'Free' solar PV panels?
There are currently at least 3 alternative schemes in which you can get 'free' solar PV panels, or at least what amounts to free in real terms. (In all cases, an MCS accredited installer should do the work involved, or eligibility for the schemes is not possible.)
1. You can register your interest in the Green Deal. Under this scheme, you take out a government backed loan to cover the cost of the panels. The loan repayments are recovered through your electricity bill, with a Golden Rule stating that you should pay out no more on the bill than you would have otherwise. With no upfront cost and the Golden Rule, this amounts to improving your property's energy efficiency at no extra cost to you overall. The lowering of the amount of energy you take from the grid offsets what you would pay out. You may self fund part of the cost of the measures to reduce the charge on the electricity bill. Government cashback is on offer for the various measures covered by the Green Deal.
2. You can self fund your panels, taking out a low cost loan, then benefit from the Feed in Tariff (FiT) and the free electricity generated. The Tariff and the energy bill savings should cover the cost of repayments in the first year and out perform in subsequent years.
3. You can apply for the 'Rent a Roof' scheme whereby an investor pays for your installation, but they take the Feed in Tariff payments in return. The investor owns the panels and has responsibility for maintaining them, after all, if they're not working, they get no revenue.
From the above, you can see that if an investor is willing to install on your property, then the pay back must be profitable for them. This is why we tend to recommend self funding with a low cost loan.