Solar, wind
and other renewable energy sources reduce consumption of fossil fuels but also
pose challenges to the electrical grid because their power generation
fluctuates, heightening the need for better battery technology to store their
energy until it's needed to feed the grid.
Existing
energy storage technologies for the electrical grid, including more
conventional lead-acid batteries and pumped hydropower – in which water is
pumped to a higher elevation and later released to flow down through turbines
to generate electricity – are not very efficient.