Solar panels and battery - any real world reccomendations?

I've had a quote back but I think they want too much:

3.9 kw system (10 * 390w Trina panels) with no battery - £5.8K (string inverter) or £6.4K (solaredge inverter).
Same as above with string inverter + 8.2kwh Givenergy battery - £9.8K
Same as above with string inverter + 13.2kwh powerwall - £15.6K

That sized solar system vs cost seems overpriced for just 3.9 kws, and the battery quotes don't seem great either.

Still pending a quote back from someone else. May need to seek a 3rd or 4th opinion. I'm definitely wondering if the gov will put forth some incentives in the next year or so to cheapen the installs a bit.

Journey said:
I know someone who has just had 15kWh of batteries installed at only £5.7k including inverter and charge controller etc. Costing him £1.12 to charge vs £4.50, so a saving of £1233 per year based on the peak rate at 30p, he uses about 19kWh a day but it's trying to reduce some peak use and shift that as well.
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I actually think this might be the best move! 2 batteries in tandem, enough capacity to charge up overnight on a cheaper off-peak tariff, predictable energy costs all year round.

I wonder if this also means you don't have the same levels of paperwork, and the DNO things etc as well, after all it's just some batteries on site :)

16kwh or so should be enough to basically go the whole day, assuming smart about usage.

Powerwall is interesting as well because it lets you use the Tesla Energy Plan - obviously it's a huge cost, but with the TEP you appear to get the same import and export rates all the time, and it turns your whole house into a giant UPS basically. https://www.tesla.com/en_GB/support/tesla-energy-plan-faqs?redirect=no - huge investment though and still a multi-year payback, especially as you need panels.

Indicative pricing of Tesla plan is very good, you get more for generation, but unit rates are a bit higher than pure off-peak charging.

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HungryHippos said:
I've had a quote back but I think they want too much:

3.9 kw system (10 * 390w Trina panels) with no battery - £5.8K (string inverter) or £6.4K (solaredge inverter).
Same as above with string inverter + 8.2kwh Givenergy battery - £9.8K
Same as above with string inverter + 13.2kwh powerwall - £15.6K

That sized solar system vs cost seems overpriced for just 3.9 kws, and the battery quotes don't seem great either.

Still pending a quote back from someone else. May need to seek a 3rd or 4th opinion. I'm definitely wondering if the gov will put forth some incentives in the next year or so to cheapen the installs a bit.



I actually think this might be the best move! 2 batteries in tandem, enough capacity to charge up overnight on a cheaper off-peak tariff, predictable energy costs all year round.

I wonder if this also means you don't have the same levels of paperwork, and the DNO things etc as well, after all it's just some batteries on site :)

16kwh or so should be enough to basically go the whole day, assuming smart about usage.

Powerwall is interesting as well because it lets you use the Tesla Energy Plan - obviously it's a huge cost, but with the TEP you appear to get the same import and export rates all the time, and it turns your whole house into a giant UPS basically. https://www.tesla.com/en_GB/support/tesla-energy-plan-faqs?redirect=no - huge investment though and still a multi-year payback, especially as you need panels.

Indicative pricing of Tesla plan is very good, you get more for generation, but unit rates are a bit higher than pure off-peak charging.

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Seems quite high...

I've been really impressed so far with the contact with GloGreen and Effective Home.

2 multi national companies, Effective Home are coming in lowest so far.

10x455W JA Solar Panels, 8.2 GivEnergy, 3.6 GivEnergy inverter @ £8136...

I am plotting my household usage and I think I can get away with the above and the 1 or 2 times I may make a brew or cook the tea on an evening would mean pennies worth of energy from the grid...not enough to justify bigger systems.
 
Batteries are going to be expensive - off the top of my head anything decent which will survive many years of charge cycles will be around £400-500+ per kwh for li-ion and £150-170ish per kwh for AGM and you probably won't save much money from it. (Maybe more so now with the unit cost of electricity going up if battery prices don't rise in step).
 
The company I spoke to at the start of last week quoted a 10 day lead time to generate a quote, I think it's a bit insane, but that means in theory it should appear here by the end of this week hopefully.

The previous one I mentioned that wanted £9.8K for the 3.9KW system and 8.2kwh battery has indicated they might be able to get nearer to £9K but it would hinge on an in person site survey.

GloGreen have quoted £9.5K but that is for an extra panel (4.29KW instead of 3.9KW) same battery, and a slightly bigger inverter, 5KW instead of 3.5KW. They think they could squeeze an additional panel onto my roof using the same one as the one above. I haven't yet asked if this is there best price or not, they too would probably go a bit lower.

Effective Home have so far not replied, not to my phone call nor to my filling out the email form.

Ultimately with energy prices going up, I think it's not a bad time to get solar, and the battery storage should be useful as I spend a fair bit of time at home and my XCH farm needs power all the time. I also have aircon so I can cool my house on hot days without feeling the bills too badly. My main goal is to keep my monthly outgoings as reasonable as I can.

My only hold up is that I reckon at some point gov will come up with some new grants for solar installs, and of course it will probably happen right after I get them added. But I can't really account for this one way or another.
 
problem is everyone else has figured out the same thing that the breakeven for solar and battery has dropped now that prices have increased.

a tip for adding a battery after the solar panel install, to qualify for the 5% vat you only need to buy a single PV panel. Most suppliers have small panels for camper vans which are cheap and easily sold on ebay :D
I still do not have my GE 8.2 battery as there is no stock in the UK at the moment, no eta yet
 
BE is still fairly high though, it's not as if I'll likely see the cash back (with no interest) for a good number of years, if prices stay around £0.28 / kwh like they are going to in April.

If prices keep going up the efficiency will go up with it, and the BE point will come down. But at £9K for 4KW system and the 8.2kwh battery, it's looking like it's still going to be about a 9-10 year repayment.

You could do 2 batteries and then your power is basically assured with an off-peak tariff, and the panels just topping up in the day. That £9K would likely become more like £13K though.
 
starting to look at this as well, trying to work out if its a better investment than paying the money into the mortgage.... the energy saving trusts' calculator suggests around a £400 a year cost saving (panel's only) but the installers are coming in at almost twice that. I assume its realistically somewhere in the middle but seems odd the the energy saving trust is so negative!
 
Because it’s entirely dependent on the size of the array, it’s orientation, shading, gradient and how much if that power you export to the grid.

For a relatively small, sub optimal array with no battery storage which would describe most rooftop situations in the U.K., £400 doesn’t sound that far off. That’s probably not updated for the £lol energy prices either.
 
I'm working with the same output panels (angles and area) on both sides but energy saving trusts calcs are going with £0.20 i think so theres defiantly some uplift needed in there, got another year on the £0.25 fix thankfully (unless shell energy go under...) but as soon as that ends its bend over time!
 
Siliconslave said:
starting to look at this as well, trying to work out if its a better investment than paying the money into the mortgage.... the energy saving trusts' calculator suggests around a £400 a year cost saving (panel's only) but the installers are coming in at almost twice that. I assume its realistically somewhere in the middle but seems odd the the energy saving trust is so negative!
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I am hoping panels would keep costs down month to month, which in turn frees up cash for other options, losing a chunk in one go in the process of course.

I am still not really totally sold on battery storage, especially where I think I can use a lot of what I generate day to day, and on the hottest/sunniest days I can turn the extra generation into cooling from my AC.

I think panels installed for £5K or so may be easier to stomach, will have to see if I can to get that kind of level. Extra £4K on a battery would be in theory let me use almost 100% of the energy I generate, but I think even without that I'd be at something like 70% based on constant background draw.

Have you had any quotes?
 
Siliconslave said:
starting to look at this as well, trying to work out if its a better investment than paying the money into the mortgage.... the energy saving trusts' calculator suggests around a £400 a year cost saving (panel's only) but the installers are coming in at almost twice that. I assume its realistically somewhere in the middle but seems odd the the energy saving trust is so negative!
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Are you asking for input? If so some idea how how much you are willing to spend and an indication of how many square metres of useable roof space is a good start, along with your roof azimuth(s) and angle from the ground.

Same for the question regards mortgage vs. expenditure - lots of variables there.

Then your plans for the future eg. staying put or moving, any idea if more of your usage will become electric, such a induction hob vs gas, or a heat pump vs a gas boiler or even getting a BEV vs. ICE vehicle, bearing in mind we are talking of a system life span of 20 years+ so you need to think further out than just the next fixed electric tariff. How much power do you use now? What is the base load of your house during the night/day.

For me the decision wasn't primarily financial, only a small part. I wanted to have my own generation, be able to power my home, car and heating or the grid if required and try to be part of the solution not the problem, as people who don't have the means can't, but being in a situation to 'afford' it means I'll do do what I can.

Basically lots and lots of questions, and lots of answers based on those questions, will lead to yet more questions. :D
 
Whatever your scenario, I think if you're planning to move within 5 years, it's not worth it really. I think also if you don't have the cash to buy outright or pay 0% interest on finance it's not worth it either for sure.

As @Journey said it's definitely a long term thing, if you're staying put for a decade or so I don't think you can go too far wrong, but other factors do exist.
 
Sorry i did rather post that and run - Were not planning on going anywhere in the next 15 years or so (although 25 does take me to an age where I may consider downsizing I guess!) but that being said mortgages aren't cheap (even with the low rates) and paying say £5k off now saves a fare chunk of interest over the years - i'm paying much more on mortgage interest a month than on electricity (for now at least).

I'm happy with the maths generally but what i'm trying to understand is what a realistic generation profile looks like? As I say the energy saving trust seems to be about 1/2 what the installers approximate, in-fact they call it out in their assumptions:

For the avoidance of doubt, the results in this calculator are not exactly the same as those estimated by the Standard Estimation Method which is used by MCS certified installers in solar PV quotations. The methodology used in this calculator is based on the Government's Standard Assessment Procedure (SAP) 2012 which uses different assumptions for the average level of solar radiation in an area.
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So which end of the scale do you go for?
 
They should be able to give you rough ideas of how many kwh the system will generate based on size of panels, orientation of roof etc.

After that I think you can kind of work it out yourself to a point. In my case a 10 x 390w panel system estimates around 3500 kwh per year, maybe a little higher.

The more of it I use, the more I save, but let's assume I use 50% of the total generation, then it would save me 1750 x unit rate (£0.28 in April for me) = £490 per year.

If I use more of it, the savings will be greater, opposite with less. You ideally want to combine the sunniest/longest days with things you can use the generation with, for example I have my NAS on 24/7 so it's always chewing some power, and my aircon will pair well with solar to cool the house when it's stupidly hot and sunny outside.

How many kwh per day do you use roughly now?
 
Siliconslave said:
Sorry i did rather post that and run - Were not planning on going anywhere in the next 15 years or so (although 25 does take me to an age where I may consider downsizing I guess!) but that being said mortgages aren't cheap (even with the low rates) and paying say £5k off now saves a fare chunk of interest over the years - i'm paying much more on mortgage interest a month than on electricity (for now at least).
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Obviously you've given no details or figures to go on. However, if you were to dump £5k one-off in to the mortgage as an overpayment then still continue to pay an ever increasing amount for your electricity over the next 5, 10, 15 years, how long before the interest savings would be out done by the cost of the electricity? Have you also considered you could put the saved money from your bill into the mortgage monthly/yearly? All you need to do is take the unit cost for that year and multiply it by the number of units generated. So if your unit cost was 21p, and you made 4308 units, you could pay off £904.68 and you'd be in the same or better position as if you paid £5k into the mortgage, but every year that goes by you'd be paying more and more off the mortgage, as the unit rate cost went up, after 10 year you might have paid off an extra £10-12k depending on the electricity cost over that 10 year period. You just have to pretend the £5k went into the bank not on the roof. :)

However, without figures then it is really hard to be accurate.
 
I assume you can charge the batteries off-peak if solar is no good, I can see that as a benefit, such that even if solar trickles on bad days you can still have a full battery to take you through the day charged at 5p rather than 28p. That would help improve ROI of install.
 
sandys said:
I assume you can charge the batteries off-peak if solar is no good, I can see that as a benefit, such that even if solar trickles on bad days you can still have a full battery to take you through the day charged at 5p rather than 28p. That would help improve ROI of install.
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The batteries have a bigger pay-off in winter rather than the summer since you can charge them "off peak" overnight for this very reason (minimal solar generation in winter).

In summer the ROI of batteries is minimal. As an example my typical nightly usage is just 0.22kWh / hour, or 2kWh from 10pm - 7am.

I've just started this journey for my home too, still very much at the early stages of learning and data gathering though. This is what it looks like so far:

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