Last year we had a Year 10 student from a local secondary school carry out a project for Chester Community Energy as part of the volunteering section of her Duke of Edinburgh Bronze Award.

The project used generation data from our 3 PV sites; she looked for patterns in our data and compared our generated data with the expected production (that was used in the business case at the beginning of the project).

Her main conclusions were:

• The predicted generation figures used in the CCE financial model have been very pessimistic for all sites and all years apart from 2024 (a very poor year for solar generation). For all sites and all years generated electricity has been significantly higher than predicted by between 6 – 17%.
• Year to year variation in production is so great that no conclusions can be drawn about typical yearly degradation (which was fixed at 0.72% in the financial model). i.e the annual variance in the data meant we were unable to determine an annual degradation rate for the panels; manufacturers data could not be confirmed nor denied.
• The largest variation of generation for specific months as a percentage of the average was in winter. We think this is because the weather is more random and as a result having one sunny day makes a significant difference as well as having less generation anyway due to less hours of sunlight.
• There is a significant difference in generation between Neston and Christleton, but we don’t know why (approx 5%); they are of the same age, similar size, orientation and inclination.

The report is attached for your interest – as many of you also have PV panels at home, and no doubt also carry out some data analysis of your own systems, we thought you may be interested in her findings!

Link to DofE CCE data analysis report

As a Board we would like to encourage this sort of investigation – if you are interested in delving deeper into the CCE dataset and have the time to do some work in this area, please let us know.