How do solar panels work?
Solar panels work by using photovoltaic (PV) cells to turn daylight into direct current (DC) electricity. An inverter then converts that into the alternating current (AC) your home uses. You use the electricity as it is generated, store the surplus in a battery, or export it to the grid for payment. Panels generate from daylight, not direct sun, so they produce power even on cloudy UK days.
The process, step by step
- Daylight hits the photovoltaic cells in each panel and knocks electrons loose, creating DC electricity.
- An inverter converts the DC into 230V AC electricity for your home.
- Your appliances draw this free electricity first, before any grid power.
- Surplus charges a battery (if fitted) or is exported to the grid under the Smart Export Guarantee.
- At night or on dull days you simply draw from the battery or the grid as normal.
What a panel actually produces
A typical modern panel is rated at around 400 watts. In the UK each kilowatt-peak (kWp) of panels generates roughly 850 kWh of electricity a year, adjusted for your region, roof direction and shading. So a common 5 kWp system of about 13 panels produces around 4,000 kWh a year, a large share of an average home's electricity.
Frequently asked questions
- Do solar panels need direct sunlight?
- No. Panels generate from daylight, so they produce electricity under cloud, just at a lower output than in bright sun.
- What happens to electricity I do not use?
- It charges your battery if you have one, otherwise it is exported to the grid and you are paid for it through the Smart Export Guarantee.
Related questions
Indicative estimates based on UK average data. Last updated 27 May 2026.