From NOT A LOT OF PEOPLE KNOW THAT
By Paul Homewood
When we look at lulls in wind power, we usually focus on winter when demand is at its highest. But what about summer when wind power really does drop off for long periods? There is an assumption that this is not a problem because demand for electricity is much lower then and there will be plenty of solar power on hand.
But this might not be the case.
If we look back to last August, for instance, wind power for the month as a whole had an average load factor of 17.4%. From other sources, such as Renewable Obligations, we can estimate the split between offshore and onshore as 18.0% and 14.5% respectively. This is supported by data for the London Array, which suggests that load factors often drop below 18% in spring and summer.
Of course, the real situation is much worse than the monthly averages suggest. During the month of August as a whole, there were long spells when wind power ran at 2 GW, and often much less. For example, between the 10th and 15th power dipped to an average of just 1.6 GW.
Total wind capacity at the time was 28.4 GW, so 2 GW would represent a load factor of just 7%.
So now let us fast forward to 2030, when we are targeting 40 GW of offshore wind, 30 GW of onshore and 40 GW of solar.
Total power demand averaged 26 GW last August, and based on the average monthly load factors we get this projection for 2030:
Solar, by the way, is based on a load factor of 15.5%, the average in Q3 last year.
So we have a total of 17.5 GW from wind and solar, which as we have seen could easily dip to 10 GW and below during those wind droughts. Nuclear and biomass should provide another 8 GW, so even on the average load factors, supply will be very tight. But last August there were 20 days when wind output was below average:
What are we supposed to do then, even assuming we have enough battery storage to meet demand at night.
The situation will of course be exacerbated with the extra demand from EVs, which the government wants us to charge at night, when there is no sunshine!
The chart below gives the profile of demand for August 1st:
Demand is at its lowest from midnight to 7.00 am, and peaks between 4.00 pm and 11.00 pm, hitting its highest at 7.30 pm.
Bearing in mind that nuclear and biomass might provide 8 GW, whilst wind power might drop to 4 GW or less, where will the electricity come from to charge our cars up? Or anything else for that matter?
This crazy situation highlights one more myth – that surplus wind power in summer can be used to produce hydrogen, for use in winter. As we can see, in a typical summer month there is not enough power on the grid to meet demand, never mind store.
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