As the world transitions to renewable energy such as wind and solar, a pressing problem begins to surface. How do you power cities with renewables when it gets dark or the wind stops blowing? As governments decree that coal and natural gas generation is undesirable, what alternative energy generation or storage systems are available?
A serious issue is how do we store energy? Batteries similar to those used in electric cars are bulky and have their own environmental drawbacks. Some experts have proposed large-scale lithium battery “farms,” some the size of city blocks, to store electricity for use during periods when generation can’t meet demand.
There’s a technology that I’ve only heard of recently that can help to solve the storage problem: gravity batteries.
According to Wikipedia: “A gravity battery is a type of electricity storage device that stores gravitational energy, the energy stored in an object resulting from a change in height due to gravity, also called potential energy. A gravity battery works by using excess energy (usually from sustainable sources) to raise a mass to generate gravitational potential energy, which is then lowered to convert potential energy into electricity through an electric generator.”
An example, using a car to represent stored energy, is pictured below. While the sun is shining, the car is pushed up the hill using solar energy. At the peak of the hill, the car has potential energy. When the sun sets, the car descends the hill, expending its energy to generate electricity.
Now, imagine that, instead of a car, it’s a very heavy weight that’s suspended by a cable in a tower. Renewable energy lifts the weight to the top of the tower and then later in the day the weight is released and descends slowly. During the descent the cable runs a generator that produces electricity.
Gravity batteries don’t just have to use heavy weights. The most common example of a gravity battery today is also one in widespread use already. Power companies and water companies pump water into elevated reservoirs to store energy. Later, when they want to access that energy, the water is released and flows into another reservoir, flowing through a hydroelectric turbine before getting there.
Believe it or not, you could build your own hydro gravity battery like this guy.
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One of the big downsides of renewable energy is its lack of continuous energy generation. Natural gas, coal and nuclear power plants can run 24 x 7 but environmental groups have declared them undesirable, even as a backup to renewables.
By their very nature, solar and wind power cannot provide power generation 100% of the time. Gravity batteries of all types can supply electricity to the power grid when the sun don’t shine.
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“In my opinion, a society that aims for equality before liberty will end up with neither equality nor liberty. A society that aims first for liberty will not end up with equality, but it will end up with a closer approach to equality than any other kind of system that has ever been developed.”
- Milton Friedman, ‘Milton Friedman Speaks: The Role of Government In A Free Society’.
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Ahhhhahahaha! (Hat tip to Mike G.)
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