Solar Power Report: December 2025 and the year

steevc(80)

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Here is my monthly report on how our solar panel system did in December. We have:

20x400W panels = 8kW
5kW GivEnergy inverter
9.5kWh GivEnergy battery

This is the year:

Month	Generated	Used	Exported	Imported
January	78kWh	468kWh	38kWh	434kWh
February	192kWh	554kWh	146kWh	514kWh
March	619kWh	503kWh	535kWh	430kWh
April	927kWh	288kWh	790kWh	330kWh
May	967kWh	292kWh	845kWh	173kWh
June	1044kWh	332kWh	1037kWh	337kWh
July	878kWh	309kWh	858kWh	294kWh
August	769kWh	424kWh	810kWh	465kWh
September	560kWh	421kWh	576kWh	445kWh
October	209kWh	405kWh	251kWh	452kWh
November	151kWh	445kWh	157kWh	452kWh
December	109kWh	287kWh	153kWh	318kWh

Consumption was down in December as we were away from just before Christmas, That did mean we could export more than we might have otherwise. We have passed the shortest day and we do get some sun. We are unlikely to get much snow that might cover the panels.

These are the totals for the whole of 2025. I took these figures from the inverter app rather than adding them up in the table above:

Generated: 6411kWh
Used: 4861kWh
Exported: 6168kWh
Imported: 4644kWh

Generation

The graph makes it clearer how our generation varies over the year. You can see that in most months we export most of it. We are at 52° North, which is slightly north of Calgary in Canada and about the same as Warsaw in Poland.

If we just had the panels then we would not save much in winter, but we can charge the battery on morning cheap rate and run the house off that all day so we rarely use peak rate power. The difference is 8.5p compared to 30.6p per kWh on our tariff. We get 15p/kWh for what we export, so I have it set to dump some of the battery in the evening for a little extra profit.

We get our electricity and gas from Octopus (referral link) who are now the largest energy supplier in the UK. They are really proactive on encouraging people to get solar panels and heat pumps as well as electric vehicles. We got our system installed by them. We did have some issues with it tripping a breaker, but it has been fine since they last looked at it.

Electricity cost

You can see that the cost of our electricity does not vary that much over the year. Of course we use more lights in winter, but they are mostly LED these days and so use very little power. Our heating runs on gas, so that varies more. One of the kids has an electric car that gets charged at our place sometimes. We may get one too eventually and that will make a big difference to our energy usage. If you can charge at home, especially on cheap rate, then they can be much cheaper to run than cars that burn oil.

Exports

What we exported more than paid for our imports. I estimate that we could be paying around £1500 per year for electricity if we did not have this system, so that is a significant saving and it should pay for itself in about ten years, depending on how energy prices change. We are paying about the same for gas as for electricity. We may consider getting a heat pump that could cut our heating costs.

I reduced our monthly energy payments a while back to see if we could get through the year on the credit we build up in the summer. I am going to increase those payments slightly now I know how it has gone.

I think solar is an attractive option for those who can install it, but it will depend a lot on what tariffs you can get for import and export. Those who live nearer the equator could generate a lot more. You may not even need a roof as some can have a balcony system like @louis88.