Summary Electricity Storage
In a world in which the need for electricity keeps increasing year after year, electricity storage has become a priority concern, as it offers the only solution for balancing supply and demand. With more and more electricity generated from renewable energies, the intermittent nature of those sources has to be addressed. Clearly, to avoid power outages, it is crucial to store excess output so that it can be reinjected into the grid when needed. Large-scale storage solutions are available and include artificial reservoirs in the mountains, compressed air storage and batteries. However, researchers over the world are working on developing more versatile systems. One interesting avenue - power-to-gas - uses electricity to create hydrogen or methanol, which can be stored to later release energy when burned or used in fuel cells. Although it still poses a challenge, home energy storage is expanding. As batteries continue to improve, mobile storage systems are becoming accessible to everyone. Lithium-ion batteries are the big winner in the mobile sweepstakes, but in France they face competition from lithium-metal-polymer batteries, which are used in the Autolib' service's electric Bluecar. This competition signals the emergence of a new market for stationary storage applications. Whether for collective or individual solutions, growth in the storage market is set to be exponential. Nevertheless, one major drawback looms in the background: rare earths, which are used in many of the solutions, are produced in a limited number of countries, including China, and the known volumes of commercially viable reserves will only last for a few decades at the current pace of production.