Year 1 7 Apr 2025 – 6 Apr 2026 Updated 8th November 2026
Total benefit
£2,809
Saved on bills
£1,795
Earned exporting
£1,013
Top solar day
70.7
kWh on 16 May 2025
Solar generated
9,451
kWh · 28% used at home
Battery discharged
6,375
kWh · £876 of the saving
Exported
6,801
kWh sold back to the grid
EV charging
£177
2,531 kWh · not counted as saving
Would have paid
£3,904
with no solar and no battery
Actually paid
£2,109
before export payments and standing charge
Household use
15,918
kWh · 12% not bought from the grid
Paid back
24%
£4,536 of £18,990 · 5.5 yrs to go
Heating
7,315
kWh · £968 of the bill
By month Apr → Apr
Solar Used Battery Exported Benefit (£) Cash flow (£)
2,228 0 kWh £333 0 −£413

This tool was built with Claude

Every line of it — the Octopus and AlphaESS clients, the settlement model, this screen — was written in conversation with Anthropic's Claude. Here is what that cost.

Tokens
110.8million
across 364 requests · measured
Electricity
2.3kWh
estimated · 0.7–8.3
Carbon
294g CO₂e
estimated · 83–1,039
Fresh water
2.5litres
cooling only · 0.7–9.0

Roughly 3.3% of what this roof made on its best day.

Only the token count is measured. Anthropic publishes no per-token energy figures, so the rest is inferred from Google's first-party measurements of its own models and from published per-token estimates — two methods that disagree by about ninety times, which is why these are ranges and not numbers. The water figure covers datacentre cooling only, not the water used to generate the electricity, so read it as a floor. Model training is excluded: it is shared across everyone who ever uses the model and cannot be fairly attributed to one project.

By month Apr → Apr
Solar 9,451kWh Used 15,918kWh Battery 6,375kWh Exported 6,801kWh Benefit (£) £2,809 Cash flow (£) −£1,096
2,228 0 kWh £333 0 −£413
Apr Jun Aug Oct Dec Feb Apr