By Paul Homewood
This is a follow up to yesterday’s post on peak gas demand.
About 40% of natural gas consumption is for residential heating, which accounts for most of the peaking in winter months. Another third goes to electricity generation, which in our Net Zero world will not be needed.
As homes switch to heat pumps, gas consumption will fall and electricity use will rise. However, heat pumps are more energy efficient than gas boilers. Typically air source heat pumps will use a third of the energy of a gas boiler to produce the same amount of heat.
Both this factor and the issue of CCGT plants mean that electricity demand will not increase as much as gas will fall – similarly with peak demand.
To see what this means, I have analysed the National Grid’s Future Energy Scenarios (FES), published in July. They have four scenarios, but the most relevant one to this topic is Consumer Transformation (CT):
Other scenarios assume more use of hydrogen.
Their modelling for 2035 shows that gas consumption will fall from 878 to 402 TWh by 2035:
Numbers are based on the following heating mix:
Note that there are an extra 10m heat pumps, but 15m gas boilers remain. There will be 3 million of the more efficient ground source heat pumps, which sounds wildly over optimistic, given the cost and lack of garden space in most homes.
Also FES assume that homes will be 20% more energy efficient, again a highly unlikely scenario, unless hundreds of billions are spent insulation.
Finally it is assumed there will be 26 million electric cars on the road by 2035.
When these assumptions are all built in, FES reckon that electricity demand will peak at 87 GW, compared to around 50 GW now. However this is not peak at all, only the peak in an average winter. A more realistic projection would be 100 GW.
Untangling the FES workings, it would appear that FES have assumed a heat pump efficiency factor of 400%. But at the coldest times, a figure of 250% at best is more likely. Plugging these more realistic assumptions in would mean that those 10.2 million heat pumps will add approximately 35 GW to peak demand, about 10 GW more than FES projects.
Exclude that 20% energy efficiency saving, and you can add another 10 GW on.
All in all, we are probably looking at peak demand for electricity as high as 120 GW by 2035. And it will be much higher still if homeowners, who cannot afford heat pumps, opt for conventional electrical resistance heaters.
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December 12, 2022 at 11:01AM
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