A New Age for Geothermal
taylorvich writes:
https://newatlas.com/energy/quaise-energy-reaches-back-push-geothermal-power-forward/
Quaise Energy has been dazzling us lately with its bleeding-edge plans to tap super-deep, superheated steam as a global power source. Now, the company's reaching back over a century to adapt yesterday's technology for tomorrow's energy.
Quaise Energy can't be accused of being unambitious. Geothermal power has a tremendous potential for providing humanity with unlimited energy for the foreseeable future, but it suffers from the fact that it's only really practical in a few places where the sources of subterranean heat are close enough to the surface to be easily tapped.
What Quaise Energy wants to do is get around this by going straight to the source. In other words, instead of waiting for the heat to come to us, we go to the heat. Using a traditional rotary drill bit and a gyrotron-powered energy beam to burrow up to an incredible 12.4 miles (20 km) to a region in the Earth's crust that is heated to 500 C (932 F).
Not only would this make geothermal power accessible in almost any place that isn't a high mountain chain, it also brings a bonus. At this depth and that heat, water is heated and squashed to the point where it is supercritical. That is, when the temperature is above 373.9 C (705.2 F) and the pressure is over 218 atmospheres, the water enters a state where it is neither a liquid nor a gas. Instead, it behaves as a single homogeneous fluid and shifts from being an almost-liquid to an almost-gas depending on the current conditions.
When in a supercritical state, water has lower viscosity than liquid water, yet higher than steam, allowing for improved flow dynamics in turbines and heat exchangers. It also has lower thermal conductivity than liquid water but higher than that of dry steam, aiding heat transfer. It expands very rapidly when depressurized, and its specific heat capacity changes dramatically near the critical point, allowing for efficient energy absorption. This gives it higher thermal efficiency and the ability to hold 10 times more energy than regular water or steam.
If that isn't enough, it can even clean the pipes it's flowing through thanks to its ability to dissolve salts and other impurities.
[...] The question is, how to make it work? For the answer, Quaise went back to the first geothermal plant, Larderello 1, that opened in Italy in 1914. Instead of having one loop with water going into the Earth and then returning steam to the surface, this used two loops of water with one collecting the heat deep underground and the second swapping the heat from the first to bring it to the turbines on the surface.
[...] "The applications are diverse, from power plants to regional heating to domestic ground-source heat pumps, and there are a lot of fresh new eyes on the field," said Daniel W. Dichter of Quaise Energy. "There's a renaissance happening in geothermal right now."
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