With the advancement of technology and plummeting costs, the only real flaw in renewable energy sources is their interpretability. What to do in a city of tomorrow that gets all of its energy from solar panels – when night falls? A similar problem is found with wind turbines when the wind stops even for a moment.
Pictured: A solar facility in the desert.
For smaller objects such as vaccation homes or street lights, rechargeable batteries are used. But for entire cities and industrial zones traditional chemical batteries would be impossible; too expensive and with too little capacity. To find a solution, it is first necessary to know how any power plant works. Coal, oil, gas or even nuclear fuel in classical thermoelectric power plants is used to heat up water and turn it into steam. Steam, of course, takes up more space than water (that’s why a kitchen pressure cooker is under pressure when its heated). Pressured like that, the steam goes trough a pipe where it rotates the blades of a turbine. And from a turning turbine we easily get electricity.
Pictured: Water heats up and exits as steam, which rotates the propeller and creates electricity. A similar process happens in thermoelectric power plants, except the paper windmill isn’t held by hand.
The solution for solar power plants? Simply use the suns energy to heat up underground pools of salt. Simple kitchen salt melts at 800 C, and there are other kinds of salt with different characteristics.
At night (or on a cloudy day) melted salt is pumped trough pipes hugging a water boiler and just like in an ordinary fossil fuel power plant, the water is heated and water steam rotates the turbine and makes electricity.
But how much are melted salt pools practical? Well, they have been on the market for some time now, the salt doesn’t have to be changed or refilled during the power plants work life and once heated pools loose about 0.5 C of heat every day until used. The next plan is to replace salt with molten sand. So basically, creating a power plant that works on lava. Pretty impressive.