ElectraTherm’s 4100C Green Machine is generating power at the Florida Canyon Mine in Imlay, Nev., using low-temperature (170-240°F/77- 116°C) geothermal brine.
Representatives from the Department of Energy were on hand for the commissioning of the Green Machine to observe the demonstration of creating power from such low temperatures, according to an ElectraTherm spokeswoman.
ElectraTherm’s Green Machine utilizes organic Rankine cycle (ORC) technology to generate electricity from low temperatures. First, hot water enters the Green Machine to boil a working fluid into a vapor. The high-pressure vapor expands through ElectraTherm’s patented twin-screw power block, spinning an electric generator. After turning the twin-screw expander, the vapor is then condensed back into a liquid through the use of an external air-cooled condenser. Following condensing, the working fluid flows back to the evaporator as a liquid to repeat the process.
The machine for the Florida Canyon Mine was manufactured with a cleanable heat exchanger, an increased power output of up to 75 kW and a fully-containerized solution for ease of transportation and installation through a grant from the Department of Energy for $982,000.
The Florida Canyon Mine also marks the first installation where ElectraTherm is providing not only the ORC equipment but also ORC power generation as a metered service.
This project follows the commissioning of a Series 4000 ElectraTherm Green Machine at a geothermal well in Romania in 2012. The Romanian Green Machine produces 50 kW from the geothermal hot water (216°F/102°C) without any fuel or emissions, and has reached 2,200 hours of run time. To further increase the application’s efficiency, once geothermal water has passed through the heat exchangers to pressurize the Green Machine working fluid, it continues on to heat nearby residential buildings in the winter.
According to reports by Massachusetts Institute of Technology and the National Renewable Energy Laboratory, there are tens of thousands of oil and gas wells in the US alone that co-produce hot water at optimal temperatures for the Green Machine, which water could be re-captured as fuel to generate more power for drilling.
Earlier this week, Conergy announced it is building another 2 MW solar power plant in the Romanian region of Slobozia, with demand for renewable energy ramping up in the country in order for energy providers to earn green certificates.