The amount of electricity that you will be able to generate from your panels depends on: 

  • The size of the system (number of panels, and the power rating of the panels) 
  • The amount of light that falls on your panels, which is determined by their orientation and any overshadowing and your location in the UK. 

Electricity generation is not constant – it varies dramatically both across the day and across the year, to reflect the changing levels of light. 

This depends on where you live and the orientation of your roof. There is standard data table for the UK that provides one single factor for Cumbria.  

The power of typical solar panels is currently around 400Wp (the p stands for ‘peak’ and 400W is the power of the panel in standardised laboratory tests). For a 12 panel system, the total power is therefore 4.8kWp. Using the standard Cumbrian factor, this will result in an estimate that the system on a south-facing roof, will generate around 4,000 kWh per year. 

However, there is a variance across Cumbria since some places are sunnier or cloudier than average. So be mindful that the quote you receive might be an over- or under-estimate of what your system will produce. You can explore the differences across Cumbria on this map.