Solar Panels?

[cb31]

SoliD said:

Ouch, i've just committed to 18 x 370w panels and 2x 8.2KW Givenergy batteries for 12.1k.

Some serious price gouging going on at the moment, I requested a quote a couple of weeks ago and they got back to me today. Apparently they are very busy and there is a wait for surveys. They wanted £12.5k for 16 x 375w panels, no battery. A Tesla powerwall was an extra £10.5k.

The energy saving trust calculator suggested an install price just under £8k so they can poke it, not getting ripped off by that much.

[gangzoom]

cb31 said:

l They wanted £12.5k for 16 x 375w panels, no battery. A Tesla powerwall was an extra £10.5k.

£10k is actually about the 'standard' price for a PW+install even back in 2019, so surprisingly little price inflation there.

[Thebaggers]

For comparison, I am putting in 20 solaredge panels installed in roof in GSE trays with a solaredge inverter for £7.5k in Hampshire (ex vat)


This is on a new garage, interestingly it was cheaper to cover one complete side of the roof in solar cells compared to the other side in tiles! Solar is a cheap roof covering.

[bobfather]

I don't understand the economic argument for solar panels. A panel and battery installation costing say £10k. Assuming annualised performance, owners suggest poor winter good summer, so let's say 50% contribution coming from the panels. Even at today's high prices, I'm paying £70/month for electricity. Part of that is the service charge, so electricity use costs less than £70/month. 50% efficiency means the panels would save me less than £45/month, less still when prices come back to normal. The best I can expect is payback after 19 years. I assume by that time I would have also incurred battery replacement costs, callouts, and the panels and tech pack will be very outdated.

Is the refund for supplying the grid during peak performance big enough to make this work?

[RemarkLima]

Interesting thread...

Are the DIY kits any good?

https://www.roofgiant.com/flat-roofing-solar/plug-...

More for charging a car in the day for example, and the day time use... I have a flat roof garage some these could be placed on top without too much pain...

[SoliD]

bobfather said:

I don't understand the economic argument for solar panels. A panel and battery installation costing say £10k. Assuming annualised performance, owners suggest poor winter good summer, so let's say 50% contribution coming from the panels. Even at today's high prices, I'm paying £70/month for electricity. Part of that is the service charge, so electricity use costs less than £70/month. 50% efficiency means the panels would save me less than £45/month, less still when prices come back to normal. The best I can expect is payback after 19 years. I assume by that time I would have also incurred battery replacement costs, callouts, and the panels and tech pack will be very outdated.

Is the refund for supplying the grid during peak performance big enough to make this work?

So in my instance, I currently use 8000KW or so, my install is approx £12k for 18 x 370w panels and 2x 8.2KW batteries - this should give me 6500KW every year minimum Solar generation, but this is quite conservative on the installers part and i'm actually hoping for 7200 or so in an average year up to 7800 with a good year of sun.

I currently have a 20p/kwh tarrif as I got a good rate early in the year, all of his power i will be looking to use either through my aircon in the summer/PHEV charging as well as usual clothes washing/cooking/dishwasher etc means I'm saving £1300 per year.

So this leaves me with about 1500KW to pay off the grid, but if I move to something like Octopus Go with the 7.5p overnight rate in the depths of winter I can charge my batteries up overnight for £112.50 compared to £300 and thus save another £187.50.

This is obviously quite high usage compared to yours, but this is using electric as the primary heat source (AC) and for cooking (induction hobs and oven) I should in theory with the aircon being used as the primary heat source save on my gas usage as well, so potentially further savings.

[Biggus thingus]

Can anyone explain to me if a 3kw system on the roof and a 5.2kw battery with night charging is a good idea at £10.5K?

Would a fully charged battery be enough power for everything till bedtime? Providing that dishwasher and washer are going through the day

[sfella]

bobfather said:

I don't understand the economic argument for solar panels. A panel and battery installation costing say £10k. Assuming annualised performance, owners suggest poor winter good summer, so let's say 50% contribution coming from the panels. Even at today's high prices, I'm paying £70/month for electricity. Part of that is the service charge, so electricity use costs less than £70/month. 50% efficiency means the panels would save me less than £45/month, less still when prices come back to normal. The best I can expect is payback after 19 years. I assume by that time I would have also incurred battery replacement costs, callouts, and the panels and tech pack will be very outdated.

Is the refund for supplying the grid during peak performance big enough to make this work?

For me the first application is for a property we are hopefully completing on in a few weeks. We'll be responsible for the bill for 3 dwellings,one of which is all electric (heating and cooking)

As well as helping (hopefully) reduce bills I would also like to be less dependent on the grid and know that I'm a small way I'm doing the right thing. I'm no eco warrior but as a parent I would like to leave behind a world not totally destroyed.

[deanobeano]

Biggus thingus said:

Can anyone explain to me if a 3kw system on the roof and a 5.2kw battery with night charging is a good idea at £10.5K?

Would a fully charged battery be enough power for everything till bedtime? Providing that dishwasher and washer are going through the day

For me, 5kW hours of battery wouldn't be enough. Especially if you cook with electric.

Have a look at your smart meter readings (which should be uploaded to your electricity account). Look at your half hour usage between dusk and dawn (maybe Oct or March to get an average). If your usage regularly exceeds 5kW hours then a bigger battery would be advisable.

Also, check if you can add additional batteries in the future and what the max power the battery / inverter can provide - this may be alot less than your max draw (ie running oven or hob etc).

[Biggus thingus]

deanobeano said:

For me, 5kW hours of battery wouldn't be enough. Especially if you cook with electric.

Have a look at your smart meter readings (which should be uploaded to your electricity account). Look at your half hour usage between dusk and dawn (maybe Oct or March to get an average). If your usage regularly exceeds 5kW hours then a bigger battery would be advisable.

Also, check if you can add additional batteries in the future and what the max power the battery / inverter can provide - this may be alot less than your max draw (ie running oven or hob etc).

Thanks for the advice

Unfortunately we have no smart meter installed. Would energy company be able to provide that info?

I think this market is about to explode. Did a quick google on local suppliers/installers and 1st one i tried stated no quotes till April to enable them to catch up with their backlog!

[CoupeKid]

Negative experience here.

About 4 years ago we had panels installed. 4Kw from memory. We’re on an East-West axis with quite a steep pitched roof.

The money we make from the Feed In Tariff is nowhere near what we were forecast and our electricity use is quite small anyway.

We probably do halve our grid electricity use over the year but we’re on quite a good deal from Utility Warehouse so don’t save thousands.

If electricity prices keep going up we might have made a good investment otherwise we’ll be lucky to break even over the 20 year lifetime of the system.

Aspect is going to make a difference so if you have a large roof facing south you’ll generate more than us for the same size array.

We’d been talking about it for a while and only went ahead when my MIL gifted us some money so I don’t feel it’s earned money wasted.

Edit - 37% energy independence over the lifetime of the system to date (includes more winters than summers) according to the system’s stats.

Edited by CoupeKid on Sunday 13th March 10:47

[snowman99]

RemarkLima said:

Interesting thread...

Are the DIY kits any good?

https://www.roofgiant.com/flat-roofing-solar/plug-...

More for charging a car in the day for example, and the day time use... I have a flat roof garage some these could be placed on top without too much pain...

When they say DIY, how DIY is it really, it’s hardly going to be plugging the panels into a mains socket?

[Jambo85]

Biggus thingus said:

Can anyone explain to me if a 3kw system on the roof and a 5.2kw battery with night charging is a good idea at £10.5K?

Would a fully charged battery be enough power for everything till bedtime? Providing that dishwasher and washer are going through the day

With a 3kW system (quite small really), if you have a hot water cylinder with immersion heater, then a diverter to put excess power there will probably use most of your surplus. And is a lot cheaper than a battery.

If your dishwasher and washing machine will accept hot feeds then you can effectively use your hot water cylinder as a battery for them.

[AW10]

Biggus thingus said:

Can anyone explain to me if a 3kw system on the roof and a 5.2kw battery with night charging is a good idea at £10.5K?

Would a fully charged battery be enough power for everything till bedtime? Providing that dishwasher and washer are going through the day

It really depends on how much you use and what time of day you use it.

A not-great analogy… it’s like asking “should I spend £X to buy a car that gets 75 mpg?” without the background information of how many miles you drive. The answer is rather affected by if you drive 25K miles per year or 5K miles per year.

But to give you a data point… a friend had a 3.5 kWp system and a 5.2 kWh battery installed about a year ago. “Normal” domestic use - 2 people in a 3 bed semi with gas CH. Over the course of a year he and his wife used 2561 kWh of electricity. 769 kWh was consumed straight off the panels. 978 kWh (an average of less than 3 kWh per day) came from the battery. The remaining 814 kWh came from the grid. So he has saved about 1750 kWh per year. At 20p per kWh that’s £350/year. He paid £10.5K. Ignoring inflation and rising leccy prices that’s a 30 year payback. Ouch. Bad “investment”. Triumph of marketing over fact.

[Gareth79]

I've been looking at this recently, I may attempt a DIY job, which I appreciate will make export impossible, but I can live with that. There's a local solar farm selling off 260W panels for £40 each (I assume after X years it's more efficient land use to upgrade to the latest panels), and I have a patio roof I can probably get 6 on at least, and then 2 more nearby on a spare bit of lawn. Again, not optimal but considering the total cost will probably be less than just the scaffolding for a roof install I can live with that...

Edit: for an inverter there's plenty of 2nd hand ones available. A battery system is something I'd buy new though. I'd probably set something up to charge any spare capacity with cheap-rate electric too.

Edited by Gareth79 on Friday 18th March 00:11

[Mikebentley]

AW10 said:

Biggus thingus said:

Can anyone explain to me if a 3kw system on the roof and a 5.2kw battery with night charging is a good idea at £10.5K?

Would a fully charged battery be enough power for everything till bedtime? Providing that dishwasher and washer are going through the day

It really depends on how much you use and what time of day you use it.

A not-great analogy… it’s like asking “should I spend £X to buy a car that gets 75 mpg?” without the background information of how many miles you drive. The answer is rather affected by if you drive 25K miles per year or 5K miles per year.

But to give you a data point… a friend had a 3.5 kWp system and a 5.2 kWh battery installed about a year ago. “Normal” domestic use - 2 people in a 3 bed semi with gas CH. Over the course of a year he and his wife used 2561 kWh of electricity. 769 kWh was consumed straight off the panels. 978 kWh (an average of less than 3 kWh per day) came from the battery. The remaining 814 kWh came from the grid. So he has saved about 1750 kWh per year. At 20p per kWh that’s £350/year. He paid £10.5K. Ignoring inflation and rising leccy prices that’s a 30 year payback. Ouch. Bad “investment”. Triumph of marketing over fact.

Thanks for that. It’s definitely an ouch moment reading that. I also wonder if you stop looking at your consumption as the mentality might be “we’ve got that covered “. Still not a sound investment though.

[AW10]

There are a lot of over-inflated figures being bandied about by the people selling the products so I thought it useful to post up a real world example where the reality didn’t live up to the hype.

Even a local solar panel supplier and installer that I thought was a straight talker gave me some crazy figures for the reduced import based on direct use and out of hours usage from a battery. He couldn’t/wouldn’t reply on the report I sent him from my mate’s system.

As always, buyer beware. Even rising leccy prices will mean many average households won’t recoup their outlay for a long time, if ever.

As an old boy who was a neighbour of my parents used to say “figures don’t lie but liars can figure”.

[Traffic]

Added some numbers to another thread a while back, no harm in adding some refreshed numbers here....

March 2022
Total Electricity Consumed = 868Kwh

• 71% from the grid = 620Kwh
• 29% from solar panels = 247Kwh

Electric costs for the 620Kwh consumption = 1,197 Swedish Krona

Surplus solar electricity sold to the grid 483Kwh = 714 Swedish Krona.

Not bad for chilly Sweden in March! :-)

[ARHarh]

Just for a bit of balance, my 4kw south facing system in North Shropshire made 592 kw between 17/11/2021 and 18/02/2022. this was actually quite a good winter 1/4 for electic generation.
Over the last 8 years it has produced 4002kw each year on average.
Yesterday it made 13kw.

[Condi]

AW10 said:

There are a lot of over-inflated figures being bandied about by the people selling the products so I thought it useful to post up a real world example where the reality didn’t live up to the hype.

Even a local solar panel supplier and installer that I thought was a straight talker gave me some crazy figures for the reduced import based on direct use and out of hours usage from a battery. He couldn’t/wouldn’t reply on the report I sent him from my mate’s system.

As always, buyer beware. Even rising leccy prices will mean many average households won’t recoup their outlay for a long time, if ever.

As an old boy who was a neighbour of my parents used to say “figures don’t lie but liars can figure”.

There are also installations which have done better than expected. My uncle had an early FIT supported system installed with an estimate payback of 8-10 years, which had covered it's costs in 7 years. With rising energy costs and an inflation linked FIT income he is considerably better off than he would have been without solar.