Solar panels, battery and economy 10

[Calmdown14]

So I know the general consensus is solar panels aren't worth it in terms of pay back but wonder if anyone can help with our specific circumstances?

• We are all electric (no gas where I live, solid internal walls and concrete floors make oil or an air source heat pump a no go)

• We are on economy 10. Means 10hours off peak electric is half the price of the peak electric (spread over three time periods rather than all at night like economy 7).

• We are in Scotland (sunny but cold east coast) and can get an interest free loan from the government to cover panels and battery up to 11k repayable over 10 years.

For anyone with a solar and battery system, how much on average do you save each month?

And if you are on this kind of split tariff do you save by charging the battery off peak and discharging at expensive times?

I'm currently using £80 of electric each month but it goes up massively in winter and with October increases the October to April cost is likely to be £200 plus.

Loan repayments would be £92 a month so if I can save that then effectively the technology wouldn't cost me anything. But is this unrealistic as a saving? There are lots of figures on line but they aren't based on all electric systems or economy 10

Hi OP.

EVM, electric vehicle man did a video on his own solar panel , home battery, cheap tariff set up a few months ago.
He lives in Yorkshire , not as north as you but not the south coast either

Thanks @tanstaafl that's useful.

The battery is a big cost but there's definitely something that grates about getting 5p to sell in back to the grid and then paying 32p to use it later!

We are pretty good at only using washing machine, dishwasher off peak but the fridge, water heater etc run 24 hours and diverting any of this to the lower tariff by storing it offers a benefit over and above the solar panels .... hopefully. But working out how much is tricky

You’ve probably decided by now but payback on panels is good unless you’re planning on moving quickly. Our panel and battery set up is going in next week. We are also having a solar immersion link to use any excess to heat the hot water and we are having islanding to enable us to use whatever is in the battery in the event of a power cut. It’s costing £14k that gives us 5.6 kw panels, 8kw battery plus the immersion heater plus the us landing. Yes the buy back rate on solar generated electricity is scandalous but we are planning on using it all if we possibly can.

we currently use 7,000 kwh of electricity a year plus oil for heating and hot water. That’s around £3,000 in electricity costs. We will still of course need some power from the grid at certain times of the day particularly in winter so we hope to be about 2/3 energy self sufficient which would save about £2k a year. We then hope to reduce oil costs by 1/3 by using the solar immersion which saves another £750ish

So we save £2750 a year. Which means they pay back in 6 years. For us that’s a decent investment in the property and the environment.

What did you decide OP? We’re in a similar location and dilemma currently. I was a bit underwhelmed with the savings from the battery and was considering panels only - a larger proportion of the payback seemed to come from the panels alone (about 2/3 panels 1/3 battery) and for the additional cost (and lower life expectancy) of the battery, we didn’t think it was worth it for panels plus battery, but panels alone seemed reasonable?

When you say an air source heat pump won't work because of solid walls and floors, I assume you mean that it would be too difficult to fit pipes and radiators to use wet central heating.

Another option to reduce hearing costs could be direct air to air heating by a heat pump - effectively a reversible air con system. This should still give the primary advantage of getting effectively "free" heat energy out of the air, reducing heating bills by maybe half to two thirds depending on the temperature outside.

It's not an especially common option, but it's something I've been vaguely considering for an outbuilding/garden office, and might be worth investigating further.