This is an article about a fact. In an electrical grid, the power must be produced in real time, as it is being used; if supply to the grid is less than demand at any time, there will be a blackout. For the grid to function, supply and demand must be balanced at all times.  

It’s one of those facts that’s so simple that once you’re aware of it it’s difficult to imagine not knowing it. Yet everyone who knows it only knows it because someone once told them, or because they read it somewhere. I know it because I read it in a comment under a blog post when I was unemployed in my early twenties. It was the kind of blog written and read by people who would be described in polite circles as climate change deniers, and it had a tool on it which allowed those commenting below the posts to add references in proper academic footnotes; such was the obsessive and fastidious nature of the readership it attracted. 

Yet had I not read it that day out of sheer boredom, I think it’s quite likely I would never have thought about it at all, as I hadn’t up until that point. Previously, I think I had perhaps imagined that electricity could whiz around the grid, and if there were a little excess produced while everyone was still in bed, then it would be there to cover a shortfall when everyone woke up and put the kettle on. But it’s not a question that had troubled me at all until I read it there, in what had been intended as a throw-away line at the start of a comment, as the writer prepared to make a far more complicated technical point. Whoever wrote it certainly wasn’t writing for the kind of reader who didn’t know the fact already. 

It’s not an especially interesting fact in itself, unless your line of work relates fairly directly to grid stability. However, this previously mundane fact has recently been made highly salient by the energy transition. This is because the transition entails swapping fossil fuel generation, which can be controlled by human inputs, for weather-based renewables which fluctuate according to the whim of nature. Suddenly, our fact has become probably the most important single fact to be aware of if one is going to take a view on energy policy.  

… the optimal percentage of intermittent generation in a grid is zero

Our fact makes this transition contingent either on the sudden development and implementation of electricity storage facilities which don’t yet exist, or else on society and the economy learning to accept regular blackouts. Whilst a large, stable grid can bear some amount of intermittent generation, especially if it has substantial capacity from sources that are suited to being ramped up or down at short notice, the fact remains that the optimal percentage of intermittent generation in a grid is zero. 

I don’t imagine that many people among the general public are aware of this fact explicitly; however I had been working on the assumption until very recently that pretty much everyone involved in the energy sector or in the national debate around energy policy is aware of it. I had also assumed that enough people working more generally in government, in senior positions in financial services and in the prestige media were aware of the fact; to the point that Britain’s governing classes generally behaved collectively as if they understood it. 

Among such people, the orthodox position is to favour the continued addition of more intermittent renewables to the energy mix. I had assumed that this was a collective, strategic act of social and political positioning, intended to spur on the transition away from fossil fuels, and to put commercial and political energy behind the attempt to work out some kind of technical solution to the problem. But when push came to shove, I guessed that they’d swerve before the lights actually went off. 

Some others were obviously either far more hopeful about the prospects for a sudden breakthrough in battery storage technology than I am, or they estimated the costs of climate change as being so high as to make the risk of blackouts seem worthwhile. I also put some of it down to the fact that a lot of people working in the realm of public policy have a tendency to overestimate the ability of industry to absorb costs, or to come up with magical fixes to any technical problem if they put their minds to it hard enough.   

It has recently struck me though, that it might be that a lot of these people, even some very senior people, are just not aware of the fact at all. Clearly, plenty of these people are aware of it; but it might be that most of them aren’t. Certainly, I’ve never seen this particular fact spelled out straightforwardly in any mainstream news or commentary outlet like the Economist or the Financial Times (and why would it be? It’s not as if it’s breaking news).  

Let’s imagine that, among members of the governing, professional and media classes, people can be broken down broadly into the following three categories:   

[1] Those who are not aware of the fact at all; 

[2] Those who are aware of the fact, but who want to push on with the transition to intermittent renewables anyway either because of their degree of alarm about climate change, or because of their desire to reshape the economy and society for political reasons; 

[3] Those who have heard the fact, but see enough of the first two types of people who don’t seem to be bothered about it, so they either forget about it, or decide not to worry about it themselves.

Given the approximate distribution of technical knowledge among the kind of people who run Britain, it wouldn’t surprise me if the breakdown were roughly even between the three groups above. If so, the third category might be especially important because of the degree to which people who aren’t from a technical or scientific background are likely to discount their own technical or scientific concerns. Especially about anything that has the kind of political and moral momentum behind it that the energy transition currently does. 

The result of this might be that, even though there are people among them who are aware of this basic fact of how electricity grids work, the people who run Britain might collectively behave as if they don’t. This is an alarming realisation, but one that makes it easier to understand how we arrived at the position we’re at. If correct, it also means that those of us who believe we urgently need to stop the addition of intermittent generation to the energy mix are currently approaching the argument in entirely the wrong way. 

In debates online about energy policy, one can often hear people who are sceptical about weather-based renewables ask “what about when the wind isn’t blowing or the sun isn’t shining?” This is clearly a reference to our fact, and presupposes a knowledge of it. Yet if the listener isn’t aware of it, it seems obtuse and particularly pertinent. After all, Britain is generally either a breezy or a blustery country most of the time, and the sun isn’t going to stop shining for somewhere in the region of another five billion years. 

To the unaware, references to the unreliability of renewable power sources aren’t interpreted as an attempt to anchor the discussion to an indisputable fact; it’s interpreted as a dog whistle to people who are wrong and bad and dangerous. It’s the equivalent of saying “I’m not racist, but…” but for energy policy. It’s a verbal signpost to anybody who considers themselves forward-thinking or progressive that they don’t need to listen any further, and that the person they are talking to is a crank or a wrong ‘un. 

Instead, the fact must be stated, directly and clearly, again and again, every time the subject is addressed. And it must be impressed upon the general public, until those who would prefer that people didn’t know about it are forced to come out and try to deny it. Currently, among the elite, our fact can be ignored by those who want to ignore it because it is politically tainted and low-status.  It’s a fact that populists and sceptics talk about, and can therefore be dismissed as fake, or as some kind of conspiracy theory. 

However, if the public can be made to understand that loading the grid with intermittent power sources without backup means regular blackouts, and that backing up the British grid with batteries would cost at least the equivalent of the UK’s whole annual national income, and that backing up the intermittent sources without batteries  (in the absence, at least, technologies that are hardly conceived of yet) means ramping up diesel generators and producing enough CO2 to render the whole exercise pointless, it will put the burden on those who think that it’s a good idea to go through with it in the next few years to justify themselves.  

If the next leader of the opposition were to actually grasp this issue properly, they could lead, if not quite a revolution, then perhaps something a little like it.