AEP’s Storage Delusions

By Paul Homewood

h/t Ian Magness

AEP is away with the fairies again!


Today’s electricity price shock is the last crisis of the old order. Britain will soon have far more power at times of peak production than it can absorb. The logistical headache will be abundance.

Wind and solar provided almost 60pc of the UK’s power for substantial stretches last weekend, briefly peaking at 66pc. This is not to make a propaganda point about green energy, although this home-made power is self-evidently displacing liquefied natural gas (LNG) imported right now at nosebleed prices.

It is a point about the mathematical implications of the UK’s gargantuan push for renewables. Offshore wind capacity is going to increase from 11 to 50 gigawatts (GW) by 2030 under the Government’s latest fast-track plans.

RenewableUK says this country currently has a total of 86GW in the project pipeline. This the most ambitious rollout of offshore wind in the world, ahead of China at 78GW, and the US at 48GW.

Much of the power will have to be stored for days or weeks at a time. Lithium batteries cannot do the job: their sweet spot is two hours, and they are expensive. You need “long duration” storage at a cost that must ultimately fall below $100 (£82) per megawatt hour (MWh), the global benchmark of commercial viability.

That is now in sight, and one of the world leaders is a British start-up. Highview Power has refined a beautifully simple technology using liquid air stored in insulated steel towers at low pressure.

This cryogenic process cools air to minus 196 degrees using the standard kit for LNG. It compresses the volume 700-fold. The liquid re-expands with a blast of force when heated and drives a turbine, providing dispatchable power with the help of a flywheel.

Fresh tanks can be added to cover several days or even weeks of energy storage. The efficiency loss or “boil off” rate from storage vats is 0.1pc each day, and much of this is recaptured by the closed system.

“Think of us as pumped-hydro in a box. We can store for very long periods, and discharge over long periods,” said Rupert Pearce, Highview’s chief executive and ex-head of the satellite company Inmarsat.

“We can take power when the grid can’t handle it, and fill our tanks with wasted wind (curtailment). At the moment the grid has to pay companies £1bn a year not to produce, which is grotesque.”

Highview is well beyond the pilot phase and is developing its first large UK plant in Humberside, today Britain’s top hub for North Sea wind. It will offer 2.5GW for over 12 hours, or 0.5GW for over 60 hours, and so forth, and should be up and running by late 2024.

Further projects will be built at a breakneck speed of two to three a year during the 2020s, with a target of 20 sites able to provide almost 6GW of back-up electricity for four days at a time, or whatever time/power mix is optimal.

Most North Sea wind lulls last less than 24 hours. Research by Delft University found that the longer Dunkelflaute events – caused by cold high-pressure weather systems – tend to range from 50-100 hours. They typically occur in November, December, and January. …

Mr Pearce said Highview’s levelised cost of energy (LCOE) would start at $140-$150, below lithium, and then slide on a “glide path” to $100 with over time. The company has parallel projects in Spain and Australia but Britain is the showroom.

Yet another puff piece for Highview!

But perhaps AEP should learn how to use a calculator!

Highview plan to build 18 plants, each of about 2.5 GWh – see their website here. That makes a total of 45 GWh.

During January 2020, a not untypical month weather wise, wind power fell below 7 GW, or about 30% of capacity, for 163 hours in succession. The average output in that period was 3.8 GW, which was 15.8% of the then capacity.


According to the National Grid’s Future Energy Scenarios, demand in winter will rise to about 80 GW, of which biomass and nuclear will supply 15 GW. Gas generation will, according to AEP, be a thing of the past, while solar power is negligible in winter and there is little else other than wind to fill the gap.

Wind power is projected at a nameplate capacity of 109 GW, but with an average output of about 44 GW.

Another low wind interlude such as January 2020 would see that 44 GW drop to 16 GW for a week, and quite probably longer.

Now do the sums:

A shortfall of 28 GW x 163 hours = 4564 GWh.

Highview’s eighteen proposed plants will supply just 45 GWh.


A slight problem, I think AEP!

As ever, he simply does not understand the energy market. In particular, he does not understand that all forms of storage, whether lithium, pumped storage or cryo are only useful for short term balancing. Even the National Grid’s Future Energy Scenario  recognises this:


Maybe it is time that the Telegraph employed a proper energy expert to report on the topic.


July 30, 2022 at 06:51AM

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