The roofs of domestic-scale properties used to haveone overall main function – to keep the weather out. But since the first solar-PV panels were fitted in the UK in 1994, it has become increasingly clear that, to reduce carbon emissions and thus contribute to the transition to net-zero, all suitable roofs need to be electricity generators as well as weather protection.

Based on the author’s 10 years’ experience of roof-mounted PV systems, this paper reports on system performance over the recent 3½ years, including part-charging an electric car. The practicalities of specifying the system , the options available and the operational considerations complete the exploration of a modern system. The paper reports in some detail on the results from 3½ years’ operation.

The paper also explores financial considerations, largely in a UK context, but a framework is given for decision-making in other generation and financial situations.

Finally, the paper briefly discusses the wider implications of such systems, for example for local and national AC grids.