A firm that plans to use gravity to generate electricity has passed a key milestone in the development process.

Edinburgh-based Gravitricity is running a £1 million project to demonstrate the potential of its technology which will involve harnessing the power generated when large weights are lowered.

It has raised the prospect of the technology being used around the world, in generating systems installed in disused mine shafts.

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The demonstration project will feature a 15-meter high tower which was installed at Forth Ports’ Prince Albert Dock in Edinburgh.

Gravitricity will complete a two-month test programme. The company expects this will its modelling and give it valuable data in advance of the firm starting work on its first full-scale project in a mine shaft later this year.

The company was founded by technology consultant Charlie Blair.

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Mr Blair has said Gravitricity's technology involves using excess electricity to raise a weight in an underground shaft to charge the system, and then lowering the weight to discharge electricity back to the grid.

Gravitricity will use a £640,000 grant from the Government’s Innovate UK programme to help fund work on the demonstration project.

It is working with winch specialist Huisman.