The beginning of the end for coal-fired electricity generation in Britain was… well, when was it? Was it when anthropogenic climate change was first recognised? That would be 1896. No, it wasn’t then, and it wasn’t in 1912 either, when Popular Mechanics slipped a mention of it to budding engineers of the day.
The writing was on the wall more than a hundred years before the Kyoto Protocol in 1997 marked the world’s first attempt to do anything about it. But still, the huge and unavoidable carbon dioxide emissions of coal power generation weren’t enough to set coal on the trajectory to finally shutting down on 1st October this year.
The beginning of the end came from sulphur. At the start of 2008, coal-fired power stations had all made their choices between the options presented under the EU’s Large Combustion Plant Directive, namely: clean up the sulphur, or run for a limited number of hours over a limited number of years and then close. I am obfuscating the detail, but that was pretty much the effect.
Removing sulphur from flue gas means a combination of buying cleaner coal and fitting expensive kit to scrub the sulphur oxides out of the flue gas. “Cleaner” coal is a matter of small degrees at best, and buying that just sends the other stuff somewhere else. Flue-gas desulphurisation does work (for the sulphur, not the carbon dioxide) and a number of the bigger stations in the UK fitted it. Ratcliffe-on-Soar, the last coal station on the bars, was one of those.
But the really weird behaviour came from the stations that took the exit route. They had to budget their remaining run hours over the remaining years, watching two clocks at once while taking opportunities whenever gas prices (the fuel of their main competitors) were high. The kicker was that the run hours clock went down at the same rate whether a station was generating 2000MW or 2MW. Time to thrash those assets.
This is how, when Flexitricity’s virtual power station went live on a perfectly ordinary June day in 2008, we were called straight away to deliver Short Term Operating Reserve (STOR). This happened in the early evening, when everything would normally be calm and quiet. The limited life coal stations had adopted a practice of generating at full power during the day, and then throwing the stations off the bars as fast as they physically could at the most convenient trading boundary, which was 7pm. This was a headache for National Grid (as we knew it) but an opportunity for demand-side flexibility. The evening STOR calls continued for a while, and we delivered them using a mix of small generation, industrial load and district energy, but mood of the electricity system is constantly changing. There was a period of unreliability at nuclear stations; gas and European interconnectors also had unhappy periods. Most of these phases improve over time through a mixture of maintenance and plant retirals, but while they’re happening, our customers are happy to help out, by being flexible while getting on with their day job. And that flexibility is still there when the next bundle of trouble arrives, as it always does.
So the beginning of the end for coal was the beginning of the beginning for small, distributed resources participating in flexibility markets. The end of the end for coal coincided with the transformation of National Grid into the National Energy System Operator (NESO), with a much wider brief. Grid was surprised – but not caught out – by the huge success that wind and solar developers have had; now as NESO, the same people are pushing Government to go faster (Clean Power 2030 | National Energy System Operator).
But how big was the resource to which we have now bid farewell? Wikipedia will quickly tell you how many gigawatts coal was able to generate at peak, but during his time at the University of Strathclyde, Simon Gill came up with an interesting alternative measure. If you add up all the energy that Britain’s four pumped-storage hydro stations can hold, you come up with less than 30GWh. In 2014 – shortly before the limited run stations finally closed – the stored energy in coal yards at power stations amounted to 142,000GWh. You can’t compare exactly like for like – pumped storage is at least twice as efficient at producing energy as coal – but however you do it, coal storage was massive. And it’s gone.
When there was coal burning, there was also coal mining. From this, we must learn another lesson. As a teenager in Lanarkshire in the eighties, I saw first-hand the devastation that the collapse of a large industrial sector wreaks on communities. Several generations can see the scarring left behind when the economy moves away. We cannot repeat that; there can be no transition without a just transition.
Now that we know the true cost of burning coal, we shouldn’t regret its passing. We can store energy in other ways, and we can be responsive in ways that weren’t recognised when coal was king. Flexitricity is firmly committed to using small, agile resources, from smart EV chargepoints up to large-scale batteries, to keep costs down, keep the lights on, and keep electricity green.