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Battery Wastage: Why battery storage for rooftop solar doesn’t pay

Consumers warned to avoid battery storage for rooftop solar systems

London 16 April 2018. Rechargeable batteries are said to be a way to extend the appeal of rooftop solar installations, storing the energy generated during the day for use at night. Home energy storage looks set to become big business: Tesla has already entered the marketplace, looking to apply its expertise in batteries to generate a new source of income. Other big-name motor manufacturers are expected to follow.

However, a new paper published by the Global Warming Policy Foundation (GWPF) reveals that consumers are in danger of being fleeced. The paper’s author, power engineer Dr Capell Aris, has examined the economics of battery stores and finds that in the UK their high cost means that they will never pay for themselves. As he explains:

“The price of  batteries is relatively high, but the possible savings from adding them to a rooftop solar installation are quite limited, particularly as a fraction of the typical electricity bill.  When you add up the costs and benefits, it is quite clear that they are a waste of money.”

That could change if the price of batteries were to fall dramatically, but the gap between costs and benefits is currently so wide that this is unlikely in the near term. As Aris explains:

“There is no doubt that battery prices are falling, but even if we make some fairly optimistic assumptions about performance, prices would have to fall by another 50% just to break even. They would need to come down even further than that to give a financial return. It’s hard to see this happening any time soon. Battery storage for rooftop solar is simply not an economic prospect, and will likely remain that way.”

Click for full paper