Experiments with domestic load shedding in the UK


Electricity demand varies throughout the day. When demand is higher, electricity prices go up. Most UK consumers are insulated from this variability - we pay a fixed price per kWh no matter what the actual wholesale cost.

But it doesn't need to be this way. Exposing users to the immense variability in pricing is probably too dangerous - as seen in Texas recently. Imagine if your electricity provider could say "hey, prices are going to be high tonight. We'll pay you to use less electricity!"

Well, that's what my energy provider are doing! Here's an email I received from them:

Screenshot of an email. It says "Hi Terence, You'll earn 1800 OctoPoints – that's £2.25 worth – for every unit of electricity you cut down between 5:00 PM and 6:00 PM on 15th November. Opt in now to save power and earn rewards in this Session. You'll go into a draw to win an extra 400,000 OctoPoints – that's £500 worth! – just for opting in. Important: you need to opt in before the Session starts if you want to earn rewards."

Join Octopus and we both get £50!

The UK is experimenting with flexible energy pricing. This is made possible by the large-scale rollout of smart meters. They measure electricity consumption and report it back at up-to half-hourly intervals1.

My solar panels already take advantage of this capability. I get paid the half-houly market-price for every kWh of sunshine I export. Octopus publish their price so, in theory, I could tell my battery to store energy at midday when it is cheaper and then sell back to the grid when it is more expensive.

Now, there's just one catch with this offer. The reduction is based on your average usage at that time. If you usually have your electric oven on between 1700-1800 then you'll be able to make some big savings. But if you're already fairly efficient, it is less likely you'll be able to take advantage of this.

The day before the experiment, this was our half-hourly usage:

A consumption graph showing a small amount of electricity usage during the timeframe.

So, if we were to turn off all our electricity we might be given about £1.95 as a reward. Not nothing, but perhaps not worth sitting in the dark for an hour?

But, in the spirit of experimentation, we tried it! Lights off, TV & games consoles off, chargers unplugged, no cooking or cups of tea. We made our own entertainment2.

What we earned & what we learned

Using our home monitoring software, here's what happened to our electricity use for that hour:

Bar graph showing electricity use.

As you can see, at 1700 we dropped our usage significantly. The hours before and after, we were using about 900Wh. But from 1700-1800 we were down to about 184Wh.

That's about 20% of our usual use for that hour. Our usual cost at that time of day would have been around £0.20 for the hour. Instead, we only used about 4 pence-worth of electricity.

A few days later, we got this message from our electricity provider:

You saved 74% in the last session. Amazing effort, well done! You cut down by 74%.

OK! They base the average over the last few weeks, so it isn't surprising that their numbers differ slightly from mine.

So, how much of a reward do they pay us?

So far you've earned 936 OctoPoints (or £1.17) over 1 Saving Session.

I have no idea why they do this in points. Presumably I might be able to exchange the points for a chance to win a prize? Seems silly to me; just use money.

And then, of course, the inevitable "nudge":

Other Savers in your area (SW1A) typically cut down 86%. You're saving 12% less than your neighbours.

I'm not sure how I feel about that sort of nudge. I think we did everything we reasonably could. I'm not a big fan of that sort of competition.

Was it a hardship for us to turn out the lights for an hour? No. But there is a slightly worrying idea that people might feel pressure to turn off vital things like life-saving equipment, freezers, or alarms.

Will people change their behaviour for a couple of quid? That remains to be seen. Should people have to change their behaviour? That's a more complex question. Janet Gunter has a blog post which explores the limitations of this approach.

The idea of a personal carbon footprint has despicable origins - but when scaled up to a population level, it can be a useful way to phrase a problem.

If people merely shift their electricity consumption to an hour before or after the load shedding period, does it have a meaningful impact?

Anyway, I think it is useful to do experiments like this. Perhaps thousands of people will find it useful and it'll scale up to millions of people. Perhaps it won't make a difference at all. But the only way we can find out is by experimenting. And I'm eager to see what happens!

If you're interested in trying this, join Octopus and we both get £50!


How did the rest of you do?


  1. It is a bit more complicated than that. And there are legitimate privacy / security concerns. But this post focuses on the positive side of the equation. Please don't use the comments for rants about your energy provider; write your own blog post instead. 
  2. Get your mind out of the gutter! We read books and played boardgames by candlelight!