St Swithin’s day, mixed weather for the next forty days.
Today is the 15th July, and I am writing this as I have a brief moment of perkiness which will wipe me out for the rest of the day.
Stop writing then!
I’m chronically bored. Every movement is painful and I’ve not been able to work since last week. Having signed myself out last week, I saw the doctor yesterday… which was exhausting. Like I say, a brief respite…
Go on then… but you should be resting!
Legend has it that rain today will mean rain for the forty days, but the British weather is much too fickle to follow any rules. Indeed, the only predictable thing about the UK climate is the unpredictability.
In my fair town, we get 4,383 hours of daylight a year, rendering 1,460 meaningful solar generating hours.
That’s a bit of a swizz, isn’t it?
Love the Brit’s turn of phrase. No, you would expect that due to the angle of the sun to the horizon, that makes perfect sense. Just under a third of daylight hours providing some level of sunshine. We get much more of the available daylight as sunshine during the summer, less during the winter.
In the summer, because of the longer days, we typically start to generate electricity from 6am, in July, start generating more than we use from 8am. As our panels face due south with a big house behind them, we cease generating about 19:30. Extrapolate that out and 1,460 potential hours of generation sounds about right.
Indeed, this year has been a bit of a bumper year compared to last year, with a generation total of 2.4kWh by today compared to 1.9kWh from the 1st January 2024 to the 15th July 2024.
This makes having the batteries really pay in for us. Last year, we were billed for 568.9kWh. This year, we have been billed for 12.2kWh.
For those who are more comfortable working in percentages, that’s 98% less or our electricity coming from the grid, and electricity price has jumped from 21p per kWh to 24.77p. We’ve paid on average less than 23p a day for the electricity we have used from the grid in July, so far.
Of course, the batteries are only half that story. We’re not buying gas or paying a standing charge. The heat pump is returning a seasonal performance factor > 4, meaning for each kWh we use, we get at least 4kWh of heating. If we’re careful with our usage, even boiling a kettle or charging the car is being done within our usage envelop.
Our batteries have a maximum power delivery of 5kWh – so if our usage is less than that (and whatever is coming off the roof, a maximum of 3.5kWh), it should be free. I am certainly watching when I am boiling the kettle. Of course, it can be caught short, with an unexpected demand not being met by the battery unless you conciously make the decision to go “off-grid”.
This picture is reversed in the winter, when there is much less solar power to be had and the house really wants to be heated and lit. Our shortest day is only 7 hours 32 minutes of daylight – if we’re awake for the rest of the time, that needs heating and light. Call us southern softies.
That’s kind of the point. It’s why I don’t mind paying a standing charge too much, just wish it wasn’t quite as much as 43.75p a day.
You would say that, wouldn’t you? You want to have your cake and eat it too!
Well, I think we should be incouraging people to move away from fossil fuels towards greener alternatives and more than 50% of our electricity comes from renewable sources in the UK.
The standing charge to heat your house by gas has a standing charge of 33p a day (ish). Which seems the wrong way round.
Doesn’t that hit those who cannot afford to make the move with a double whammy?
Yes, it could. But there is help for people in that position as per details of ECO4, ecoFlex, and home upgrade grants. These schmes aims to help people who cannot afford to make such moves. For ECO Flex, the family income needs to be less than £31,000 pa, and helps to pay for a variety of measures, including insulation, heat pumps, double glazing, and solar panels. HUG is for everyone making a positive move, and ECO4 is for those on benefits.
Which could be a good way for this change of pricing to work. The main issue with our system is, you have to apply for it, no-one is watching to see if you are in trouble.
For ECO4, the only downside, it seems to me, is you need to be “off the gas network”. I don’t know if that means you cannot use gas or if it means you have to be using oil fired heating from a tank…
There’s a big difference here between making a postive move or taking a step away from non-networked heating sources, surely?
Posted: July 19th, 2025 under Driving off the grid.