- Email: [email protected]
International collaboration in the IAEA nuclear hydrogen production program for benchmarking of HEEP
i n t e r n a t i o n a l j o u r n a l o f h y d r o g e n e n e r g y x x x ( 2 0 1 6 ) 1 e6
Available online at www.sciencedirect.com
ScienceDirect journal homepage: www.elsevier.com/locate/he
International collaboration in the IAEA nuclear hydrogen production program for benchmarking of HEEP R.S. El-Emam, I. Khamis* Department of Nuclear Energy, International Atomic Energy Agency (IAEA), Vienna International Centre, P. O. Box 200, A-1400, Vienna, Austria
article info
abstract
Article history:
The Hydrogen Economic Evaluation Programme (HEEP) was developed by the International
Received 30 April 2016
Atomic Energy Agency (IAEA) to perform economic assessment of nuclear hydrogen pro-
Received in revised form
duction technologies. Yet HEEP is still under update to reflect latest advances in nuclear
27 July 2016
hydrogen production research and development. This paper presents an overview of HEEP
Accepted 28 July 2016
and latest benchmarking results with emphasis on its capabilities. Comparative assess-
Available online xxx
ment was performed to examine the accuracy of the calculations. Executing same case studies several times showed accurate reproducibility of the results which assured the
Keywords:
consistency of HEEP results. Five generic and detailed case studies with different nuclear
Economics
power plants and hydrogen generation plants were considered in comparative assessment
Hydrogen production
with the results of G4-ECONS and H2A software. The chronological and financial param-
Nuclear energy
eters were also varied through these cases. Furthermore, to demonstrate the capabilities of
HEEP
HEEP, some results of other comparative case studies that were performed by PAEC in
IAEA
Pakistan and AECL in Canada will be highlighted. The consistency and accuracy of the
Cost
performed analyses confirm the credibility and reliability of HEEP. © 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.
Introduction Stakeholders and experts worldwide believe that hydrogen is a sustainable alternative with high potential to cover the world's future energy demands, especially with the current environmental concerns against the use of fossil fuels. With the growing interest in hydrogen economy, the International Atomic Energy Agency (IAEA) developed the Hydrogen Economic Evaluation Programme (HEEP) to assist Member States in performing economic analyses for nuclear hydrogen production processes. There are several possible routes for producing
hydrogen using the nuclear energy. Fig. 1 shows the routes for producing non-carbon based hydrogen from water using electric power and/or thermal energy, produced from a nuclear power plant. Other carbon based processes may be also considered such as natural gas reforming, and coal or biomass gasification. The most promising hydrogen production technologies have been integrated with different nuclear power plants in HEEP, including conventional and high temperature electrolysis, and thermochemical and hybrid thermochemical cycles such as Sulphur-Iodine (SeI), Hybrid-Sulphur (HyS) and others [1]. HEEP is capable of performing comparative studies, not only between nuclear energy sources for hydrogen
* Corresponding author. E-mail address: [email protected] (I. Khamis). http://dx.doi.org/10.1016/j.ijhydene.2016.07.256 0360-3199/© 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved. Please cite this article in press as: El-Emam RS, Khamis I, International collaboration in the IAEA nuclear hydrogen production program for benchmarking of HEEP, International Journal of Hydrogen Energy (2016), http://dx.doi.org/10.1016/j.ijhydene.2016.07.256
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i n t e r n a t i o n a l j o u r n a l o f h y d r o g e n e n e r g y x x x ( 2 0 1 6 ) 1 e6
studies and elaborations on HEEP capabilities and its modules [3e8]. In this paper, benchmarking of the updated version of HEEP was performed. Several case studies were investigated and compared against other models of economic hydrogen assessment. Other studies that used HEEP and compared its results with other codes and tools are also highlighted.
IAEA activities for HEEP benchmarking
Fig. 1 e Potential pathways for current non-carbon based nuclear hydrogen production technologies.
production, but also for cogeneration with electric power production [2]. The HEEP models are based on technical, economic, as well as chronological inputs, and on cost modelling. The package also facilitates performing a broader investigation for more understanding of the feasibility of different hydrogen production scenarios including storage, transportation, and distribution, with the capability to eliminate or include specific details as required by the users. Fig. 2 shows the main four modules of HEEP and the categories of the parameters required as input data. The list of technical parameters required for the HEEP modules is shown in Fig. 3, while the cost elements of the modules are shown in Fig. 4. HEEP estimates the levelized cost of hydrogen, considering many aspects of capital investments which eventually affect the calculated cost. The capital investment, which is the sum of all expenditures incurred in design, licensing, manufacturing and erection, construction, and commissioning of the plant, can be raised at a given equity to debt ratio i.e. the funding of the project can be raised through equities or can be raised through market borrowings, or combination of both. The cash flow during construction is also another important parameter, which affects the interest during construction. This is particularly prominent in case of nuclear power plant requiring high capital investments with longer construction period. The updated version of HEEP was released in December 2014 and available on the IAEA website. Several publications in the literature included different case
Fig. 2 e Categories of input parameters as defined in HEEP.
A preliminary benchmarking of HEEP was performed earlier by Khamis and Malshe [1] on the beta-version of HEEP. The results were encouraging and the elements of hydrogen production cost showed good agreement with data from the literature by the Korean Atomic Energy Research Institute (KAERI) for a case that considered using high temperature reactor coupled with SeI plant for hydrogen production. However, based on the recommendations and outcomes of the preliminary studies, HEEP underwent through several updates and changes in its core modules. The IAEA conducted a Coordinated Research Project (CRP) for further elaboration on using and benchmarking of HEEP. Ten Member States were represented in this project and the participants performed benchmarking and comparative assessment using different generic case studies and country specific cases to examine and assure the reproducibility and accuracy of HEEP results. These cases were performed by experts and researcher from Argentina, China, Japan, Germany, Canada, Pakistan, Rep. of Korea, Indonesia, Algeria, and the USA. It was agreed that the accuracy of the results, using common financial and chronological assumption, assured the capability of HEEP as a tool for performing economic assessment of nuclear-based hydrogen production. Benchmarking of the current version of HEEP (V.2.2t) is performed in form of comparative study with the results of G4-ECONS, developed by KAERI; and H2A, developed by the US Department of Energy (DOE). Five different case studies were considered for, covering different reactor and hydrogen generation technologies. Table 1 shows a summary of the technologies utilized for the nuclear power plants and the hydrogen generation plants and their respective capacities. Case I considers 4 kg/s of nuclear hydrogen production using Conventional Electrolysis (CE) combined with Advanced Pressurized Water Reactor (APWR) with capacity of 2 359.5 MWe. APWR and CE were also the technologies considered in Cases II and III, with different capacity configuration: 2 719.0 MWe and 8 kg/s for Case II; and 2 1117 MWe and 12 kg/s for Case III, respectively. In Cases IV and V, High Temperature Gas-cooled Reactor (HTGR) is used as the nuclear power plant with capacity of 2 509.3 MWth and 2 630.7 MWth, respectively. High Temperature Steam Electrolysis (HTSE) producing 4 kg/s is considered for coupling with the HTGR for Case IV, while the SeI thermochemical hydrogen plant with same production capacity is considered for Case V. The technical parameters and cost input data of the considered nuclear power plants and the coupled hydrogen generation plants are listed in Tables 2 and 3. The chronological and financial data for the considered projects are shown in Tables 4 and 5. Furthermore, assessments of HEEP conducted by other users of the software are discussed. This includes one case
Please cite this article in press as: El-Emam RS, Khamis I, International collaboration in the IAEA nuclear hydrogen production program for benchmarking of HEEP, International Journal of Hydrogen Energy (2016), http://dx.doi.org/10.1016/j.ijhydene.2016.07.256
3
i n t e r n a t i o n a l j o u r n a l o f h y d r o g e n e n e r g y x x x ( 2 0 1 6 ) 1 e6
Fig. 3 e Main HEEP technical input parameters.
Fig. 4 e Main cost parameters in HEEP.
study performed to show the differences between HEEP, G4ECONS and H2A. This case considered Super Critical Water Reactor (SCWR) with capacity of 1200 MWe coupled with HTSE plant for hydrogen generation with capacity of 1925 Mm3/y. Capacity factor of 90%, operational period of 40 years, and discount rate of 5% were considered. Another comparative study, performed by the Pakistan Atomic Energy Commission (PAEC), is also presented. In this study, HEEP results were compared with the results of PAEC's own-developed code, ASAD. The results of HEEP and ASAD were compared for two case studies of nuclear hydrogen production. ASAD is a spread-sheet based software that uses discounted cost methodology to estimate the levelized cost of hydrogen production, heat, and electricity generation. This model requires input of overnight capital cost. Both debt and equity parts of this capital cost are equally distributed throughout the construction period. Interest during construction is capitalized. Repayment of debt component starts from the first year of operation and equally distributed over debt repayment period.
ASAD uses linear depreciation over the specified period with zero salvage value. The model assumes all O&M costs as variable, and the O&M cost in all years of operation is the same. This model does not consider refurbishment during entire life of the plant. The model considers expenditures of initial fuel core in last year of nuclear power plant construction and annual fuel cost in the year of operation (including first and last years of operation) is same. The decommissioning cost is equally distributed over the decommissioning period. The two cases considered for this comparison used SeI thermochemical plant for hydrogen production coupled with: single unit 600 MWth gas turbine high temperature gas cooled reactor (GTHTGR) with 202 MWe net electrical generation capacity, for Case A; and with a pebble bed modular HTR of 2 250 MWth capacity, for Case B. In Case A, the nuclear power plant generates more electricity than required for the hydrogen generation plant. Excess electricity is supplied to electric grid. For Case B, the reactor supplies high temperature thermal energy to the S-I hydrogen production plant. There is no electricity generation equipment with the nuclear plant and the 20 MWe required electricity is supplied from the grid. The technical, financial and chronological data of the two cases are listed in Tables 6e8.
Results and discussion The benchmarking through the assessment of the first five case studies has been performed, and HEEP results are discussed in this section. The results in Fig. 5 show the comparative analysis of the levelized hydrogen cost
Table 1 e Capacities and types of the nuclear power plant and hydrogen generation plant in the considered cases.
Nuclear Power Plant
Hydrogen Generation Plant
Case I
Case II
Case III
Case IV
Case V
2 359.5 MWe APWR CE 4 kg/s H2
2 719.0 MWe APWR CE 8 kg/s H2
2 1117.1 MWe APWR CE 12 kg/s H2
2 509.3 MWth HTGR HTSE 4 kg/s H2
2 630.7 MWth HTGR SeI 4 kg/s H2
Please cite this article in press as: El-Emam RS, Khamis I, International collaboration in the IAEA nuclear hydrogen production program for benchmarking of HEEP, International Journal of Hydrogen Energy (2016), http://dx.doi.org/10.1016/j.ijhydene.2016.07.256
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Table 2 e Nuclear power plant technical features and cost elements. Nuclear power plant
Number of units Capacity factor (%) Availability factor (%) Thermal rating (MWth/unit) Heat for H2 plant (MWth/unit) Electricity rating (MWe/unit) Initial fuel load (kg/unit) Annual fuel feed (kg/unit) Capital cost (CC) (USD/unit) CC fraction for power generating infrastructure (%) Fuel cost (USD/kg) O&M cost (% of cc) Decommissioning cost (% of CC)
Case I
Case II
Case III
Case IV
Case V
APWR
APWR
APWR
HTGR
HTGR
2 93 100 1089 0 359.5 27,000 9000 3.16 109 10 1850 1.66 2.8
2 93 100 2178 0 719.0 54,000 18,000 4.66 109 10 1365 1.67 2.8
2 93 100 3385 0 1117 75,000 25,000 5.96 109 10 1260 1.66 2.8
2 90 100 510 510 0 14,000 5000 4.02 108 0 3660 5.84 10
2 90 100 630.7 630.7 0 18,000 6000 6.05 108 0 5535 1.82 10
Table 3 e Hydrogen generation plant technical features and cost elements. Hydrogen plant design
Number of units Capacity factor (%) Availability factor (%) H2 generation rate (kg/year/unit) Heat consumption (MWth/unit) Electricity consumption (MWe/unit) Non-process electricity consumption (MWe/unit) Capital cost (CC) (USD/unit) Energy usage cost (USD) O&M cost (% of cc) Decommissioning cost (% of CC)
Case I
Case II
Case III
Case IV
Case V
CE
CE
CE
HTSE
SeI
1 80 100 1.26 108 0 719 0 4.28 108 0 4 10
1 93 100 2.53 108 0 1438 0 8.45 108 0 4 10
1 80 100 3.92 108 0 2234 0 1.31 109 0 4 10
1 90 100 1.26 108 1020 0 0 4.59 108 0 17.23 10
1 90 100 1.26 108 1261.4 0 42.8 6.66 108 2.7 108 6.68 10
estimations using HEEP, G4-ECONS, and H2A. In general, the levelized cost of hydrogen for the Cases I to V, calculated using HEEP, showed good agreement with the ones calculated through G4-ECONS and H2A. For Case IV the levelized cost resulted from G4-ECONS is 5% higher than that of HEEP. The differences between the results of HEEP and G4-ECONS were investigated. In general, G4-ECONS is reliable in calculating energy cost as long as the energy required from the hydrogen plant is within the reactor capacity. Therefore, the energy cost is not an input data, and it is calculated from the reactor module. On the other hand, in HEEP, if the energy required from the hydrogen plant is within the reactor capacity, the
Table 4 e Chronological data input for the nuclear plant projects. Case I Case II Case III Case IV Case V Construction period (yr) Operation period (yr) Decommissioning (yr) Refurbishment (yr) Spent fuel cooling (yr) Waste cooling (yr) Cooling before decommissioning (yr)
5
5
5
3
3
40 10 1 2 10 2
40 10 1 2 10 2
40 10 1 2 10 2
40 10 1 2 10 2
40 10 1 2 10 2
energy usage cost is zero, and If the energy required from hydrogen plant exceeds the reactor capacity, then the corresponding difference between the two will be an input value as energy usage cost. Also, in HEEP, all the financial parameters such as tax rate, inflation rate, equity to debt ratio, and interest rate are listed separately as input parameters. However, in G4-ECONS, financial parameters are all incorporated into the real discount rate. With respect to the comparison with H2A; both HEEP and H2A give contribution of each cost component: capital cost, running cost, and decommissioning cost. However, H2A does not provide the result as percentage share of each of the facilities associated with hydrogen generation and distribution. In HEEP, all details are to be provided as a separate entity of each plant or facility (source of heat/electricity, storage and transportation) associated with hydrogen production. As an output, HEEP gives contribution of each facility in the total
Table 5 e Financial parameters for the five case studies. Discount rate Inflation rate Finance equity: debt Borrowing interest Tax rate Depreciation period
5% 1% 70%:30% 10% 10% 20 year
Please cite this article in press as: El-Emam RS, Khamis I, International collaboration in the IAEA nuclear hydrogen production program for benchmarking of HEEP, International Journal of Hydrogen Energy (2016), http://dx.doi.org/10.1016/j.ijhydene.2016.07.256
i n t e r n a t i o n a l j o u r n a l o f h y d r o g e n e n e r g y x x x ( 2 0 1 6 ) 1 e6
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Table 6 e Technical features of the nuclear power plants. Reactor type
Number of units Capacity per unit Capacity factor Capital cost (cc)
Annual O&M Annual fuel cost Decommissioning cost Construction period
MWe (net) MWth % M USD M USD/MWe M USD/MWth % of cc M USD % of cc Years
Case A
Case B
GTHTR
HTR-PM
1 202 600 90 547 1.35 0.91 3.81 10.28 10 3
2 100 250 90 1000 5 2 3.18 14.4 8 3
Table 7 e Technical features of the hydrogen generation plants. Process type
Number of units Capacity factor Production capacity Thermal energy required Power required Capital cost Annual O&M cost
Case A
% kg/s M kg/year MWth/unit MWe/unit M USD/unit % of cc
Case B
SeI
SeI
1 90 0.58 18.29 170 23 186 5.46
1 90 1.36 42.89 250 20 200 5.46
hydrogen cost. H2A considers the cost components of all facilities on lump sum basis and does not have any separate module for consideration of cost inputs from the nuclear power plant. The results in Fig. 5, show good agreement between HEEP and H2A results for the considered cases. The potential causes of the small differences between the results of the two tools were investigated. In H2A, debt portion (market borrowing) of the capital cost is incurred in the first year of the construction period itself. Repayment of debt component starts from the first year of construction period. In HEEP, debt part, incurred in each year of the construction period, is based on the fraction of cash flow during that year and debt-equity ratio. Repayment of debt part borrowed in each year starts from the respective year of incurring. Another
Fig. 5 e Benchmarking results of HEEP with G4-ECONS and H2A for the considered case studies.
cause of the differences in the results, mainly in Cases I, II, and III, is the construction period. The version of H2A used for comparison considers construction period not exceeding 4 years. While in HEEP there is no limit on construction period setting and it was used as 5 years for these specific cases. When these cases were executed in HEEP after modifying the construction period to match that of the H2A, the match and agreement between the estimated costs improved as shown in Fig. 6. Fig. 7 shows a comparison of HEEP, G4-ECONS, and H2A results for the case executed through AECL, on SCWR [9]. The cost shows good agreement between the three tools. The cost breakdown ($/kg) were reported as 0.28, 0.27, and 0.27 for the hydrogen plant capital component, 0.39, 0.39, and 0.36 for the hydrogen plant non-energy component, and 2.89, 2.95 and 2.95 for the hydrogen plant energy component, for HEEP, G4ECONS, and H2A, respectively. In Fig. 8, HEEP and ASAD comparative results are shown. The levelized cost of hydrogen generation is estimated with HEEP and compared with the results of ASAD code. Differences in levelized cost calculations of the two models are relatively small. The differences might be caused as a result of some financial parameter considerations. Another possible issue causing the difference in the estimations is the rounding error as HEEP rounds-off some output values to two decimal points. Also, HEEP estimates the levelized decommissioning cost of the hydrogen
Table 8 e Financial and chronological data for the considered cases.
Nominal discount rate Inflation rate Equity to debt ratio Interest on borrowings Tax rate Depreciation period Borrowing return period Operating life Cooling before decommissioning Number of Refurbishments Decommissioning period
Case A
Case B
5% 0% 0%:100% 5% 0% 20 year 40 year 40 year 2 year 1 10 year
5% 1% 70%:30% 10% 10% 20 year 40 year 40 year 2 year 1 10 year
Fig. 6 e Comparative benchmarking of HEEP with H2A results.
Please cite this article in press as: El-Emam RS, Khamis I, International collaboration in the IAEA nuclear hydrogen production program for benchmarking of HEEP, International Journal of Hydrogen Energy (2016), http://dx.doi.org/10.1016/j.ijhydene.2016.07.256
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i n t e r n a t i o n a l j o u r n a l o f h y d r o g e n e n e r g y x x x ( 2 0 1 6 ) 1 e6
considered as living software with potential updated by incorporating sensitivity analysis module covering several parameters in the coming update of the software.
Acknowledgement
Fig. 7 e Comparison of HEEP, G4-ECONS, and H2A results.
The authors would like to thank Mr. A. Antony (India), Ms. A. Bohe (Argentina), Ms. R. Boudries (Algeria), Ms. E. Dewita (Indonesia), Mr. I. Dincer (Canada), Mr. M.Ghulam (Pakistan), Mr. J. Kim (Rep. of Korea), Mr. S. Revankar (USA/Rep. of Korea), Mr. K. Verfondern (Germany), Mr. X. Yan (Japan), and Mr. P. Zhang (China), for their valuable input and contribution through their participation in this IAEA CRP on HEEP benchmarking.
references
Fig. 8 e Comparative analysis of HEEP with ASAD results.
production facility lower than estimates of ASAD model. This may be due to the fact that for (N) years of decommissioning period, HEEP displays (N-1) years in the decommissioning cost window for hydrogen plant, which was not considered in the ASAD estimations.
Conclusion According to the results of the technoeconomics of the generic case studies; consistency of HEEP calculated results are found to be very satisfactory. Users are satisfied with HEEP as a userfriendly tool for performing analysis of nuclear hydrogen production systems. With avoiding un-necessary technical details, user obtains levelized cost of hydrogen, electricity, and thermal energy production. The computational models of HEEP appeared to be sensitive to different technical and economic parameters that affect the hydrogen cost such as the economy scale, the process applied to produce hydrogen, and the economic parameters in different countries. HEEP is
[1] Khamis I, Malshe UD. HEEP: a new tool for the economic evaluation of hydrogen economy. Int J Hydrogen Energy 2010;35:8398e406. [2] Khamis I. An overview of the IAEA HEEP software and international programmes on hydrogen production using nuclear energy. Int J Hydrogen Energy 2011;36:4125e9. [3] El-Emam RS, Dincer I. Comparative study on nuclear based hydrogen production: cost assessment. In: International Conference on Smart Energy Grid Engineering (SEGE'14), Oshawa; 2014. [4] El-Emam RS, Ozcan H, Dincer I. Comparative cost evaluation of nuclear hydrogen production methods with the Hydrogen Economy Evaluation Program (HEEP). Int J Hydrogen Energy 2015;40(34):11168e77. [5] El-Emam RS, Dincer I. Hydrogen production from nuclear energy: comparative cost assessment. In: Dincer I, Colpan CO, Kizilkan O, Ezan MA, editors. Progress in clean energy, vol. II. Springer International Publishing; 2015. p. 615e29. [6] Ozcan H, El-Emam RS, Dincer I. Comparative assessment of nuclear based hybrid sulfur cycle and high temperature steam electrolysis systems using HEEP. In: Dincer I, Midilli A, Kucuk H, editors. Progress in sustainable energy technologies: Generating renewable energy. Springer International Publishing; 2014. p. 165e80. [7] Kim J, Lee K, Kim M. Calculation of LUEC using HEEP software for nuclear hydrogen production plant. In: Transactions of the Korean Nuclear Society Spring Meeting, Jeju, Korea; May 7-8, 2015. [8] Lee T-H, Lee K-Y. Preliminary hydrogen production cost estimation based on the HEEP. In: Transactions of the Korean Nuclear Society Autumn Meeting, Gyeongju, Korea; October 24e25, 2013. [9] Sadhankar R, Sopczak L. Atomic Energy Canada Limited (Canadian Nuclear Laboratories). Personal communication Jan. 2016.
Please cite this article in press as: El-Emam RS, Khamis I, International collaboration in the IAEA nuclear hydrogen production program for benchmarking of HEEP, International Journal of Hydrogen Energy (2016), http://dx.doi.org/10.1016/j.ijhydene.2016.07.256
Available online at www.sciencedirect.com
ScienceDirect journal homepage: www.elsevier.com/locate/he
International collaboration in the IAEA nuclear hydrogen production program for benchmarking of HEEP R.S. El-Emam, I. Khamis* Department of Nuclear Energy, International Atomic Energy Agency (IAEA), Vienna International Centre, P. O. Box 200, A-1400, Vienna, Austria
article info
abstract
Article history:
The Hydrogen Economic Evaluation Programme (HEEP) was developed by the International
Received 30 April 2016
Atomic Energy Agency (IAEA) to perform economic assessment of nuclear hydrogen pro-
Received in revised form
duction technologies. Yet HEEP is still under update to reflect latest advances in nuclear
27 July 2016
hydrogen production research and development. This paper presents an overview of HEEP
Accepted 28 July 2016
and latest benchmarking results with emphasis on its capabilities. Comparative assess-
Available online xxx
ment was performed to examine the accuracy of the calculations. Executing same case studies several times showed accurate reproducibility of the results which assured the
Keywords:
consistency of HEEP results. Five generic and detailed case studies with different nuclear
Economics
power plants and hydrogen generation plants were considered in comparative assessment
Hydrogen production
with the results of G4-ECONS and H2A software. The chronological and financial param-
Nuclear energy
eters were also varied through these cases. Furthermore, to demonstrate the capabilities of
HEEP
HEEP, some results of other comparative case studies that were performed by PAEC in
IAEA
Pakistan and AECL in Canada will be highlighted. The consistency and accuracy of the
Cost
performed analyses confirm the credibility and reliability of HEEP. © 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.
Introduction Stakeholders and experts worldwide believe that hydrogen is a sustainable alternative with high potential to cover the world's future energy demands, especially with the current environmental concerns against the use of fossil fuels. With the growing interest in hydrogen economy, the International Atomic Energy Agency (IAEA) developed the Hydrogen Economic Evaluation Programme (HEEP) to assist Member States in performing economic analyses for nuclear hydrogen production processes. There are several possible routes for producing
hydrogen using the nuclear energy. Fig. 1 shows the routes for producing non-carbon based hydrogen from water using electric power and/or thermal energy, produced from a nuclear power plant. Other carbon based processes may be also considered such as natural gas reforming, and coal or biomass gasification. The most promising hydrogen production technologies have been integrated with different nuclear power plants in HEEP, including conventional and high temperature electrolysis, and thermochemical and hybrid thermochemical cycles such as Sulphur-Iodine (SeI), Hybrid-Sulphur (HyS) and others [1]. HEEP is capable of performing comparative studies, not only between nuclear energy sources for hydrogen
* Corresponding author. E-mail address: [email protected] (I. Khamis). http://dx.doi.org/10.1016/j.ijhydene.2016.07.256 0360-3199/© 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved. Please cite this article in press as: El-Emam RS, Khamis I, International collaboration in the IAEA nuclear hydrogen production program for benchmarking of HEEP, International Journal of Hydrogen Energy (2016), http://dx.doi.org/10.1016/j.ijhydene.2016.07.256
2
i n t e r n a t i o n a l j o u r n a l o f h y d r o g e n e n e r g y x x x ( 2 0 1 6 ) 1 e6
studies and elaborations on HEEP capabilities and its modules [3e8]. In this paper, benchmarking of the updated version of HEEP was performed. Several case studies were investigated and compared against other models of economic hydrogen assessment. Other studies that used HEEP and compared its results with other codes and tools are also highlighted.
IAEA activities for HEEP benchmarking
Fig. 1 e Potential pathways for current non-carbon based nuclear hydrogen production technologies.
production, but also for cogeneration with electric power production [2]. The HEEP models are based on technical, economic, as well as chronological inputs, and on cost modelling. The package also facilitates performing a broader investigation for more understanding of the feasibility of different hydrogen production scenarios including storage, transportation, and distribution, with the capability to eliminate or include specific details as required by the users. Fig. 2 shows the main four modules of HEEP and the categories of the parameters required as input data. The list of technical parameters required for the HEEP modules is shown in Fig. 3, while the cost elements of the modules are shown in Fig. 4. HEEP estimates the levelized cost of hydrogen, considering many aspects of capital investments which eventually affect the calculated cost. The capital investment, which is the sum of all expenditures incurred in design, licensing, manufacturing and erection, construction, and commissioning of the plant, can be raised at a given equity to debt ratio i.e. the funding of the project can be raised through equities or can be raised through market borrowings, or combination of both. The cash flow during construction is also another important parameter, which affects the interest during construction. This is particularly prominent in case of nuclear power plant requiring high capital investments with longer construction period. The updated version of HEEP was released in December 2014 and available on the IAEA website. Several publications in the literature included different case
Fig. 2 e Categories of input parameters as defined in HEEP.
A preliminary benchmarking of HEEP was performed earlier by Khamis and Malshe [1] on the beta-version of HEEP. The results were encouraging and the elements of hydrogen production cost showed good agreement with data from the literature by the Korean Atomic Energy Research Institute (KAERI) for a case that considered using high temperature reactor coupled with SeI plant for hydrogen production. However, based on the recommendations and outcomes of the preliminary studies, HEEP underwent through several updates and changes in its core modules. The IAEA conducted a Coordinated Research Project (CRP) for further elaboration on using and benchmarking of HEEP. Ten Member States were represented in this project and the participants performed benchmarking and comparative assessment using different generic case studies and country specific cases to examine and assure the reproducibility and accuracy of HEEP results. These cases were performed by experts and researcher from Argentina, China, Japan, Germany, Canada, Pakistan, Rep. of Korea, Indonesia, Algeria, and the USA. It was agreed that the accuracy of the results, using common financial and chronological assumption, assured the capability of HEEP as a tool for performing economic assessment of nuclear-based hydrogen production. Benchmarking of the current version of HEEP (V.2.2t) is performed in form of comparative study with the results of G4-ECONS, developed by KAERI; and H2A, developed by the US Department of Energy (DOE). Five different case studies were considered for, covering different reactor and hydrogen generation technologies. Table 1 shows a summary of the technologies utilized for the nuclear power plants and the hydrogen generation plants and their respective capacities. Case I considers 4 kg/s of nuclear hydrogen production using Conventional Electrolysis (CE) combined with Advanced Pressurized Water Reactor (APWR) with capacity of 2 359.5 MWe. APWR and CE were also the technologies considered in Cases II and III, with different capacity configuration: 2 719.0 MWe and 8 kg/s for Case II; and 2 1117 MWe and 12 kg/s for Case III, respectively. In Cases IV and V, High Temperature Gas-cooled Reactor (HTGR) is used as the nuclear power plant with capacity of 2 509.3 MWth and 2 630.7 MWth, respectively. High Temperature Steam Electrolysis (HTSE) producing 4 kg/s is considered for coupling with the HTGR for Case IV, while the SeI thermochemical hydrogen plant with same production capacity is considered for Case V. The technical parameters and cost input data of the considered nuclear power plants and the coupled hydrogen generation plants are listed in Tables 2 and 3. The chronological and financial data for the considered projects are shown in Tables 4 and 5. Furthermore, assessments of HEEP conducted by other users of the software are discussed. This includes one case
Please cite this article in press as: El-Emam RS, Khamis I, International collaboration in the IAEA nuclear hydrogen production program for benchmarking of HEEP, International Journal of Hydrogen Energy (2016), http://dx.doi.org/10.1016/j.ijhydene.2016.07.256
3
i n t e r n a t i o n a l j o u r n a l o f h y d r o g e n e n e r g y x x x ( 2 0 1 6 ) 1 e6
Fig. 3 e Main HEEP technical input parameters.
Fig. 4 e Main cost parameters in HEEP.
study performed to show the differences between HEEP, G4ECONS and H2A. This case considered Super Critical Water Reactor (SCWR) with capacity of 1200 MWe coupled with HTSE plant for hydrogen generation with capacity of 1925 Mm3/y. Capacity factor of 90%, operational period of 40 years, and discount rate of 5% were considered. Another comparative study, performed by the Pakistan Atomic Energy Commission (PAEC), is also presented. In this study, HEEP results were compared with the results of PAEC's own-developed code, ASAD. The results of HEEP and ASAD were compared for two case studies of nuclear hydrogen production. ASAD is a spread-sheet based software that uses discounted cost methodology to estimate the levelized cost of hydrogen production, heat, and electricity generation. This model requires input of overnight capital cost. Both debt and equity parts of this capital cost are equally distributed throughout the construction period. Interest during construction is capitalized. Repayment of debt component starts from the first year of operation and equally distributed over debt repayment period.
ASAD uses linear depreciation over the specified period with zero salvage value. The model assumes all O&M costs as variable, and the O&M cost in all years of operation is the same. This model does not consider refurbishment during entire life of the plant. The model considers expenditures of initial fuel core in last year of nuclear power plant construction and annual fuel cost in the year of operation (including first and last years of operation) is same. The decommissioning cost is equally distributed over the decommissioning period. The two cases considered for this comparison used SeI thermochemical plant for hydrogen production coupled with: single unit 600 MWth gas turbine high temperature gas cooled reactor (GTHTGR) with 202 MWe net electrical generation capacity, for Case A; and with a pebble bed modular HTR of 2 250 MWth capacity, for Case B. In Case A, the nuclear power plant generates more electricity than required for the hydrogen generation plant. Excess electricity is supplied to electric grid. For Case B, the reactor supplies high temperature thermal energy to the S-I hydrogen production plant. There is no electricity generation equipment with the nuclear plant and the 20 MWe required electricity is supplied from the grid. The technical, financial and chronological data of the two cases are listed in Tables 6e8.
Results and discussion The benchmarking through the assessment of the first five case studies has been performed, and HEEP results are discussed in this section. The results in Fig. 5 show the comparative analysis of the levelized hydrogen cost
Table 1 e Capacities and types of the nuclear power plant and hydrogen generation plant in the considered cases.
Nuclear Power Plant
Hydrogen Generation Plant
Case I
Case II
Case III
Case IV
Case V
2 359.5 MWe APWR CE 4 kg/s H2
2 719.0 MWe APWR CE 8 kg/s H2
2 1117.1 MWe APWR CE 12 kg/s H2
2 509.3 MWth HTGR HTSE 4 kg/s H2
2 630.7 MWth HTGR SeI 4 kg/s H2
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Table 2 e Nuclear power plant technical features and cost elements. Nuclear power plant
Number of units Capacity factor (%) Availability factor (%) Thermal rating (MWth/unit) Heat for H2 plant (MWth/unit) Electricity rating (MWe/unit) Initial fuel load (kg/unit) Annual fuel feed (kg/unit) Capital cost (CC) (USD/unit) CC fraction for power generating infrastructure (%) Fuel cost (USD/kg) O&M cost (% of cc) Decommissioning cost (% of CC)
Case I
Case II
Case III
Case IV
Case V
APWR
APWR
APWR
HTGR
HTGR
2 93 100 1089 0 359.5 27,000 9000 3.16 109 10 1850 1.66 2.8
2 93 100 2178 0 719.0 54,000 18,000 4.66 109 10 1365 1.67 2.8
2 93 100 3385 0 1117 75,000 25,000 5.96 109 10 1260 1.66 2.8
2 90 100 510 510 0 14,000 5000 4.02 108 0 3660 5.84 10
2 90 100 630.7 630.7 0 18,000 6000 6.05 108 0 5535 1.82 10
Table 3 e Hydrogen generation plant technical features and cost elements. Hydrogen plant design
Number of units Capacity factor (%) Availability factor (%) H2 generation rate (kg/year/unit) Heat consumption (MWth/unit) Electricity consumption (MWe/unit) Non-process electricity consumption (MWe/unit) Capital cost (CC) (USD/unit) Energy usage cost (USD) O&M cost (% of cc) Decommissioning cost (% of CC)
Case I
Case II
Case III
Case IV
Case V
CE
CE
CE
HTSE
SeI
1 80 100 1.26 108 0 719 0 4.28 108 0 4 10
1 93 100 2.53 108 0 1438 0 8.45 108 0 4 10
1 80 100 3.92 108 0 2234 0 1.31 109 0 4 10
1 90 100 1.26 108 1020 0 0 4.59 108 0 17.23 10
1 90 100 1.26 108 1261.4 0 42.8 6.66 108 2.7 108 6.68 10
estimations using HEEP, G4-ECONS, and H2A. In general, the levelized cost of hydrogen for the Cases I to V, calculated using HEEP, showed good agreement with the ones calculated through G4-ECONS and H2A. For Case IV the levelized cost resulted from G4-ECONS is 5% higher than that of HEEP. The differences between the results of HEEP and G4-ECONS were investigated. In general, G4-ECONS is reliable in calculating energy cost as long as the energy required from the hydrogen plant is within the reactor capacity. Therefore, the energy cost is not an input data, and it is calculated from the reactor module. On the other hand, in HEEP, if the energy required from the hydrogen plant is within the reactor capacity, the
Table 4 e Chronological data input for the nuclear plant projects. Case I Case II Case III Case IV Case V Construction period (yr) Operation period (yr) Decommissioning (yr) Refurbishment (yr) Spent fuel cooling (yr) Waste cooling (yr) Cooling before decommissioning (yr)
5
5
5
3
3
40 10 1 2 10 2
40 10 1 2 10 2
40 10 1 2 10 2
40 10 1 2 10 2
40 10 1 2 10 2
energy usage cost is zero, and If the energy required from hydrogen plant exceeds the reactor capacity, then the corresponding difference between the two will be an input value as energy usage cost. Also, in HEEP, all the financial parameters such as tax rate, inflation rate, equity to debt ratio, and interest rate are listed separately as input parameters. However, in G4-ECONS, financial parameters are all incorporated into the real discount rate. With respect to the comparison with H2A; both HEEP and H2A give contribution of each cost component: capital cost, running cost, and decommissioning cost. However, H2A does not provide the result as percentage share of each of the facilities associated with hydrogen generation and distribution. In HEEP, all details are to be provided as a separate entity of each plant or facility (source of heat/electricity, storage and transportation) associated with hydrogen production. As an output, HEEP gives contribution of each facility in the total
Table 5 e Financial parameters for the five case studies. Discount rate Inflation rate Finance equity: debt Borrowing interest Tax rate Depreciation period
5% 1% 70%:30% 10% 10% 20 year
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Table 6 e Technical features of the nuclear power plants. Reactor type
Number of units Capacity per unit Capacity factor Capital cost (cc)
Annual O&M Annual fuel cost Decommissioning cost Construction period
MWe (net) MWth % M USD M USD/MWe M USD/MWth % of cc M USD % of cc Years
Case A
Case B
GTHTR
HTR-PM
1 202 600 90 547 1.35 0.91 3.81 10.28 10 3
2 100 250 90 1000 5 2 3.18 14.4 8 3
Table 7 e Technical features of the hydrogen generation plants. Process type
Number of units Capacity factor Production capacity Thermal energy required Power required Capital cost Annual O&M cost
Case A
% kg/s M kg/year MWth/unit MWe/unit M USD/unit % of cc
Case B
SeI
SeI
1 90 0.58 18.29 170 23 186 5.46
1 90 1.36 42.89 250 20 200 5.46
hydrogen cost. H2A considers the cost components of all facilities on lump sum basis and does not have any separate module for consideration of cost inputs from the nuclear power plant. The results in Fig. 5, show good agreement between HEEP and H2A results for the considered cases. The potential causes of the small differences between the results of the two tools were investigated. In H2A, debt portion (market borrowing) of the capital cost is incurred in the first year of the construction period itself. Repayment of debt component starts from the first year of construction period. In HEEP, debt part, incurred in each year of the construction period, is based on the fraction of cash flow during that year and debt-equity ratio. Repayment of debt part borrowed in each year starts from the respective year of incurring. Another
Fig. 5 e Benchmarking results of HEEP with G4-ECONS and H2A for the considered case studies.
cause of the differences in the results, mainly in Cases I, II, and III, is the construction period. The version of H2A used for comparison considers construction period not exceeding 4 years. While in HEEP there is no limit on construction period setting and it was used as 5 years for these specific cases. When these cases were executed in HEEP after modifying the construction period to match that of the H2A, the match and agreement between the estimated costs improved as shown in Fig. 6. Fig. 7 shows a comparison of HEEP, G4-ECONS, and H2A results for the case executed through AECL, on SCWR [9]. The cost shows good agreement between the three tools. The cost breakdown ($/kg) were reported as 0.28, 0.27, and 0.27 for the hydrogen plant capital component, 0.39, 0.39, and 0.36 for the hydrogen plant non-energy component, and 2.89, 2.95 and 2.95 for the hydrogen plant energy component, for HEEP, G4ECONS, and H2A, respectively. In Fig. 8, HEEP and ASAD comparative results are shown. The levelized cost of hydrogen generation is estimated with HEEP and compared with the results of ASAD code. Differences in levelized cost calculations of the two models are relatively small. The differences might be caused as a result of some financial parameter considerations. Another possible issue causing the difference in the estimations is the rounding error as HEEP rounds-off some output values to two decimal points. Also, HEEP estimates the levelized decommissioning cost of the hydrogen
Table 8 e Financial and chronological data for the considered cases.
Nominal discount rate Inflation rate Equity to debt ratio Interest on borrowings Tax rate Depreciation period Borrowing return period Operating life Cooling before decommissioning Number of Refurbishments Decommissioning period
Case A
Case B
5% 0% 0%:100% 5% 0% 20 year 40 year 40 year 2 year 1 10 year
5% 1% 70%:30% 10% 10% 20 year 40 year 40 year 2 year 1 10 year
Fig. 6 e Comparative benchmarking of HEEP with H2A results.
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considered as living software with potential updated by incorporating sensitivity analysis module covering several parameters in the coming update of the software.
Acknowledgement
Fig. 7 e Comparison of HEEP, G4-ECONS, and H2A results.
The authors would like to thank Mr. A. Antony (India), Ms. A. Bohe (Argentina), Ms. R. Boudries (Algeria), Ms. E. Dewita (Indonesia), Mr. I. Dincer (Canada), Mr. M.Ghulam (Pakistan), Mr. J. Kim (Rep. of Korea), Mr. S. Revankar (USA/Rep. of Korea), Mr. K. Verfondern (Germany), Mr. X. Yan (Japan), and Mr. P. Zhang (China), for their valuable input and contribution through their participation in this IAEA CRP on HEEP benchmarking.
references
Fig. 8 e Comparative analysis of HEEP with ASAD results.
production facility lower than estimates of ASAD model. This may be due to the fact that for (N) years of decommissioning period, HEEP displays (N-1) years in the decommissioning cost window for hydrogen plant, which was not considered in the ASAD estimations.
Conclusion According to the results of the technoeconomics of the generic case studies; consistency of HEEP calculated results are found to be very satisfactory. Users are satisfied with HEEP as a userfriendly tool for performing analysis of nuclear hydrogen production systems. With avoiding un-necessary technical details, user obtains levelized cost of hydrogen, electricity, and thermal energy production. The computational models of HEEP appeared to be sensitive to different technical and economic parameters that affect the hydrogen cost such as the economy scale, the process applied to produce hydrogen, and the economic parameters in different countries. HEEP is
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Please cite this article in press as: El-Emam RS, Khamis I, International collaboration in the IAEA nuclear hydrogen production program for benchmarking of HEEP, International Journal of Hydrogen Energy (2016), http://dx.doi.org/10.1016/j.ijhydene.2016.07.256