Panels & output
How much electricity does a 300W solar panel generate?
A 300W panel is at the compact end of the panels used in plug-in solar — a good fit where space is tight, such as a small balcony. Its 300W is a rated figure, so the practical question is the energy it produces in real UK light.This guide gives realistic figures and context. For how the sizes compare, see the wattage guide.
Written and edited by Christopher Panteli
Christopher is the founder and editor of MyPlugInSolar. He oversees the site’s research standards, data tools and editorial process. He is not an electrician or solar installer, and specialist technical claims are sourced from official documentation or reviewed by appropriately qualified professionals.
Realistic 300W output
Using the UK rule of thumb of roughly 0.8–0.95 kWh per year per watt for a well-sited, south-facing panel, a 300W panel produces around 240–285 kWh per year in good conditions — less if it's shaded, vertical or poorly angled. For a figure based on your location, use the calculator.
| Period | Indicative output |
|---|---|
| Bright summer day | 1.2–1.8 kWh |
| Dull winter day | 0.1–0.4 kWh |
| Full year | 240–285 kWh |
Where a 300W panel fits
A single 300W panel suits compact balconies and small walls where a larger module won't fit. Two 300W panels (600W DC) work well on an 800W microinverter. The factors that change output — orientation, tilt and shade — matter more than the exact rating; see direction and angle and shading.
Output versus savings
As with any size, a 300W panel only saves money on the electricity you use while it's generating. Match it to your daytime base load, and remember plug-in solar is not yet legal to use in the UK (legal status).
Frequently asked questions
- How much does a 300W solar panel produce per day?
- It varies by season — roughly 1.2–1.8 kWh on a bright summer day and a few tenths of a kWh on a dull winter day, averaging around 240–285 kWh across a good UK year when well sited.
Sources
- 1. PVGIS (Photovoltaic Geographical Information System) — European Commission, Joint Research Centre
Estimate your solar potential
See how much electricity a small system could generate at your postcode, and the indicative bill saving.