From Oregon Public Broadcasting:
The idea is to inject water into the cracks of hot rock 10,000 feet underneath the western flank of the Newberry Volcano, where temperatures can exceed 550 degrees Fahrenheit. That’s a nice heat source for making steam to power a turbine. Geothermal energy is normally generated by pulling preexisting hot water and steam from the ground. Linda Christian, the Newberry project manager for BLM, backed up [AltaRock President Susan] Petty’s arguments. She said her agency will know the individual chemicals being used in the proprietary products, which are “like biodegradable plastic bags” that degrade when they get near the heat deep underground. Christian added that the injection process – which she called hydro-shearing – is shouldn’t be confused with hydraulic fracking, which uses a whole different mix of chemicals to break up shale rock and hold it open.