What Happens When The Coal Plants Shut?

By Paul Homewood

Coal power generation has been running at 12.8% of UK demand in the last 24 hours, about 5GW.

This has not been untypical so far this month, with the first 19 days averaging 6.8 GW:

The average only tells us so much, however, as coal power has peaked at close to 10 GW on most days.

With wind averaging 13%, most of the rest has come from dispatchable sources, coal, gas, nuclear and bio.

At its peak this month, dispatchable power reached 43.3 GW, still well within capacity.

GW	Peak	Capacity
Coal	10.1	13.4
Gas	24.3	31.8
Nuclear	6.8	9.5
Bio	2.1	2.8
Total	43.3	57.5

However demand has peaked at 50.4 GW, which would leave things very tight without wind power. There are, of course, the interconnectors, but these have only been running at about 1 GW this month.

So, looking ahead, what happens when all of our coal plants are closed down?

The most recent Capacity Market Auction, held last year and covering the winter of 2020/21, includes 6.1 GW of coal/bio, out of a total auction of 52.4 GW:

http://ift.tt/2qWCFFB

We need to take account of a couple of factors though:

1) The capacity required is on a “de-rated” basis. This reflects the fact that generators cannot guarantee to be working at 100% of capacity all the time.

Building in a safety factor of 85%, the figure of 52.43 GW actually requires installed capacity of 61.7 GW.

2) Contracts are awarded to storage projects, even though they can only supply power for a short period, quite likely much less than may be needed.

It would appear that the government is now changing the rules to reflect this. Storage may be useful for short term balancing requirements, but not for stand by capacity.

3) Interconnectors can only guarantee power if surplus power is available across the Channel.

4) Demand Side Response (DSR), as with storage, may not be able to cope with long periods of demand.

All in all, if we look at just the truly dispatchable sources, we find that things look much tighter:

		Current
	2020/21	De-Rated
GW	Auction	Capacity
CCGT	22.6	27.0
CHP	4.4	2.8
Coal/Bio	6.1	13.8
Hydro	0.7	1.4
Nuclear	7.9	8.1
OCGT	3.8	1.2
Total	45.5	54.3

Take the current 11.4 GW of de-rated coal capacity out of the mix, and we are down to the bones already, even assuming we can rely on storage, DSR and I/Cs.

There does not appear either to be much existing CCGT capacity waiting to join the Auction either. Although the National Grid do not show it explicitly, nearly all existing CCGT were awarded contracts for 2020/21.

The government hope is that, once all coal plants are shut, new CCGTs will spring up to replace them. But things may not be as simple as that.

Given the unfair competition from heavily subsidised renewables and the promise of rising carbon prices, there is little incentive to build new CCGT plants, even with the subsidy from the Capacity Market, as Trafford Power have found out to their cost.

To make matters worse, many existing CCGTs may not stay open till the mid 2020s, either because of age or economics. The CCC’s Fifth Carbon Budget, for instance, assumed that 6 GW of gas capacity would be gone by 2025, and 10 GW by 2030.

Realistically we need at the very least 60 GW of dispatchable capacity, even without the extra demand from EVs.

Even allowing for Hinkley Point, this would require another 18 GW of new capacity to be built somehow in the next seven years. There is no sign at all of this happening.

Sources

All data, unless otherwise stated is from BMRS:

http://ift.tt/2lUpvXs