News Brief

Wind Power A Better Energy Investment Than Storage

It’s energetically cheaper to waste wind energy than to build batteries to store it, according to a new study.

Researchers suggest there are times when wasting wind energy makes sense. Building so many turbines that energy is wasted at peak production may be more energy efficient than building storage for fewer turbines.

Although batteries make sense for storing solar energy—compensating for intermittent production that does not always align with peak demand—it’s more energy-efficient to simply put up more wind turbines rather than store their excess production, a new study published in Energy and Environmental Science suggests.

Stanford University researchers compared the energy investment needed to build different wind and solar storage technologies and then evaluated energy stored on electric energy invested (ESOIe), the ratio of electrical energy stored over the lifetime of a storage device to the amount of embodied electrical energy required to build the device. Compressed-air energy storage and pumped-storage hydroelectric systems both had ESOIe values of more than 700 kWh:1 kWh, while lithium batteries had a much lower ratio of 32kWh:1 kWh.

But if building the large facilities needed for pumped hydro or compressed air storage is not an option, the study concluded, battery storage makes sense for solar energy storage but not for wind. That’s because of the higher embodied energy of photovoltaics, due in large part to the intensive process of purifying silicon. For wind, the authors conclude, “Attempting to salvage energetically cheap power…using energetically expensive batteries is wasteful from a societal perspective.” Building enough turbines (or more transmission lines) to meet demand at lowest production may create massive surpluses that go to waste at high production, but it would still be more energetically efficient than using current battery technology, according to the study.

The researchers prefaced their conclusions by acknowledging that energy storage has other auxiliary functions that should be taken into account, such as stabilizing the electric grid and providing back-up power.

Published November 1, 2013

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