How do you guys keep track of ROI on your panels / battery?

UncleK

I'm a nerd and have a spreadsheet where I track it all, including adding the data from my GroWatt app. I calculate what the electricity would have cost us if we would have bought it rather than generated it from our solar PVs. So the bill we just received for the last 31 days from Octopus was for £156 minus £49 they paid us back for power sold to them, so £107 net. I calculated that we further saved £171, so that's power that went straight from the panels to our appliances. That's just one month and we've only had the whole system a few months, so we need to take a year's view to have an idea of ROI but we're certainly pleased so far.

My motivation is partly to post-justify that we did the right thing and hopefully be a bit smug about it, partly to make sure we are operating the system (panels/batteries) right and partly to make sure that things are going right with Octopus and the smart meter.

EcoScruples

16 months in and the average savings is building up nicely, currently on track to payback in 7.4 years. This includes an updated price cap calc since install.

I have estimated my inverter and battery to last 10 to 12 years which gives me a good 2 to 4 years before the need to spend on those.

Mikeyboy01443

EcoScruples said:

16 months in and the average savings is building up nicely, currently on track to payback in 7.4 years. This includes an updated price cap calc since install.

I have estimated my inverter and battery to last 10 to 12 years which gives me a good 2 to 4 years before the need to spend on those.

Mine is about the same, 17 months i think... and mine is probably about 3 and a bit years left to pay for itself. So i haven't looked at this thread in a while but I imagine there are different schools of thought when it comes to how it's paid back? 

paul991

remember to subtract the interest you would of received in a savings account

Alnat1

paul991 said:

remember to subtract the interest you would of received in a savings account

Why? If we hadn't spent the money (it was an inheritance) on solar/battery we might have blown it all on a huge holiday, a hot tub etc. Savings accounts were earning very little and inflation was starting to creep up at the time. The cost of installation now is much higher than it was a few years ago too.

Maybe you should consider that the money in the savings account would actually be worth less due to inflation over the last few years. Inflation has been running at much higher rates than the interest paid on savings.

Mikeyboy01443

Alnat1 said:

paul991 said:

remember to subtract the interest you would of received in a savings account

Why? If we hadn't spent the money (it was an inheritance) on solar/battery we might have blown it all on a huge holiday, a hot tub etc. Savings accounts were earning very little and inflation was starting to creep up at the time. The cost of installation now is much higher than it was a few years ago too.

Maybe you should consider that the money in the savings account would actually be worth less due to inflation over the last few years. Inflation has been running at much higher rates than the interest paid on savings.

Exactly... i didn't buy solar as an investment or to make money, would i have paid my utility bills with whatever i may have made in a savings account then? It would not have made as much then...

Martyn1981

paul991 said:

remember to subtract the interest you would of received in a savings account

If you do that, then you also have to consider the interest earned on the returns/savings. 

EricMears

Our panels were installed in August 2011 with FIT payable for 25 years.

Receipts exceeded cost by June 2018 and are likely to represent double that cost by June 2024 when we'll still only be halfway through the contract.

paul991

I didnt buy  mine as a investment too, but was in reply to the question which was ,how do you track the ROI? and its allways the forst question I get ask when people see them on the roof. They  dont pay  do they?

Spies

According to my spreadsheet my system has paid back just over 1/4 of the outlay in 2 years.