Weights show the way to cheap stored power

(Eco Business, 25 Nov 2019) New ways to generate renewable electricity will offer cheap stored power and a solution to balancing supply and demand.

Finding effective ways to store energy until it’s needed is a major obstacle for the renewable electricity revolution, but two new mechanical systems mean cheap stored power could soon be widely available.

Cheaper than batteries, both have the virtue of being able to produce full power within a second of being switched on. And the energy they generate can also be stored for months without any loss of power.

Although developed by different teams completely independently and with different markets in mind, the two systems have great similarities. They use surplus electricity from renewables (wind or solar power) to winch a weight up a mineshaft or a mountain. When there’s a need to generate more electricity, the weight is released to fall to the bottom again, turning turbines attached to it by cables and so providing instant power to the grid.

One system envisages helping populations on isolated islands or in dry places where conventional hydro-electricity is not available, but where surplus sun and wind power can haul loads of sand or water up thousands of feet of mountainside.

The system, combining a technique known as Mountain Gravity Energy Storage (MGES) with hydropower, has been proposed by IIASA, the Austria-based International Institute for Applied System Analysis, and is described in the journal Energy. It allows the energy to be stored for months.

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Eco Business, 25 Nov 2019: Weights show the way to cheap stored power