1
Thesis
Chemical Engineering Bachelor
Economic Analysis of Hydrogen Production by Photovoltaic Electrolysis
Luciano Gajardo
KTH Stockholm
2014
2 KEMITEKNIK
HÖGSKOLEINGENJÖRSUTBILDNINGEN
Thesis
Title: Economic Analysis of Hydrogen Production by Photovoltaic Electrolysis Swedish Title: Ekonomisk analys av vätgasproduktion genom fotovoltaisk elektrolys Workplace: The State University of São Paulo (UNESP) Faculty of Engineering at
Guaratinguetá Energy Department Supervisor at KTH: Rolando Zanzi
Supervisor at workplace: Jose Luz Silveira
Student: Luciano Gajardo
Date: 9/15/2014
Examiner: Sara Thyberg Naumann
Keywords: Economic analysis, photovoltaic electrolysis system, hydrogen production cost, steam reforming
3 Abstract
Awareness of the climate situation and greenhouse gas emissions from fossil fuels has focused attention on hydrogen as a renewable and sustainable energy resource.
In this work an economic analysis of hydrogen production by a photovoltaic electrolysis system was conducted. Equations and solution methods from previous works [1, 2] have been used to compile the results. In order to run the electrolysis of water, electricity from the photovoltaic system was used. The photovoltaic electrolysis system for this analysis has been sized with data from previous works [3, 4] to satisfy the hydrogen consumption for a fuel cell bus.
Annual savings, payback time and production costs of hydrogen and electricity were compared to analyses conducted by Paolo Laranci [1] and Lucia Bollini Braga [2]. CO2 emissions from steam reforming of natural gas and sugar cane bagasse ethanol have been calculated. In addition ethics for using natural gas and sugar cane bagasse for fuel production was studied to determine the
advantages and disadvantages for respective hydrogen production processes.
The estimated production cost for photovoltaic electricity calculated in this thesis was higher than the result achieved in Larancis [1] work. In addition the production cost was higher than for electricity from hydropower and photovoltaic-systems in Latin America [2] and also than for the electricity tariff in Brazil [1]. Payback time and annual savings calculated in this thesis was found to be higher than for Larancis photovoltaic system. To reduce the production cost solar cells with higher efficiency should be used, investments costs for the system reduced and governmental subsidies raised.
The estimated production cost for photovoltaic electrolysis hydrogen calculated in this thesis was higher compared to Lucia Bollini Braga's. The production cost for hydrogen by steam reforming of natural gas and sugar cane bagasse ethanol was also an economically favorable alternative. For hydrogen produced by photovoltaic electrolysis to be an economically advantageous alternative the electrolysis operating hours should increase likewise the electrolyser efficiency. In addition the investment cost for the electrolyser should decrease. By using photovoltaic electrolysis to produce hydrogen fossil CO2-emissions are eliminated and abundant solar energy can be utilized.
Brazil is a country that possesses great natural resources of sugar cane bagasse. Steam reforming of ethanol from sugar cane bagasse could be a future option for producing sustainable, economically favorable and ethically acceptable hydrogen in Brazil.
4 Sammanfattning
Medvetenheten om klimatsituationen och utsläppen av växthusgaser från fossila bränslen har riktat uppmärksamheten mot vätgas som är en förnybar och hållbar energiresurs.
I detta arbete har en ekonomisk analys för produktion av vätgas genom fotovoltaisk elektrolys av vatten genomförts. Ekvationer och lösningsmetoder från tidigare arbeten [1, 2] har använts för att sammanställa resultat. För att driva elektrolysen av vatten används elektricitet från det fotovoltaiska systemet. Systemet för denna analys har dimensionerats med hjälp av data från tidigare arbeten [3, 4] för att satisfiera konsumtionen av vätgas för en bränslecellsbuss. Årliga besparingar, payback och produktionskostnader för vätgas och elektricitet har jämförts med analyser utförda av Paolo Laranci [1] och Lucia Bollini Braga [2]. Koldioxidutsläpp för ångreformering av naturgas och etanol från sockerrörs bagass har beräknats. Utöver detta har en etikstudie för användning av naturgas och etanol (ur sockerrörs bagass) vid bränsleproduktion gjorts för att avgöra fördelar och nackdelar med respektive system för vätgasproduktion.
Den i detta arbete beräknade produktionskostnaden för elektricitet från det fotovoltaiska systemet var högre än resultatet som åstadkoms i Larancis [1] arbete. Vidare var den i detta arbete beräknade produktionskostnaden högre än för elektricitet från vattenkraft och fotovoltaisk energi i Latinamerika [2] samt elpriset i Brasilien[1]. Payback-tiden och de årliga besparingarna visade sig vara högre för det fotovoltaiska systemet beräknat i denna analys än för Larancis system. För att minska
produktionskostnaderna bör solceller med högre verkningsgrad användas, investeringskostnader av fotovoltaiska system minskas och statliga subventioner för installationen ökas.
Den i detta arbete beräknade produktionskostnaden för vätgas genom fotovoltaisk elektrolys var högre jämfört med Lucia Bollini Bragas system. Produktionskostnaden för vätgas genom
ångreformering av naturgas och etanol (ur sockerrörs bagass) var likaså ett mer ekonomiskt gynnsamt alternativ än fotovoltaisk elektrolys. För att vätgas producerat genom fotovoltaiskt elektrolys ska vara ekonomiskt fördelaktigt bör elektrolysens drifttimmar ökas, elektrolysen verkningsgrad öka och investeringskostnader för elektrolysen minska. Genom att använda
fotovoltaisk elektrolys för att framställa vätgas elimineras fossila CO2-utsläpp och solenergi som finns i stort överskott kan utnyttjas.
Brasilien är ett land som besitter stora naturresurser i form av sockerrör. Ångreformering av etanol från sockerrörs bagass kan vara ett framtida alternativ för att framställa hållbar, ekonomiskt gynnsam och etiskt accepterad vätgas i Brasilien.
5 Acknowledgement
Writing my thesis abroad made me realize how much effort was put into this study. Arriving at the São Paulo State University gave me another perspective on renewable energy and its possibilities to reduce the environmental issues. Through my work at the GOSE group at São Paulo State University (UNESP) campus Guaratinguetá I learned how we can use the energy from the sun to reestablish the global environment from down spiking to a more sustainable nature and preserving the essence of it.
Developing new techniques and allowing more research on this topic can be the solution.
I want to give my thanks to Professor Jose Luz Silveira my supervisor at São Paulo State University for collaborating and the feedback and support from my supervisor from the Royal Institute of
Technology KTH in Sweden Professor Rolando Zanzi.
Special thanks to my friends at UNESP campus Guaratinguetá, Fernando Araujo for his everlasting dedication, Nestor Proenze for his support and guidance and all the people involved at the university.
This experience was enabled thanks to the Linnaeus-Palme program at KTH.
Luciano Gajardo
Tuesday, August 5, 2014.
6 List of acronyms
CO2 Carbon dioxide
CUTE Clean Urban Transport for Europe
FEG Faculdade de Engenharia de Guaratinguetá
W Watt
Wh Watt hour
Nm3 Normal cubic meter UNESP São Paulo State University
USHER Urban Solar- Hydrogen Economy Realisation
Wp Peak Power
7
Index
Abstract ... 3
Acknowledgement ... 5
List of acronyms... 6
1. Introduction ... 8
2. System for hydrogen production ... 9
2.1 Economic analysis Photovoltaic system ... 10
2.2 Economic analysis Photovoltaic Electrolysis system ... 13
3. Hydrogen production cost for steam reforming processes. ... 15
3.1 Steam reforming of natural gas ... 15
3.2 Steam reforming of sugar cane bagasse ethanol and its potential in Brazil ... 16
4. Discussion ... 18
5. Conclusion ... 19
6. Reference list ... 20 Appendix 1 Economic Calculations
8 1. Introduction
The global energy demand is increasing and so are the environmental issues along with it. Renewable energy resources are the main focus for replacing the use of fossil fuels. Fossil fuels represent around 85 % of the world energy consumption [6]. Renewable sources such as solar, wind and hydro power reduces the impact on the global warming mainly by not emitting greenhouse gases such as CO2. These renewable substitutions are more sustainable and hydrogen is the future energy carrier.
The 1920s and 1930s were the first decade’s when hydrogen was used as auxiliary fuel [7]. The petrol crisis of 1973 gave scientists, engineers and politicians reasons to consider hydrogen as a sustainable and economically viable substitution. Today most of the hydrogen is produced from natural gas [7].
Producing hydrogen from renewable photovoltaic energy has opened a new market and has drawn a lot of scientific attention.
Today the majority of photovoltaic techniques consist of crystallized silicon solar cells and a smaller percentage consisting of thin film solar cells. The main issue for this technology is to produce electricity for production of ecological, economically viable and sustainable hydrogen [8].
Water electrolysis represents 4 % of the world hydrogen production [9].
Using electricity produced from solar cells water electrolysis can produce hydrogen with a purity of 99.9995 % and has the capacity of producing hydrogen up to thousands of Nm3h-1[10].
The integrated technologies on the market today are alkaline water electrolysis, polymer electron membrane (PEM) electrolysis and solid oxide high temperature electrolysis [10].
The aim for this thesis project was to analyze the production cost for photovoltaic electrolysis hydrogen and comparing the result with studies made by Lucia Bollini Braga [2] and Paolo Laranci [1].
The economic study in this project has included calculations of:
Production cost for electricity from a photovoltaic system.
Production cost for hydrogen from a water electrolysis system.
Annual savings and payback time for installed photovoltaic system.
The result is compared with:
Production cost for electricity from hydropower and photovoltaic systems in Latin America and the electricity tariff in Brazil
Annual savings and payback time for installed photovoltaic system from analysis made by Paolo Laranci [1]
Production cost for photovoltaic electrolysis hydrogen and hydrogen produced by steam reforming of sugar cane bagasse ethanol and natural gas from analysis made by Lucia Bollini Braga [2].
The photovoltaic electrolysis system should be a standalone system providing all the required hydrogen to satisfy a fuel cell bus consumption aiming for a production of 2.05 kg H2 h-1. The system should be sustainable in terms of using a renewable non fossil energy resource, non-toxic material, technically feasible, economically viable and ethically accepted. The project is a literature study using equations and approximations developed by Professor Jose Luz Energy Department campus
Guaratinguetá. The equations and approximations are used to calculate the production cost for electricity and hydrogen by photovoltaic electrolysis. The economic analysis of the electricity and hydrogen production cost is restricted to the photovoltaic system and the water electrolysis system.
The CO2 emissions for steam reforming of natural gas and sugar cane bagasse ethanol are analyzed to determine which of the hydrogen production processes is the most advantageous economically and environmentally. In addition the advantages and disadvantages between the hydrogen
9 production system determined in this thesis and the systems determined in Lucia Bollini Braga and Paolo Larancis thesis are described.
2. System for hydrogen production
The hydrogen production system feeding the fuel cell bus for this thesis is shown in fig. 1. The battery is used to store electricity from the solar cells before using it in the electrolyser. The construction and sizing of the system is based on the CUTE program [3]. The generated electricity comes from a photovoltaic generator which consists of 72 high performance single crystalline cells which is directly coupled with a unipolar electrolysis. The hydrogen which is produced is stored in tanks. The
hydrogen is purified before entering the fuel cell. The electricity generated from the photovoltaic system is stored in a battery system which is a transparent stationary type. The battery supplies electricity to components such as pumps and compressors. The compressors maintain the needed pressure for the hydrogen flow in the pumps [1]. A controller is installed in the system to regulate the charge of the battery and protect the electrolysis from excess voltage or intensity [3].
Following parameters and data are used for the sizing and calculations of the system [3]:
Maximum peak power of the selected module 170 Wp
Produced energy from the photovoltaic generator 795 MWh year-1
Efficiency of the photovoltaic generator 13,7 %
Efficiency of the electrolysis ~65 % [16]
Total modules required in photovoltaic system 3110
Electrolysis working at 225-250 kW
3 different operating hours for electrolysis is:
1278 hours year-1 1643 hours year-1 2008 hours year-1
Water flow required by the electrolysis 60 kg h -1
Produced hydrogen is 2.05 kg h-1
Power in produced hydrogen 68.4 kW
Heat value for hydrogen 120*103 kJ kg-1 [2]
Fig. 1 The system used to supply the fuel cell bus with hydrogen [4]
10 2.1 Economic analysis Photovoltaic system
A methodology has been developed by Professor Jose Luz Silveira 1994 and Silveira, Welter, Luengo 1995 [1] to estimate the production cost for electricity, annual savings and payback period for a photovoltaic system. The methodology has been applied in this thesis, see Appendix 1 for calculations and equations. The installed power of the photovoltaic generator is 529 kWp-1
[3]. The cost for maintaining the photovoltaic system is about 10 % of the total investment cost Ipl, divided by the energy produced in a year Ep. Components such as inverters and charge controller is
approximately 20% of the photovoltaic module cost. The cost for the battery can be approximated as 20 % of the photovoltaic module cost [1]. Production cost Cel for electricity from a photovoltaic system as a function of the governmental subsidy % for the installation is illustrated in fig. 2. The production cost for electricity from the photovoltaic system which was calculated for this economic analysis was 0.27-0.42 US$ kWh-1.
Fig.2 Production cost for electricity from the photovoltaic system
Production cost for electricity in Larancis thesis can be seen in fig. 3.
The same module cost was used 4 US$ Wp-1. The installed power was 10 kW and r is the interest rate [1].
Fig. 3 Production cost for electricity. Larancis system [1]
0 0,1 0,2 0,3 0,4 0,5
0 5 10 15 20 25 30 35 40 45 50 Cel. US$ kWh-1
Subsidy. %
Production cost C
elfor electricity from a
photovoltaic system. 10 years amortization period
Interest rate 4 % Interest rate 8 % Interest rate 12 %
11 The expected annual saving Se is an output value depending on the subsidy from the government and is determined by the annual gains in producing electricity see fig. 4 for plot. It shows the profit made by generating electricity from solar energy. The marginal cost represents the cost for distributing the electricity and eventually connecting it to a grid, since the system is a standalone system. If the value for the expected annual saving is positive the installation of the photovoltaic system is economically convenient [1, 11]. The expected annual saving is positive making the installation of the photovoltaic system economically convenient starting with:
0.27 US$ kWh-1 marginal cost and 50 % subsidy
0.30 US$ kWh-1 marginal cost and 30 % subsidy
0.32 US$ kWh-1 marginal cost and 20 % subsidy
Fig.4 Expected annual savings from the photovoltaic system
Larancis resulting expected annual savings [1] can be seen in fig. 5.
Fig.5 Expected annual savings. Larancis system [1].
-150000 -100000 -50000 0 50000 100000
0,18 0,2 0,22 0,24 0,26 0,28 0,3 0,32 0,34
Se . US$ year--1
Marginal cost. US$ kWh-1
Expected annual saving S
e.10 years amortization period. 4
% annual interest rate
Subsidy 0%
Subsidy 5%
Subsidy 10%
Subsidy 20%
Subsidy 30%
Subsidy 50%
12 The payback time indicates when the photovoltaic system turns profitable and the investment costs have been recovered. The positive value indicates the payback time see fig. 6. The payback time for the installed photovoltaic system was having:
14 years with 50 % subsidy
18 years with 25 % subsidy
19 years with 20 % subsidy
Fig.6 Expected annual savings.
Larancis resulting expected annual savings [1] can be seen in fig. 7.
Fig.7 Expected annual savings. Larancis system [1]
-150000 -100000 -50000 0 50000 100000
5 7 9 11 13 15 17 19 21 Se. US$ year-1
Amortization period. Years
Expected annual benefit S
e. 4 % annual interest rate.
Subsidy 0%
Subsidy 20%
Subsidy 50%
13 2.2 Economic analysis Photovoltaic Electrolysis system
The production cost for hydrogen using electrolysis with renewable energy resource from a
photovoltaic system can be calculated through a methodology developed by Silveira and Gomes [2].
The methodology was applied in this thesis see Appendix 1 for calculations and equations. The power consumed by the electrolysis is 225 kW [3]. The production is sized for a production of 2.05 kg H2 h-1. The investment of the electrolysis system was 243 709 US$ [3]. The production cost for hydrogen with a water electrolysis system using photovoltaic electricity is seen in fig. 8. The curves are plotted as a function of amortization time k and electrolysis operation hours H. The production cost for hydrogen as a function of amortization period is:
1.4-4.0 US$ kWh-1 operating 1278 hours year-1
1.3-3.3 US$ kWh-1 operating 1643 hours year-1
1.2-2.9 US$ kWh-1 operating 2008 hours year-1
Fig. 8 Production cost for hydrogen from water electrolysis using photovoltaic electricity Hydrogen production cost for a similar photovoltaic electrolysis system is shown in figure 9 made by Lucia Bollini Braga [2]. Lucia Bollini Braga electrolysis system had a power consumption of 5.5 kW and a production of 0.0899 kg H2 h-1. Investment cost 50 633.91 US$ and photovoltaic electricity cost of 0.11-0.31 US$ kWh-1.
Fig.9 Production cost for hydrogen from water electrolysis using photovoltaic electricity. Lucia Bollini Braga system [2]
0 1 2 3 4 5
0 2 4 6 8 10
CH2 US$ kWh-1
k year
Production cost C
H2for hydrogen from a electrolysis system using photvoltaic electricity. 8 % annual interest
rate
H 1278 [hours/year]
H 1643 [hour/year]
H 2008 [hour/year]
14 The production cost calculated in this thesis for photovoltaic electrolysis hydrogen as a function of annual interest rate r is seen in fig.10:
1.3-1.4 US$ kWh-1 operating 1278 hours year-1
1.2-1.3 US$ kWh-1 operating 1643 hours year-1
1.1-1.2 US$ kWh-1 operating 2008 hours year-1
Fig. 10 Production cost for hydrogen from water electrolysis using photovoltaic electricity
Lucia Bollini Braga hydrogen production cost analysis as a function of annual interest rate r seen in fig. 11.
Fig. 11 Production cost for hydrogen from water electrolysis using photovoltaic electricity. Lucia Bollini Braga system [2]
0,8 0,9 1 1,1 1,2 1,3 1,4 1,5
0 5 10 15
CH2US$ kWh-1
r %
Produciton cost C
H2for hydrogen from a electrolysis system using photovoltaiv electricity. 9 years
amortization
H=1278 hours/year H=1643 hours/year H=2008 hours/year
15 3. Hydrogen production cost for steam reforming processes.
To evaluate the most environmental and economically advantageous hydrogen production process this section presents the production cost, CO2 emissions and ethic for steam reforming of natural gas and sugar cane bagasse ethanol. The production cost is collected from an analysis made by Lucia Bollini Braga [2].
3.1 Steam reforming of natural gas
The production cost for hydrogen by steam reforming of natural gas according to Lucia Bollini Braga [2] is shown in fig. 12-13. Data [2] for sizing of the steam reforming system by Lucia Bollini Braga was:
Generation cost of natural gas 0.08 US$ kWh-1
Production cost for hydrogen 0.49-3.87 US$/kWh. See Fig.12.
90 % efficiency for steam reformer
Investment for reforming system 29 488.26 US$
A production of 0.0899 kg H2 h-1
Fig.12 Production cost for hydrogen by steam reforming of natural gas [2]. K is the amortization period
Fig.13 Production cost for hydrogen by steam reforming of natural gas [2]
Today natural gas can be extracted with beneficial technologies in shale formations making it
economically profitable. Great sources of natural gas have been found in the United States as well as in China and Canada. Weighing the benefits of extraction against the issues has raised concerns
16 about threatening other operators such as the economic status of agriculture and tourism due to the drilling. Meanwhile others propone [12] that replacing coal with natural gas in power plants can reduce greenhouse emissions by 50 %. Considering methane and its volatility the fact is that it contributes to the production of hazardous irritant tropospheric ozone which increases the risk for mortality and morbidity. Methane is compared to CO2 more difficult to get rid of as a greenhouse gas. Extracting shale gas has not been shown to put a lot of pressure on health risk. The United States with excess of natural gas has decreased the drilling [12].
Steam reforming of natural gas emits ten times more CO2 than steam reforming of ethanol due to great emissions during the extraction of natural gas. The greenhouse effect is shown to decrease by 90 % using the Brazilian ethanol and its benefits on the carbon cycle [5].
3.2 Steam reforming of sugar cane bagasse ethanol and its potential in Brazil
The production cost for hydrogen by steam reforming of sugar cane bagasse ethanol according to Lucia Bollini Braga [2] is shown in fig.14-15. Data [2] for sizing of the steam reforming system by Lucia Bollini Braga was:
Generation cost for sugar cane bagasse 0.0035 US$ kWh-1
Generation cost for ethanol 0.3471US$/kWh1
Production cost hydrogen 0.29-2.58 US$/kWh. See fig. 14.
85 % efficiency for steam reformer
Investment for reforming system 20 000 US$
A production of 0.0899 kg H2 h-1
Fig.14 Production cost for hydrogen by steam reforming of sugar cane bagasse ethanol [2]. K is the amortization period
17
Fig.15 Production cost for hydrogen by steam reforming of sugar cane bagasse ethanol [2].
Bioethanol can be produced from sugar cane bagasse and Brazil has the largest share of sugar cane resources in the world [13]. The majority of ethanol production from sugar cane bagasse in Brazil takes place in pasturelands and these areas are relatively unimportant compared to places such as the Amazon Rain Forest [14]. CO2 emission for the ethanol life cycle is 10% less than the emission of gasoline cycle which is 3368 kg per 1000 liters [5].
18 4. Discussion
Photovoltaic system
The calculated cost for producing electricity from the photovoltaic system in this thesis was 0.28-0.42 US$ kWh-1. The analysis made by Laranci [1] shows a production cost of 0.19-0.51 US$ kWh-1. The fact that the results differs can be explained by the use of different parameter values for the installed power, the investment cost and the produced energy per year. The energy produced is determined by the efficiency of respective solar-systems. The production cost for photovoltaic and hydropower electricity in Latin America is 0.11-0.31 US$ kWh-1 and 0.02-0.105 US$ kWh-1 respectively [2]. The electricity tariff in Brazil is 0.08 [1]. This clearly shows that using the photovoltaic electricity
calculated in this thesis is too expensive. However making solar cells more efficient and lowering the investment cost for the installation of a photovoltaic system could lower the production cost. In addition increasing the governmental subsidies could also lower the production cost.
The payback period for the Laranci photovoltaic system was at least 9 years. The corresponding payback time for the system of this thesis was 14 years. Intuitively a higher investment cost should result in a longer payback period. Annual savings are inversely proportional to the production cost for electricity. Production cost is directly proportional to an increasing amortization period.
Maintenance, inverter, charge controller and battery costs where set by rough approximations which undeniably could have contributed for a source of error when calculating the production cost for photovoltaic electricity. Using more accurate approximations could give the methodology for calculating the productions cost a higher degree of precision.
Electrolysis system
The calculated production cost for hydrogen by photovoltaic electrolysis for the system of this thesis was 1.2-4.0 US$ kWh-1. Lucia Bollini Bragas photovoltaic electrolysis system followed similar outcome in production cost trend from 0.83-7.17 US$ kWh-1. The production cost for steam reforming of natural gas and sugar cane bagasse ethanol was 0.49-3.87 US$ kWh-1 and 0.29-2.58 US$ kWh-1 respectively. The amount of produced hydrogen is different for respective hydrogen production system and likewise the operating hours. Lucia Bollini Braga uses longer operation hours which were directly proportional to the lower production cost. The investment cost Lucia Bollini Braga used for the electrolyser is also lower with a factor of 10. The efficiency for the electrolyser in this thesis is
~65 % compared to 90 % and 80 % for respective steam reformers. Enhancing the electrolyser efficiency, lowering the investment cost and increasing operating hours could make the production of hydrogen by photovoltaic electrolysis economically favorable. Photovoltaic electrolysis and steam reforming of sugar cane bagasse do not emit fossil CO2 which is a great environmental advantage.
Also the CO2 life cycle emissions for steam reforming of natural gas is ten times higher than for steam reforming of sugar cane bagasse ethanol due to great emission during extraction of natural gas.
Cleary the economically favorable hydrogen production system which was included in this thesis is steam reforming of sugar cane bagasse
19 5. Conclusion
The production cost for photovoltaic electricity calculated in this thesis was higher than the one achieved by Paolo Laranci. The annuals savings were higher and the payback time higher than for Larancis photovoltaic system. The production cost calculated in this thesis is too high compared to photovoltaic and hydropower electricity in Latin America today. It is also higher than the electricity tariff in Brazil. Using solar cells with higher efficiency, lowering the investment cost of the
photovoltaic system and increasing the governmental subsidy for installing the system could lower the production cost and payback time. However a photovoltaic system uses abundant renewable solar energy and does not emit fossil CO2.
The production cost for photovoltaic electrolysis hydrogen calculated in this thesis was higher than that of Lucia Bollini Braga for a similar system. Both steam reforming of natural gas and sugar cane bagasse ethanol showed a lower hydrogen production cost. However the advantage of using a photovoltaic electrolysis system is avoided fossil CO2 emissions. The production cost for photovoltaic electrolysis hydrogen could be lowered by enhancing the electrolyser efficiency, lowering the
investment cost for the electrolyser and operating for longer periods. Generating sugar cane bagasse ethanol for hydrogen production by steam reforming is the most economically and environmentally favorable alternative. It is a low cost alternative, ethically accepted and produced in a sustainable way. Steam reforming of sugarcane bagasse ethanol could be a hydrogen production processes with high potential in Brazil.
20 6. Reference list
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[4] Colin Saunders. (Ongoing) Urban Solar- Hydrogen Economy Realisation (USHER), University of Cambrigde (UK)
[5] Silveira, J. L., Braga, L. B., de Souza, A. C. C., Antunes, J. S., and Zanzi, R. (2009) The benefits of ethanol use for hydrogen production in urban transportation, Renewable and Sustainable Energy Reviews 13, 2525-2534.
[6] Edenhofer, O., Pichs Madruga, R., and Sokona, Y. (2012) Renewable energy sources and climate change mitigation : special report of the Intergovernmental Panel on Climate Change, New York:
Cambridge University Press, New York.
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[8] Tributsch, H. (2008) Photovoltaic hydrogen generation, International Journal of Hydrogen Energy 33, 5911-5930.
[9] Zeng, K., and Zhang, D. (2010) Recent progress in alkaline water electrolysis for hydrogen production and applications, Progress in Energy and Combustion Science 36, 307-326
[10] Federico A.Giudici. (2008) Feasibility study of hydrogen production using electrolysis and wind power in Patagonia, Argenitna, University of Florida.
[11] Silveira, J. L., Tuna, C. E., and Lamas, W. d. Q. (2013) The need of subsidy for the implementation of photovoltaic solar energy as supporting of decentralized electrical power generation in Brazil, Renewable and Sustainable Energy Reviews 20, 133-141.
[12] de Melo-Martín, I., Hays, J., and Finkel, M. L. (2014) The role of ethics in shale gas policies, Science of the Total Environment 470-471, 1114-1119.
[13] Hotza, D., and Diniz da Costa, J. C. (2008) Fuel cells development and hydrogen production from renewable resources in Brazil, International Journal of Hydrogen Energy 33, 4915-4935.
[14] Goldemberg, J., Coelho, S. T., and Guardabassi, P. (2008) The sustainability of ethanol production from sugarcane, Energy Policy 36, 2086-2097.
[15] Forest Time, Demand Media. (2012) Pay Scale for a Solar Energy Technician, Work Chron.
http://work.chron.com/pay-scale-solar-energy-technician-19567.html
[16] Matthius Ruete. (2001-2006) Detailed summary of achievements, Clean Urban Transport for Europe, European Union.
[17] Info@sydvatten.se. (2011) Vanliga frågor, Sydvatten http://www.sydvatten.se/vanliga-fragor
