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UK Solar PV flyer - snake oil or just sloppy?


Jim Backus

Jan 1, 1970
A leaflet delivered recently included the following:

"The Department of Energy and Climate Change will apply the following
tarriff for feed in:

41.3p for every unit generated by your solar PV equipment
plus 0.03p for every unit exported to the National Grid

What does this mean to you in real terms?

Typically a PV solar installation of 3kW will generate approx 2.57kW
of power.
41.3p x 2570W will mean a total annual generation cash back payment
of GBP1,061.

If 1.28kW of the 2.57kW generated is not consumed by you in the home
and is
exported to the grid you will receive and additional payment of

It continues in similar vein.

The first thing I notice is that the author uses 'kW' and 'unit'
interchangeably. A unit in the UK
is 1kWh. It may be that this is deliberate to avoid confusing the lay
reader but it sure
confuses me!

So working back from the cash back payment of GBP1061 and the per unit
rate of 41.3p this
implies that a 3kW installation is capable of generating 2,569kWh over
a year. Alternatively,
assuming an average of 12 hours 'sun-up' daylight per day over a year
this suggests an
average generation of 586W.

Question 1: is this a realistic output for the UK bearing in mind that
the latitude of the UK is between 50 & 60 degrees North?

The second point concerns the power exported to the National Grid. If
we assume that the 1.28kW quoted means 1,280kWh then the additional
payment should be GBP0.38.

Question 2: has my maths failed me or has the leaflet calculated the
additional payment based on GBP0.03 instead of GBP0.0003?

All comments gratefully received - TIA

Jim Backus

Jan 1, 1970
Answer 2.

The UK Feed-In tariff 'The Clean Energy Cashback scheme' stipulates a
minimum export tariff of 3p per kWh exported. The producer of your
flier made the mistake of suffixing with p rather than prefixing with

Apologies for the blatant plugs but I hope the information helps.

Thanks for your reply and Jean Marc's

It looks as though the flyer was more sloppy than deliberately
misleading; as an engineer these mistakes are very apparent. However
it is probably misleading to quote the benefit from the export tariff
when the average UK household consumption is significantly more than
would be generated by a 3kW array.

I'll have a look at the links offered. My house has a generally south
facing pitched roof and might accomodate both solar PV and solar hot