The coal mining industry is dying (despite what some people would have you think), and it isn’t coming back. But a new startup is breathing life into mining communities with an ingenious design that uses old mine shafts to generate energy. Gravitricity has devised a giant weight system that drops down into disused mine shafts to create power on demand using gravity.
Here’s how it works: “Our patented technology is based on a simple principle: raising and lowering a heavy weight to store energy.” It’s sort of the same principle used to run pendulum clocks, with a weight acting as a power generator to keep the clock running. A weight up to 3,000 tons is suspended in a mine shaft, and energy is generated or expended by lowering and raising the weight.
The system is capable of generating up to 20 MW of power in shafts varying from 500 feet to 5,000 feet. It can last 50 years without degradation, and it’s cost-effective because it uses existing infrastructure. In areas where mine shafts don’t exist and solar or wind isn’t effective, a hole could be dug for the system.
Part of what makes Gravitricity’s design so great is that it doesn’t rely on sun or wind, which can be unpredictable. When you need energy, the weight can drop in a second for power on-tap, or be released slowly for sustained energy. And because it doesn’t use a battery for energy storage, you don’t have the problems of disposal and degradation inherent in batteries.
Gravitricity is still in the development phase, but the startup just received nearly a million dollars from a grant from Innovate UK. If the system takes off, it could mean jobs and money – along with clean energy – for communities that are struggling as coal mines decline.