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The idea of drilling deep geothermal to repurpose existing fossil plants is an elegant one. I imagine others have thought of this before, but it was new to me.
by theptip 5y ago
The idea of drilling deep geothermal to repurpose existing fossil plants is an elegant one. I imagine others have thought of this before, but it was new to me. Being able to take over the existing equipment (turbines, power transmission connections) seems appealing.
Of course, it all depends on how expensive the drilling process is vs. the existing capital asset in the turbines, but maybe you could hit a price point where the repurposed geothermal plant is way cheaper than new solar / gas builds in the 2030s? This would be a transitional tailwind, just when we need it. Down the road, these plants would become more expensive because you'd also need to build new turbines/transmission lines. And at that time maybe solar or fusion is a cheaper solution (or not, who knows). But this could really help with the transition away from fossil fuels, if it was delivered next decade or two.
A question - does deep drilling like this have any downsides, as fracking does? I'm guessing it's less bad since you're not pushing pressurized fluid into the bedrock, instead you're just making a pipe that contains the water.
- fly-guy 5y agoENergy conversion equipment can't easily be re-purposed for geothermal. The temperatures are usually much lower, and the working fluids are often hydrocarbons instead of steam.
- theptip 5y agoQuaise seems to think it's possible: > “What we intend to do is go to existing power plants—it could be a coal power plant, it could be a gas power plant, any of the thousands of fossil-fired power plants that exists in the United States and around the world—and we will propose to them to create a small geothermal field around them, which is matched to the turbine specification of the power plant. What comes out of the ground is steam that feeds into the turbine, and the rest is what they’ve always done. The turbine creates electricity. The plant is already connected to the grid,” https://www.powermag.com/a-game-changing-vision-for-geothermal-energy/#:~:text=%E2%80%9CWhat%20we%20intend,to%20the%20grid%2C https://www.powermag.com/a-game-changing-vision-for-geotherm... Could just be marketing fluff; I'm not an expert here. But don't coal plants exclusively use steam turbines? Edit: Seems that lots of energy in the US comes from steam turbines: https://www.eia.gov/energyexplained/electricity/how-electricity-is-generated.php#:~:text=Steam%20turbines%20are%20used%20to%20generate%20the%20majority%20of%20the%20world%E2%80%99s%20electricity%20and%20they%20accounted%20for%20about%2044%25%20of%20U.S.%20electricity%20generation%20in%202020 https://www.eia.gov/energyexplained/electricity/how-electric....
- irq-1 5y agoIt's also the drilling industry. There are millions of skill people and a worldwide supply chain already setup. As a bonus, these are the same companies and people who would lose their jobs when drilling for oil and gas is overtaken by geothermal.
- abrazensunset 5y agoIt's worth noting that hydraulic fracturing itself is rarely the problem. Issues come from moving fluid volumes somewhere else during production: subsidence due to extraction from the place where the hydrocarbons are, or (most often) from injecting produced water into disposal wells, eventually triggering faults. Some of that produced water was introduced by the operations, but most of it was just in the ground with the oil & gas being produced. It's possible to directly trigger small faults with while fracturing the rock, or to do something stupid like fracture into a freshwater zone other people are using, but that's not what's driving quakes in e.g. Oklahoma.