The Guildford Ambient picnic had at least one stage where only solar or renewable energy was permitted; some of the equipment was powered by an auto-tracking solar cell and a large bank of ex-MOD submarine batteries. This was enough to power a fairly large sound system.

There was also a large bus with a wind generator, which some Europeans had brought in.

This stuff is certainly feasible – and I know crews who want to do it.

The problem at the moment is most events are unlicensed to the priority is unfortunately finding the venue and keeping plod from stopping it – TBH the environmental impact of free parties as a whole can be fucking appalling (trash, extra traffic, mindless vandalism) and needs to be addressed.

It does need a bit of tolerance on the “other side” though so people can set up in “safe havens” without risk of being turned over..