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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Monday, 21 November 2016
Today, 21st November 2016, at 1030 am, UK electricity consumption at nearly 44GW is 3 GW higher than at the same time last week. On this basis, consumption is likely to hit 50 GW at around 530pm tonight.
It's fairly windy, so we are getting about 9.5% of our electricity from wind. Of course at 530pm we will be getting zero from PV, so all those panels we have fitted make no difference to our requirement for peak generation capacity.
To see the data in more detail, go to http://nationalgrid.stephenmorley.org/
Are you telling your friends that you are shifting your discretionary consumption (e.g. washing machines, dishwashers, tumble driers, immersion heaters) out of the peak period from 3 to 8pm? I am!
Comments gratefully received below.
Friday, 4 November 2016
As the graphs for today, 4th November show,the clocks going back last weekend heralded a return to our traditional winter consumption pattern.
Each weekday, we have a daytime plateau from about 830am to 3pm, then a rise of 7GW to a peak at 530pm. Demand then drops back to the level of the daytime plateau by 830pm and continues to fall to a trough at around 4am.
The move from BST to GMT seems to exacerbate this peaky pattern. last Friday, before the clock change,as we can see from the Past Week chart on the right, had a much lower peak than any day this week.
Does the government take the extra required capacity cost implied by this into account when deciding on clock changes?
In any case, we are the ones who can make a difference by time-shifting our consumption.