New report by Bill Ponton, “The Rising Cost of Wind Energy: A Fact Check,” contains a short but concise section addressing the question of energy storage. Here is the question that needs to be addressed: If, after the first round of over-construction, the addition of new wind energy sources adds little useful energy and most of the added generation ends up being wasted. “cut down”, then why not add some batteries or other energy storage to the system? Wind energy proponents argue that some form of battery can store excess electricity production until it is needed, and everything then balances out in perfect equilibrium.
Is there any problem here? Ponton does simple calculations with its UK 2022 spreadsheet to know how much storage in GWh will be needed and what its functional characteristics should be. His results are very similar to those of the comparison exercises performed by Roger Andrews for California and GermanyAnd Ken Gregory for USA
The main problem identified by Ponton is the same problem identified earlier by Andrews and Gregory. Before you factor in the very high cost of storing electricity, there is another big hurdle, which is the ability of the wind supply to generate electricity that varies with the seasonal pattern. Therefore, in order to supply electricity to match electricity demand, the storage balance must be built up over a six-month period to a very large extent, and then discharged over the next six-month period.
Ponton considers a case for a tripling of the UK’s rated wind power generation capacity, from the current 28 GW to 84 GW. Average usage is around 35 GW and peak usage is around 45 GW; so the rated wind capacity of 84 GW provides plenty of backup power to charge the battery when the wind blows at full capacity, or even close to that.
The next Ponton assumes the purchase of 12,000 GWh of battery storage. With that said, here’s a chart of his additions and withdrawals from the archive based on UK 2022 data:
You can immediately see that the winds are much stronger and more stable in Spring and Autumn than in summer. Then here’s a graph of the storage balance, assuming you initialized the system with no storage on January 1, 2022:
The battery accumulates up to 12,000 GWh around March, then discharges it until September, and then starts building a backup storage balance starting in October. Under 2022 specific weather conditions, 12,000 GWh of storage is enough for year use, with a September minimum of over 1,000 GWh.
For those readers who don’t remember Andrews and Gregory’s previous results, here’s Andrews’ comparison chart for California based on 2017 data:
And here’s Gregory’s chart for the US with two different lines representing 2019 and 2020 data, both showing a characteristic seasonal pattern:
All of these results illustrate the point that energy storage units to complete the task of using excess wind output must have a moderately large capacity. And capacity to charge and discharge in a large annual cycle. Ponton’s comment:
Non-existent batteries are supposed to store such long-term energy.
Pumped water storage is at least theoretically capable of charging and discharging to meet this criterion of the annual cycle, but it also has the problem of enormous cost and, even more importantly, a complete lack of suitable location. lifebuoy:
If there were UK locations for pump storage, it would cost $2 trillion. The UK will have to build 500 pumped storage facilities with a capacity of 24,000 MWh [each]. Each will be about the same size as the largest existing facility in Bath, VA, with a construction cost of $4 billion.
My own comments: Ponton’s illustration of 12,000 GWh of storage needed for year use represents around 14-15 days of average UK usage. That’s pretty low compared to the amount of storage Andrews and Gregory found needed for California and the entire US, which is between 25-30 days of average use. I think the difference is explained by the following:
- Andrews and Gregory assume that the renewable energy mix of wind and solar power facilities is in proportion to what is currently available in California and the entire United States, respectively. Ponton assumed only the wind as a renewable addition. This makes a significant difference because solar production is much more seasonal than wind power and operates at a much lower average annual power factor. (Note that both California and the entire US have a significant solar mix. Since solar is strongest in the summer, the peak of the annual charge/discharge cycle in the Andrews and Gregory spreadsheet is on year-end than in the Ponton spreadsheet. But the annual cycle pattern is essentially the same.)
- Ponton assumes that the kind of “other” generation that currently exists in the UK remains the same. This “other” category includes a combination of things like coal, nuclear, hydro and biomass, most or all of which might be on the radar of environmentalists. As shown on Ponton’s chart, the “other” category operates at a fairly steady rate of around 10 MW, accounting for almost a third of average UK usage as “background load” generators. The continued existence of this “other” category significantly reduces the seasonality of annual production compared to where wind is expected to take over all power generation.
- Ponton makes no assumptions about losses during storage, such as losses from each charge/discharge cycle, or dissipation losses due to energy stored in batteries for months on end. Since the price he paid was absurd before adding these extras, he could be forgiven for not continuing to beat that horse to death.
Ponton doesn’t charge a price for 12,000 GWh of storage using lithium ion batteries, which makes sense since those batteries aren’t capable of storing energy for 6 months to a year without serious loss. But just to give an idea, at $250 per kWh (lower than current grid-scale storage prices), 12,000 GWh would run around $3 trillion – roughly equal to the entire annual GDP of UK. If you start trying to switch coal and nuclear production in the UK to wind power, and then if you factor in the huge losses from trying to store electricity for a year before using it, you can multiply by 3 that trillion dollars by a factor of 2 or 3 or maybe 4. Whatever.
As said many times at this site, this will never happen. The only question is how catastrophic the fall will be when it all falls apart.
Once again, a big thank you to Bill Ponton for his efforts to demonstrate these issues, all for free.
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