Economic Analysis of Hydrogen Production by Photovoltaic Electrolysis

Sammanfattning: 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.