Program Performance Goal: By 2008, develop turbine technology that is capable of efficiently utilizing coal derived gases, including hydrogen, for the production of electricity in FutureGen plants.

Combustion (gas) turbines are key components of advanced systems designed for new electric power plants in the United States. Clean, increasingly fuel-efficient, and relatively low-cost, gas turbine technology is needed to ensure the success of future advanced power systems.

Typically, a natural gas-fired combustion turbine-generator operating in a "simple cycle" converts between 25 and 35 percent of the natural gas heating value to useable electricity. Today, most new smaller power plants also install a recuperator to capture waste heat from the turbine's exhaust to preheat combustion air and boost efficiencies. In most of the new larger plants, a "heat recovery steam generator" is installed to recover waste heat in the exhaust to generate steam for a steam turbine-generator. This configuration is called a "combined cycle" and can increase efficiencies of combustion systems to the 50 percent level.

In 1992 the U.S. Department of Energy's Fossil Energy program began an intensive effort to break through technical barriers that had essentially capped gas turbine efficiencies. Within eight years, this program produced turbine systems that could operate at temperatures in excess of 2600 degrees F (300 degrees hotter than conventional turbines) and achieve efficiencies above 60 percent, a mark once thought unachievable. At the same time, new combustion techniques were developed to limit the formation of nitrogen oxide (NOx) emissions (the principal air pollutant released by gas turbines). As a result, future high-efficiency natural gas turbines will continue to be one of the cleanest ways to generate electricity from fossil fuels.

Now, the Energy Department's Fossil Energy program has taken on a new challenge: developing a gas turbine that burns fuels derived from coal. Synthesis gas, produced by a coal gasifier is comprised primarily of carbon monoxide and hydrogen. It presents a major challenge for turbine technology. Synthesis gas has far lower energy content than natural gas and can vary more in composition. Both factors can affect combustion stability. Synthesis gas also contains more impurities (even after cleanup) and even a trace amount of contaminants can damage fragile turbine blades.  High concentrations of hydrogen can create higher NOx emissions due to its rapid heat release and hotter flame temperature compared to natural gas.  Therefore, research is needed to find better ways to burn hydrogen.  The hydrogen in synthesis gas offers the prospect of operating turbines with zero emissions of pollutants.

The Energy Department's turbine program continues to develop key technologies that will enable advanced turbines to operate cleanly and efficiently when fueled with coal derived synthesis gas and hydrogen fuels. Developing turbine technology to operate on coal derived synthesis gas and hydrogen is critical to the development of advanced power generation technologies such as integrated gasification combined cycle and fuel cell/turbine hybrids. It will also be important to the eventual deployment of FutureGen plants that couple production of hydrogen and electricity from coal with sequestration of the carbon dioxide that is produced.

The federal turbine R&D program is an investment in secure U.S. electric power production that is clean, efficient, affordable and fuel-flexible, and will make possible the continued use of coal our Nation's largest domestic fossil energy resource.