As renewable energy production increases, so does the need for new storage methods to be used without sunlight or wind,media reported. Now, a Scottish company called Gravitricity has broken ground on a demonstration ground, an innovative new system that stores energy in the form of “gravity” by lifting and dropping huge objects.
When heavy objects are suspended in the air by powerful cables and winches, they can store large amounts of potential energy. When this energy is needed, it can be put down in the wellhead, turned on the winch, and then delivered to the grid. Gravitricity says these units have peak power outputs of 1 to 20 megawatts and can work for 50 years without losing performance. The system can change from zero to full power in less than a second and can quickly release load power in 15 minutes or reduce its speed to a level that lasts up to 8 hours.
To charge the huge mechanical battery, electricity from renewable sources powered the winch and then lifted the heavy object back to the top of the tower. Overall, the efficiency of the system is between 80 and 90 per cent.
Ultimately, such systems should be able to store energy at a lower cost than other grid-scale energy storage systems. The concept sounds very similar to that proposed by Energy Vault, which uses a crane to lift concrete blocks into a tower. Gravitricity, however, seems to have gone further. The company is in the early stages of building a demonstration facility and will test the concept next year. It is understood that the tower is 16 meters high and can lift two 25-ton objects and generate 250 kilowatts of electricity.
“In testing, we’re going to put the weight together to produce full power and verify our reaction speed,” says Miles Franklin, Chief Engineer of Gravitricity, “and then we’ll test the two single weights, one by one, to verify a smooth energy output over a long period of time, and we’ll do other test projects to demonstrate and refine the full capabilities of the system.” “
Huisman, based in the Czech Republic, is understood to be building custom winch and control systems for Gravitricity, while Kelvin Power is building a tower in Leicester, England. These separate parts will be shipped to The Port of Liss in Edinburgh for the construction of the demo machine.
Testing of the facility will begin in spring 2021 and a comprehensive 4 MW project will begin later that year.