Fuel-Free, Emission-Free Power from a Geothermal District Heating System in Japan
The Power+ runs off low temperature geothermal steam from a small district heating system. As the Power+ generates power, it also provides cooling with zero environmental impact or imposition on the onsen’s primary function as a community resource. The power generated is sold to the local utility at an attractive feed-in-tariff rate for renewables.
ElectraTherm utilizes Organic Rankine Cycle (ORC) and proprietary technologies to generate up to 110kWe of electricity from low temperature water ranging from 77-122°C. At this site, the onsen provides varying flows of geothermal steam at approximately 110°C. Unlike other renewable sources, geothermal heat is baseload, providing a continuous hot water flow with power generation capabilities 24/7. Hot geothermal water is the fuel used to create a high pressure vapor that expands through ElectraTherm’s patented twin screw power block, spinning an electric generator to produce clean electricity while simultaneously cooling the water up to 20°C.
“The US Department of Energy sponsored a program in 2012-2013 for ElectraTherm to develop a ‘micro-geothermal’ power plant that could tolerate remote, unmanned operation and also be able to handle the challenges presented by varying geothermal resources,” said John Fox, CEO of ElectraTherm. “This is the first commercial site in Japan to showcase that investment.”
“We are thrilled with the reliability and proven success of the Power+ Generator,” said Kazunori Ueda, Project Lead and Director of Sales & Marketing, Sankou Denki. “3,000 hours with very high availability speaks to the robust operation of ElectraTherm. Since Japan offers an attractive feed-in-tariff rate for geothermal at 40 Yen/kWh (~$.33/kWh), we believe there is great potential to repeat this success at the hundreds of similar districting heating systems and onsens (hot springs) throughout Japan.”