Green Energy Powers Ahead

Thursday 8th June 2017

Renewables Outpace Traditional Power Generators

If you hadn’t seen it, Wednesday 7th June marked a small but historical moment in the UK Energy Sector. For the first time the total amount of electricity generated from renewable sources (wind, solar, biomass) exceeded half of total demand at 50.7%. Add in low carbon nuclear energy and only 28% of power was produced from “thermal generation i.e. fossil fuels such as coal, oil and gas.

That’s great news for anyone who is remotely concerned about climate change…which should be just about everyone. It does however also reveal the unfolding technical, commercial and political issues that will be increasingly pulling in different directions.

Why?…Wednesday’s event coincided with an unusually clear, windy June day, with the midsummer sun at its height around 2pm…perfect conditions for renewables.

A Technical Issue

It is not widely understood outside the sector that power has to be generated in the same instant that it is consumed. Mains voltages cannot be stored on any significant scale, meaning that the power network-operator is engaged in a 24/7 balancing act to make sure that exactly the right amount of generation capacity is in use to meet demand. Renewables are capable of generating significant amounts of power, but are bedevilled by the unpredictability of the wind and the habit of the sun to disappear at night! This is known as the “intermittency” problem.

Despite promising progress we are still a long way off creating batteries that are capable of storing and supplying bulk mains-voltage electricity to consumers. Large units are genuinely big and need significant space. Smaller “in-home” units are more practical but remain expensive for the average household.

Unsolved, this problem leads to network-instability, leading to voltage-reductions or “brown-outs”. In an economy reliant on sensitive IT systems this is a recipe for chaos. At a more human level, throw in a windless, freezing January night and you have the potential for full-on power-cuts at the darkest and coldest time of year!

A Commercial Problem

Until a feasible power-storage solution can be found, we will have to continue relying on traditional “thermal” generation. When wind and solar were in relatively scarce supply this was not a problem. On “Green Wednesday” though, the amount of wind-power was so great that its traded price fell to near zero, driving much gas-powered generation out of the market. That’s great isn’t it? Well yes and no.

We need to replace ageing generation built in the 1960s and a significant proportion of that, in the absence of a power-storage solution, will have to be the more controllable “thermal” generation filling in the gaps in the renewable supply. Of the choices available, gas-fired generation is the cheapest and least environmentally damaging, but the economics of building power stations require them to be run enough to earn back the original investment. If they don’t run then you have a “white elephant” or, most likely, no power station at all as it will not be built in the first place.

So the technical “brown-out” issue can only be resolved in the short to medium term by thermal generation…but if it is repeatedly “backed-out” of the market by unpredictable gluts of very cheap wind power, then it won’t be built.

The regulator has modified the market rules to encourage more spare capacity to run (at a premium price) when renewables cannot make up the shortfall. Unfortunately, this has had the unintended consequence of encouraging the installation of temporary, diesel-fired generation-sets…just about the most polluting solution of them all!

What About the Politics

The politics are accordingly, very messy indeed. The need to have significant thermal generation on stand-by to smooth out the power-supply will inevitably push up electricity prices…try explaining to the public why power station owners are being paid to stand idle?

Similarly, constructing additional “no-carbon” nuclear “baseload” generation takes decades, is undeniably highly expensive, involves difficult partnering choices and provokes objections at all levels.

Even if we solve the battery conundrum, the debate over who pays for the mass roll-out of the technology will make the current arguments over stretched government budgets seem tame.

So What Does it all Mean?

“Green Wednesday” should of course be a matter of celebration. It does however bring the day closer when the UK Government and the Great British Public will have to face up to some difficult realities. Recent events alone show, that when it comes to facing up to difficult realties…the GBP would rather not think about it!