UKC

Someone was asking for real life performance figures vs projections from solar installations, but that thread has been archived.

We paid £9k for 5.4 kW system with 8.6kW battery in the NE of England and were forecast a 12 yr payback time.

Foregoing the battery would have reduced the forecast payback time but we felt anything that reduced our import from the grid would be an environmentally sound proposition, plus we intend to install a heatpump down the line, which should see us make more use of the battery.

It's been installed for a year now and the app says we've generated 5.2 MWh, with 2.9 MWh exported.

It also says we've been 61% self sufficient during that year, purchasing 936 kWh and consuming 1.5 MWh.

I assume that means there was around 800 kWh lost to inefficiencies in inverter, battery, etc.

I'm getting 15p outside of peak time (so when most of that is generated) and the internet says the current average cost per kWh on a standard variable tariff is 24.5p

So I make that about £800 payback in the first year, which is fairly bang on prediction.

9grand over 12 years = 800 per year, that's a payback? Either someone has an amazing crystal ball or they don't understand the concept of interest.

Or maybe put a bit more tactly.

I have been looking at the cost benefit of a similar system but:

You have to look at the two scenarios of installing or not.

Then make assumptions or predictions of

Interest lost on the capital you have spent or cost of loan.

Inflation or rising electric prices.

Residual value of capital after inflation.

Future possible costs of panels etc.

Better efficiency of panels , atm panels only convert approx 20% of potential solar energy.

More data on panel and battery lifespan.

Its complicated! I got a headache and decided to spent the money on trips. ( Which brings another factor, dont need domestic power if away. )

Paid 18k for a 15kw system with a 10kw battery. 6 year predicted payback, been 100% self sufficient since it was installed last Monday but we are also low on our energy use because we moved out to get the asbestos roof replaced and though we are back in now the workshop isn't set up and running yet so our energy use will be increasing back to its normal usage in a week or so. Based on past usage we should be around 95% self surficcient. 

This is something I'm very happy about because my 20p a unit electricity tarrif ends in December and there is no cap on commercial bills like there is domestic. 

I am sure you will have plenty of opportunity to update us on future thoughts on how well its going. Good to have some more real world info  on installation cost and actual generation.

Can you tell us your previous annual consumption?

Our solar panels go in next week. Heat pump went in last week. Just embracing the joys of installing underfloor insulation crawling around under the floors. Satisfying but hard work. Looking forward to becoming a solar power need.

We paid 13k for 9.5kwh battery and 5.5array. In the last 21 months we've generated 10.36 Mwh and used 7.2Mwh. I reckon this puts us on a 6 year payback if not quicker. We do have a south facing unshaded roof in Cambridgeshire. I'm currently paying Octopus £1/month for combined gas and electricity but my credit balance is still increasing! I took the view I'd invest when I was working and reap the benefits when a pensioner,

Nope but I can find out and let you know. I let my new manager run with the project and I just looked at the headline numbers. 

Apparently as of this morning, 6 days in we have exported 200kw.