The city of Phoenix, Ariz. is taking raw biogas produced at its wastewater treatment plant and cleaning it before it is compressed and injected in natural gas pipelines. The ultimate commodity is known as renewable natural gas, produced from any organic material found in landfills, sewage treatment or bio-digesters — and an excellent substitute for fossil fuels in microgrids.
The city is converting an existing resource into energy that would otherwise get sent into the atmosphere and create greenhouse gas emissions. While such renewable natural gas is now mostly used in the transport sector, it can also be used to heat homes and businesses. Microgrids need to be able operate independently of the main grid — to island themselves — in the case of an outage and thus must be reliable and resilient.
By Ken Silverstein, Microgrid Knowledge