Photovoltaic solar panels (PVs) use light to generate electricity. They are particularly well suited to sites where a grid connection would be difficult or expensive or that are only used in the summer. For an independent power supply, solar works well with wind as there is a good balance of power throughout the year. For small-scale energy production, solar photovoltaics is the most reliable and the easiest to install.
Photovoltaic systems use photovoltaic cells to convert solar radiation into electricity. The cells consist of multiple layers of semi-conducting silicon-based materials. When light shines on the cells, an electric field is created across the layers, causing electricity to flow. The greater the intensity of sunlight, the greater the flow of electricity.
A single photovoltaic cell (above left) produces only a tiny amount of energy, so the cells are connected together into a solar panel (above right) in order to boost their power. Solar panels, in turn, can then be connected together in order to build larger and more powerful systems.
Start-up costs used to be high but have been falling by between 20-30% a year for most of the past decade and are now often the cheapest form of electricity production for micro power generation. Photovoltaic panels have some key advantages over other renewables:
- Easy to install
- Little or no maintenance
- No moving parts
- Can be sited virtually anywhere, so long as there is little or no shade
- More suitable for urban areas than other renewable energy sources