Google développe un projet de stockage d'énergie renouvelable (en anglais)
In 2010, Google founded a research and development facility called “X”. This company describes itself as a “moonshot factory”, a moonshot being a project or a proposal that addresses huge problems, proposes a radical or unusual solution, and uses breakthrough technologies.
In this context, Google recently launched the Malta project, in which the huge problem is represented by the mismatch between the availability of renewable energy and the moment when it is needed, the radical solution is a grid-scale energy storage technology that can “time shift” renewables, and the breakthrough technology would consist in storing electricity as heat in giant tanks of molten salt.
More precisely, X-company is currently developing a system which involves two gigantic vats containing molten salt and two other vans containing ultracool antifreeze. The whole system relies on heat pumps: when supplied with electricity, a heat pump sends hot air into the salts vats and cold air into the antifreeze vats. There, the energy can be stored for hours or even days before it needs to be used. Once a switch is flipped, air from the two sets of vats can be mixed together, and the mixing of hot and cold air creates powerful gusts that spin a turbine, producing electricity.
Unlike lithium-ion batteries used until now to store energy, this system can store much more energy and can be built in more places at less cost. This technology is currently in development. The next step is to build a megawatt-scale prototype plant which would be large enough to prove its efficiency at commercial scale. The energy storage market could see about USD 40 billion in investment by 2024, according to Bloomberg New Energy Finance, which estimates that roughly 790 megawatts of energy were stored last year and overall capacity is expected to hit 45 gigawatts in seven years.