People often ask whether running an off-grid home makes financial sense. After twenty years of keeping detailed records, we can give an honest answer — and the answer is yes, comfortably. We have no electricity bill, we generate a meaningful tax-free income, and our running costs are well understood and predictable.
What it cost to build
The system came together in stages over eleven years, as technology improved and prices — particularly for solar — fell dramatically.
| Item | Year | Net cost |
|---|---|---|
| Wind turbine, SMA control equipment, original battery bank, planning | 2006–07 | ~£17,600 |
| Kevlar blade replacement | 2009 | £1,050 |
| Solar PV — 4 kWp across two roofs | 2012 | ~£7,200 |
| Industrial traction battery bank replacement | 2017 | ~£6,000 |
| Total capital invested | ~£31,900 |
The 2007 installation benefited from a £5,000 government grant; the figure above is net of that. The solar in 2012 was partly self-installed, which kept the cost down — and by then panel prices had fallen to a fraction of their 2007 levels, making the addition an easy decision.
The alternative — connecting to the public mains — was quoted at £115,000 in 2006 for a 2km buried cable from the A47 (overhead lines not being permitted in the Broads National Park). Off-grid was not a lifestyle choice; it was straightforwardly the sensible option.
Running costs
Twenty years of records give a clear picture of what the system actually costs to run. The headline is that costs have fallen substantially over time as diesel use has declined — and the largest single cost category, fuel, is now a fraction of what it was in the early years.
Diesel fuel
The system has matured significantly since installation, and the diesel generator now runs less and less. In the early years (2007–2017), with the original battery and only the wind turbine and later 2012 solar to support it, the generator started automatically 90–250 times a year. Since the upgraded traction batteries were installed in November 2017, that has dropped dramatically — to between 23 and 35 auto-starts a year, totalling fewer than 250 running hours.
Spring and summer typically deliver multi-month renewable-only runs. The longest unbroken stretch on record is 148 days (March to July 2019), with comparable runs of 135 days in 2022, 121 days in 2024, and 116 days in 2025. As of early May 2026, the current run is 56 days and counting, since 9 March. A single delivery of diesel now lasts 18 months or more.
| Period | Annual diesel cost |
|---|---|
| 2005–2006 (generator as primary source) | ~£2,300/year |
| 2009–2012 (wind turbine running, no solar yet) | ~£1,200/year |
| 2013–2017 (wind and solar combined) | ~£580/year |
| 2021–2025 (current position) | ~£400/year |
Wind turbine maintenance
The turbine is maintained biennially by an experienced wind turbine engineer — lowered, inspected, springs checked, bearings re-greased. It is a straightforward routine that has kept the machine reliable for nearly two decades. Average annual cost over the full period: approximately £490, though recent visits have run higher as costs have risen with inflation.
Generator servicing
Annual servicing by a local engineer who has looked after the engine throughout. At its current rate of use the engine barely works up a sweat. Average annual cost: approximately £75.
Solar panels and SMA inverter equipment
In thirteen years of continuous operation, the solar panels and their Sunny Boy inverter have required no maintenance and no repairs whatsoever. No callouts, no component replacements, nothing. This is probably the most striking single fact about the system's reliability.
Running costs in summary
| Item | Average per year (full 20-year period) | Recent years |
|---|---|---|
| Diesel fuel | ~£890 | ~£400 |
| Wind turbine maintenance | ~£490 | ~£600 (biennial, amortised) |
| Generator servicing | ~£75 | ~£60 |
| Unscheduled repairs | ~£70 | ~£200 (prudent reserve) |
| Solar and SMA equipment | £0 | £0 |
| Total | ~£1,525/year | ~£1,260/year |
The early years were more expensive than they needed to be — the generator ran more heavily than it should have while the wind system's configuration was being optimised. Running costs have settled considerably since then and are now broadly stable.
The Feed-in Tariff
Both the wind turbine and the solar panels are registered under the UK government's Feed-in Tariff (FiT) scheme, which pays a guaranteed rate for every unit of electricity generated — whether used in the house or not. The payments are index-linked, rising each April with RPI, and entirely tax-free. They are backed by a government contract, not subject to market fluctuation.
Current generation rates (before the April 2026 RPI uplift): approximately 16p/kWh for the wind turbine and 26p/kWh for the solar panels. Based on our historical generation averages — around 3,500 kWh/year from the turbine and 6,300 kWh/year from the solar — the combined annual FiT income is approximately £2,300/year.
Total received since the scheme began: approximately £15,300. With the wind contract running to April 2030 and the solar contract to October 2032, there is approximately £13,400 of further income still to come.
The financial picture overall
Adding it all up — FiT income, avoided electricity bills, and running costs — the system currently delivers a net financial benefit of around £2,760 per year compared with being on the grid. That figure has grown as electricity prices have risen and as the system has become more efficient; it was considerably smaller in the early years when the generator was running heavily.
Over twenty years the cumulative avoided electricity bill alone — nothing paid for electricity since 2005, no standing charges — runs to an estimated £24,000 at conservative historical rates. At current rates of 24p/unit plus £220/year standing charge, the annual saving is around £1,720 and rising.
The system has not been cheap to build or to run. But it has worked — consistently, reliably, and with improving economics year on year. The investment has been justified many times over.
Financial figures are based on our own verified records spanning 2005–2026. Averages are calculated across the full operating period. FiT projections assume continued generation at historical averages with annual RPI uplifts of approximately 3–4%. Electricity saving estimates use current unit rates and standing charges.