By Paul Homewood
John Brown has sent me an analysis he has carried out of how much wind power capacity we would need to run the grid, assuming surplus wind is converted to hydrogen, which is then used to produce electricity in turn.
John has downloaded all of the BMRS data for last year, ie the wind generation and demand data at 5-minute intervals. His model then calculates how much wind capacity we would need to meet demand at all times of the year.
Demand averaged 29 GW last year, but this amount is incidental. Obviously even in a Net Zero future there will be other sources of power, such as nuclear. Equally demand will be much higher in years to come. But what the model enables us to do is to quantify how much wind capacity we would need for any given level of demand, assuming there are no other sources that can be switched on and off to cope with the intermittency of wind power.
The model comes up with the following calculations:
- Total demand – 262 TWh
- Actual wind generation in 2022 – 62 TWh
- Wind generation needed to meet demand – 370 TWh
In simple terms, we would need six times as much wind capacity as we have currently, which is about 28 GW. In other words, 168 GW, although this could change slightly according to the mix of on and offshore.
The reason why the total generation needed, 370 TWh, is so much higher than demand is the hopelessly inefficiency of the hydrogen process. John has assumed that electrolysers work at 52% efficiency, and that burning hydrogen in a thermal generator works at 40% efficiency. Both assumptions seem reasonable. In other words, the efficiency rate for the full cycle is 20.8%. In simple terms, you need 5 units of wind power to make 1 unit of power from hydrogen.
With this inefficiency, it is little wonder that making electricity from hydrogen is going to be ridiculously expensive, even before the costs of building and running electrolysers and new hydrogen power plants is are factored in.
The model assumes that we start the year with 20 TWh of hydrogen in storage – ie the amount of hydrogen required to generate 20 TWh of electricity. This was needed to ensure there was sufficient hydrogen to meet wind shortfalls. Even then, the hydrogen storage fell to 0.79 TWh at one time of the year. We would clearly need much in store to cope with the really still winters we get from time to time – maybe 30 TWh.
Others may be able to quantify this in terms of the volume of storage needed, but it seems to me to be colossal.
Based on the cost of Hornsea 2, £6 billion for 1.3 GW, John reckons we are looking at close to £1 trillion to build the wind capacity required, with a necessary safety margin built in. And remember that these wind farms will only last around 15 to 20 years, so the whole cycle will have to occur again and again.
And this just addresses current demand, which could double by 2035. Even allowing for a contribution from nuclear and hydro, we could still be looking at needing 500 TWh a year from wind power, meaning close to 400 GW of wind capacity. Put another way, we would have to start building wind capacity at a rate of 30 GW a year.
It ain’t going to happen!
via NOT A LOT OF PEOPLE KNOW THAT
June 21, 2023 at 09:16AM
Iowa Climate Science Education 