Friday has arrived, and the 'A Taste of Science for the Weekend' corner is here again - number 103.
This time - what is a supercritical fluid, and could humanity's future be hiding deep underground.
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Earth is a giant battery.
Beneath our feet, a molten mass slowly churns at temperatures of thousands of degrees, the result of gravity compressing it and radioactive decay. A small portion of this energy reaches Earth's crust, providing an infinite reservoir of energy that can be converted into electricity.
Geothermal power plants rely on pumping this heat up from deep underground using a conducting fluid. The fluid heats up and is pumped back to the surface while still scorching hot, turning into steam that spins a turbine to generate electricity.
Applying this method is mainly feasible in certain locations on Earth. In these areas, there's a rock layer with cracks that water can penetrate deep down and heat up significantly. As the water heats up, it rises toward a natural reservoir, and cold water takes its place.
In places where these conditions don't occur naturally, you need to drill through layers of hard rock to reach the required depth. During drilling, the immense heat deep underground softens and warps the drill bits, dissolved minerals in the ground crystallize on their way up and clog the pipes, and steam pressure causes heavy wear on the system and can even break it apart.
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The insatiable hunger for energy that characterizes the AI revolution has led to a renewed boom in this field, and tech companies like Google and Meta have already signed long-term agreements to purchase this kind of energy.
To increase output, new methods have been developed in recent years for extracting energy even from areas lacking the necessary natural conditions. In one method, high-pressure water is injected into a hard rock layer deep underground until cracks form that water can penetrate and heat up in.
In another method, metal piping is inserted deep underground in a closed loop, and the water in the piping absorbs heat through the pipe walls. This method is more stable and reliable but also more complex to carry out.
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Another interesting method is based on supercritical fluid.
A supercritical fluid is a fluid at such high temperature and pressure that the distinction between gas and liquid ceases to apply to it. It's dense and holds a lot of energy like a liquid, but its viscosity resembles that of a gas, allowing it to penetrate even tiny cracks.
The fascinating fact about supercritical fluid is that it doesn't form and break internal hydrogen bonds the way regular water does, and can therefore carry between 5 and 10 times more energy.
In certain places on Earth, there are underground reservoirs of water in this state, but no drill bit exists yet that's tough enough to reach them and survive the scorching temperatures along the way.
To solve the drilling problem, unconventional methods are currently being explored, such as drilling using powerful electrical pulses, jets of hot gas, and even electromagnetic waves.
Drilling using electromagnetic waves relies on high-energy millimeter wavelengths. The energy of these waves melts and vaporizes the rock, and recent experiments have shown that this method can drill up to 50 times faster than conventional drilling.
If an economical way is found to produce energy this way, it will be possible to build a power plant that supplies completely green energy anywhere on Earth, and the world as we know it will be changed beyond recognition.
In the video: a geothermal power plant in Iceland.
Happy Shabbat 😊
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👋 Hi, I'm Shlomo Strauss and my posts are not written by artificial intelligence.
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