3 years of domestic solar stats in the UK


After 3 full years of having solar panels on our London roof, they've generated 11,950kWh of electricity. Nice!

Here's how those three years look, according to our smart meter.

kWh
Solar Generation11,950
Solar Export7,346
Grid Import7,521

Quick maths!

The difference between the generation and the export is our solar consumption: 4,604kWh over 3 years.

So we directly use about 38% of the solar we generate. The remaining 62% gets sold back to the grid. I thought our consumption would be higher; we work from home during daylight hours and we have a modest 2kWh battery. But it is exactly in line with what we were seeing after one year.

Our solar consumption and grid import is the total electricity that we used: 12,125kWh over 3 years.

The average UK home uses around 3,800kWh of electricity per year. We're a bit higher than that. Despite all our energy efficiency measures, we use about 4,000kWh per year.

That means, on average, solar produced 99% of our electricity needs across three years!

You can read more about our solar installation if you'd like to understand the number of panels, details of the inverter, and other technical gubbins.

Money Money Money

People always ask how much the panels cost. That's a difficult question to answer. Every house is different. We have a 3 storey house, which meant extra costs for scaffolding. Our roof was in decent shape, so didn't need reinforcement - and we sold the tiles which were removed. The panels we wanted weren't in stock, so we got a slight discount. Etc etc etc. Basically, go get a couple of quotes and see how much it will cost in your specific circumstances.

The next question is about how much money it has saved us. Again, that's slightly complicated. Energy prices have been "interesting" in the UK. At an average price of 30p/kWh, the panels have saved us about £1,400 over the three years.

But! We also sell the excess electricity. We get paid a variable amount depending on demand - usually between 15p to 30p per kWh. By my calculations, we've sold about £1,500 worth of electricity over 3 years.

Let's call it a total saving of £1,000 per year. If electricity prices go higher, we'll save more. If they drop, we'll save less.

Open Data

Every day, a robot uploads our solar generation data to GitLab where it is freely available for research purposes. The solar stats from our previous home are also available.

☀️

Solar "just works". Yes, even in dreary, rainy, cloudy, foggy UK. Yes, even if your roof doesn't face the optimal direction. Yes, there is a large up-front cost. But even with the current technology, solar is a completely viable way to generate your own electricity and save money.


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One thought on “3 years of domestic solar stats in the UK”

  1. said on mastodon.social:

    @Edent Nice work. Interesting day. Solcast predicted 11 kWh for today. Crappy morning. With the rain, generated about 2 kWh. Solcast said 9 kWh left in the day at 12pm. I thought I might use Agile for an afternoon top up, but decided to trust Solcast. The battery is now 100% full. Agile has some minus slots tonight. Might charge the battery anyway

    Out of interest, what would you call a self sufficient day? When the solar generates more than the consumption or more than the import from the grid

    Reply | Reply to original comment on mastodon.social

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