Solar Gurus, please disect!

[SteamyTea]

47 minutes ago, SimonD said:

north face

So put up expensive panels that have lower efficiency, facing away from the sun for 9 months of the year. Just offer to pay a quid per kWh for your electricity.

There are much easier cash savings to be made.

[Nickfromwales]

9 hours ago, SteamyTea said:

So put up expensive panels that have lower efficiency, facing away from the sun for 9 months of the year. Just offer to pay a quid per kWh for your electricity.

There are much easier cash savings to be made.

North facing does come into play for some of our proposals, but only when economy of scale (and sufficient irradiance) justify it; mostly on very large or commercial projects but almost never sensible on domestic.

[SteamyTea]

1 hour ago, Nickfromwales said:

North facing does come into play for some of our proposals

Nearly half the yearly production though, so effectively doubling the installed price.

 

Left is South facing and right is North facing.

 

[SimonD]

15 minutes ago, SteamyTea said:

Nearly half the yearly production though, so effectively doubling the installed price.

Nowhere near doubling the install cost, partly because it's a self install. It takes me up an inverter size (just), but this is helpful if I can add more panels somewhere else in time. The marginal cost of this is less than £100 for the inverter up-size, plus about £500 in panels and the rails, a few hundred quid maybe. Using planned 510W panels, and only assuming a 30-35% generation ratio, I'd still get about £120-£250 generation gain per year - it's essentially a free way to widen the generation window during the summer due to gains morning and evening. Personally I think the numbers actually stack up as the TOU tariff we're on is 30p peak/kWh

A few years ago someone in the solar industry talked me out of accepting a load of panels removed from a commercial installation where they were going through a standard 10 year swap out. I always regret that decision. If I have the opportunity now to build in long-term almost free value, I'm going to take it.

 

[SimonD]

1 hour ago, Nickfromwales said:

but almost never sensible on domestic.

This is a timely reminder to always run the numbers!