Tim wrote:
This story caught my eye this morning.

http://m.stv.tv/news/scotland/east-c...-solar-meadow/

A college plans to spend £300,000 on a solar array generating 1076 KW and
are expecting to save £150,000 a year on electricity bills. The surplus
will be used locally and there is no mention of any FIT.

Can this possibly work or has someone got their sums very wrong?

Tim
"generate 1076KW of energy a day"

A KW is not a unit of energy.

So is impossible to say what the thing means.

Lets say there is 1076KW of panel *capacity*. That's about 1000 square
meters. Not unreasonable - say 30 x 30m.

But if they reckon to install 1000 square meters of panels for £300,000
they must be on a different planet. Id say £1000/KW capacity is nearer
the mark so make that £1M installation, give or take.


Now the AVERAGE insolation in Scotland is about 90w/sq m day and night
summer and winter.

So at say - 30%? - efficiency that's 30W/sq meter so 30KW average,

rounding up to 10,000 hours in a year that's 300MWh.

At 20p extortion rate per unit that's £60,000 a year for electricity
whose wholesale value is about £12,000, and which could be bought retail
for around £30,0000

So net savings are £30,000 against a capital cost of about £1m

ROI of 3%?

Now add in 7.5% O & M and depreciation, and the O & M bill is now
£75,000 p.a.

So a net annual loss of £45,000 for a capital expenditure of a million.

You can see why solar PV is no longer worth installing when the FIT rate
drops from 45p to 20p a unit.