Therefore it might not be best described as a market failure. It could be better described as a failure due to planning regulations that only give power to land-owners.
This is big problem in Europe, since as you point out: many people rent.
If a proposition for solar panels is actually realistic and a net positive, the owners should be easily convinced without resorting to force.
They do not pay for the electricity used in the property.
Therefore there is no way for it to be in their economic interests.
I would certainly pay a bit more in rent for a place where my energy use was subsidized by panels.
The incentives of the owner need to be aligned with the incentives of the tenant, that is the failure.
Either, as you point out, tenants need to be given powers to install solar panels, and given security of tenure to take advantage of the long term investment, (which seems to me would go further than mere planning regs). Or incentivise the owner to install solar panels, this seems more straight forward, although might not necessarily benefit the tenant.
In terms of concrete results the second one seemed like a likely candidate to me. Donating to them is unacceptable to me because they are based in the US and require a lot of personal information before they will accept a donation.