We don’t have too much energy storage - but we do have anarchy

A campaign focussed on protecting rural Scotland from the chaotic roll-out of energy infrastructure has claimed that there is a massive oversupply in the battery storage facilities in Scotland which are being approved. This reflects a problem Common Weal has persistently raised, which is that there is no coherent planning of what is being done.

Assessing the claims made in this report is not easy because it appears to use the wrong unit of measurement. There are two measurements (actually, three) that are relevant. One is rate of charge – how fast the battery can capture energy. This is often but not always the same as the rate of discharge (how fast the battery can push stored electricity back out).

Both of those are measured in MegaWatts or GigaWatts. But that doesn't tell you the total amount of storage capacity – think of it like a bath. The charge and discharge capacity is like 'how big is the tap?' while the total capacity is a 'how big is the bath?' question. That is measured in MegaWattHours or GigaWattHours – that means 'for how many hours can a battery supply one MegaWatt or GigaWatt of electricity?'.

It is also confused because there are different purposes of energy storage. The report takes its 'total required capacity' numbers from a report by Neso (the National Energy System Operator, the body that overseas the electricity running through the grid). But that relates to what is known as energy smoothing.

This is only one of the three roles of storage. There is a kind of very technical, incredibly short-term energy storage that deals with mismatches of fractions of a second that has always been part of the grid. Then there is 'smoothing' which helps deals with peaks and troughs through the day or week, particularly important when there is a large amount of wind or solar capacity in an energy system.

That is where this form of battery storage comes in. But there is a third form of storage – interseasonal storage. That is energy storage that stores the power generated in particularly windy or sunny periods in the year and stores it to be used when those forms of generation are low. Solar clearly generates more in the summer, wind in the autumn, winter and spring.

Neso is referring to smoothing storage because it wants to rely on English nuclear for more of its supply. Under that scheme, in Scotland we continue to pay wind farm operators to switch their turbines off if electricity is being generated at the 'wrong time' and then pay for expensive nuclear to be sent up from the south of England when we are not generating enough.

To be clear, what Neso has set out is the maximum supply rate, not maximum supply time. Scotland's peak energy usage is something like 5GW, so the rate of supply needed to keep Scotland powered will never be much more than 5GW (until we electrify car transport). But if the battery storage was 5GWH, that means we only have an hour of total storage.

But that does not mean Common Weal disagrees with the basic argument in this paper. Because interseasonal storage is not best achieved through batteries but through hydrogen. Common Weal took a very cautious approach and proposed a substantial oversupply of hydrogen storage (which can be used for heating and transport too).

Which means we estimated about 8,000 GWH of storage in hydrogen for electricity, potentially a thousand times more than the current installed battery capacity (which we don't know because the report uses charge rate).

That work was done in 2019 and we stated that it would not become clear what the balance would be between battery and hydrogen storage. Which is precisely why we called for a Scottish Energy Development Agency to make sense of all of this on behalf of Scotland and to plan the route forward.

What is happening is the polar opposite of that. Rather than a national system of deciding what the nation needs we have a regionalised system responding to what energy speculators want. They want battery because there is a market for battery and they can make a profit – whether it is good for Scotland or not and whether it is planned in the right place or not.

This report is flawed but it's central premise remains correct; we are treating our energy system not as a national utility but as a wild speculative investment opportunity for anyone who wants to set up a battery storage company and milk the ridiculous pricing system bolted on to our energy system.

And the report is absolutely right that it is therefore being planned very badly and that it is rural communities and particularly lower income communities who are paying the price. Scotland should step up and take a grip of this mess immediately by establishing a Scottish Energy Development Agency and doing some proper, transparent planning at the national level.