gravity
Gravitational batteries store energy using gravity. They are often used to store energy from renewable sources such as solar and wind. For example, a gravity battery might use solar power to pump water upwards on a sunny day and then, on a cloudy day, allow the water to flow downwards (using gravity) and generate hydroelectric power. generate electricity from
The biggest problem with renewable energy is that when the sunlight or wind goes out, so does the electricity. For the time being you need a battery to store the extra power, but not all “batteries” have to be chemical: just use gravity!
curse of bountiful
Let’s say you are not keeping pace with the progress of renewable energy solutions like solar power. In that case, you might think that the main challenge is to get enough electricity from solar and wind, but it’s often the opposite.
When your renewable energy source generates more electricity than you need, you either have to use it or lose it. That’s why grid-connected solar home installations can feed electricity back into the grid, and you can even pay for it!
Off-grid solar home installations use battery arrays to store excess energy so that it can be used at night or when it is cloudy. Specialized deep-cycle lead acid batteries are popular for this use, but lithium-based solutions such as the Tesla Power Wall are becoming a better solution these days.
Whether lead acid or lithium, these batteries store energy using an electrochemical process, but what if you could store and release electricity without the need for an electrolyte?
Gravitational batteries have capacity (energy)
That’s where the idea of the gravity battery comes from. Gravity is the force that keeps us firmly on the ground. That’s why “what goes up must come down.” It takes a huge amount of energy to overcome gravity. You need a building-sized chemical rocket to launch a relatively small spacecraft with few astronauts in orbit.
When you lift an object on the table, the calories you burn to lift it are converted into potential energy, which is now stored in that object. If your cat later drops the object off the table, that potential energy is released when the object falls back to the ground.
A gravity battery converts that potential energy into electricity, but there are many different ways to convert potential energy into electrical energy.
Different types of gravity batteries
gravity
The most common example of a gravity battery today is already in widespread use. Electricity companies pump water into elevated reservoirs to store energy. Later, when they want to access that energy, the water is released and flows through a hydroelectric turbine to another reservoir before reaching there. These water pump turbine systems work well, but there are only so many places you can build them, not to mention that they don’t actually degrade in a useful way.
There are companies like Gravitricity that are manufacturing large gravity batteries that can be installed anywhere, unlike water storage solutions. Their demonstration rig uses two 25-tonne weights in a 15 m (49.21 ft) rig to supply 250 kW of power. The company claims that its technology can deliver up to 20MW and that its systems have a design life of 50 years.
The advantage of these systems is that you can produce a lot of electricity in a short amount of time or over a long period of time. It’s also great as a way to be sure if there is a momentary drop in your renewable energy, as it takes less than a second to reach full power output. Most importantly, it operates cheaper in the long run than lithium battery installations that provide similar performance, so it has attracted the attention of renewable energy producers!
On a smaller scale, there are products like the (now defunct) Gravity Light where lifting a weight provides about 20 minutes of illumination and eliminates the need for the dreaded kerosene light.
Gravity batteries are likely to be a major component of practical and sustainable renewable energy grids, thanks to their simplicity and potential longevity.
