THE technology
The Binary Cycle System
Electricity from a low-enthalpy geothermal system
In the Western Canada Sedimentary Basin, the highest temperatures are found in the deepest part of the basin along the Cordillera in the west, reaching up to 160 degrees C. Considered low from the geothermal perspective, this temperature is unsuitable for use in conventional geothermal power plants. However, temperatures as low as 80 degrees C, can be utilized with the application of the binary cycle system, e.g., the Organic Rankine Cycle (ORC), where the heat from the geothermal brine is transferred through a heat exchanger to a secondary working fluid with a low flash point. Pressure from the vaporized working fluid drives the turbine to generate electricity. The geothermal brine and the ORC fluid never come into contact as each is in a closed loop. Neither fluid is exposed to the environment, making the system practically emission-free.
There are about 2200 orphan wells in Alberta and some 500 of them have encountered temperatures sufficient to feed a binary system power plant. These wells can potentially be refurbished to be used either as production or injection units.