14 April 2021

A tale of two Mondays: What Britain’s greenest day tells us about the future of energy

By Tom Greatrex

At lunchtime on Easter Bank Holiday Monday, April 5, Britain’s electricity system was the greenest it had ever been. Sunny and windy weather, low demand for power, and the continuous operation of the nuclear fleet meant that almost 80% of electricity was generated by low-carbon sources: wind, solar and nuclear. Only 10% of power was from gas, and coal was, thankfully, nowhere to be seen. The carbon intensity of the grid dropped to an all-time low of 39 grams of CO2. A low-carbon grid isn’t just possible, it’s already here.

Fast-forward seven days, and the picture couldn’t be more different. A spring cold snap brought cloudier skies and low wind, all on a day in which the easing of Covid rules saw a return to more normal energy trends. Exactly a week on from ‘Green Monday’, over half of Britain’s electricity came from fossil fuels. Coal plants were fired up, and carbon intensity approached 300g of CO2. Old habits, it seems, die hard.

We have been here before. Take the first few weeks of March, for instance. On Wednesday March 10, wind and nuclear output meant two-thirds of Britain’s power came from low-carbon sources. A week earlier, however, two-thirds came from coal and gas, the highest levels in over a year (almost 67%). Britain’s reliance on fossil fuels whenever the weather turns is unstable and unsustainable and will continue to rear its dirty head, unless we tackle it head on. We can do that by building more of the only big-hitting low-carbon power source in the UK that isn’t affected by the changeable nature of the UK’s weather: nuclear.

The UK’s nuclear power stations are the vital source of firm, low-carbon power necessary to complement our investment in renewables. They have already saved more emissions than any other energy source in British history, 2.3bn tonnes, or all emissions from 2015 through to 2020. However, we desperately need new investment to preserve this contribution. Half the nuclear fleet will retire in less than three years, and seven of eight stations by 2030. The Climate Change Committee (CCC) estimates that without new projects, our clean power capacity will fall by 30%, when we need four times more by 2050.

Since the CCC projects that almost 40% of our net zero demand should come from sources like nuclear, we have no time to delay. We need to get on and build more nuclear power stations. That will improve our baseline of low-carbon output, cutting emissions and providing essential grid stability, even as demand for electricity booms. If we don’t, we will get as many days like April 12 as we get days like April 5.

As the UK strives for a zero-carbon society, we should, of course, celebrate these ‘greenest grid’ records. We will certainly need many more of them to meet our climate goals. Balancing and greening the grid is an enormous day by day challenge, but we can’t pick and choose our days to laud while ignoring others that don’t so neatly fit the narrative. The goal is clear – every single day has to be like Easter Monday or better to hit net zero. Getting there will require a herculean shift in how the electricity system performs – it means more wind, more solar and, crucially, more nuclear. Only then can we escape the fossil fuel trap and have the sustainable, emissions-free world that is the challenge of our times.

Click here to subscribe to our daily briefing – the best pieces from CapX and across the web.

CapX depends on the generosity of its readers. If you value what we do, please consider making a donation.

Tom Greatrex is Chief Executive of the Nuclear Industry Association.

Columns are the author's own opinion and do not necessarily reflect the views of CapX.