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The Scottish company Gravitricity is planning a project to store surplus energy from renewable energy in the Port of Leith. A prototype installation connected to the 250 kW grid will be carried out to test its ability to stabilize the grid. The system consists of a 16m platform that operates at a depth of up to 1500m.
Scottish company Gravitricity has developed a gravity energy storage system that it says is ideal for storing solar and wind energy.
A 16m high platform uses excess clean energy to lift a mass on a 150-1500m axis and discharges the electricity thus stored by releasing the mass to spin an electric generator.
Gravitricity said the mass used can range from 500 to 5,000 tons, and the discharged electricity could power approximately 30,000 homes for two hours.
The system has sophisticated winches and a control system that the company says can lower the mass very quickly, making it flexible enough to stabilize power grids at 50Hz and respond to energy demand in less than a second. . "Our technology has the response time of lithium-ion batteries," the company said.
The Edinburgh-based company said the system offers a 25-year service with no performance loss or cyclical degradation and can be located anywhere, including in city centers. Additionally, the developer noted that the disused mine shafts are ideal locations.
Pilot project
Gravitricity will begin construction of a £ 1 million (€ 1.14 million) pilot project in October at an industrial site in Port of Leith, Scotlands largest deep-water port.
Completion of the project is scheduled for December. The 250 kW prototype will be connected to the ports electricity grid and its response speed will be evaluated to stabilize the grid. "The demonstrator at the Port of Leith will allow the technology to be tested on a much smaller scale, using an above-ground structure," the company said.
The pilot system will use two 25-ton weights suspended by steel cables. "This two-month trial program will confirm our model and give us valuable data for our first large-scale 4 MW project, which will begin in 2021," said Miles Franklin, senior engineer at Gravitricity.
The tower for the Port of Leith facility will be supplied by UK company Kelvin Power and the winches and control system will come from Huisman, a Dutch manufacturer of lifting, drilling, pipe laying and mooring systems.
The project is supported by the government agency Innovate UK with a grant of £ 640,000.
Storage by gravity
The American company Energy Vault unveiled gravity-based storage technology that was based on a 35-ton crane and concrete blocks a year ago. That system was said to take into account volatility in energy supply and demand, weather conditions and inertia, according to its developer, and was backed by a $ 110 million (€ 102 million) investment by Japanese lender SoftBank in August. "Energy Vault will demonstrate the first 35 MWh storage tower in northern Italy in 2019," announced the Japanese consortium at the time.
The Austrian research organization, the International Institute for Applied Systems Analysis (IIASA), suggested last year the storage of gravitational energy for locations with low energy demand . In that case, the technology involved two cranes on the edge of a mountain from a storage location at the base and an electric motor at a top storage location to transport a solid mass of sand or gravel. |
