Finding the chase and cutting to it

It’s the 2nd weekend of October, and, technically, we did past the milestone earlier in the year of having generated more than the whole of 2024, but we are currently sitting at having generated 3.5MWh off our roof mounted solar panels since 1st January 2025.

It’s the first year we have had batteries in play, so since March 2025, we have had use of 90% of that energy. It doesn’t mean we are off grid, but it should mean we do pay less for what we use as less is coming from the grid. So, is that actually the case?

Up to yesterday (as that how our smart meter reports), we have used 3.85505 MWh from the grid. Plus the 3.5 MWh we generated, that makes our total usage circa (3.9 + .9*3.5) = 7.05 MWh. And that’s before we hit the cold parts of this year.

Now, we’re doing a great deal with our electricity: heating the house, all the hot water we use, and of course, powering the electric vehicle (why this part of the blog is called “Driving off the grid”). 6.9 MWh isn’t too bad and 3.9 MWh off the grid, is pretty remarkable.

The current estimates for people running an EV and a heat pump is between 7 and 12 MWh. We might get to use 10 MWh for the calendar year, if use 2.4 MWh for November and December, as we did last year. The majority of that came from the grid last year, because we only had the one battery, just 100 kWh were provided by our solar cells and our single battery.

I always like to compare this to our gas usage, and for that I need to go back to 2023.

Month	Gas usage (MWh)
October 2023	0.569986
November 2023	1.657321
December 2023	2.134510
Total	4.361817

So, actually, while the energy use this year seem high for October, for December and November, they seem very reasonable. Of course, we are doing much more with that power. The gas was only keeping us warm and heating our water, not powering our transportation and providing hot meals and lighting and entertainment and clean clothing.

But you would say that, you are generating much of that power yourself!

Up to a point. Going by our general stats from the solar cells over the eleven years we have had them installed, we have had the best of the year. From here on in, the days are getting shorter and the sun is no longer as high in the sky.

In April, our generation is typically around 350 kWh (0.35 MWh), in October, more like 240 kWh (a good year), November is in the low 100s kWh and December, that figure drops to 50 kWh. (Edit from 14th November – this year came in as 185 kWh! November looks much better so far, and we’ve reached 3.6 MWh for the year.)

With the shortest day of the year, December is definitely the darkest month and the one where we are not getting as much off the roof. January looks more like November and February and October are comparable.

Hence the new triple glazing upstairs to stop our loses through the windows. It should mean we make the most of our heating.

Due to the nature of where we live, April and May are often our best generating months thanks to there being fewer leaves on the trees. We’re not in favour of pruning trees to give us better solar generation, but do enjoy those couple of months when a higher sun, sparser foliage, and cooler temperatures suit us to a tee!