We've had solar panels since 2011, on our north south facing roof, purely to take advantage of the feed in tariff. We got in just before it was changed and make a tidy sum. Except last year. On taking the reading in June hubs asked "did I do this already?" I replied no. He said the reading was extremely low. I had to remind him the first 4 months of the year had been wall to wall grey cloud, zero sun. I certainly wouldn't want to rely on them for my electricity! Not in this country.....Oh and when we first put them up, every man and his dog suddenly wanted to buy our roof space....
We also installed solar panels when the FIT payment was at its most generous so that was about 12 years ago. We get a reasonable return and we live in mid wales. Not known for wall to wall sunshine. Like you would not want it as main source….Our neighbours also rushed out to get them.
I think we've got 11 more years before the FIT ends. We've never had them cleaned, apparently they don't need it, and we get a good return in the North of England when the weather is kinda normal. Last year was unusual, we don't get that much continual cloud for so long. Ours take account of the heat I.e strength of the sun as well. So this time of year they really start to work well especially at the moment. It's glorious 🙌 well, if you watch BBC it's a horrific catastrophe and we're all frying 🤣🤣🤣
Ours have never been cleaned. But On a day like today torrential rain and thunderstorms natural cleaning 😊well it is wales still get a worthwhile payout. Like you we are in our 70s so we don’t take as much interest as we used too sunshine back tomorrow…. Pay for a couple of boxes of wine 😂😂🥂
Most installations have more capacity in the panels than can be supplied to the grid. So our 14 panels can generate over 4kWp but our grid supply is limited to 3.68. Even after 10 years it won't be evident that we're losing output. It will start to become obvious at that point though, but at 77 now I'll probably be past caring :)
Isn't the average output of your panels more like 25% of max capacity, after taking into account that max can only be achieved for a little while around high noon on sunny summer days assuming an ideal southern exposure?
Knowing very little (to be truthful, nothing) about solar panels I wondered about their lifespan. I do have anecdotal knowledge of the quality of some new-build housing and certainly would not trust all builders to install panels of the highest quality. When maintenance costs etc are factored in, I cannot imagine that I would rush to buy a new-build property. If I hear of someone in the family contemplating such a move, I’ll forward this article to them with all due speed.
I do wish they would stop calling it green or clean energy, there's no such thing. Every type of energy generation comes at a cost to the environment, wind and solar farms are really damaging to wildlife. Never mind the costs of making the wretched things and shipping them here from China. Its greenwashing, that's what it is.
Nobody is more sceptical than I am about AGW in general and Net Zero in particular, but the numbers you quote from EST are only referring to solar generation and the top-end is indeed about what we get from our solar panels, although we benefit by a similar amount from the FIT scheme we joined in 2018 and which is no longer available.
However having a battery changes the game completely. We went for a Tesla Powerwall as it has automatic home backup which means if the grid goes down it switches to battery - so fast that the Sky box doesn't even notice. Not all batteries do this and it will be vital when Mad Ed's policies result in blackouts and has already saved us a couple of times.
It also adds extra savings by storing the generated power for when it's needed so you use more of what you generate.
I also fill the battery up to 100% at the overnight cheap rate and then sell approx. 10kWh of my battery capacity every evening during the peak period at 29.3p. On a day that's very sunny that means we lose about 50p, but it guarantees that we get almost £3 every day which is not certain as even in summer there are at least a couple of duller days each week that reduce the power generated significantly. This may seem counter intuitive, but the "free" solar costs you because you can't sell it to the grid, and the day export rate on Octopus Flux is currently 10.11p and the night import rate 16.4p.
I am not convinced that solar (+ battery) on every new build is a good idea, but there are significant savings to be made.
I estimate that the solar panels we bought at the start of 2019 will be paid off in another couple of years and the battery in less than 10 years - significantly less if electricity prices go up again.
We are a retired couple at home all day so could use solar when the sun was shining for dishwasher or washing machine. We have no EV or other major appliances. In Jan and Feb we saved about £30/m compared to last year. March was a saving of £70 and April £85 (exceptional) we will stay at about that level until September so will have built up a big surplus in our account to pay our Octopus bill through the winter. Our total annual bill for gas CH and water and electricity is now about £450 but there's also £320 FIT payments to offset against that..
Everyone needs to think carefully about their own situation - if we were out all day I would manage my battery differently I think - and do the calculation according to their circumstances.
We were lucky enough to be able to buy the battery from savings and will recoup the cost with plenty of life still left in the battery. It's not for everyone but we like the security of knowing that we can stay powered up for several hours of the grid does go down.
PS Solar panels are showing no signs of degradation after 6 years and we've never had them cleaned either. This is on a SW facing roof at 43 degrees in Central England. I expect them to last well past the payback period, but only time will tell.
PPS we saved a bit more money on the CH before we had the battery by using a smart-switch that turned on a fan heater when we were generating more than 1kW in the winter. Now we still do that if it's sunny but cold. but not as much so means our gas bill is a tad higher. We also have a wood-burner, but we only light that if it's really cold. House is 60s detached build, old double glazing and some wall insulation (but not much) but I doubled up the roof insulation which made the house appreciably warmer.
From what I read it seems that much of the benefit could be derived from a battery alone. Equivalent to Economy 7 and modern storage heaters if your heat was all electric.
On the complicated load shifting, like you say, that's easier for retired people. Complete pita for young families.
The answer will depend very much on individual circumstances. We make a bit more from direct energt than from FIT and that is likely to increase if Net Zero continues and prices rise. But FIT is no longer available.
I've already explained why we charge up at night. If it's gloomy the next day we will use some of that from the battery to save paying the day import rate. If it's sunny we will sell that power at the evening peak. This only works on the tariff we are currently on. If you're on a different tariff or the prices diverge more it may not make sense.
The Tesla Powerwall is the Rolls Royce of batteries; I looked at them about 3 years ago. They are very expensive indeed. I wonder if Roger’s calculations take account of the opportunity cost of the capital invested in his Powerwall? Unless he is factoring in his financing cost, ie the interest foregone on his savings, the analysis is misleading.
Yes you're right. The PW2 cost £8K, financed from savings, so with current interest rates and as a top-rate tax-payer, that's a couple of hundred quid a year on the debit side. We also lost some of our FIT payment, but that's accounted for.
I like to buy quality products as they tend to last longer and we have a 10 year guarantee that it'll still be at 80% capacity. They should be useful for much longer than 10 years though and the home backup aspect is very important to us. There are ostensibly cheaper batteries, but they you have to add in the cost of the extra components for automatic switching in a power cut.
There are also lots of apps around for Tesla - their app itself is great, and there is a NetZero app which lets you control the battery (and other Tesla devices like an EV that we don't have) at a very detailed level with a series of automations e.g. when battery level falls to 30% stop exporting.
Like you I looked into this 3 years ago with a year’s worth of detailed daily data from our panels and I simulated in a spreadsheet what size battery made sense for us as small users with no big appliances who are home all day so can use dishwasher/washing-machine when sun shines. The answer was 2-3kWh, but even then the ROI was over 12 years so not justifiable imo. 18 months ago I did the exercise again but taking into account what we could earn from exporting under the tariffs now available (as opposed to what we get now from FIT deemed export).
The answer was the Tesla which was now VAT-free would have an ROI of about 10 years, and my subsequent experiences think that it will actually be less than that, esp. if prices rise.
Good summary, yet there are more bits: Safety. Battery storage, if present, will almost certainly be of similar technology to what's used in EVs. As we've all seen, these are prone to spontaneously catch fire. A hot, unquenchable fire that’ll likely take any surrounding structure with it. Likely a rare, but serious risk.
Much more likely to cause trouble, yet more mundane problems include the problems of equipment breakdown. Sure, most components come with warranty or service plans. That’s all well and good, but I seriously doubt that any firm warranties its products for anywhere near their expected service life. A further problem is that a lot of these firms will go out of business, merge etc. Bye bye warranty service commitments. This is only a suspicion, but I suspect it’s a time-honored strategy in business to sell long-term service contracts and then to declare bankruptcy, move operations, or tae some other action that lets you keep the money and shed the obligation. Sure, there are consumer protection laws against such gambits, but they are limited in power. Merely filing bankruptcy at least freezes them, if not making them entirely ineffectual.
Even if the vendor remains in business, maintenance is entirely hostage to the availability of replacement parts and competent technicians. The former are almost entirely from overseas suppliers. Wars, economic embargoes or simply the obsolescence leading to stopping production unpredictably makes those supply lines constrict or vanish entirely. The latter issue is a domestic one; suffice to say that our workforces are not, on average, becoming more intelligent, honest or skillful.
The problem is that the rooftop solar and the price paid for electricity contributions to the grid are based on subsidies that could be revoked by the next government. Surely a huge risk?
My comment applies to the owner of rooftop solar, which is subject to the whims of State and Federal largesse. The contracts in domestic solar do not protect the owner if the buy-back price is reduced from purchase price levels to wholesale (about 5c/kwh from 13 c/kwh).
This does apply to commercial scale solar/wind vendors too in that huge investments in manufacturing and supply chains can be at risk at whim.
It's a good point. Roger Hughes at Edinburgh University show that most UK wind is uneconomic. Since they have been "invested in" by large UK pension institutions, when the subsidy regimes expire he claims they will have to be bailed out by the tax payer. This is already happening - MPs either have or are about to vote for UK tax payers compensating them for the destruction in value arising from MPs mindless decision to move their colossal pension funds over to wind and other loss making rackets.
We've had solar panels since 2011, on our north south facing roof, purely to take advantage of the feed in tariff. We got in just before it was changed and make a tidy sum. Except last year. On taking the reading in June hubs asked "did I do this already?" I replied no. He said the reading was extremely low. I had to remind him the first 4 months of the year had been wall to wall grey cloud, zero sun. I certainly wouldn't want to rely on them for my electricity! Not in this country.....Oh and when we first put them up, every man and his dog suddenly wanted to buy our roof space....
> and make a tidy sum
You're welcome :)
We also installed solar panels when the FIT payment was at its most generous so that was about 12 years ago. We get a reasonable return and we live in mid wales. Not known for wall to wall sunshine. Like you would not want it as main source….Our neighbours also rushed out to get them.
I think we've got 11 more years before the FIT ends. We've never had them cleaned, apparently they don't need it, and we get a good return in the North of England when the weather is kinda normal. Last year was unusual, we don't get that much continual cloud for so long. Ours take account of the heat I.e strength of the sun as well. So this time of year they really start to work well especially at the moment. It's glorious 🙌 well, if you watch BBC it's a horrific catastrophe and we're all frying 🤣🤣🤣
Ours have never been cleaned. But On a day like today torrential rain and thunderstorms natural cleaning 😊well it is wales still get a worthwhile payout. Like you we are in our 70s so we don’t take as much interest as we used too sunshine back tomorrow…. Pay for a couple of boxes of wine 😂😂🥂
I'm in my 50s 🤣 but I take your point 🤣
And the efficiency of the panels drops at least 1/2% a year.
Most installations have more capacity in the panels than can be supplied to the grid. So our 14 panels can generate over 4kWp but our grid supply is limited to 3.68. Even after 10 years it won't be evident that we're losing output. It will start to become obvious at that point though, but at 77 now I'll probably be past caring :)
Isn't the average output of your panels more like 25% of max capacity, after taking into account that max can only be achieved for a little while around high noon on sunny summer days assuming an ideal southern exposure?
It's probably less than that. I think solar farms prioduce about 20% of their nameplate capacity and they're normall optimally sighted.
Yes. It's a little better closer to the equator, worse closer to the poles, and bad in foggy, rainy 'ol London Town
Knowing very little (to be truthful, nothing) about solar panels I wondered about their lifespan. I do have anecdotal knowledge of the quality of some new-build housing and certainly would not trust all builders to install panels of the highest quality. When maintenance costs etc are factored in, I cannot imagine that I would rush to buy a new-build property. If I hear of someone in the family contemplating such a move, I’ll forward this article to them with all due speed.
See https://www.pv-magazine.com/2023/07/06/new-research-claims-85-solar-plants-in-czechia-reached-end-of-lifetime-after-only-12-years/ for some real-life scenarios of what’s out there in the field.
Thank you. “Wow” is the only thing I can say.
But Ed says Green electricity is cheaper. Surely there must be some mistake?
Or not......
I do wish they would stop calling it green or clean energy, there's no such thing. Every type of energy generation comes at a cost to the environment, wind and solar farms are really damaging to wildlife. Never mind the costs of making the wretched things and shipping them here from China. Its greenwashing, that's what it is.
The idea that Ed could make a cogent and accurate statement about anything is rather touching 🙂
Of course it's greenwashing. Most of it is stupidity on a stick....
Yep. Sheer lunacy.
Nobody is more sceptical than I am about AGW in general and Net Zero in particular, but the numbers you quote from EST are only referring to solar generation and the top-end is indeed about what we get from our solar panels, although we benefit by a similar amount from the FIT scheme we joined in 2018 and which is no longer available.
However having a battery changes the game completely. We went for a Tesla Powerwall as it has automatic home backup which means if the grid goes down it switches to battery - so fast that the Sky box doesn't even notice. Not all batteries do this and it will be vital when Mad Ed's policies result in blackouts and has already saved us a couple of times.
It also adds extra savings by storing the generated power for when it's needed so you use more of what you generate.
I also fill the battery up to 100% at the overnight cheap rate and then sell approx. 10kWh of my battery capacity every evening during the peak period at 29.3p. On a day that's very sunny that means we lose about 50p, but it guarantees that we get almost £3 every day which is not certain as even in summer there are at least a couple of duller days each week that reduce the power generated significantly. This may seem counter intuitive, but the "free" solar costs you because you can't sell it to the grid, and the day export rate on Octopus Flux is currently 10.11p and the night import rate 16.4p.
I am not convinced that solar (+ battery) on every new build is a good idea, but there are significant savings to be made.
I estimate that the solar panels we bought at the start of 2019 will be paid off in another couple of years and the battery in less than 10 years - significantly less if electricity prices go up again.
We are a retired couple at home all day so could use solar when the sun was shining for dishwasher or washing machine. We have no EV or other major appliances. In Jan and Feb we saved about £30/m compared to last year. March was a saving of £70 and April £85 (exceptional) we will stay at about that level until September so will have built up a big surplus in our account to pay our Octopus bill through the winter. Our total annual bill for gas CH and water and electricity is now about £450 but there's also £320 FIT payments to offset against that..
Everyone needs to think carefully about their own situation - if we were out all day I would manage my battery differently I think - and do the calculation according to their circumstances.
We were lucky enough to be able to buy the battery from savings and will recoup the cost with plenty of life still left in the battery. It's not for everyone but we like the security of knowing that we can stay powered up for several hours of the grid does go down.
PS Solar panels are showing no signs of degradation after 6 years and we've never had them cleaned either. This is on a SW facing roof at 43 degrees in Central England. I expect them to last well past the payback period, but only time will tell.
PPS we saved a bit more money on the CH before we had the battery by using a smart-switch that turned on a fan heater when we were generating more than 1kW in the winter. Now we still do that if it's sunny but cold. but not as much so means our gas bill is a tad higher. We also have a wood-burner, but we only light that if it's really cold. House is 60s detached build, old double glazing and some wall insulation (but not much) but I doubled up the roof insulation which made the house appreciably warmer.
What would you say is worth more:
Direct energy from the solar panels
FiT for energy from the solar panels that you didn't use
Charging the battery at night cheap and using in the day
Charging the battery up at night cheap and exporting for FiT at peak times?
From what I read it seems that much of the benefit could be derived from a battery alone. Equivalent to Economy 7 and modern storage heaters if your heat was all electric.
On the complicated load shifting, like you say, that's easier for retired people. Complete pita for young families.
The answer will depend very much on individual circumstances. We make a bit more from direct energt than from FIT and that is likely to increase if Net Zero continues and prices rise. But FIT is no longer available.
I've already explained why we charge up at night. If it's gloomy the next day we will use some of that from the battery to save paying the day import rate. If it's sunny we will sell that power at the evening peak. This only works on the tariff we are currently on. If you're on a different tariff or the prices diverge more it may not make sense.
You didn't say how much the Powerwall cost.
The Tesla Powerwall is the Rolls Royce of batteries; I looked at them about 3 years ago. They are very expensive indeed. I wonder if Roger’s calculations take account of the opportunity cost of the capital invested in his Powerwall? Unless he is factoring in his financing cost, ie the interest foregone on his savings, the analysis is misleading.
Yes you're right. The PW2 cost £8K, financed from savings, so with current interest rates and as a top-rate tax-payer, that's a couple of hundred quid a year on the debit side. We also lost some of our FIT payment, but that's accounted for.
I like to buy quality products as they tend to last longer and we have a 10 year guarantee that it'll still be at 80% capacity. They should be useful for much longer than 10 years though and the home backup aspect is very important to us. There are ostensibly cheaper batteries, but they you have to add in the cost of the extra components for automatic switching in a power cut.
There are also lots of apps around for Tesla - their app itself is great, and there is a NetZero app which lets you control the battery (and other Tesla devices like an EV that we don't have) at a very detailed level with a series of automations e.g. when battery level falls to 30% stop exporting.
Like you I looked into this 3 years ago with a year’s worth of detailed daily data from our panels and I simulated in a spreadsheet what size battery made sense for us as small users with no big appliances who are home all day so can use dishwasher/washing-machine when sun shines. The answer was 2-3kWh, but even then the ROI was over 12 years so not justifiable imo. 18 months ago I did the exercise again but taking into account what we could earn from exporting under the tariffs now available (as opposed to what we get now from FIT deemed export).
The answer was the Tesla which was now VAT-free would have an ROI of about 10 years, and my subsequent experiences think that it will actually be less than that, esp. if prices rise.
Good summary, yet there are more bits: Safety. Battery storage, if present, will almost certainly be of similar technology to what's used in EVs. As we've all seen, these are prone to spontaneously catch fire. A hot, unquenchable fire that’ll likely take any surrounding structure with it. Likely a rare, but serious risk.
Much more likely to cause trouble, yet more mundane problems include the problems of equipment breakdown. Sure, most components come with warranty or service plans. That’s all well and good, but I seriously doubt that any firm warranties its products for anywhere near their expected service life. A further problem is that a lot of these firms will go out of business, merge etc. Bye bye warranty service commitments. This is only a suspicion, but I suspect it’s a time-honored strategy in business to sell long-term service contracts and then to declare bankruptcy, move operations, or tae some other action that lets you keep the money and shed the obligation. Sure, there are consumer protection laws against such gambits, but they are limited in power. Merely filing bankruptcy at least freezes them, if not making them entirely ineffectual.
Even if the vendor remains in business, maintenance is entirely hostage to the availability of replacement parts and competent technicians. The former are almost entirely from overseas suppliers. Wars, economic embargoes or simply the obsolescence leading to stopping production unpredictably makes those supply lines constrict or vanish entirely. The latter issue is a domestic one; suffice to say that our workforces are not, on average, becoming more intelligent, honest or skillful.
I think the word is you get the government you deserve!!! .. Time for a change?
Thank you for that. It really is all quite mad.
https://baldmichael.substack.com/p/dim-and-dimmer-why-uk-scientists?utm_source=publication-search
The problem is that the rooftop solar and the price paid for electricity contributions to the grid are based on subsidies that could be revoked by the next government. Surely a huge risk?
Isn't the problem with solar is that it requires subsidies, rather than that the subsidies can be revoked Chris?
My comment applies to the owner of rooftop solar, which is subject to the whims of State and Federal largesse. The contracts in domestic solar do not protect the owner if the buy-back price is reduced from purchase price levels to wholesale (about 5c/kwh from 13 c/kwh).
This does apply to commercial scale solar/wind vendors too in that huge investments in manufacturing and supply chains can be at risk at whim.
It's a good point. Roger Hughes at Edinburgh University show that most UK wind is uneconomic. Since they have been "invested in" by large UK pension institutions, when the subsidy regimes expire he claims they will have to be bailed out by the tax payer. This is already happening - MPs either have or are about to vote for UK tax payers compensating them for the destruction in value arising from MPs mindless decision to move their colossal pension funds over to wind and other loss making rackets.
A risk possibly, but not huge. I guess in theory they could cancel the contracts but there would be a huge outcry and lots of legal challenges.