March Solar Generation and Export Numbers
The month started well with 3 days of low double digit production. On those days we even managed to export a decent amount for this time of year. The clouds then came back and production was 5 kWh or lower. We have still being charging the batteries from the grid from 4am to 7am. Weather improved around the 10th.
Export rates changed this month. They came down to 12p. This is now less than the import rate. It was the second best ever March generation which surprised me. Last year was a remarkable 407.30 kWh.
For the first time this year we had days where we generated more solar than we imported from the grid, 6 days.
Solar Generation
Looking at the numbers, we generated 342.10 kWh this month. That is a drop of 65.20 kWh compared to last year, but 219 kWh more than February. Solar production covered 46% of our house consumption.
Battery Performance
We used 183, 30 minute grid charging slots this month. We also had 167, 30 minute battery suspended slots this month, showing the system managed to suspend charging as the generation increases.
We charged the battery back to 100% via the grid during the cloudy spells. Battery Charged (kWh) this month was 352.80, and Battery Discharged (kWh) this month was 342.90. The battery has been staying topped up for longer. This led to the lower charging slot requirement.
Grid Usage
Grid Import this month was 478.60 kWh. The cost from the grid on our Cosy tariff this month was £80.36, while the Standard Tariff imported cost this month would have been £118.07.
Our Standing Charge was 48.389p. The current price cap per kWh was 27.69p. The Average grid slot cost this month was 15.07p. The Cheapest Grid Charging Slot this month at 14.62p, while the most expensive grid charging slot this month was 29.82p.
Our average unit cost for the year is 15.07p, and the average price cap for the year is 26.94p. The cheapest day was 22/03/2026 - £1.80.
Cost Savings Summary
Despite some cloudy weather, spring is kicking in and solar generation is improving, we still found value in our solar setup. We achieved savings compared to import kWh this month of £44.31. Even more importantly, we found savings compared to house consumption kWh of £110.55. Exported (kWh) this month was 44.00, giving us Exported Savings this month of £6.60.
We hope you enjoyed reading our March update. Stay tuned for our next generation report!
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 | 26 March 2026 | 19.00 |
| Best front generation | 26 March 2026 | 12.80 |
| Best back generation | 21 March 2026 | 7.30 |
| Worst generation | 6 March 2026 | 2.40 |
| Worst front generation | 6 March 2026 | 1.20 |
| Worst back generation | 6 March 2026 | 1.20 |
Export and Profit (Rate 12p kWh)
| Metric | Date | kWh | Profit |
|---|---|---|---|
| Best Battery and Solar Export Profit | 21 March 2026 | 5.00 | |
| Best kWh export day (Solar) | 21 March 2026 | 5.00 | |
| Best export profit | 21 March 2026 | 5.00 | £0.60 |
| Cheapest Day | 22 March 2026 | £1.80 |
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
Energy Breakdown
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.
Overview for the month
| Standard Tariff | 27.69p | |
| Standing Charge | 48.389p | |
| Cost from the grid | £80.36 (Cosy) | £118.07 (Standard) |
| Savings including export | £44.31 | |
| Exported (@12p kWh) | 44.00 kWh | £6.60 |
| Charging slots used | 183 | |
| Battery Suspended Slots | 167 | |
| Average unit slot price | 15.07p | |
| Cheapest slot | 14.62p | |
| Most expensive slot | 29.82p | |
| House consumed | 747.10 kWh | |
| Solar generated 2026/2025 | 342.10 kWh | 407.30 kWh |
| Battery Charged/Discharged | 352.80 kWh | 342.90 kWh |
| Percentage generated by solar | 46% | |
| Self Sustained Days (More solar than consumed) | 0 | |
| Self Sustained Days (More solar than we imported) | 6 | |
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.