Energy savings

AlphaESS inverter joined to Octopus half-hourly meter reads and tariff prices.

Solar & battery installed by Heatable

£150 off solar £75 off a battery £150 off a heat pump £150 off air conditioning £50 off your Octopus bill Referrals

Presentation Data

2024 1 Jan 2024 – 31 Dec 2024 Updated 7th November 2026, 00:30 waiting on Octopus meter

Would have paid

£1,192.48

No panels, no battery

Saved on bills

£0.00

Against no solar and no battery

Actually paid

£1,192.48

Before export payments and standing charge · £1,192.48 net of export

Earned from export

£0.00

Export payments — real money in

Total benefit

£0.00

A lower bill plus export payments, over 3239 half-hours

Saved on bills is the gap between what you would have paid and what you actually paid. Total benefit is that saving plus the export payments.

Solar generation

0 kWh

No generation recorded

Heating

2,778 kWh

£770.87 of the bill · 59.8% of what the house used

Self-sufficiency

0.0%

4,645 kWh used, 4,645 kWh bought

Battery round-trip

—

0 kWh discharged

Where the benefit came from, by day

Solar and battery are separated by costing three worlds for every half hour — no panels and no battery, panels alone, then what actually happened — and taking the differences. A negative battery day is one that spent more storing energy than it gave back; it returns when the battery discharges. Export earnings sit inside the solar bar rather than beside it: the panels-alone world already sells its surplus, so that income is part of what solar is worth.

Solar (including export earnings) Battery

View as table

Day	Solar	Battery	Total	of which export	Imported
Tue 31 Dec	£0.00	£0.00	£0.00	£0.00	97.0
Mon 30 Dec	£0.00	£0.00	£0.00	£0.00	92.8
Sun 29 Dec	£0.00	£0.00	£0.00	£0.00	109.1
Sat 28 Dec	£0.00	£0.00	£0.00	£0.00	103.9
Fri 27 Dec	£0.00	£0.00	£0.00	£0.00	104.2
Thu 26 Dec	£0.00	£0.00	£0.00	£0.00	97.4
Wed 25 Dec	£0.00	£0.00	£0.00	£0.00	85.0
Tue 24 Dec	£0.00	£0.00	£0.00	£0.00	78.2
Mon 23 Dec	£0.00	£0.00	£0.00	£0.00	81.3
Sun 22 Dec	£0.00	£0.00	£0.00	£0.00	65.3
Sat 21 Dec	£0.00	£0.00	£0.00	£0.00	70.6
Fri 20 Dec	£0.00	£0.00	£0.00	£0.00	111.6
Thu 19 Dec	£0.00	£0.00	£0.00	£0.00	58.3
Wed 18 Dec	£0.00	£0.00	£0.00	£0.00	53.3
Tue 17 Dec	£0.00	£0.00	£0.00	£0.00	60.2
Mon 16 Dec	£0.00	£0.00	£0.00	£0.00	55.2
Sun 15 Dec	£0.00	£0.00	£0.00	£0.00	106.6
Sat 14 Dec	£0.00	£0.00	£0.00	£0.00	68.6
Fri 13 Dec	£0.00	£0.00	£0.00	£0.00	108.2
Thu 12 Dec	£0.00	£0.00	£0.00	£0.00	70.5
Wed 11 Dec	£0.00	£0.00	£0.00	£0.00	67.0
Tue 10 Dec	£0.00	£0.00	£0.00	£0.00	64.4
Mon 9 Dec	£0.00	£0.00	£0.00	£0.00	90.5
Sun 8 Dec	£0.00	£0.00	£0.00	£0.00	80.6
Sat 7 Dec	£0.00	£0.00	£0.00	£0.00	68.4
Fri 6 Dec	£0.00	£0.00	£0.00	£0.00	59.4
Thu 5 Dec	£0.00	£0.00	£0.00	£0.00	63.7
Wed 4 Dec	£0.00	£0.00	£0.00	£0.00	78.1
Tue 3 Dec	£0.00	£0.00	£0.00	£0.00	68.5
Mon 2 Dec	£0.00	£0.00	£0.00	£0.00	64.3
Sun 1 Dec	£0.00	£0.00	£0.00	£0.00	63.1
Sat 30 Nov	£0.00	£0.00	£0.00	£0.00	64.2
Fri 29 Nov	£0.00	£0.00	£0.00	£0.00	78.6
Thu 28 Nov	£0.00	£0.00	£0.00	£0.00	89.8
Wed 27 Nov	£0.00	£0.00	£0.00	£0.00	68.6
Tue 26 Nov	£0.00	£0.00	£0.00	£0.00	61.3
Mon 25 Nov	£0.00	£0.00	£0.00	£0.00	58.3
Sun 24 Nov	£0.00	£0.00	£0.00	£0.00	75.0
Sat 23 Nov	£0.00	£0.00	£0.00	£0.00	76.7
Fri 22 Nov	£0.00	£0.00	£0.00	£0.00	67.7
Thu 21 Nov	£0.00	£0.00	£0.00	£0.00	88.4
Wed 20 Nov	£0.00	£0.00	£0.00	£0.00	78.5
Tue 19 Nov	£0.00	£0.00	£0.00	£0.00	53.5
Mon 18 Nov	£0.00	£0.00	£0.00	£0.00	49.6
Sun 17 Nov	£0.00	£0.00	£0.00	£0.00	49.8
Sat 16 Nov	£0.00	£0.00	£0.00	£0.00	52.7
Fri 15 Nov	£0.00	£0.00	£0.00	£0.00	42.2
Thu 14 Nov	£0.00	£0.00	£0.00	£0.00	45.2
Wed 13 Nov	£0.00	£0.00	£0.00	£0.00	53.8
Tue 12 Nov	£0.00	£0.00	£0.00	£0.00	71.2
Mon 11 Nov	£0.00	£0.00	£0.00	£0.00	71.0
Sun 10 Nov	£0.00	£0.00	£0.00	£0.00	65.0
Sat 9 Nov	£0.00	£0.00	£0.00	£0.00	75.9
Fri 8 Nov	£0.00	£0.00	£0.00	£0.00	72.1
Thu 7 Nov	£0.00	£0.00	£0.00	£0.00	59.0
Wed 6 Nov	£0.00	£0.00	£0.00	£0.00	67.1
Tue 5 Nov	£0.00	£0.00	£0.00	£0.00	71.7
Mon 4 Nov	£0.00	£0.00	£0.00	£0.00	72.1
Sun 3 Nov	£0.00	£0.00	£0.00	£0.00	52.6
Sat 2 Nov	£0.00	£0.00	£0.00	£0.00	43.6
Fri 1 Nov	£0.00	£0.00	£0.00	£0.00	42.7
Thu 31 Oct	£0.00	£0.00	£0.00	£0.00	39.3
Wed 30 Oct	£0.00	£0.00	£0.00	£0.00	35.9
Tue 29 Oct	£0.00	£0.00	£0.00	£0.00	42.2
Mon 28 Oct	£0.00	£0.00	£0.00	£0.00	56.0
Sun 27 Oct	£0.00	£0.00	£0.00	£0.00	42.8
Sat 26 Oct	£0.00	£0.00	£0.00	£0.00	44.8
Fri 25 Oct	£0.00	£0.00	£0.00	£0.00	21.2

Cumulative benefit

Running total across the selected window.

Tuesday 31 December 2024, half by half

Energy arriving above the line, energy leaving below it, and the price you were paying on the same timeline. Charging through a cheap window and discharging through an expensive one is the shape to look for.

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Solar generated Imported Exported (below the line)

Return on investment

Measured across everything on record (7 Apr 2025 to 7 Nov 2026), not the range selected above — annualising a fortnight of summer would roughly double the apparent return. The yearly figure comes from the trailing twelve months, so it covers a full seasonal cycle.

Recovered so far

£4,529

of £18,990

23.8% recovered £14,461 to go

Benefit per year

£2,651

Trailing 12 months

Annual return

14.0%

Of the £18,990 outlay

Full payback

5.5 yrs

Around Apr 2032

Versus saving it

+£3,154

Ahead of £1,375 at 4.50% a year

Versus investing it

−£3,796

Behind £8,325 from FTSE All-World

£18,990 put into FTSE All-World (VWRP.L) on 7 Apr 2025 and left alone would have been worth £27,315 on 6 Nov 2026 — a gain of £8,325. The system has handed back £4,529 over the same dates. That is the real closing price of a real fund, not an assumed rate; it is an accumulating class, so dividends are in it. No dealing costs and no tax, both of which would only make the fund look worse. The energy bills are already in this, which is the part that catches people out: £4,529 is not profit, it is the bill that did not arrive. Hold the money instead and you pay that bill in full — so the two sides are the financial benefit of each world over the same dates, with the electricity accounted for on both. Gains are compared with gains: an investment still has its £18,990 at the end and this system has hardware with a finite life instead. Two things the comparison leaves out, both of which favour the panels — these savings are not taxed, and they rise with the price of electricity. And 1.6 years is far too short a run for a stock market to mean much: this is what happened, not what tends to.

Left in a savings account at 4.50% instead, it would have earned £1,375 over the same period — the risk-free version of the same question. That rate is a sustained one rather than a headline best-buy: the base rate was 3.75% in October 2026 and the accounts paying a flat rate with no stepped bonus were around 4.3%. Interest on a balance this size runs close to the personal savings allowance, and past it for a higher-rate payer, which this does not deduct.