tim.... wrote:
I guess that this is off topic but I suspect that I will find some
experts here.

My sister has had a man around to quote for this and I've been tasked
with checking out if what she was told makes sense.

She has a bungalow with a shallow sloped roof and the quote was to
install 14 panels on an Easterly facing roof because the Southerly
facing one is shaded by a tree. So the figures a

Expected output 2928 kWh per year.

Returning 41.3 feed in tariff plus a saving on her electric bill of
50% of the output at say 12p and the other 50% output gains 3p from
the electric company.

The prices a

a) A "leasing" scheme whereby the householder pays an "installation"
fee of 2610.00 and receives the "free electricity plus the "3p" but
the company receive all of the 41.3 feed in tariff.

b) Outright purchase costing 18237.00 whereby the householder keeps
all of the returns.

I calculate that (a) returns around 220 pounds (8.4%) and (b) returns
1430 pounds (7.8%).

So the question is, are these figures actually achievable and is the
cost price competitive?

Does anybody know?

I agree with all the other posters to date. From what you describe, keep the
money in the bank earning interest which will be greater than the income and
still be an asset.