There is plenty of green electricity to be created when the wind blows, the sun shines, and the waves roll. But what do we do when the sky darkens and the weather is calm?
According to some energy experts, a greener future will need a concentration of ever-larger lithium-ion batteries. Others say that green hydrogen is the best chance for humanity.
Then there are some who gamble not on chemistry, but on gravity, the unstoppable force that surrounds us all. Gravitricity, a green engineering start-up located in Edinburgh, is aiming to make this a reality.
The company successfully tested its first gravity battery prototype in April of last year, which consisted of a 15-meter (49-foot) steel tower suspended from which a 50-tonne iron weight was suspended.
Electric motors lifted the big metal box inch by inch into the sky before gently lowering it to the ground, powering a series of electric generators with the downward drag.
« We demonstrated that we can manage the system to increase the life of specific mechanical components, such as the lifting cable, » Macpherson adds.
« The system is also built in such a way that individual components may be simply replaced rather than the complete system being replaced over time. As a result, there’s a real possibility of having a decades-long operating life. »
Energy Vault is ready to begin commercial deployment of its technology, which has been tried and tested and has earned $402 million (ÂŁ325 million) in funding.
For that, the business has created a modular structure named « EVx » that stores thousands of weights on a trolley system, which is a little more visually pleasing than the angular Swiss version.
That may be optimistic thinking, but all countries will have to embrace some type of green energy storage sooner or later.
This comprises long-term storage, such as turning down the lights for a longer period of time when renewable energy is low, and brief bursts of power as needed by the grid.
The second reason has to do with a significant issue that green energy providers face: electrical systems were built to function with traditional power plants, not renewables.
« The grid must be balanced at all times, » says Thomas Mostyn, an electrical engineer at the University of Edinburgh.
« Operators are always trying to balance supply and demand, but it’s difficult when you’re dealing with something as intrinsically intermittent as wind or solar, which may fluctuate dramatically. »
The massive weight of a gravity battery, along with its exceedingly slow fall, provides a tremendous amount of torque, allowing the system to supply full power practically instantly.
This makes the technology particularly good at keeping the grid in balance, decreasing the danger of major infrastructure damage and blackouts by smoothing out second-by-second oscillations.
It’s hard to say how many of these will come true. It is undeniable that the world requires bold and innovative climate solutions.
There are no silver bullets on this front, but gravity batteries, with their ability to harness a genuinely endless, ubiquitous force, are virtually destined to play a part.
