AnimiLimina t1_irwlph6 wrote on October 11, 2022 at 4:13 PM

Isn’t you storage capacity of excess electricity limited to the power requirements of the water pumps? And isn’t that only a small amount of your total energy output as your output is created by heating water to steam and not like in a pumped hydro from the work of the pumps.

So it’s not so much a battery in a sense that your output is the input minus losses, it’s a baseline power plant that is shut down intermittently to increase the output from net to gross by running your pumps with excess power at a earlier date.

If I’m not missing something here I’m very sceptical that this is a battery as much as a fast response generator with a efficiency boost by using excess renewables.

If anyone knows more please tell me, the article is not really useful.

El_Minadero t1_irx2l2n wrote on October 11, 2022 at 6:02 PM

> 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.

AnimiLimina t1_irx3h02 wrote on October 11, 2022 at 6:08 PM

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.

El_Minadero t1_irx3wcs wrote on October 11, 2022 at 6:11 PM

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.