Solar Payback 14 July 2021 at 10:36PM in Green & ethical MoneySaving 27 replies 661 views

Spies

So I know that these days it's really not feasiable for these panels to save you a considerable amount of money now that the FiT scheme has gone and I've tried to base my calculations on realistic use.

Would you say 30 years ROI is a sensible assumption on a system costing £4650?

Cardew

Considering ROI in purely economic terms you should take into account the loss of interest/cost of borrowing. Also repairs, inverters are costly.

Reed_Richards

My solar panels were "sold" based on a projection that the cost of grid electricity would rise year-on-year so the cost savings would rise. 

EricMears

Reed_Richards said:

My solar panels were "sold" based on a projection that the cost of grid electricity would rise year-on-year so the cost savings would rise. 

That would be a reasonable assumption - though many installers have taken a vastly inflated view of how much prices would rise.

Exiled_Tyke

Not that it will change the figures dramatically but for me with similar generation figures to this I use 100% of generation in winter as generation pretty much equals base load during the short days.   Only you will be able to estimate your consumption but I find with careful planning (timing of heavy appliances and not having more than one on at once (and using a travel kettle!)) then I can get pretty high percentage figures. 

Laycity

You can possibly get slightly higher than 33% if anybody in your household works from home and with smart use of appliances during the day time.

As mentioned grid price rises are inevitable (there's a big one impending soon for instance) and inflation is also your friend which I don't think you've factored in.

Think of it as an inflation proof investment and work out your yearly % return - it'll look a lot better than "30 years"

There are  also the green benefits which may be worth something to you....

Spies

Laycity said:

You can possibly get slightly higher than 33% if anybody in your household works from home and with smart use of appliances during the day time.

As mentioned grid price rises are inevitable (there's a big one impending soon for instance) and inflation is also your friend which I don't think you've factored in.

Think of it as an inflation proof investment and work out your yearly % return - it'll look a lot better than "30 years"

There are  also the green benefits which may be worth something to you....

Indeed the main reason is to be green but its hard to ignore the ROI.

If only FiT was still a thing.

Exiled_Tyke

I don't think I would describe electricity price inflation as 'inevitable'.  Obviously it all depends on supply and demand.  The key factors are surely going to be: uptake of EV's and the move from gas heating to electric.   While these point towards inflation the other side will be increase of renewable energy production which will most likely increase variability of wholesale prices.  With increase usage of smart meters we'll see more retail tariffs encouraging off peak usage.  Households which can make use of such tariffs (e.g. setting washing machines and dishwashers to come on during the night) may even be able to engineer an effective decreases in their average electricity price.  So whilst price rises are highly likely I wouldn't go as far as to claim they are inevitable and certainly wouldn't speculate on rates of inflation. 

ABrass

Spies said:

So I know that these days it's really not feasiable for these panels to save you a considerable amount of money now that the FiT scheme has gone and I've tried to base my calculations on realistic use.

Would you say 30 years ROI is a sensible assumption on a system costing £4650?

Are you assuming £0.13 per kWh? That seems rather low. Or I'm on a really bad deal.

Spies

ABrass said:

Spies said:

So I know that these days it's really not feasiable for these panels to save you a considerable amount of money now that the FiT scheme has gone and I've tried to base my calculations on realistic use.

Would you say 30 years ROI is a sensible assumption on a system costing £4650?

Are you assuming £0.13 per kWh? That seems rather low. Or I'm on a really bad deal.

Yeah I'm on 13p/kwh at the moment, utility point fixed from Feb.

AntonyTewks

I've been totting up my savings this year. I'm on Octopus Go so I've considered that solar car charging and hot water saves me about 5p per kWh, my export is getting me 3p and anything that's left is background usage saving 14p.

Halfway through this year on a 4kwp system, I'd generated nearly 1.8Mwh and the saving I estimated at £133, so projecting around £260 for the year. At that rate my payback will be a very long way away! But I guess the biggest savings are in the future as electricity prices increase. With the solar I've effectively paid to lock in a price for a chunk of my electricity.
The Go tariff I'm on is ridiculously cheap also