Why would we not put community solar on house roofs?

The two main reasons why community energy projects tend to put solar in at a larger scale rather than on individual home rooftops are

Cost: The cost per kWh generated is much lower, partly just economies of scale and partly because the individual home rooftop has additional building costs, such as scaffolding

Commercial complexity: Since the asset is owned by the community social enterprise it requires an agreement to host it for the duration of the asset (typically ~25 years). Doing this for one or two large-scale locations is relatively easy, it’s quite complex with individual homes. Plus selling electricity coming from multiple homes would be complex too

For some communities, “large scale” can include large rooftops of community buildings, for example, a school or business. But for Somerford Keynes village there isn’t really anything large scale unless one of the very large houses was willing to host.

Of course, this doesn’t preclude individuals from putting solar on their own roofs. Having a combination of community and personal generation can work at the same time.