February Solar Generation and Export Numbers
February brought a very wet and overcast month, leading to our lowest generation figures in recent memory. This led to the worst February generation since we had solar installed. We did have some bright days, which shows what could have been possible if it had not been so overcast. We only exported 15.50 kWh during the period, highlighting the limited output available for sale back to the grid.
Solar Generation
Solar generation for the month totalled 123.60 kWh, down 8.20 kWh compared to February last year’s 131.80 kWh. The overcast conditions heavily suppressed our panels' ability to perform at peak capacity. Solar contributed just 17% of total household consumption, which is in line with expectations for a low-light month but marks the weakest performance we’ve seen since the system was installed. There were no days where solar generation exceeded household consumption or grid imports, resulting in zero self-sustained days by either measure this month.
Battery Performance
Battery usage remained central to cost control despite the gloomy weather. The batteries were charged with 433.50 kWh and discharged 410.20 kWh, showing sustained cycling to offset higher-priced daytime electricity. We used 266 grid charging slots during the month, while the batteries were suspended for 182 slots, largely to avoid charging during periods where the tariff offered no advantage or when solar generation was minimal. A charging slow it 30 minutes in length. The average grid slot cost this month was 15.06p per kWh. The cheapest charging slot was 14.62p, while the most expensive slot used reached 29.82p. Despite some higher-priced slots being unavoidable due to demand, the overall average remained well below the current price cap of 27.69p per kWh.
Grid Usage & Cost
Total household consumption for the month was 739.30 kWh, reflecting the impact of colder weather and heating requirements. Grid imports for the month were 782.20 kWh, reinforcing how heavily winter demand relies on the grid when solar availability is minimal. The standing charge for the period was 48.389p per day.
The total cost of electricity imported on the Cosy tariff was £117.78. For comparison, importing the same energy on the standard tariff would have cost £216.59, while supplying the household entirely on the standard tariff would have resulted in a cost of £204.71. This represents a saving of £101.14 compared to standard tariff imports, and £89.26 compared to standard tariff household consumption. Exports were modest but consistent, resulting in £2.33 of export savings.
Looking at the wider picture, the average unit cost paid so far this year stands at 15.07p per kWh, significantly below the price cap average. Even in the most solar-constrained month, the combination of battery optimisation and the Cosy tariff continues to deliver substantial savings. Overall, February highlights the system operating at its most grid-dependent during wet conditions. While generation was disappointing, the financial performance reinforces how effective the system remains. The cheapest day financially was 25/02/2026 - £2.36. Despite the weather challenges, intelligent charging decisions ensure our energy costs remain manageable year-round.
According to the Octo-Aid app, this was the breakdown of our usage per rate.
Grid Usage by Rate (High, Mid and Low)
As solar panels output declines over the years I have added the previous years generation to the table at the bottom. Of course weather comes into it as well, but I thought it would be interesting to track. I have added this post that shows each year as a graph.
Octopus Energy bill
Octopus Watch Tariff Comparison Report. This does not include exporting
Best Solar Generation
| Date | kWh | |
|---|---|---|
| Generation | 26th May 2023 | 32.90 |
| Front generation | 14th June 2023 | 19.80 |
| Back generation | 7th June 2023 | 14.70 |
| Worst generation | 12th December 2022 | 0.20 |
Best Solar Export and Profit
| Date | kWh | Profit | |
|---|---|---|---|
| Exported kWh | 15th June 2024 | 22.20 | |
| Exported profit | 15th June 2024 | 22.20 | £3.15 (15p kWh) |
| Profit day | 14th April 2024 | 18.20 | £2.67 |
Solar Generation
| Metric | Date | kWh |
|---|---|---|
| Best Generation | 17 February 2026 | 9.70 |
| Best front generation | 17 February 2026 | 7.40 |
| Best back generation | 24 February 2026 | 4.20 |
| Worst generation | 3 February 2026 | 0.70 |
| Worst front generation | 3 February 2026 | 0.40 |
| Worst back generation | 3 February 2026 | 0.30 |
Export and Profit (Rate 15p kWh)
| Metric | Date | kWh | Profit |
|---|---|---|---|
| Best Battery and Solar Export Profit | 2 February 2026 | 0.30 | |
| Best kWh export day (Solar) | 24 February 2026 | 0.80 | |
| Best export profit | 24 February 2026 | 0.80 | £0.12 |
| Cheapest Day | 25 February 2026 | £2.36 |
The graph below shows the generation for both front and back panels
Total Solar Generation
The graph below shows generation, battery discharge, battery charging, export, import to use and consumption for 2026
Showing generation, battery discharge, battery charging, export, import to use and consumption for 2026
Overview for December
The graph below shows the generation for each day
Graph showing production for the month
The graphs below show the generation split between the front and back panels
Graph showing production for the front facing panels
Graph showing production for the back facing panels
The graphs below show the yearly generation split across both the back and front panels
Total Front Solar Generation
Total Back panel generation
Octopus Cosy
The costs shown here do include the standing charge. Any comparisons are compared to the unit cost if we were not on Cosy Octopus. There are two comparisons. One is the cost of what we imported from the grid for battery charging. The other is, the cost of the energy used by the house, house consumption.
February 2026 Grid Information
| Standard Tariff | 27.69p | |
| Standing Charge | 48.389p | |
| Cost from the grid | £117.78 (Cosy) | £216.59 (Standard) |
| Savings including export | £101.14 | |
| Exported (@15p kWh) | 15.50 kWh | £2.33 |
| Charging slots used | 266 | |
| Battery Suspended Slots | 182 | |
| Average unit slot price | 15.06p | |
| Cheapest slot | 14.62p | |
| Most expensive slot | 29.82p | |
| House consumed | 739.30 kWh | |
| Solar generated 2026/2025 | 123.60 kWh | 131.80 kWh |
| Battery Charged/Discharged | 433.50 kWh | 410.20 kWh |
| Percentage generated by solar | 17% | |
| Self Sustained Days (More solar than consumed) | 0 | |
| Self Sustained Days (More solar than we imported) | 0 | |
Here is the Octopus Watch report summary
Octopus Watch summary
Featured posts
Solar panel performance declines over the years. I thought it might be interesting to see how mine compares. Of course weather comes into it, but hopefully this will be a useful guide.