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El_Minadero t1_irx2l2n wrote

Reply to comment by AnimiLimina in Geothermal May Beat Batteries for Energy Storage: Enhanced geothermal systems are well suited to store excess renewable power as heat. by filosoful

> electricity limited to the power requirements of the water pumps?

Nope. Geothermal stations don't pump up water from depth. You're limited by the ability to throttle the turbines and how much energy you can inject into the geothermal loop.

Edit: there's also only so much heat the surface heat exchanger can use. Typically geothermal plants are run as stable base power loads but its possible to add a 'peaker' capability similar to natural gas plants.

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AnimiLimina t1_irx3h02 wrote

Yes not pumping up but pumping down. The described plant doesn’t use a natural reservoir but a fracked artificial one that need water injected into it. That water injection is what they want to use the excess renewable energy for and it you be equivalent to the charging of the battery.

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El_Minadero t1_irx3wcs wrote

the energy in the system is limited by both how much fluid you pump down and how hot the fluid is. Even for a static flow rate you can just keep increasing the temperature of the injected fluid to increase heat transfer. Even if the steam is supercritically heated, everything should still work.

Infact, supercritical steam is preferrable! It helps catalyze the conversion from CO2 gas to stable calcite minerals, opens up pore space at depth for more efficient heat transfer to the rock reservoir, and is much more thermally conductive than plain water or steam.

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