By Paul Homewood
Currently the National Grid shows demand for natural gas peaking at about 420 mcm (million cubic meters/day) in the UK. Over the day as a whole, it will probably average out at around 350 mcm.
How much is this in energy terms?
1 mcm = 10.55 GWh, so 350 mcm equals 3.69 TWh/day, equating to 154 GW. At peak of 420 mcm, this goes up to 185 GW.
About a quarter of this goes for gas fired generation, but even assuming this is no longer needed, these amounts would still be massive.
So how can so much energy from natural gas be replaced in a decarbonised world?
If we were to opt for full electrification, we would need to quadruple current generating capacity, clearly not a practical option, even before we addressed the problems of surplus generation in summer.
To produce this from wind power would require an additional 462 GW of nameplate capacity, assuming 40% loading and sufficient flexibility for period of intermittency. In essence, all of this would be idle in summer months, effectively doubling its cost.
What about hydrogen?
Assuming an energy efficiency ratio for electrolysis of 75% (let me know if there is a more accurate figure), daily demand of 3.69 TWh would need input of 4.92 TWh, equivalent to 205 GW. (And this assumes we can manage intra day peaks in demand).
As this electrolysis would have to use wind power, with an capacity factor of 40 % say, that would require offshore wind capacity of 512 GW, on top of other requirements. We currently have about 10 GW!
This capacity would have to run flat out in winter months, and idle for summer, as we have already seen that the amount of natural gas storage is tiny in terms of seasonal requirements.
Finally there are heat pumps, which have a higher energy efficiency than burning gas or electrical resistance heat. However, at these period of peak demand in winter, heat pump efficiency is at its lowest. Given that heating only accounts for less than a half of natural gas consumption, additional capacity needed would still be around 150 GW.
Whenever capacity issues are raised, the red herrings of storage, smart meters and EV to Grid are usually thrown in. These are utterly irrelevant, as they only shuffle demand around between different times of day.
As the above analysis shows, you cannot get a quart into a pint pot. No matter how you cut the cake, we still need huge amounts of electricity to replace the loss of natural gas from our energy mix.
And that’s before we even get onto electric cars!
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January 10, 2021 at 01:18PM