Solar power on roofs - more viable with energy price hikes?

[puffernutter]

When the Feed In tariff dropped significantly a few years ago, the idea of filling my roof with solar panels was less appealing. However with the current energy situation (even though we got a 2 year fixed rate deal last August) I wonder are solar panels the way to go to reduce energy costs - with two children (36 and 31 at home) it does feel like my bill is the same as a small country!

So what are the views? I have a terraced house with a tall roof, so I'd get someone to fit them. Companies to use/avoid. Do you buy the panels, do you rent roof space to them? I assume there must be a converter and something that decides where the energy for the house comes from - solar or grid and how much it costs?

Cheers

Peter

 

[Martin-Sy]

We've had 21 x 190 Watt panels on the roof here since 2011 when the feed-in tariff (FIT) was very attractive.
Our house faces due south and there are no obstructions to shade the panels.
It proved to be a good investment. We broke even on the investment cost after 7 years.
That's just in straight monetary terms, and doesn't include any savings on electricity bills.
With hindsight it's somewhat suspect morally, since everyone else has to pay the FIT to those with generation.

When we had them installed it was a FIT requirement that the installer was registered to do solar systems.
As you probably know the FIT scheme was closed to new applicants in 2019, so you'd need to get an estimate of what you can generate in terms of roof area, shading, location etc
We still get our FIT payment as this was guaranteed for 25 years from installation.
In rough terms we generate 4000 units per year. (4MW-h)

We bought our installation but there were companies that would install and own the panels on your house.
They got the FIT payment, you got to use the electricity. I don't know if these companies still do new installs.
So perhaps I should explain that the FIT is based on what is generated, irrespective of whether you use it or not.

The panels generate direct current. There's a clever box of tricks in the garage that converts this to AC.
It is very clever...it has to match the frequency and phase of the AC to the mains in your house.
It also regularly checks that your house is still on the 'grid'. Why....well if you got a power cut your solar system would be trying to supply the entire street too!
More significantly if the grid is OFF because someone is working on the system they might get an unexpected shock from your house generation.
So NBG in a power cut!

The solar generation is effectively in parallel with the incoming supply to your house.
If your domestic demand is less than that being generated the difference will be exported.
If your domestic demand is more than that being generated the difference will be imported.

So there is an incentive to always match your domestic use to that being generated.

Costs. Our install cost about £12.5k, but the price of the parts has come down I believe.
It's 10 years since we had ours so I cannot recommend a company. Many closed down with the end of the FIT scheme.
If you decide to go ahead, ask the installer to put netting around the edges. Pigeons like to nest under them!

HTH

 

[RWD3M]

You'd be cheaper kicking the kids out!

 

[puffernutter]

You'd be cheaper kicking the kids out!

They haven't taken the hint yet!

 

[minimutly]

My install was similar ^. 7 years and a bit to break even. These days the bits for a similar system are around £2.5k, and if you use the energy to heat water (and use it of course), the payback will be similar. I had a set installed at my daughters, in the process of fitting a tank at the moment. The FIT is no more, the income is less, but crikey, £12.5k for the install was a lot of money 10 years ago.

 

[frank horton]

watching with interest......
u are aware that solar tech is changing fast......the latest high performance panels are about 2wice the price of the norm....
but it worked out a better deal if ur a high user....
although no longer in the UK have heard that a lot of special offers (off peak etc) are not available with ur own panels.....
I would love to go completeley off grid but I need 3phase.....the change over panel/box of tricks for that is about £10,000 on it;s own plus all the batts etc....
On the negative side elec aint gonna get any cheaper after the rise......
I know of a couple that are off grid here, they say that only a couple of days in winter do they need to run the D genny.....more for a washing machine etc....
Also if there is room how about solar water heating.....we have a 2 panel system that heats our 250lt water tank.....again only a few days are we needing hot water from burning wood........
When our 2 girls left home the elec and water bills were reduced by about 1/2.....the water board came around for an inspection as they were not happy...
After we told the inspector about the girls leaving he was happily accepted with the readings....

 

[brightspark]

They haven't taken the hint yet!

spell it out to em or put the board and lodge up to pay for it

 

[slim_boy_fat]

spell it out to em or put the board and lodge up to pay for it

Ye'r a hard man.....

 

[Gareth J]

Depends on a whole host of things but yes, higher cost electric (and especially gas, actually) will help make it more likely to be viable. You won't get anything for selling back to the grid at that scale so you have to use as much as possible yourself.

As you're committing to having an installer, any you choose should be able to give you a fairly reliable estimate of output from an install. As a rough guide, for a south facing array with a decent pitch (not too flat) in a place that isn't cloudy all the time, you can roughly expect ~1000kwh/kw of panels per year. 75% of that in summer and 75% of that between 10:00 and 14:00.

That means that to make the most of the energy, you'll need to manage consumption and store excess somehow.

Around managing consumption, doing manual stuff like running washing machines and dishwashers or any high usage thing when the sun's will help.

Batteries help but are still expensive.

You can also use a diverter to heat water when the house is not demanding all the electric the panels are producing. This lets you save on alternative heating (gas?). But you'll need a decent cylinder to make the most if it. With 3 or 4 adults on board maybe 300-400 litres! But depends on your expected production as well as consumption.

Ask some local companies for a quote and estimate of production.

 

[Bladevane]

My experience is similar to @Martin-Sy . We've had panels for 7 years with an average annual generation of 4MWh, (That sounds higher to me than 4,000 KWh), and we're not even directly south facing. I did insist on having 2 strings of 8 panels each so any shading due to low sun in winter months was reduced. (In a single string the lowest generating panel pulls all that string down). We were told the typical inverter life was around 10 years and there would be PV panel degradation over time but so far, touch wood etc all has been good. I'm not sure I would go with PV panels now due to lack of FIT but hardware costs have certainly come down in the past few years so it might still be economically attractive to install. From the perspective of self-generation and climate change I am glad we had the installation when we did.

 

[minimutly]

One comment from me - beware of cowboys on your roof - they still exist. I made the lot that did my daughters remove them all and refit slates and then fix properly. They had used barn wood screw fixings into the trusses - sealed by a blob of silicon.. still pees me off thinking about it.

 

[fizzy]

My experience is similar to @Martin-Sy . We've had panels for 7 years with an average annual generation of 4MWh, (That sounds higher to me than 4,000 KWh), and we're not even directly south facing. I did insist on having 2 strings of 8 panels each so any shading due to low sun in winter months was reduced. (In a single string the lowest generating panel pulls all that string down). We were told the typical inverter life was around 10 years and there would be PV panel degradation over time but so far, touch wood etc all has been good. I'm not sure I would go with PV panels now due to lack of FIT but hardware costs have certainly come down in the past few years so it might still be economically attractive to install. From the perspective of self-generation and climate change I am glad we had the installation when we did

So you have 16 panels yes?
Are they 400w panels?

 

[Bladevane]

@fizzy I have 16 x 250W panels. Max. rated output is 4KW but I have seen the inverter putting out 4.7KW in very sunny, cooler conditions.

 

[MattF]

Ye'r a hard man.....

They're 36 & 31. He's being subtle, IMHO.

 

[DAPPH]

We've had 21 x 190 Watt panels on the roof here since 2011 when the feed-in tariff (FIT) was very attractive.
Our house faces due south and there are no obstructions to shade the panels.
It proved to be a good investment. We broke even on the investment cost after 7 years.
That's just in straight monetary terms, and doesn't include any savings on electricity bills.
With hindsight it's somewhat suspect morally, since everyone else has to pay the FIT to those with generation.

View attachment 330840

When we had them installed it was a FIT requirement that the installer was registered to do solar systems.
As you probably know the FIT scheme was closed to new applicants in 2019, so you'd need to get an estimate of what you can generate in terms of roof area, shading, location etc
We still get our FIT payment as this was guaranteed for 25 years from installation.
In rough terms we generate 4000 units per year. (4MW-h)

We bought our installation but there were companies that would install and own the panels on your house.
They got the FIT payment, you got to use the electricity. I don't know if these companies still do new installs.
So perhaps I should explain that the FIT is based on what is generated, irrespective of whether you use it or not.

The panels generate direct current. There's a clever box of tricks in the garage that converts this to AC.
It is very clever...it has to match the frequency and phase of the AC to the mains in your house.
It also regularly checks that your house is still on the 'grid'. Why....well if you got a power cut your solar system would be trying to supply the entire street too!
More significantly if the grid is OFF because someone is working on the system they might get an unexpected shock from your house generation.
So NBG in a power cut!

The solar generation is effectively in parallel with the incoming supply to your house.
If your domestic demand is less than that being generated the difference will be exported.
If your domestic demand is more than that being generated the difference will be imported.

So there is an incentive to always match your domestic use to that being generated.

Costs. Our install cost about £12.5k, but the price of the parts has come down I believe.
It's 10 years since we had ours so I cannot recommend a company. Many closed down with the end of the FIT scheme.
If you decide to go ahead, ask the installer to put netting around the edges. Pigeons like to nest under them!

HTH

Not morally suspect at all Martyn,

You chose to help improve the air we all breath & actually keep electricity security for others as well as keeping costs down by using money out your own pocket that could have been used elsewhere to a much greater effect for the benefit for you and yours as well.

The ones who ridiculed and berated you , chose not to make the investment but expect somebody to do it for free are living in cloud cuckoo land .
Had you invested in Bitcoins instead of the panels you'd be very wealthy indeed. In these days of Putin's grip on energy and the oil cartels for ever hiking up the prices .. miners demanding ever more money for a dirty fuel not many people wanted . The bigger spread of renewable energy from the home front is vital this includes nuclear generated power & heat energy .

The detractors would soon start bitching like a bulldog chewing a wasp if their electricity was cut off tonight and stayed off because no on can afford the purchase price of the material that produce the electricity and no solar PV or wind power generating was available .

Initially all new technologies start off expensive ..hence the 50p FIT inducement that the government offered to start the move to us being more green & self supporting wrt our energy resources ( Bro in law got it at 50p on th last day ) . He had to find something like a £15K loan for a 4kwhr ground array which reduced the size of his field & would make it difficult to rent out for agriculture rather than well fenced stock grazing . Like you it's only fairly recently turned to profit but when yu look at the amount of free electricity he's had off it ..he's quid' in as all the family became experts at using their generated power at the best time.

We got our panels a five or so years later & I was able to buy in cash without loan from a guy who was honest enough to tellus that due tothe drop off inth installing of panels he was able to credit broke and he'd fotted getting on gfotr 40 on other people roofs for free they get free power when it generating he got the FIT .

Had a guy from Tesla power bank come and visit me pre covid .. Knowing that we paid £2,400 or so IIRC again IIRC he calculated from our receipts that we had more than paid for the panels in just over three years So 17 years to push and the price of electricity is not ever going to go down . Suddenly going down the pub and putting the kidney & liver strained result up a wall doesn't ( never really ever did to me ) looks a very sensible thing to do you your money .
Set up you home to make it as efficient and cheap to run as you possibly can , is & has been my mantra for the la st 50 years. It's one investment that will always give you high returns. The power wall is very much insight too now the prices have come down .

 

[DAPPH]

watching with interest......
u are aware that solar tech is changing fast......the latest high performance panels are about 2wice the price of the norm....
but it worked out a better deal if ur a high user....
although no longer in the UK have heard that a lot of special offers (off peak etc) are not available with ur own panels.....
I would love to go completeley off grid but I need 3phase.....the change over panel/box of tricks for that is about £10,000 on it;s own plus all the batts etc....
On the negative side elec aint gonna get any cheaper after the rise......
I know of a couple that are off grid here, they say that only a couple of days in winter do they need to run the D genny.....more for a washing machine etc....
Also if there is room how about solar water heating.....we have a 2 panel system that heats our 250lt water tank.....again only a few days are we needing hot water from burning wood........
When our 2 girls left home the elec and water bills were reduced by about 1/2.....the water board came around for an inspection as they were not happy...
After we told the inspector about the girls leaving he was happily accepted with the readings....

I'm sure now we changed supplier a year ago we get a disability related low off peak We have the digital colour screen device to tell us everything , currently 463 watts @ 0.07 p pr KWHR even though we have a PHEV Outlander set up for off peak and a switchable over ride that uses the excess generation.

Alison was complaining, when earlier it was 820 watts at 9 p per unit ( wet room underfloor trace heat cable had come on. We also run a 180 watt dehumidifier 24/. that colledcts a litre or so every second day ... it's rarely operating yet saves us a lot of money heating overly moist air

 

[Mr Fro]

I was looking in to this at the weekend as I'm contemplating an electric car...

I'd need 16 x 400 W panels (Samsung something or other) feeding 2 x Tesla battery banks (3 would be better) to give me enough range to get to work and back. I calculated it would be around 6.5 year payback in diesel savings alone at today's prices.

I didn't adjust for weekends and used the average number of daylight hours in my calculations.

I think in reality the payback would be sooner given the rising price of fuel.

 

[roofman]

36 and 31 still at home...They might as well stay there now until the inheritance kicks in when you start your journey outer here

 

[Gareth J]

@fizzy I have 16 x 250W panels. Max. rated output is 4KW but I have seen the inverter putting out 4.7KW in very sunny, cooler conditions.

Similar here, there's actually two separate 4kW arrays. It's hard to directly compare them for a number of reasons but despite the shallower pitched ones having a number of benefits, the steeper ones produce more, and more importantly, more useful electric than the shallower ones.

In a no tarriff situation, without decent storage, it's worth considering and East West array.

 

[puffernutter]

36 and 31 still at home...They might as well stay there now until the inheritance kicks in when you start your journey outer here

Someone earlier said "charge them more" now that's the interesting part, if they only "contribute" towards the running costs and are not charged rent, then they have no rights with regards to the property! We have told them (and I think they thought we were joking) if we ever needed money and had to sell the house we would. As it stands, we can and they have no say in it at all they are not "sitting tenants".

See, there is method in my madness!