Sources of Hydrogen and the Development of a Hydrogen Economy Matt Woodson ChE 384 9/29/05

Problems with the Fossil Fuel Economy Rising costs, shrinking supplies Air/environmental pollution Greenhouse gases Dependence on foreign producers

Why Hydrogen? A cleaner, more efficient transportation sector A reduction in pollution and global warming Reduce economic dependence on foreign producers of fossil fuels

Sources of Hydrogen Reforming of fossil fuels - Use a fuel processor to split the hydrogen from the carbon atoms in a hydrocarbon Electrolysis of water - Use electricity to split water molecules to create pure hydrogen and oxygen

Reforming Fossil Fuels Steam reforming of methane: High temperature steam (700o–1100oC) reacts with methane yielding syngas CH4 + H2O  CO + 3H2 Additional H2 can be recovered from the CO through the lower temperature (about 130oC) water gas shift reaction CO + H2O  CO2 + H2

Electrolysis Currently much more expensive than reforming High temperature electrolyzers might make these systems more cost efficient To eliminate carbon emissions, hydrogen should be generated from a renewable source Solar - concentrated solar energy can generate temperatures of several hundred to over 2000oC Nuclear - High T electrolysis of steam using heat from nuclear reactors - Electrolysis using off-peak capacity

Other Sources of Hydrogen Solar Electrochemical Water Splitting (Photoelectrochemical) -Integrate a semiconducting material and an electrolyzer into a single device Solar Biological using Microorganisms -Photosynthetic organisms absorb light and dissociate hydrogen from oxygen

What will it cost? Hydrogen must be $3/kg to be competitive Reforming can produce hydrogen at $5/kg under best conditions (2003 technology) Price of hydrogen from electrolysis is tied to cost of electricity Hydrogen from electrolysis costs $5-6/kg undelivered (2004 technology)

Governmental Policies Relating to Hydrogen Hydrogen Fuel Initiative Announced in 2003, Bush pledged $1.2 billion over 5 years DOE Hydrogen Program plans to spend $64 million on research projects in the next 3 years Renewable Energy Systems and Energy Efficiency Improvements Grant

Conclusions Huge technical advances will be necessary for H2 to replace fossil fuels A move towards a hydrogen economy requires the acceptance of the marketplace; cannot be driven by government policies alone It will be several decades before the US has the capacity to produce enough H2 to impact the energy mix