Solar-hydrogen generation systems

Abstract

While we are advocating the use of coal with CO2 sequestration for most of the 21st century to provide low carbon electricity and hydrogen to power fuel cell electric vehicles, coal is a finite resource and eventually society will have to generate electricity and hydrogen from low- or zero-carbon sources such as wind or solar (or nuclear). In this chapter we explore the option of building solar photovoltaic (PV) generators with the hydrogen produced during sunlight hours stored to be used to generate electricity when the sun is not shining. We show that the lowest cost and lowest greenhouse gas (GHG) current alternative electricity generators available today [Natural gas combined cycle (NGCC) generators] to back up intermittent renewables would not allow us to meet our greenhouse gas goal of cutting GHGs to 80% below 1990 levels by 2050. In fact, even if all U.S. electricity was generated from PV solar with NGCC backup, then the GHG emissions would still be four times the GHG emissions necessary to achieve the societal GHG goal. We also show that an organization building these PV-Hydrogen systems could earn 30-year internal rates of return above 9% without a carbon tax, and between 11 and 12% with the Citizen’s Climate Lobby carbon fee and dividend.