A large private system like a nuclear plant is owned by one or a relatively few people to the many it supplies. This is a monopoly. If it is owned by the public/Government it is payed for by the customers/taxpayers but the profits are controlled by the few who build and run the facility or manage the levers of power.
A small electrical generating system can be afforded by a single person, and that person will pay himself with the savings from the system. The problem with this model is that only the wealthy and/or powerful people in society get the proceeds from the subsidies that encourage the use of alternate energy. This is capitalist democracy that makes the rich richer while it makes the poor poorer.
The alternative to these ways of doing things is the P3. This is a 'public private partnership' which does not work for the benefit of the taxpayer because private businesses are controlled by shareholders who can only make a profit if they sell their shares to the highest bidder. Really bad when the investors are private equity funds run by managers who are obliged to make the greatest profit for their investors. Community funding ultimately is controlled by a foreign national whose Government gives a 150% tax credit for investing in foreign countries. Local decisions are made by people living on the other side of the world.
This situation could be avoided if the community owned the generating system and the shareholders had to be residents of the community and not allowed to own more than 1% Investments in such a sustainable community system would stay in the community.