Centralized production of hydrogen using a coupled water electrolyzer-solar photovoltaic system

Abstract

This study investigates the centralized production of hydrogen gas (H 2) by electrolysis of water using photovoltaic (PV) electricity. H2 can be used to power all modes of transportation. The logical first large-scale application of H2 is as a replacement fuel for light-duty vehicles, light commercial trucks, and buses. Since H2 is an expensive fuel compared to gasoline, consumer acceptance of H2 is contingent on its use in advanced fuel economy vehicles such as fuel cell vehicles (FCVs), which lowers the cost of H2 relative to the cost of gasoline used by conventional fuel economy vehicles. The purpose of the study is to provide baseline projections of capital investments, levelized H2 prices, and fuel cycle greenhouse gas (GHG) emissions of a centralized PV electrolytic H2 production and distribution system. This is important in order to evaluate the economic and environmental impacts of utilizing PV electrolytic H2 as a fuel source. The use of PV electricity for electrolytic H2 production is a means of storing solar energy and overcoming its limitations as an intermittent power source. However, the intermittency of solar energy reduces the utilization capacity factor of electrolysis plants, which increases H2 production cost. The relevant question is whether the production of electrolytic H2 using PV electricity is economically viable. This study attempts to provide insight into this question. In all cases, the analysis draws on the perspective of the Terawatt Challenge for Thin Film PV in terms of PV costs, efficiencies, reliability, and progress towards these goals. The study assumes progress in PV technologies will occur. Then the important questions to be examined are: Does it matter? Will PV electricity be inexpensive enough to make electrolytic H 2 production practical? The study will answer these in the positive. The organization of the study is as follows. In the first Section, a H 2 production and distribution system is described. Secondly, capital and levelized H2 price estimates are investigated for each of the H2 system components. Thirdly, a life cycle evaluation of primary energy and GHG emissions in the H2 fuel cycle is performed. Sensitivity analyses are performed for the H2 price and the life cycle energy and GHG emissions estimates. The study concludes with a summary of findings and suggestions for future research.