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Of course, conventional power production pumps CO2 into the atmosphere, which means it is in direct contrast with plans to reach carbon neutrality.
When skies are gray and the wind is low, however, things get a little trickier. Currently we plug the energy gap by burning fossil fuels, such as natural gas.
Some people argue that green hydrogen is the answer, while others are great believers in lithium-ion batteries, which are getting ever bigger in size.
We have a number of renewable energy solutions in place. Solar panels and wind turbines are great, provided the sun shines and the wind blows.
And then there are those who believe we can solve the energy storage problem by harnessing a rather well-known force that is at play all around us: gravity.
What can we do, then, to push the renewable energy revolution forward? How can we ensure we have enough energy when solar, wind, and wave solutions are unavailable?
The idea behind gravity batteries is simple. While we have plentiful supplies of solar, wind, and wave energy, we use it to suspend a colossal weight at a predetermined height.
When supplies of those green energy sources are limited, we release the weight, powering a generator with its gravitational pull.
The idea there is that we pump water uphill while we have surplus power, and then, when needed, we channel it back down through hydroelectric generators.
As a system, pumped hydro works. There are considerable scalability limitations, however, since hydro projects are huge and very expensive.
Gravity batteries are not dissimilar in principle to another high-capacity energy storage solution, so-called “pumped hydro.”
Their specific geographical requirements (a vertiginous terrain and a huge amount of water) also mean that hydro is not going to get us to net-zero.
A certain green engineering start-up in Edinburgh, Gravitricity, is working to make gravity batteries a reality. They already tested a prototype in April 2021.
They gradually lifted a 50-tonne iron weight to the top of a 15-m (50-ft) tower and then released it slowly, powering a series of generators with the gravitational pull.
The prototype was small, but the test was successful. The team was also satisfied that the model could have an operational life of decades—an important consideration.
Gravity batteries also have another benefit over their competitor, lithium-ion batteries, in that they are actually repairable.
One key problem with lithium-ion batteries is that their storage capacity drops irreparably over time. That is to say, they can only be used for a certain, short period of time.
However, according to the company’s CEO, Robert Piconi, this is not a problem because the installations will be built near wind and solar farms far from city centers.
According to one BBC article, there is interest coming in from across Europe, America, the Middle East, Australia, and China.
Gravity batteries, by contrast, are made of individual components that are reasonably easily replaced. They are believed to have a lifespan of up to 50 years.
Couple the limited lifespan of lithium-ion batteries with the concerns about human rights abuses associated with their production, and gravity batteries seem to have the edge.
Energy Vault have received some US$400 million in investment funds and are now ready for a commercial rollout.
Of course, only time will tell whether gravity batteries are the answer to the energy storage crisis we have been searching for. For now though, things are looking good.
Sources: (BBC)
See also: Unlocking nuclear fusion: The game-changing energy revolution
It seems clear that all countries will have to move to some form of green energy storage at some point, and indeed there is considerable interest in the Energy Vault offering.
Other players in the gravity battery game do not see subterranean projects as the future, however. Swiss-based company Energy Vault, for example, prefers to keep its batteries above ground.
There are a number of challenges to be overcome before this can become a reality, but it is hoped that with enough funding a prototype will be in place by 2024.
The team at Gravitricity are now looking into whether it might be possible to extend the weights above decommissioned coal mines.
Their thinking is that we should not build towers to suspend the weights if we can make good use of the Earth’s very own geology.
In a valley in southern Switzerland, they have a prototype that stands 20 stories tall. The prototype can generate enough energy to power thousands of homes.
Today, renewable energy is seemingly everywhere. Planet Earth is lined with wind turbines and solar panels. Of course, these energy sources are only available for as long as the wind, sunshine, and waves are in good supply. So, what do we do when none of these options are available? Researchers are now considering ways to harness gravity to plug the gap.
Check out this gallery to learn all about gravity batteries and their potential.
Could gravity batteries be the answer to energy storage?
An exciting area of renewable energy research
LIFESTYLE Renewable energy
Today, renewable energy is seemingly everywhere. Planet Earth is lined with wind turbines and solar panels. Of course, these energy sources are only available for as long as the wind, sunshine, and waves are in good supply. So, what do we do when none of these options are available? Researchers are now considering ways to harness gravity to plug the gap.
Check out this gallery to learn all about gravity batteries and their potential.