy, Plug Power, Intelligent Energy announced being on the road to profitability in the coming years [9,13]. In 2013, fuel cell system revenues grew by 35% over 2012, with approximately 1.3 billion. North America and Asia were the main contributors to this growth, while Europe decreased slightly its revenues [10]. In relation to applications, during the period from 2008 to 2012, stationary applications increased remarkably in terms of number of units shipped, while transportation and portable power applications continue decreasing. In 2013 fuel cells penetrated new markets of electric power in different locations in US and South Korea [10]. In 2012 fuel cell units shipped by electrolyte were led by PEMFC (88%) [13], which is expected to grow due to its applicability for varied applications and the special interest for automotive applications. Recently, Daimler, Honda and Hyundai announced the introduction of fuel cell electric vehicles (FCEVs) in consumer markets for 2015–2017 focusing on areas where a hydrogen infrastructure already exists.

1.3. PEMFC challenges towards commercialization The success of PEMFC for transportation has promoted its use in other applications, some of them are still under development, and are expected to be commercialized in the near future [14–17]. However, there are still many issues to solve before PEMFC technology can effectively substitute for the conventional power systems. For a detailed explanation of the challenges ahead for the full commercialization and a review of PEMFC applications and its prospects, see the work of Wee [6] and the work of Chandan et al. [7]. The possibilities for introduction of PEMFC power sources into the commercial sector depend predominantly on availability of suitable and profitable high-purity hydrogen supplies [18], the scale of application and the political will for putting a premium on improving health and environment over purely economic interests. Meanwhile, until the price per kW of fuel cells is reduced, society continues to prefer internal combustion engines to FCEVs. Presently PEMFC for Fuel cell vehicles are too costly compared with hybrids, conventional gasoline and diesel vehicles. Manufacturers have to bring down production costs, to make this market profitable and accessible to more customers. Currently, one of the biggest challenges is the dependence of PEMFC technology on hydrogen supply. Although several studies have found new paths for hydrogen supply, the cost is still significant [19–22], and also the cost of the system is still too high. Therefore, cost analyses are vital to achieve market commercialization. However, one of the most remarkable difficulties for making fuel cell cost assessment is

N. Guerrero Moreno et al. / Renewable and Sustainable Energy Reviews 52 (2015) 897–906

that fuel cell technology is still evolving, so there are continuously updates on to approaches for overcoming issues. 1.4. PEMFCs cost generalities The most important tools for cost analysis of PEMFCs are the technical data and information about the testing in a real application; all of this allows estimating the potential market at industrial scale. Unfortunately, there is very little published data or information on the PEMFC in real applications; nevertheless there have been academic efforts in the direction of cost analysis. Normally authors consider high volume production when doing cost analysis; because low volume manufacturing methods are intrinsically not cost effective and therefore not relevant. Lower volume less automated operations are used, because high volume methods imply greater capital investment. In real terms it is not always possible to talk about high volume production, since this depends of the needs and capabilities of each market. Authors also use a constant energy price; however the cost of energy is changing through time [23]. Mekhilef et al. [24] compared the estimated capital costs between Internal Combustion Engine Vehicles (ICEVs) and FCEVs. They found that although FCEVs are currently more expensive, because of the costs related with system characteristics, hydrogen supply and distribution, on the other hand, the operational costs during the vehicle's lifetime are more compelling than ICEVs costs. Lipman et al. [25] examined the possibility of using fuel cell vehicles for electricity supply for offices and homes, while they are parking. This study showed that under right technical conditions, this option is economically achievable; leading to considerable annual energy savings. According to Tsuchiya, cost reduction is possible with mass production [26]. However, the analysis of cost structure showed that the bipolar plates and MEA still make up a large proportion of the stack cost, even at mass production stage. Therefore, there should be greater emphasis on research aimed at reducing the cost of these components. Furthermore it is also absolutely necessary, to place more effort on developing alternative proton-conducting membranes, which have comparable proton conductivity to Nafion based membranes but are less expensive. Also Moch and Schmid [27] concluded that at the present time, production costs for fuel cell stacks and systems are still very high but could be reduced significantly for high production volumes. Power density of the stack, platinum loading of the electrodes and market price for platinum are the factors that weigh heavily in the total cost of the stack. Regarding the PEMFC technology itself, different studies have found that the cost of electrodes (related directly with platinum cost) and membranes are the most expensive components in PEMFC, representing almost 80% of total stack cost. The cost of electrodes is high because of the high platinum catalyst loading and labor intense manufacturing techniques. Considerable research has been done since the nineteen nineties, to obtain new catalysts or combinations of materials with platinum, which reduce the platinum loading in the electrodes [28–30]. The cost of the membrane component in the total distribution of the stack is as important as the electrodes cost in the case of low production volume (i.e. 1.000 units/ year).However studies have showed, that the cost of membrane is highly reduced for high production volumes (i.e. 500.000 units/year [31–40]. The cost of membranes and electrodes will be discussed in Section 3. Despite the pressing need and growing enthusiasm for fuel cell commercialization, obstacles like deficiencies in cost, reliability and durability have not yet been sufficiently overcome. Research, on issues such as new materials as well as water and heat management, is essential to overcome these obstacles. By 2013, the U.S. Department of Energy estimated the cost of a PEMFC as $55/kW, considering high volume manufacturing (500.000 units per year). The ultimate cost target is $30/kW [37,39]. In Section 2.9 the PEMFC cost is described in more detail. This paper provides a review of the cost analysis developed for fuel cells and is focused on PEMFCs, because of the widespread

899

applicability and potential benefits of this technology, not only in energy economics, but also on the environment. PEMFC technology has been widely studied, however, in the literature there is not a previous review exclusively addressing PEMFC cost analysis. Therefore this review is expected to be useful as a tool for the development of future fuel cell cost analysis. In Section 2, a brief introduction to cost analysis is presented. Since catalysts and membranes are particularly expensive components, and knowing that extensive research is ongoing to develop new materials for reducing their cost, in Section 3 the importance of cost reduction for these components is shown. As an additional contribution to the review of fuel cell cost analysis, a scenario analysis is carried out for optimizing the cost of catalyst and membranes. This analysis aims to give a path to reach the DOE ultimate fuel cell cost target. As was mentioned above, fuel cell is an emerging technology and costs are constantly changing. Thus, here it is only feasible to make crude estimates and predictions about costs rather than give conclusive values of cost assessment. The analysis herein uses the official DOE information available up to 2013, since the 2014 update has not been published to date.

2. Types of cost analyses An economic analysis is a process carried out for examining the distribution of limited resources to achieve a certain objective in a production process. Cost analysis of fuel cells is useful to predict the feasibility of using a fuel cell in a real system. Cost analysis is also valuable to evaluate if the costs are competitive for fuel cell technology in systems already in operation. Cost analysis is also known as economic evaluation, efficiency assessment, cost–benefit analysis, or cost-effectiveness analysis. These terms in themselves cover a wide range of methods, but are often used indistinctly. The main goal of economic analysis is to obtain a clear representation of the current economic climate in a particular business to determine the capabilities to address that business. To do this, it is necessary to know the strengths and weaknesses of the market. There are different methods to carry out economic analysis. These methods ensure cost-effective operations, reduce operating cost and compare costs to expected benefits. The most used methods in different knowledge areas are the cost-effectiveness analysis, cost–benefit analysis, costutility analysis and cost-minimization analysis. However in the fuel cells area there are other methods which have been widely used like learning curves, scenario analysis, bottom up cost estimating and design for manufacture and assembly (DFMA) cost estimation. Some of these methods are the result of the specific needs for the cost analysis of fuel cells. Cost reductions in fuel cell technology are crucial to the success of fuel cells because users will not accept and use technology that is not economically profitable. In this section is described in a simple way the methods and analysis have been and can be used for economic analysis of fuel cells. 2.1. Learning curves A learning curve describes the empirical relationships between output quantities and quantities of certain inputs (mainly direct-labor hours) where learning induced improvement is present. It defines the concept that the cumulative average unit cost decreases systematically by a common percentage each time the volume of production increases geometrically (that is, increases by doubling) [41]. In aspects of production planning and control, where there are activities subject to improvement, learning curves can be useful. Learning curves have been used on fuel cell economic analysis, however presently its use in this context is limited, because this technology is still transitioning

900

N. Guerrero Moreno et al. / Renewable and Sustainable Energy Reviews 52 (2015) 897–906

through various stages of maturation. The use of learning curves will be more accurate when fuel cells achieve some extent of commercialization. 2.2. Benefit-cost analysis (BCA) Benefit-cost analysis is a process of comparing, in common units (usually dollars), all of the gains and losses resulting from some economic activity [42]. Benefit cost analysis is regularly used in environmental policy debates, mainly because it allows an assessment of the net profits of some policy to society. In the case of fuel cells, benefits-cost analysis is useful since the application of this technology has a direct impact on society. The use of fuel cells in different applications can reduce greatly the carbon dioxide (CO2), methane, nitrogen oxides (NOx), carbon monoxide (CO), and other emissions which have a negative impact over human health and environment. Fuel cells are attractive not only for its environmental benefits but can also be cost competitive in power and energy markets. 2.3. Scenario analysis A scenario analysis is the process of analyzing probable future events, considering several alternatives as possible results. It focuses on the most unpredictable areas for a certain activity, and consistently establishes different probable options in which the activity could be developed, and also determines how these options would affect the activity's success [43]. Scenario analysis is commonly used for fuel cell economic analysis, in combination with other cost analysis, such as DFMA (design for manufacture and assembly), learning curves and bottom up cost analysis. Scenario analysis enables projections to long term. For fuel cells, costs are dependent of several factors, such as costs of materials and components, costs of hydrogen and volume of production. Each of these factors can give rise to different scenarios into fuel cell cost analysis. 2.4. Cost minimization analysis (CMA) Cost minimization analysis compares the costs of inputs in order to find the activity or output with the lowest cost. Costminimization analysis is the simplest method of economic evaluation, because only costs are evaluated. This analysis measures and compares input costs and assumes outcomes to be equivalent. The use of CMA has been limited because it is appropriate mainly when different activities have equal outcomes, and CMA focuses only on the cost. Therefore, before conducting a cost-minimization analysis for fuel cell technology, practical evidence should demonstrate that outcomes with fuel cells versus alternatives materials are essentially equivalent or only yield minimal differences [44]. 2.5. Cost effectiveness analysis Cost effectiveness analysis (CEA) is a technique that relates the level of performance and the involved cost to complete this level [45]. In the same way as cost benefit analysis, it compares the costs and outcomes for a given process. The difference lies in outcomes is understood as “performance for Cost” and ”benefit” for cost benefit analysis, what makes cost benefit analysis go further and deeper in cost analyses. When applying CEA to fuel cells, it is necessary to determine if fuel cell technology satisfies the objectives; for example for PEMFC if this technology satisfies the demand of power and at the same time is affordable for a particular application (in automotive industry, portable or electric generation in small buildings).

2.6. Design for manufacture and assembly cost estimation (DMFA) DFMA technique is an accurate methodology of design and cost estimation developed by Boothroyd and Dewhurst and adapted by Directed Technologies Inc. (DTI). DFMA cost estimation is the combination of DFM (Design for Manufacture) software and DFA (Design for Assembly) software. DFM promotes the design of the components that form the product in the most economical way. This approach can be used in any stage of the process, but it is especially advantageous if it is used early in the design stage. DFA facilitates a quick cost estimation of producing a design, creating consequently a more economical assembly [46]. Thanks to this analysis, companies can make in short time projections and/or modifications over the fuel cell technology they are already using or are planning to use. This analysis will result in future costs savings. DFMA has been used mainly by companies who are using or manufacturing fuel cell technology and also by the U.S. Department of Energy (DOE) [32–39].

2.7. Bottom up cost estimating In bottom up cost estimating technique, the cost of a major component is split up into smaller subcomponents. Because of all the consideration given to the cost of each subcomponent, there is a greater detail and consistency in the cost estimation of the big component. Bottom up cost estimating has been used widely for PEMFC cost analysis [47–49], this analysis allows to obtain the total manufacturing costs from the cost of each component (i.e., membranes and electrodes in the fuel cell stack, fuel processor, compressor/expander as major components in the fuel cell system).

Table 1 Methods of cost analysis used for fuel cell systems. Method

System

Application

Year

Reference

DMFA

PEMFC PEMFC PEMFC PEMFC PEMFC PEMFC PEMFC PEMFC PEMFC PEMFC PEMFC

Automotive Automotive Automotive Automotive Automotive Automotive Automotive Automotive Automotive Automotive Automotive

2001 2003 2008 2010 2011 2012 2012 2012 2011 2006 2006

[32], [33], [34], [35], [36], [37], [38], [39], [52], [53], [54],

PEMFC

SOFC

Automotive Automotive Stationary power Stationary power

2004 2009 2008 2010

[26], [27], [55], [56],

PEMFC PEMFC/SOFC PEMFC PEMFC

Stationary power Automotive Stationary power Stationary power

2000 2009 2001 1997

[57], [58], [59], [60],

PEMFC PEMFC PEMFC PEMFC PEMFC PEMFC

Automotive Automotive Automotive Stationary power Automative Automative

2009 2010 2005 2007 1998 2007

[47], [48], [49], [44], [51], [61],

PEMFC

Stationary power Stationary power

2009 2013

[62], [63],

BCA Learning curves

Scenario analysis

Bottom-up estimating

CMA MPM CEA Learning curves

N. Guerrero Moreno et al. / Renewable and Sustainable Energy Reviews 52 (2015) 897–906

901

fuel cells in high volume production is not yet feasible, despite important advances. In Table 2 some costs of PEMFC for different years and methods are presented. Since these analyses have been mainly done by DOE, the cost analyses basically used the same methods (DFMA and Bottom-up) through different years. Although other cost estimates are available, it is not simple to make comparisons between different types of studies, even if they were estimated for the same year. Because they depend on likely and often discordant assumptions (kind and size of membrane, active area of the fuel cell, platinum load, production target, etc.). For this reason, in Table 2, to make comparisons, costs are limited to the available and comparable information for the 50–80 kW fuel cell stack, operating at 0.6–0.7 V/cell, using Nafion based membranes as polymer electrolyte, electrodes based on platinum as catalyst and the anode being fed with direct hydrogen as fuel. The costs were also updated to 2013 using the annual Chemical Engineering Plant Cost Index (CEPCI). According to the results of these studies, it can be seen that in recent years the cost of fuel cells has been strikingly reduced in time. Cost analyses of PEMFC have been focused on transportation with a net power (1–100 kW) per unit; however, it is important to remember that the historical and the current market for fuel cells have been greater for other applications. It is also worth noting that some of these studies have not considered inflation and also emphasize that it is still unrealistic to talk about high production volume of fuel cells. Once the technology reaches greater maturity, cost analyses will be closer to real

2.8. Market penetration model (MPM) The market penetration model (MPM) is a stochastic simulation model developed by the US Department of Energy (DOE). This model was developed to predict energy consumption as function of time and fuel type. In fuel cells this model has been used to estimate the probable number of FCEVs, that could be sold in a particular market (continent, country, state) over some time period [50,51].

2.9. Cost of PEMFC Cost analyses have been emphasized in PEMFC (see Table 1), because once this technology becomes widely used, its impact over worldwide economy will be substantial. Most of these studies were concentrated on transportation, since this application is a high consumer of energy that represents an important market. A fuel cell cost estimating is not that simple, however, with significant research and investment, realistic estimation of the fuel cells market will become reliable. There are only a few independent cost analyses of fuel cells, most of the studies of fuel cells found in the literature were conducted by companies subcontracted by DOE [32–40]. Although considerable research has been done to improve the PEMFC performance, to increase durability and to reduce costs, few studies have used these results directly to make costs projections; this probably because manufacturing of Table 2 Cost of PEMFC through different analyses. Year estimated

Cost stack ($/kW)

Cost system ($/kW)

Cost stack updated to 2013 ($/kW)

Cost system updated to 2013 ($/kW)

2001 2003

59 170

118 262

85 167

245 370

DFMA

2004 2005

72 67

97 108

92 81

124 131

Bottom up

2005 2007

67 31

108 59

81 33.5

131 63.7

Bottom up

2008

29

57

28.6

56

2008

33.4

66.6

32.9

65.6

2010 2015

27.1 23

57 46.5

28 22.8

58.7 46

2008

37.7

75

37.2

74

2010 2015

29.4 25

61.8 50.6

30.3 24.8

63.7 50

2010

25

51

25.8

52.5

2011 2012

22 20

49 47

21.3 19.4

47.5 45.6

2008

29

57

28.6

56

2009 2010

22.3 22.3

55.2 55.2

24.2 23

60 57

up

2013

27

55

27

55

DFMA

SNP – stack net power, NR Not reported, Pt load – load of platinum for estimated year.

Method Assumptions

DFMA

DFMA

DFMA

SNP:80 kW Pt load:0.30 mg cm  2 Active Area:446.4 cm2 SNP:80 kW Pt load:0.75 0.30 mg cm  2 Active Area:223 cm2 SNP:80 kW Pt load:0.75,0.30 Pt load:0.75,0.30 0.25 mg cm  2 Active Area:323 260, 277 cm2 SNP:80 kW Pt load:0.25,0.30 0.2 mg cm  2 Active Area:424 291, 292.5 cm2 SNP:80 kW Pt load:0.25,0.30 0.2 mg cm  2 Active Area:323 260, 277 cm2 SNP:80 kW Pt load:0.15,0.19 0.2 mg cm  2 Active Area:323 260, 277 cm2 SNP:80 kW Pt load:0.25,0.15 0.15 mg cm  2 Active Area:277 304, 195 cm2 SNP:80 kW Pt load: 0.15 mg cm  2 Active Area:NR

Reference

[32], [33], [54],

[42],

[34],

[35],

[37],

[48],

[39],

902

N. Guerrero Moreno et al. / Renewable and Sustainable Energy Reviews 52 (2015) 897–906

Fig. 2. Evolution of PEMFC system cost. Fig. 1. Evolution of PEMFC stack cost.

market. That is, because the fuel cell is still a new technology, cost analyses are far from accurately representing the current and near markets. Based on the data from Table 2, Figs. 1 and 2 graphically show the historical cost behaviour of PEMFC, using DMFA and Bottom up estimating. As it is expected, there are a few variations in the cost even for the same year estimated, due to the differences in the assumptions used for each cost analysis. Comparatively, it can be seen a trend in time leading to a reduction of the cost of the fuel cell stack and also the system. When fuel cells were an emerging technology, the overall cost estimated of fuel cells in was considerable high. This high cost at that time was related to the low investment on research and development of fuel cells, when government funding had previously been mainly oriented on batteries and biofuels. In 2003 government commitment for fuel cell research increased, and the effect of the increased budget is reflected in significant cost reduction in subsequent years, for stack and for fuel cell systems. Although the economic recession, caused the closure of some fuel cell companies in the last decade, this recession also prompted surviving companies to make fuel cell technology commercially more feasible. These companies invested enough on R&D to lead to continuous cost reduction, resulting in, the number of patents on fuel cells to increase substantially. The numbers are 24 patents in 2000 and 886 patents in 2013 [9,10].

3. The importance of the reduction of membranes and catalyst costs over the PEMFC cost As was previously mentioned, to make PEMFC commercially feasible, a major challenge is the hydrogen fuel. PEMFCs run best on very pure hydrogen, hydrogen rich gas from reformate tends to contain varying amounts of carbon monoxide (CO), which can have disastrous effects on the efficiency of anode reaction and fuel cell performance [64]. This characteristic is closely related to and dependent on the electrodes and membranes. Often the constituent materials making up the electrodes do not tolerate carbon monoxide at the temperature of operation dictated by the membranes; if this problem can be overcome, then costs would be reduced significantly. PEMFCs cost is best when made in very high volume production (500.000 units/year). The acronym MEA (Membrane Electrode Assembly) is normally used when discussing membranes and electrodes. The MEA, comprises an approximately 50 μm thick polymer electrolyte membrane sandwiched between two gas diffusion layers (GDL) which are about 0.1 millimetre thick, with electrode which is about 1 μm thick between GDL and membrane. Although electrode is the component with highest cost in the fuel cell stack at high volume production

(500.000 units/year), the membrane and GDL are also expensive materials, particularly in the low volume production which represents the current state of manufacture in the fuel cell industry [65,66]. At high volume production the cost of membranes and GDL are projected to be greatly reduced. The major cost driver for membranes is volume and the driver for the electrode is the material cost. Usually the electrode has a precious metal catalyst, typically platinum. This metal is chosen, because Pt is a relatively stable material which is effective for accelerating the otherwise slow oxygen-reduction reaction (ORR) which occurs at the cathode. The ORR is the rate limiting factor for power generation and performance in the fuel-cell. Platinum is expensive and scarce. The average price of Platinum reported in 2012 was $1555/Troy oz. and $1490 /Troy oz. in 2013 [67]. For several years the cost analyses which were reviewed in this paper used a fixed price of $1100 /Troy oz in 2012 [31,32]. This value was fixed for the purpose of insulating it from platinum price fluctuations. However, in 2013(the last year reported), cost analysis used an updated price of $1500 /Troy oz [39]. Research in vehicle manufacturing companies has reduced the amount of platinum in fuel cells, which has partially solved the problem of the catalyst cost; however completely eliminating the use of platinum in PEMFC remains a major challenge for the scientific community. In relation to cost of membranes, this cost depends on the type of polymer used, the volume of material and also the manufacturing process itself. Material cost (polymer) represents the 90% of the total cost of the membrane [23,47]. This material is very important because it must be stable, durable and chemically compatible with the bonding requirements of the other components of the MEA (electrode and GDL). New materials are desired for replacing traditional Nafion membranes (Dupont trademark); in particular materials that allow working at higher temperatures (over 100 1C)), without humidification and with good thermal, chemical and mechanical properties. After years of research, basically three research approaches have been taken for developing advanced membranes: (1) modifying perfluorinated ionomer membranes (Nafion), (2) functionalization of aromatic hydrocarbon polymers/membranes; and (3) composite membranes [68]. The most widely studied polymers after Nafion are the sulfonated polyether-ether ketone (SPEEK), and polybenzimidazole (PBI) [68–71]. Currently the research trend is focused on the third approach, the composite and hybrid membranes, which combines the properties of both a polymeric component and an inorganic part. Composite membranes show enhanced properties and performance when they are used as polymer electrolyte membranes into a fuel cell [72–74]. Although PBI based membranes have been successfully used by BASF in their MEAS, these membranes have been used mainly for research; they still need to be improved to be used in fuel cell industry on a large scale. Based on available cost analyses, it

N. Guerrero Moreno et al. / Renewable and Sustainable Energy Reviews 52 (2015) 897–906

can be seen that despite viable technological alternatives for replacing Nafion-based membranes, these membranes still dominate cost analyses. This is probably because of current fuel cell technology components are designed for Nafion membranes systems, which make the estimated cost analysis more accurate and closer to a realistic value. Results from research, show that the quantity of platinum in the fuel cell can be highly reduced. One way is to use different materials to support Pt catalyst [75–79], enhancing its dispersion, durability and performance; these support materials can be carbon particles, carbon nanotubes particles, graphene and recently metal particles in a structure with a non-Pt metal core with a Pt shell. Another way is to alloy platinum with less expensive metals like palladium (Pd), ruthenium (Ru), and especially silver (Ag) [80,81]. Also new methods on the catalyst preparation and application, suggest substantial reduction in platinum loading obtaining good fuel cell performance [82–84]. Recent research even has indicated that platinum might be completely replaced by non-Pt catalysts [85–87]. It is important to mention that for the catalyst, the goal is not only to reduce the platinum loading in the fuel cell electrode, but also to preserve or enhance the catalytic activity of the reaction rate of oxygen reduction and hydrogen oxidation reactions or else the system size and cost suffer substantially. Specifically, the impact of changing catalyst loading can be confirmed using the Automotive Simplified Cost Model Function, for a particular platinum loading [36,38]. Catalyst is a vital factor in system total cost. The operation conditions as well as the cost of the system are determined in large part by the catalyst component. In the case of membranes is necessary to replace the

Fig. 3. Cost contribution by component to the total cost system at low and high volume production.

903

polymer for materials at lower cost than Nafion, which at the same time, provide good thermal, mechanical and chemical stability allowing fuel cells to work under the desired operating conditions. 3.1. Costs and production volume It is well known that mass production of PEMFC technology will lead to cost reduction. Conforming to the last analyses, at low volume production (1000 units/year), the membrane cost dominates the stack cost, as it represents 32% and catalyst representing 16% of the total cost. At high volume production (500.000 units/ year), this percentage changes to 11% for membrane and 49% for catalyst [38,39]. In the same way, the MEA represents 30–35% of total system cost at high volume production, with catalyst and membrane contributing about 75 % of total MEA cost [37–39,63]. In Fig. 3 is shown the cost contribution by component. To interpret this figure and Fig. 4, one considers that the total system cost is the sum of catalyst, membrane, other MEA and other system costs. Where MEA total cost is the sum of catalyst, membrane, and other MEA cost (GDLs, gaskets, etc.). The other system costs include: additional costs of the fuel cell stack, the bipolar plates, and the balance of plant cost (humidifier, heat exchanger, gas supply, etc.). In this work costs were grouped this way to facilitate their interpretation, they are treated separately in the references [37–39]. From Fig. 3, it can be seen that the total system cost of the fuel cell varies in a significant way, from $197/kW to $47/kW for 2012 technology and from $280/kW to $55/kW for 2013 technology, when production target is increased to 500.000 units/year. In this figure there is a considerable increase in the cost at low production volume for 2013 compared to 2012 technology; this increase is a consequence of the update in the platinum price considering the market behaviour and the last DOE requirement for heat rejection [39]. As mentioned above, the membrane cost is more significant at a low production rate with a cost of about $44/kW and about $53/kW, while at a high production rate the membrane cost is $2.14/kW and 2.95/kW for 2012 and 2013 technology respectively. Catalyst cost becomes proportionately more important at high volume production with a cost of $9.5/kW and $13/kW representing about 20 and 24% of system total cost, for 2012 and 2013 technology respectively. Whereas at low volume the cost represents only about 10% of system total cost for 2012 as well for 2013. The cost of the MEA corresponds to about 60% for 2012 and about 50% for 2013 of the cost of fuel cell system at low production volume, at high production volume the MEA cost corresponds to 30 and 35%. Here, it is important to highlight that the current status of fuel cell technology is small scale production; therefore it is crucial to

Fig. 4. Impact of MEA cost reduction over system total cost for 500.000 units/year.

904

N. Guerrero Moreno et al. / Renewable and Sustainable Energy Reviews 52 (2015) 897–906

reduce the MEA costs through research and development for a material worthy of production at large scale. 3.2. Scenario analysis: reducing the cost of MEA The development of the MEA is a potential opportunity for cost reduction since catalyst and membrane components account for a considerable amount of the total fuel cell cost. The performance and the reduction in cost of one of these components lead to the reduction in costs of other components; for example, the simplification in the performance of the membrane (operation at low relative humidity of gas feeds) leads to cost reduction by the elimination of the humidifier. Based on last cost analyses reported by DOE [37–40], to be consistent about this codependency between components, the MEA cost was changed by varying proportionally other system components, according to the weight (percentage) of that component over the system total cost. To make a specific change economically feasible in PEMFC technology, a combination of factors must be analyzed. Since this is out of the scope of this work, the cost variation is evaluated considering the same production characteristics used by the US DOE for the 2013 cost analysis [38,39] but checking the impact of changing MEA cost over the PEMFC system cost. The cost basis of the fuel cell system considered was $47/kW for 2012 technology status and $55/kW for 2013 technology updated and an ultimate cost target of $30/kW. The reduction in MEA cost was based on recent results in research focused on platinum reduction for the catalyst [58,64–69] and also taking in account that membranes cost target is 20/m2 by 2017 [70]. The reduction on MEA cost was adjusted from 10–50% in attempts to achieve these targets. In Fig. 4, the results from the scenario analysis are shown. It was found that by reducing the MEA cost up to 27 % the $40/kW cost target by 2020 is achieved, this corresponds to a reduction in the cost of the catalyst of $3.55/kW and $0.8/kW of the membrane cost. While reducing the MEA cost up to 45%, the $30/kW ultimate cost target can be achieved, corresponding to a total reduction on catalyst cost of $6.41/kW and$1.44/kW on membrane cost. These reductions seem attainable considering sustained trends with: increasing production levels, the progress in PEMFC research and also the historical behavior of cost reductions. Furthermore, the automotive industry is one of the largest sources of CO2 emissions and the use of FCEVs represents a significant reduction in these emissions. This advantage of the FCEVs over traditional automobiles usually is not included in the cost analysis, because it is not easy quantifiable in terms of cost versus other contributions to cost. However, beyond the benefits related to CO2 reduction regulations which automobile manufacturers must comply, PEMFC provides similar quality of life benefits to society and the environment in general.

4. Conclusions A literature review of fuel cell cost reveals that analyses are focused mainly on PEMFC, because this kind of fuel cell has projected application in many diverse areas. This is the first review where the divergent approaches of fuel cell cost are summarized and explained. Cost analysis of the PEMFCs shows that this technology is commercially feasible only through mass production, because costs are substantially reduced as production volume is increased. However mass production will be possible only if technology challenges are overcome, in particular developing cost efficient catalysts and membranes, which impact significantly the total cost of the fuel cell system. Research concentrated on these issues is vital if fuel cell technology is to be commercialized on a large scale. A scenario analysis shows that reducing MEA cost up to

27% makes achievable the $40/kW cost target by 2020, which corresponds to a reduction in the cost of the catalyst by $3.55/kW and of membrane by $0.8/kW. Reduction at MEA cost up to 45% would seem necessary to attain the DOE ultimate cost target of $30/kW. This implies a total cost reduction of catalyst by $4.6/kW and of membrane by $1.3/kW for a market with high volume production (500.000 units/year).

Acknowledgements We would like to thank CONACYT of Mexico for all the financial support for this research. References [1] Zhang Jianlu, Xie Zhong, Zhang Jiujun, Tang Yanghua, Song Chaojie, Navessin Titichai, et al. High temperature PEM fuel cells. J Power Sources 2006;160 (2):872–91. [2] Cha Suk-Won, Colella Whitney, Prinz Fritz B. Fuel cell fundamentals. New York: John Wiley & Sons; 2006. [3] Lee Ji-Yong, Yoo Moosang, Cha Kyounghoon, Lim Tae Won, Hur Tak. Life cycle cost analysis to examine the economical feasibility of hydrogen as an alternative fuel. Int J Hydrogen Energy 2009;34(10):4243–55. [4] Peighambardoust SJ, Rowshanzamir S, Amjadi M. Review of the proton exchange membranes for fuel cell applications. Int J Hydrog Energy 2010;35 (17):9349–84. [5] Handbook, fuel cell. EG&G technical services. Inc., Albuquerque, NM, DOE/ NETL-2004/1206; 2004. [6] Wee Jung-Ho. Applications of proton exchange membrane fuel cell systems. Renew Sustain Energy Rev 2007;11:1720–38. [7] Chandan Amrit, Hattenberger Mariska, El-Kharouf Ahmad, Du Shangfeng, Dhir Aman, Self Valerie, et al. High temperature (HT) polymer electrolyte membrane fuel cells (PEMFC)—a review. J Power Sources 2013;231:264–78. [8] Rayment Chris, Sherwin Scott. Introduction to fuel cell technology, vol. 2. University of Notre Dame; 2003. p. 49–150. [9] 2012 Fuel Cell Technologies Market Report. US Department of Energy. Office of energy and renewable energy fuel cell technologies office; 2013. p. 1–42. [10] 2013 Fuel Cell Technologies Market Report. US Department of Energy. Office of energy and renewable energy fuel cell technologies office; 2014. p. 1–61. [11] Established, Fuel Cells Becoming. The fuel cell industry review 2013. A quarterly journal of research on the science and technology of the platinum group metals and developments in their application in industry, vol. 57, no. 4; 2013. p. 310. [12] Pathways to commercial success: technologies and products supported by the fuel cell technologies office. Prepared by Pacific Northwest National Laboratory for the U.S. Department of Energy Fuel Cell Technologies Office; 2013. [13] Sandra Curtin, Gangi Jennifer, Skukowski Ryan. The business case for fuel cells 2013 reliability, resiliency and savings. Fuel cell 2000; 2013. [14] Cottrell Clint Alex, Grasman Scott E, Thomas Mathew, Martin Kevin Braun, Sheffield John W. Strategies for stationary and portable fuel cell markets. Int J Hydrog Energy 2011;36(13):7969–75. [15] Wang Yun, Chen Ken S, Mishler Jeffrey, Cho Sung Chan, Adroher Xavier Cordobés. A review of polymer electrolyte membrane fuel cells: technology, applications, and needs on fundamental research. Appl Energy 2011;88 (4):981–1007. [16] Kocha Shyam S. Polymer electrolyte membrane (PEM) fuel cells, automotive applications. In: Fuel cells. New York: Springer; 2013. p. 473–518. [17] Ma Yan, Karady George G, Winston III Anthony, Gilbert Palomino, Hess Robert, Pelley Don. Economic feasibility prediction of the commercial fuel cells. Energy Convers Manag 2009;50(2):422–30. [18] Yacobucci Brent D, Curtright Aimee E. A hydrogen economy and fuel cells: an overview. In: CRS report for congress; 2004. p. 1–12. [19] Hwang Jenn-Jiang. Sustainability study of hydrogen pathways for fuel cell vehicle applications. Renew Sustain Energy Rev 2013;19:220–9. [20] Shang Jinlei. The role of hydrogen and fuel cells for ultra low carbon vehicles [Ph.D. dissertation]. University of Birmingham; 2014. [21] Aceves Salvador M, Petitpas Guillaume, Espinosa-Loza Francisco, Matthews Manyalibo J, Ledesma-Orozco Elias. Safe, long range, inexpensive and rapidly refuelable hydrogen vehicles with cryogenic pressure vessels. Int J Hydrog Energy 2013;38(5):2480–9. [22] Greene David L, Duleep Gopal. Status and prospects of the global automotive fuel cell industry and plans for deployment of fuel cell vehicles and hydrogen refueling infrastructure. Monograph. Oak Ridge National Laboratory; 2013. [23] Taleb Ali, Kjeang Erik, Maine Elicia. Cost analysis for durable proton exchange membrane in PEM fuel cells. In: Proceedings of PICMET'12 technology management for emerging technologies (PICMET). Sheraton Wall Centre Hotel Vancouver, Canada: IEEE; 2012. p. 2943–50. [24] Mekhilef S, Saidur R, Safari A. Comparative study of different fuel cell technologies. Renew Sustain Energy Rev 2012;16(1):981–9.

N. Guerrero Moreno et al. / Renewable and Sustainable Energy Reviews 52 (2015) 897–906

[25] Lipman Timothy E, Edwards Jennifer L, Kammen Daniel M. Fuel cell system economics: comparing the costs of generating power with stationary and motor vehicle PEM fuel cell systems. Energy Policy 2004;32(1):101–25. [26] Tsuchiya Haruki, Kobayashi Osamu. Mass production cost of PEM fuel cell by learning curve. Int J Hydrog Energy 2004;29(10):985–90. [27] Mock Peter, Schmid Stephan A. Fuel cells for automotive powertrains—a techno-economic assessment. J Power Sources 2009;190(1):133–40. [28] Carlson Eric J, Thijssen JHJ. Precious metal availability and cost analysis for PEMFC commercialization. Part IV. F 1; 2003. p. 513–6. [29] Mathias Mark, Gasteiger Hubert, Makharia Rohit, Kocha Shyam, Fuller Tim, Xie Tao, et al. Can available membranes and catalysts meet automotive polymer electrolyte fuel cell requirements. Am Chem Soc Preprints, Div Fuel Chem 2004;49(2):471. [30] ACI Technologies, Inc. Manufacturing Fuel Cell Manhattan Project, U.S. Government Contract No. N00014-08-D-0758; November 2011. [31] Satyapal Sunita. Fuel cell cost reduction and R&D progress through the US Department of Energy's Hydrogen Program. Hydrogen Program US Department of Energy. Washington. DC; June 2007. [32] James Brian D, Sandy Thomas CE, Ho Jonathan, Lomax Jr Frank D. F. DFMA cost estimates of fuel-cell/reformer systems at low/medium/high production rates. Progress report for fuel cells for transportation; 2001. p. 44. [33] James B, Ariff G, Kuhn R, Myers D. DFMA cost estimates of fuel-cell/reformer systems at low/medium/high production rates. Report hydrogen, fuel cells, and infrastructure technologies. DOE FY 2003 progress report, Directed Technologies Inc. (DTI); 2003. [34] James BD, Kalinoski JA. Mass production cost estimation for direct H2 PEM fuel cell systems for automotive applications: 2008. Update DOE Fuel Cell Technical Publications; 2009. [35] James Brian D, Kalinoski Jeffrey A, Baum Kevin N. Mass production cost estimation for direct H2 PEM fuel cell systems for automotive applications: 2010 update. Directed technologies inc. report; 2010. [36] James Brian D, Baum Kevin, Spisak Andrew B. Mass production cost estimation of direct H2 PEM fuel cell systems for automotive applications: 2011 update report by strategic analysis, Inc. under Contract No. DE-AC36-08GO28308 for the US Department of Energy; 2011. [37] Spendelow Jacob, Marcinkoski Jason. Fuel cell system cost—2012. DOE fuel cell technologies program record; 2012. [38] James Brian D, Spisak Andrew B. Mass production cost estimation of direct H2 PEM fuel cell systems for transportation applications: 2012 update. Report by strategic analysis, Inc., under Award Number DEEE0005236 for the US Department of Energy, vol. 18; 2012. [39] James Brian D, Jennie Moton M, Colella Whitney G. Mass production cost estimation of direct H2 PEM fuel cell systems for transportation applications: 2013 update. Report by strategic analysis, Inc., under Award Number DE-EE0005236, 2012. [40] Dimitrios Papageorgopoulos, Fuel cells sub-program—session introduction. Annual Merit Review and Peer Evaluation Meeting; 2012. [41] Riahi-Belkaoui Ahmed. The learning curve: a management accounting tool. Quorum Books; 1986. [42] Environmental policy analysis for decision making. Principles of benefit-cost analysis. The economics of non-market goods and resources. vol. 1; 2003. p. 105–40 [Chapter 7]. [43] Casey Mary Anne, Donner Jonathan, Kirsch Stuart, Maack Jonathan N. Social analysis: selected tools and techniques. Social Development Department, The World Bank; 2001. [44] Obara Shinya. Equipment arrangement planning of a fuel cell energy network optimized for cost minimization. Renew Energy 2007;32(3):382–406. [45] Lancaster Frederick W. The cost-effectiveness analysis of information retrieval and dissemination systems. J Am Soc Inf Sci 1971;22(1):12–27. [46] Boothroyd Geoffrey, Dewhurst Peter, Knight Winston A. Product design for manufacture and assembly. Taylor and Francis. 6000 Broken Sound Parkway N.W., Suite 300. Boca Raton, Florida: CRC Press; 2010. [47] Sinha Jayanti, Lasher Stephen, Yang Yong. Direct hydrogen PEMFC manufacturing cost estimation for automotive applications. In: 2009 DOE annual merit review. Washington, DC; 2009. [48] Sinha Jayanti, Lasher Stephen, Yang Yong, Kopf Peter. Direct hydrogen PEMFC manufacturing cost estimation for automotive applications. 2010 DOE annual merit review. Washington, DC; 2010. [49] Carlson EJ, Kopf P, Sinha J, Sriramulu S, Yang Y. Cost analysis of PEM fuel cell. National Renewable Energy Laboratory NREL, systems for transportation, Report No. NREL/SR-560-39104; 2005. [50] Greenberg, Joel S. Economic principles applied to space industry decisions, vol. 201. Aiaa; 2003. [51] Thomas CE, James Brian D, Lomax Jr Franklin D. Market penetration scenarios for fuel cell vehicles. Int J Hydrog Energy 1998;23(10):949–66. [52] Ahluwalia RK, Wang X, Kwon J, Rousseau A, Kalinoski J, James B, et al. Performance and cost of automotive fuel cell systems with ultra-low platinum loadings. J Power Sources 2011;196(10):4619–30. [53] Owen Anthony D, Cockroft Colin. A cost–benefit analysis of Perth's hydrogen fuel cell buses. Report for the minister for planning and infrastructure and for the Western Australian; 2006. [54] Jayakumar K, Pandiyan S, Rajalakshmi N, Dhathathreyan KS. Cost–benefit analysis of commercial bipolar plates for PEMFC's. J Power Sources 2006;161 (1):454–9.

905

[55] Ginsberg E, Rinebold J, Aresta P, Drejer T. Fuel cell economic development plan – hydrogen roadmap. Report by The Connecticut Center for advanced technology, Inc.; 2008. [56] Rivera-Tinoco Rodrigo, Schoots Koen, Van Der Zwaan Bob. Learning curves for solid oxide fuel cells. Energy Convers Manag 2012; (57): 86–96. [57] Kreutz Thomas G, Ogden Joan M. Assessment of hydrogen-fueled proton exchange membrane fuel cells for distributed generation and cogeneration. In: Proceedings of the 2000 US DOE hydrogen program review; 2000. p. 1–43. [58] Contestabile M. Analysis of the market for diesel PEM fuel cell auxiliary power units on board long-haul trucks and of its implications for the large-scale adoption of PEMFCs 2009:1–15. [59] Kazim A. Economical and environmental assessments of proton exchange membrane fuel cells in public buildings. Energy Convers Manag 2001;42 (6):763–72. [60] Barbir Frano, Gomez Teresa. Efficiency and economics of proton exchange membrane (PEM) fuel cells. Int J Hydrog Energy 1996;21(10):891–901. [61] Cockroft Colin J, Owen Anthony D. The economics of hydrogen fuel cell busesn. Econ Rec 2007;83(263):359–70. [62] Staffell I, Green RJ. Estimating future prices for stationary fuel cells with empirically derived experience curves. Int J Hydrog Energy 2009;34 (14):5617–28. [63] Staffell Iain, Green Richard. The cost of domestic fuel cell micro-CHP systems. Int J Hydrog Energy 2013;38(2):1088–102. [64] Zaidi Javaid SM. Polymer membranes for fuel cells, Takeshi Matsuura, editor. 233 Spring Street, New York, NY 10013, USA:Springer; 2009. [65] Marcinkoski Jason, James Brian D, Kalinoski Jeff A, Podolski Walt, Benjamin Thomas, Kopasz John. Manufacturing process assumptions used in fuel cell system cost analyses. J Power Sources 2011;196(12):5282–92. [66] Weakley Steven A. Pathways to commercial success: technologies and products supported by the fuel cell technologies program. no. PNNL-21804. Pacific Northwest National Laboratory (PNNL), Richland, WA, US; 2012. [67] Supplies, lower, and recycling expected. Platinum 2012 interim review. A quarterly journal of research on the science and technology of the platinum group metals and developments in their application in industry, vol. 57, no. 1, p. 70–1, 2013. [68] Wannek Christoph, Glüsen Andreas, Stolten Detlef. Materials, manufacturing technology and costs of fuel cell membranes. Desalination 2010;250 (3):1038–41. [69] Shao Yuyan, Yin Geping, Wang Zhenbo, Gao Yunzhi. Proton exchange membrane fuel cell from low temperature to high temperature: material challenges. J Power Sources 2007;167(2):235–42. [70] Houchins Cassidy, Kleen Greg J, Spendelow Jacob S, Kopasz John, Peterson David, Garland Nancy L, et al. US DOE progress towards developing low-cost, high performance, durable polymer electrolyte membranes for fuel cell applications. Membranes 2012;2(4):855–78. [71] Wu Jinfeng, Yuan Xiao Zi, Martin Jonathan J, Wang Haijiang, Zhang Jiujun, Shen Jun, et al. A review of PEM fuel cell durability: degradation mechanisms and mitigation strategies. J Power Sources 2008;184(1):104–19. [72] Gatto I, Stassi A, Baglio V, Carbone A, Passalacqua E, Aricó AS, et al. Optimization of perfluorosulphonic ionomer amount in gas diffusion electrodes for PEMFC operation under automotive conditions. Electrochim Acta 2015;165:450–5. [73] Xu Chenxi, Liu Xiaoteng, Cheng Jigui, Scott Keith. A polybenzimidazole/ionicliquid-graphite-oxide composite membrane for high temperature polymer electrolyte membrane fuel cells. J Power Sources 2015;274:922–7. [74] Kim Deuk Ju, Jo Min Jae, Nam Sang Yong. A review of polymer-nanocomposite electrolyte membranes for fuel cell application. J Ind Eng Chem 2015;21:36–52. [75] Zhang Jie, Tang Shuihua, Liao Longyu, Yu Weifei. Progress in non-platinum catalysts with applications in low temperature fuel cells. Chin J Catal 2013;34 (6):1051–65. [76] Jeon In-Yup, Choi Hyun-Jung, Choi Min, Seo Jeong-Min, Jung Sun-Min, Kim Min-Jung, et al. Facile, scalable synthesis of edge-halogenated graphene nanoplatelets as efficient metal-free eletrocatalysts for oxygen reduction reaction. Sci Rep 2013;3. [77] Hsieh Chien-Te, Gu Jun-Lun, Chen Yu-Chia, Tzou Dong-Ying. Pulse microwave synthesis of palladium catalysts on graphene electrodes for proton exchange membrane fuel cells. Electrochim Acta 2013;98:39–47. [78] Antolini Ermete. Graphene as a new carbon support for low-temperature fuel cell catalysts. Appl Catal B: Environ 2012;123:52–68. [79] Liu Minmin, Ruizhong Zhang, Wei Chen. Graphene-supported nanoelectrocatalysts for fuel cells: synthesis, properties, and applications. Chem Rev 2014;114(10):5117–60. http://dx.doi.org/10.1021/cr400523y. [80] Andrés Godínez-García, Juan Francisco Pérez-Robles, Hader Vladimir Martínez-Tejada, Omar Solorza-Feria. Characterization and electrocatalytic properties of sonochemical synthesized PdAg nanoparticles. Mater Chem Phys 2012;134(2):1013–9. http://dx.doi.org/10.1016/j.jpowsour.2014.09.17. [81] Jiang Rongzhong, Moton Elizabeth, McClure Joshua P, Bowers Zachary. A highly active and alcohol-tolerant cathode electrocatalyst containing Ag nanoparticles supported on graphene. Electrochim Acta 2014;127:146–52. [82] Mróz Waldemar, Budner Bogusaw, Tokarz Wojciech, Piela Piotr, KorwinPawlowski Michael L. Ultra-low-loading pulsed-laser-deposited platinum catalyst films for polymer electrolyte membrane fuel cells. J Power Sources 2015;273:885–93. [83] Shukla S, Domican K, Karan K, Bhattacharjee S, Secanell M. Analysis of low platinum loading thin polymer electrolyte fuel cell electrodes prepared by

906

N. Guerrero Moreno et al. / Renewable and Sustainable Energy Reviews 52 (2015) 897–906

inkjet printing. Electrochimica Acta 2015;156:289–300. http://dx.doi.org/ 10.1016/j.electacta.2015.01.028. [84] Fofana Daouda, Natarajan Sadesh Kumar, Hamelin Jean, Benard Pierre. Low platinum, high limiting current density of the PEMFC (proton exchange membrane fuel cell) based on multilayer cathode catalyst approach. Energy 2014;64:398–403. [85] Koh Joon-Ho, Abbaraju Ravikanth, Parthasarathy Preethy, Virkar Anil V. Design and synthesis of degradation-resistant coreshell catalysts for proton exchange membrane fuel cells. J Power Sources 2014;261:271–7.

[86] Fofana Daouda, Natarajan Sadesh Kumar, Hamelin Jean, Benard Pierre. Low platinum, high limiting current density of the PEMFC (proton exchange membrane fuel cell) based on multilayer cathode catalyst approach. Energy 2014;64:398–403. [87] Nabae Yuta, Sonoda Mayu, Yamauchi Chiharu, Hosaka Yo, Isoda Ayano, Aoki Tsutomu. Highly durable Pt-free fuel cell catalysts prepared by multi-step pyrolysis of Fe-phthalocyanine and phenolic resin. Catal Sci Technol 2014;4 (5):1400–6.