Hydrogen power… at what cost? By Susan Zinga

Producing hydrogen from: Cents per kWh Pros Cons Fossil-fuel (coal/natural gas/oil) 0.4 - 2 Inexpensive Airborne pollutants Biomass 4 - 7 Renewablefuel source Possible airborne pollutants Nuclear 5 - 7 Little or no airborne pollutants Radiation risks and spent fuel disposal issues Wind (on-shore) 5 - 9 Non-polluting Moderately expensive Solar 9 - 18 Non-polluting Very expensive Source: International Energy Agency

During his most recent State of the Union address, President Bush expressed interest in fuel cells and requested an additional $1.2 billion in funding to help bring this technology "from the laboratory to the showroom." He focused on automotive applications of fuel cells, and since then, the popular press has written many articles explaining how fuel cells work and what needs to be done to move us toward a hydrogen-powered economy. In this issue of the Southface Journal, we'll take a look at stationary fuel cells used for electricity generation and the resulting environmental benefits and drawbacks.

Fuel cells, like photovoltaic systems, produce direct current (DC) electricity that is usually converted to alternating, or AC current, for use in American homes and business. In one sense they can be considered environmentally-friendly power generation sources because water, heat, and carbon dioxide are the only by-products of this electricity generation process. The U.S. Department of Energy (DOE) claims that advanced fuel cells can reduce carbon dioxide emissions by 60% over conventional coal plants and 25% compared to today's centralized natural gas power plants. Further, DOE claims that the CO2 emitted is in concentrated form, which makes its capture and sequestration much easier.

However, there are many reasons that fuel cells are not currently in abundant use for on-site electricity production. The main reason is that their capital costs are significantly higher, making them a less economically feasible option. At present, a diesel engine power generator costs $400/kW while a fuel cell may cost $3,000 - $4,500/kW.

Fuel cells are powered by oxygen and hydrogen. Clearly, the oxygen fuel source is readily available, but producing the hydrogen is controversial. It must either be derived from the methane found in organic matter such as natural gas and biomass wastes or extracted from water using an electrolysis process. Electrolysis is quite energy intensive and the electricity used in this process must come from nuclear, fossil-fuel, or renewable (i.e. wind, solar) fuel. Each power generation source has its own drawbacks. Hydrogen derived from nuclear-powered electrolysis incurs the same set of risks for radiation contamination that disposal of spent fuel faces, whenever this fuel source is used. Fossil-fuels such as coal and oil avoid these risks and are quite inexpensive, but they can pollute our environment by emitting tons of sulfur dioxide (SO2), nitrogen oxide (NOX) and toxic elements such as mercury in addition to huge amounts of carbon dioxide. Producing electricity for electrolysis from renewable sources, adds no harmful air emissions, but is quite expensive as shown in the table on page 12. The use of biomass waste as fuel, however, can be less costly than other renewable energy sources and almost as non-polluting if the proper technologies are employed.

A bio-based renewable fuel such as animal waste or landfill gas can be used as the hydrogen source for a fuel cell. Or the biomass can be used to directly generate the electricity sold to consumers, bypassing the fuel cell altogether. The source of the biomass dictates the type of conversion process it must undergo to make it suitable for hydrogen extraction. Some of these processes are costly and some are still in the research and development phase. Therefore, biomass for hydrogen extraction must still overcome many obstacles before it becomes a commercially viable option. Nevertheless, until these problems are resolved, biomass can still be used to directly generate electricity while minimizing airborne pollutants through the application of the proper technologies.

Although fuel cell technology offers us hope for decoupling our need for power from our dependence on fossil fuels, we are still far from incorporating it into our daily lives. Yet, we should still strive to improve fuel cell technology and reduce costs for the benefit of the environment and our quality of life.