Could the UK run on 100% renewable energy?

Of the many statements that Energy and Climate Change Secretary Amber Rudd has made recently, the one with the most profound implications is probably one that appears pretty uncontroversial: ‘We have to secure baseload electricity’.

Ms Rudd was defending the government’s intention to give the proposed Hinkley C nuclear power station financial support until 2058, while insisting that most renewables be subsidy-free kinda now.

Baseload electricity is the minimum electricity we need to keep society ticking over. That we need nuclear, coal or maybe gas-fired stations chugging away 24 hours a day is a commonly held belief, certainly among British politicians and media commentators.

I used to assume it was true too. Now, I’m not so sure.

In August the Energy & Climate Intelligence Unit hosted a public event at which we saw a very different vision of an electricity network put forward by a German expert, Malte Jansen, from the Fraunhofer Institute in Kassel.

His project is called Kombikraftwerk. It has nothing to do with evolving electro-pop bands from the 70s, and everything to do with modeling the energy systems of the future. It’s a super detailed, evidence-based simulation of how the German grid might run at some point in the future on 100% renewables.

It uses real-world data on when and how much solar, wind and biogas power can be generated and stored, how demand varies and where new renewable power stations might be built.

As time runs forward in their simulation, electricity comes into the grid from various sources – wind, solar, biogas, hydro etc. Power flows between different regions of the country, and over the border in both directions.

When demand exceeds supply, non-essential power guzzlers are switched off and backup storage systems switched on. When there’s spare power, it’s used to produce hydrogen for use later on, or for heating, or it’s exported.

The exact solution for any given situation is largely worked out by the market. When wind and solar are generating they’ll take the top spot (being virtually free), and other supply- or demand-side measures come in depending on price.

And, in the simulation, it works. Take a look.

The Kombikraftwerk boffins aren’t the first to claim that a 100% renewables system can work but as far as I can see their simulation is by far the most detailed.

So, could the same conclusions apply in the UK? In short, ‘yes’, says Malte Jansen.

Blown away in the wind?

The first question always comes: ‘but the wind doesn’t blow and the sun doesn't shine all the time’.

True; and the first answer is ‘but there isn’t peak demand all the time either’. (Clue: It’s called ‘peak’ demand for a reason.) The key, according to Professor Catherine Mitchell, is to move towards a more flexible electricity grid, with smaller peaks in demand and less demand overall too.

The second question is ‘so what happens for the two-week period in winter when the wind doesn’t blow and the sky is all cloudy?’

In the Kombikraftwerk scenario, long-term troughs are primarily filled by burning biogas – produced during the year through anaerobic digestion, stored underground (as natural gas is now), and delivered to generators.

That’s one aspect that might not work quite so well for the UK, given that anaerobic digestion is way less developed here and that there’s extra pressure on land. But other solutions might well be available, such as increased interconnection with hydro-rich Norway.

Crunch time for UK policy

The government’s statutory advisor, the Committee on Climate Change (CCC), calculates that the best route for the UK to meet its target of cutting emissions by 80% by 2050 includes ‘virtually decarbonising’ the power sector by 2030.

The government, the CCC and other research groups all foresee doing this with a mix of nuclear, renewables, and fossil fuel-burning with carbon capture and storage (CCS).

But the first scheduled new nuclear reactor, at Hinkley Point, is increasingly troubled. Treasury officials think it doesn’t offer value for money, the hardware is afflicted by 'anomalies', and Lord Howell described it as ‘one of the worst deals ever’.

And CCS? Well – as they used to say about nuclear fusion, it was five years away 10 years ago and it still is.

So what happens if new nuclear and CCS don’t come to pass? Can the goal of ‘virtually decarbonising’ the power sector within 15 years be met with renewables alone?

All of our speakers said ‘yes’. Not without challenges, but also with many benefits too.

And Malte Jansen showed us how a 100% renewables system can be made to work - variable technologies like wind and solar backed up by constant ones such as hydro, biogas or biomass and tidal, re-inforced by a variety of storage methods, with measures reducing overall demand and flattening peaks.

And all, Ms Rudd, without baseload power.

This blog was originally potsted on the

Titile Image: Tommy Clark, Creative Commons