What fuel cells bring to the power equation
- January 31, 2015
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By Scott Samuelsen
The United States, along with the rest of the developed world, has relied on combustion the past century to drive the economy and meet societal needs for food, services, commodity goods and mobility. The examples are pervasive, spanning from the generation of electricity to the propulsion of automobiles, trucks, buses, railroads, aircraft and ships.
With the recognition of the finite resources of fossil fuels, the geo-politics associated with petroleum, and the need to curtail the emission of greenhouse gases (GHGs), attention is being directed to environmentally sensitive alternatives to combustion that will achieve higher efficiencies and operate with non-petroleum and bio-fuels that are domestically sourced.
In addition to GHGs, combustion systems also emit “criteria pollutants,” the emission of which degrades the quality of air in urban environments with eye-stinging gases, small inhalable particles, and an aerosol dense haze. Even the most advanced combustion controls, while effective in reducing emissions over the last four decades, are unable to reduce criteria pollutant emissions to levels required to protect the public health. Ideally, an alternative technology to combustion would emit virtually zero criteria pollutants.
The United States has been a leader in advancing clean energy alternatives to combustion that achieve these ideals. For example, as a result of federal funding in combination with private investments dating back to the 1970s, commercially viable fuel cell technology has emerged with celebrated high efficiency, an accompanying reduction in greenhouse gases, and virtually zero emission of criteria pollutants. When operated with natural gas, fuel cells are the most energy efficient and environmentally sensitive means to produce electricity. When operated on a biogas, fuel cells generate a stable output of renewable, carbon neutral electricity around the clock and complement, thereby, other renewable resources such as solar and wind that are inherently intermittent.
Four other attributes of stationary fuel cells are notable. First, in contrast to many combustion systems, fuel cells require virtually zero water in the generation of electricity. Second, fuel cells are quiet and well suited for distributed generation (DG) at locations such as hospitals, universities, hotels, office buildings, and homes. Third, fuel cells have high residual heat energy in the exhaust, which can be captured in DG applications and used for heating or cooling, thereby further reducing GHGs. Fourth, fuel cell systems deployed as distributed resources alleviate the need for investment in additional electrical transmission lines.
Today, stationary fuel cells are commercially installed across a wide variety of market applications including universities, hospitals, data centers, water resource recovery facilities, and at leading companies such as Verizon, AT&T, Wal-Mart, Coca Cola, eBay, Federal Express and Google. In California, in excess of 100MW are deployed. As the track record of success continues to grow in California and widen across market sectors, a portfolio of customers and utilities are following suit throughout the U.S. and the world. In South Korea, for example, installations are approaching 300MW. Manufacturers participating in these markets with commercial product include FuelCell Energy, Bloom Energy, and Doosan Fuel Cells America. Going forward, LG Fuel Cells and GE Fuel Cells are preparing commercial launches.
In parallel to 1MW-class installations, large fuel cell plants are being commissioned. Referred to as TIGER (Transmission Integrated Grid Energy Resource) Stations, recent examples include a 15MW deployment in Bridgeport, Connecticut and a 59MW deployment in South Korea. TIGER Stations are filling a void for environmentally sensitive and efficient grid-support attributes on the utility side of the meter.
The increasing interest in fuel cell systems is associated with the match of fuel cell technology to meeting electricity system and environmental goals throughout the country, and the world. Instead of focusing solely on addressing one energy challenge at a time (e.g., reducing GHGs, reducing particulate emissions, installing more renewable power, reducing water demand in the power sector, increasing energy reliability), fuel cells address these challenges concurrently and provide, thereby, an attractive and viable alternative to combustion power generation systems.
Scott Samuelsen, Ph.D., is director of the National Fuel Cell Research Center and professor of mechanical, aerospace and environmental engineering at the University of California, Irvine.
- 1838: date that first crude fuel cell was created by William Grove (Wikipedia)
- 1939: date of first successful stationary fuel cell created by Francis Thomas Bacon (Wikipedia)
- 35: Wal-Mart stores powered by fuel cells (fuelcells.org)
- 85%: average fuel cell efficiency in a combined heat & power system (fuelcells.org)
- 5 kW-2.8 MW: range of system sizes for stationary fuel cells (NREL)
- 1.4 MW: size of the fuel cell power plant at University of California, Irvine Medical Center (NFCRC)
- 120+ MW: fuel cell power shipped in 2012 (fuelcells.org)
- 170+ MW: installed fuel cell capacity in the U.S. (fuelcells.org)
- 2,446,000+ MWh: estimated electricity generated from stationary fuel cells systems worldwide since 1-1-2013 (fuelcells.org)
- $55/kW: 2014 cost status for automotive fuel cell system (DOE)
- $30/kW: ultimate target for automotive fuel cell system—expected to be reached after 2020 (DOE)
- 23: types of fuel cells: metal hydride, electro-galvanic, DFAFC, zinc-air battery, microbial, UMFC, regenerative, direct borohydride, alkaline, direct methanol, reformed methanol, direct ethanol, PEM, RFC, phosphoric acid, solid acid, molten carbonate, TSOFC, protonic ceramic, direct carbon, planar solid oxide, enzymatic biofuel, magnesium-air (Wikipedia).