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They're adapting fracking techniques to use for geothermal, which opens up many more sites. Historically geothermal has had limited potential, and the best sites have already been developed. So geothermal + fracking creates a lot more viable land. Traditional geothermal is you dig a really deep well and get a geyser of hot water or steam to come up. Fervo is doing "Enhanced" or "Engineered" geothermal where you dig two wells: an injection and an extraction well. You frack the rock in between, creating lots of small channels for water to flow between them. The water absorbs the heat from the rocks as its circulating from the injection well to the extraction well. The kind of rock that's good at this heat transfer is different from shale rock that oil & gas frackers have experience with... it's harder, less porous, not partial-dino-juice. So they're taking a lot of the same core concepts from the oil & gas industry (horizontal drilling, geology simulations, etc), but their IP is in adopting the techniques to work with geothermal-favorable rock. Another interesting concept I heard Fervo researching: this kind of geothermal is not "baseload" style power, so there's a few tricks they can do to get better cost efficiency and peaker-like or battery-like behavior. Remember the two wells that form the circulation loop: injection and extraction? Well, you need pumps on both sides (remember, this isn't "geyser-style" geothermal where natural pressure and geology do all the work). Pumps take energy to run, something like 20-30% of the overall extraction output (you put a unit of energy in to run the pumps and you get 3-5 units of energy back out the other end). Not great, not terrible either... it's an energy return comparable to solar and wind. But what you can do is run the injection pump when power prices are low (ie when there's an excess of solar on the grid), pressurize all your fracked channels underground (the reservoir), and then when grid prices rise in the evening you run just the extraction pump to pull out the pre-heated, pre-pressurized water. You're still at a 3-5x energy return, but the time-shifting has made the cost multiplier more favorable. My understanding is it's still in research phase, but Fervo is piloting this technique. Like another thread said, they're pre-IPO now, so they've been flooding the renewables media with all these stories. They filed an S-1 recently, but always read the eventual S-3 before considering your investment options blahblahblah. |