# UK plug-in solar yield by city, methodology

**Source file:** `uk-plug-in-solar-yield-by-city.csv`
**Publisher:** Plug Solar Hub (plugsolarhub.co.uk)
**Maintained by:** Adeniyi Adeniji, Founder
**Snapshot date:** April 2026
**Cities covered:** 29 UK reference cities (England, Scotland, Wales, Northern Ireland)

## What this dataset contains

For each of the 29 reference cities, one row showing:

1. Annual generation in kWh per year for an 800W south-facing plug-in solar kit at 30 to 35 degree tilt with a performance ratio of 0.82.
2. Modelled annual savings at three self-consumption rates (30%, 45%, 60%).
3. Modelled annual savings with a battery, at 85% effective self-consumption.
4. Payback period in years at the mid self-consumption rate, and with a battery.

## Yield source

Annual generation figures are PVGIS-derived (European Commission, Joint Research Centre, Photovoltaic Geographical Information System, version 5.3) for each city's centroid coordinates. Inputs to PVGIS:

- System size: 800W (typical UK plug-in solar kit ceiling under the BSI plug-in solar product standard expected July 2026, and matching DNO G98 sub-800W threshold)
- Orientation: south
- Tilt: 30 to 35 degrees (UK optimum is roughly latitude x 0.76 + 3.1 degrees per Duffie and Beckman)
- Loss / performance ratio: 0.82 (covers inverter efficiency, soiling, wiring, temperature)

The same PVGIS source is used live in the `/calculator` tool at plugsolarhub.co.uk for postcode-resolved estimates. The static CSV is the city-level baseline; the live tool refines using exact lat/lng from postcodes.io.

## Savings model

Annual saving = (self-consumed kWh x import rate) + (exported kWh x SEG export rate)

- Import rate: **27.7 p/kWh**, Ofgem Q2 2026 default tariff cap (1 April to 30 June 2026, Direct Debit, national average).
- Export rate: **5 p/kWh**, indicative Smart Export Guarantee rate (Octopus Outgoing equivalent; varies by supplier).
- Kit cost: **GBP 499**, current UK retail benchmark for an 800W plug-in kit (April 2026).

## Self-consumption sensitivity

- **Low (30%)**: working household, weekdays mostly out, no battery.
- **Mid (45%)**: default model, mixed occupancy.
- **High (60%)**: working-from-home or part-time-home household, no battery.
- **With battery (85%)**: typical 1.92 to 2 kWh battery (Stream Pro / EcoFlow class).

## Underlying authorities cited

- PVGIS v5.3, European Commission JRC: https://re.jrc.ec.europa.eu/pvg_tools/en/
- Ofgem Q2 2026 default tariff cap: https://www.ofgem.gov.uk/energy-regulation/domestic-and-non-domestic/energy-pricing-rules/energy-price-cap
- BS 7671:2018 + Amendment 4:2026, IET Wiring Regulations: https://knowledge.bsigroup.com/articles/bs-7671-2018-a4-2026-pre-order-the-latest-amendment-to-the-uks-wiring-regulations
- BSI plug-in solar product standard (expected July 2026): announcement at https://www.gov.uk/government/news/government-to-make-plug-in-solar-available-within-months

## Citation

Plug Solar Hub, 2026. *UK plug-in solar yield by city*. April 2026. Available at: https://plugsolarhub.co.uk/data/uk-plug-in-solar-yield-by-city.csv

## Licensing

CC BY 4.0. Free to use with attribution to Plug Solar Hub.

## Contact

Adeniyi Adeniji, Founder, Plug Solar Hub
a.adeniji@hotmail.com
plugsolarhub.co.uk