Highly efficient DFC-ERG hybrid power plants generate ultra-clean power and heat for natural gas pipeline applications
The innovative Direct Fuel Cell – Energy Recovery Generation (DFC-ERG™) system is a high efficiency, low carbon solution that recovers energy normally lost at natural gas letdown stations. The hybrid multi-megawatt power plant generates ultra-clean electrical power and heat while emitting virtually no harmful pollutants. Natural gas travels long distances in pipelines at high pressure. Before it can be safely distributed to homes and businesses, the pressure must be reduced, releasing energy that is normally lost. Typically the pressure is reduced by squeezing the gas through a valve. Since this pressure reduction process causes the gas to cool, similar to releasing air from a bicycle tire, heat needs to be provided to prevent the pressure reduction machinery from freezing. Combustion-based boilers are used to generate the heat needed on-site.
Instead of using a valve, which wastes the pressure energy, the DFC-ERG power plant directs the high-pressure gas through a turbo expander to harvest this energy for power generation in a manner similar to a water turbine. This recovered energy generates about one megawatt of emissions-free electricity when located at high pressure letdown stations. The integration of the fuel cell more than doubles the amount of ultra-clean power that is delivered to the electric grid, while the continuous heat generated by the fuel cell eliminates the need for the boiler and its associated emissions.
DFC-ERG hybrid fuel cell power plants offer unparalleled efficiency. This distributed generation solution operates 24 hours a day as a combined heat and power (CHP) plant and achieves electrical efficiency of 60 percent and higher. This is almost double the fuel-to-electricity conversion efficiency of most combustion-based distributed generation technologies. Since the fuel cell power plant operates without combustion, pollutants like smog creating nitrogen oxide (NOx) and particulate emissions are less than one percent of those emitted from combustion-based power plants of similar size. Since natural gas pressure-reducing stations are often located near or within urban centers, power is generated where it is needed most, thereby reducing the need for transmission and its associated costs and permitting challenges.