Our local sustainability group has partnered with a solar scheme to offer a solar panel installation at what seems like a pretty good deal.
I’ve had a desk top study/quote done and it seems reasonable to me.
I get the basics of what’s been said, but what should I be checking to see if a) it’s a good deal and b) it’s worth doing at all?
I could easily disappear out of my depth into a google vortex – so just wondering what the main points to check would be?
cheers

I’m also investigating this, so here’s a bump for your question and hopefully we’ll both get some advice…..

When I got panels a year or so ago, the economics didn’t stack up for the batteries. YMMV if you’ve got an EV and smart electricity tariff though. Get the most panels you can fit on your roof in as southernly a position as possible and sign up for export payments. Bulb have been easy and one of the best paying for me.

Make sure the battery you are getting is eligible for a good smart tarrif… Not all batteries are.

Thanks. Sounds like a good start.
Re: battery, I just assumed it would charge up during the day and we’d use it in the evening, but may not be as simple as that.
The economics I haven’t really looked into, mostly because I suspect it doesn’t really stack up, so we’re doing it more just for sustainability reasons.

as trail rat says get a battery that will work with a smart tariff

Re: battery, I just assumed it would charge up during the day and we’d use it in the evening, but may not be as simple as that.

Yep, but what trail rat is alluding to is with a smart tariff and a smart battery you can also have the option to top up the battery over night at the very cheapest rates from the grid and prioritize discharging the battery at the most expensive grid times each day ie 4-7pm etc. So basically your PV, battery, smart tariff and the grid should all learn and work together to give you the lowest leccy cost if not zero.
Can I suggest you research Agile Octopus which works with the likes of GivEnergy Batteries.

It might be tough to make it stack up until you start adding EV cars and leccy heating

I believe there also is an export Agile Octopus tariff as well, so if that is particularly high the smart inverter will export to the grid when you’ll get paid the most.

Yep that’s it but not all batteries work with all tarrifs

Without the tarrifs the battery is a total red herring. With a half decent tarriff it just about makes sense

Great advice, cheers.
Octopus has been mentioned – will lock into the offer and details etc.
Cheers

so we’re doing it more just for sustainability reasons.

This is the interesting one at the moment as actually, the embodied carbon in most solar & battery setups is pretty huge, so the ‘pay-back’ time doesn’t really work with the likely lifespan of the system. Trying to get all this information as a home-owner is not the easiest unfortunately and I think is the big challenge for the push to true Net Zero. Try and find out as much info as you can on the sourcing of the equipment and I’d also seriously look into solar hot water as the embodied portion is typically lower and efficiency greater. Then maybe focus on reducing electric use and rely a bit on the ongoing de-carbonisation of the grid (edit; you could also look into sustainable energy providers, Ecotricity and the like).

Good forum and information on here, also supply good quality kit.
https://www.navitron.org.uk/

I found the level of detail this guy has gone into strangely fascinating, plenty of reading if you want it.

Battery geekery

Take any calculations on payback with a huge pinch of salt. Be aware solar pv generates bugger all from October to April. Take a look at insulation and draught proofing your home as a priority.

I would look at the numbers for solar alone as well as (/before) looking at the numbers for both. There’s a bit of interplay but overall I’d see them as distinct, not inextricably intertwined in a “system”.

Simplified financial analysis of a generating device is straightforward. And on the basis that you’re adding renewable generation to the mix in place of buying grid power, the carbon/sustainability advantage is clear enough. Estimating output per year I’d start with a reasonable established local benchmark. Start with say 1000kWh for each kW capacity you’re installing. Annual “Income” is then splitting that generated power between what you’ll save in power you’d have bought from the grid, so price at what you’d buy it for, and that which you’ll export, so check what you can export for, plus any subsidy/tax etc considerations, which should also be straightforward. And small nowadays. And stick a finger in the air for inflation, but it’s not zero.

I’m out of touch with some of the key variables so I don’t quote numbers but those variables should not be hard to source.

If someone gave me some payback figure without the workings I think I’d pay it little attention, ask for their inputs, check them and do it myself. It’s not hard.

Batteries, however, open a more subjective debate. Sustainability impact is arguable. And as others have mentioned above the financial case relies on particular circumstances to make it worth doing. And the calculations are therefore also pretty subjective in my view. That’s not to say it’s a terrible idea, I might do it myself, just that it’s not a clear case.

The issue with payback figures is they estimate usage on site and I would say nearly always massively over estimate this. Without batteries most generation is at a time you won’t use it, and with batteries most generation is still in the wrong season for most use. In the summer you will generate far more than batteries can store and in the winter generate bugger all. I am definately not saying don’t do it, just don’t believe the bs.