Repeating previous mistakes

The challenge of developing large scale electricity storage has defeated many technical innovators in recent decades

I have been following and contributing to the debate about future energy supplies for 15 years and have seen many opinions expressed that suggest we should spend large sums repeating previous mistakes. 

However, I was quite incredulous when I read the item in the last PE, reporting that the IMechE Energy and Climate Change guru was criticising the government for its failure to encourage energy storage to support intermittent, renewable power sources. The challenge of developing large scale electricity storage has defeated many technical innovators in recent decades. I know of no new schemes that are ready to be adopted on a large scale. Those that are still at the conceptual stage will take decades and many millions of pounds to reach a useful size. Even if some technology proved manageable, the cost would make renewable power sources even less competitive (especially those in remote situations).

In any event, there are only a small number of days each year when high renewable output offers the potential to accumulate energy in storage systems. The majority of the time, it is the inadequate output during periods of high demand i.e. long periods generating less than 100 MW, from installed capacity of 6000 MW, that is their inherent disadvantage.

An example will illustrate the magnitude of challenge with electricity storage. (I should be very interested to have sight of the IMechE equivalent calculations.) A 3 MW wind turbine generating surplus power when operating between midnight and 6am would generate 18,000 kWh. If a typical car battery is 50 amp hour at 12 volt it represent 0.6 kWh, it would take 30,000 car batteries with 300 tonnes of lead to provide storage for one turbine. If storage used compressed gas, pumped water or chemicals, even large quantities of materials would be required because of lower energy density. It is unlikely that the commercial generators would rush to incur this expense, even if the government paid the development costs, without higher renewable subsidies.

Paul Spare, Davenham

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