Wednesday, 23 November 2016

How much storage would each domestic PV installation need to provide to make an impact on peak demand?

There are now over 900,000 solar PV installations in UK.
Our peak electricity demand of 52 GW in the last twelve months only exceeded 50 GW for a few hours, and never for more than an hour at a time.How much storage would each PV installation need to provide to eliminate this peak, and thereby contribute to the cost of handling the electricity they provide in summer when it is not much needed?
For the sake of simple arithmetic, let's be generous to the PV owners.
Let's only ask them to contribute 1.8GW for one hour, which is 2 kWh each. They might need to do this ten times per year.
A 100 amp hour 12volt leisure battery costs about £75 retail. So a couple of these would do the trick, plus associated electronics, say £450 total cost. An order for 900,000 might bring the unit costs down a bit.
At ten cycles per year, the batteries would last for many years, possibly as long as the solar installation.
In the context of a £4500 cost of a typical domestic PV installation, this seems a reasonable price to pay.
In the big picture, £450 million or thereabouts to save 1.8 GW of peak generation capacity is a bargain.

Given the large scope for peak chopping, should we ever seek to have more than 50 GW of hard capacity on the system?

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