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

[minimutly]

All the guestimates of energy output can be sourced from the net. You need to provide location direction the panels face and the angle they will be installed at. Panel output (efficiency), any shading and the type of inverter will make small adjustments to the expected average annual leccy production.

My advice is to avoid the temptation of free panel installation with a contract for the income (they do still exist, I think). Think what happens if/when you might want to move house. That could/would/should cost you thousands off your selling price!

Always get several quotes. Not all companies are truthful, many have gone bust to start up again afresh, so no long term guarantees for them to fulfil. Some may promise far more output than available in reality.

Leccy costs will only rise. You need to be able to work out the practical pay-back period - dont just trust the installer salesperson!

3.68kW is the normal current allowance to be fed into the grid from a single phase property. Permission may be available for more than that at the discretion of the utility.

There are options to consider - like battery storage. Would you use the leccy yourself, if it is not stored. Are you envisaging a battery electric car in the future is yet another thing to consider.

On top of all that, do remember that solar likely produces 8 times as much leccy in the summer than during the winter months. Yearly outputs are not always the best way to plan a system.

What about hot water? Solar thermal panels, while only harvesting heat energy, might be better than using higher grade energy for that purpose, although solar PV panels are relatively cheap, these days, and leccy is a high grade energy source.

No to the last bit - solar leccy, fed into a bit of kit that feeds an immersion heater has got to be better than water pipes, and steaming antifreeze in your loft....
Don't do it.

 

[minimutly]

I may be a bit behind, but I know for definite I get around £1800 a year, and it's index linked and gauranteed for 25yrs from the installation date. Maybe fit has stopped for new installations?

Not arguing with that. I'm with you, best cheque I ever wrote.

 

[Gareth J]

Something to consider; prices of stuff can go down as well as up. Gas and electric costs are very high and apparently due to stay high for a while. But no one will guarantee they'll be this high over the longer term. I would be cautious about accepting an installation offer based on paybacks times calculated using today's costs.

 

[not done it yet]

No to the last bit - solar leccy, fed into a bit of kit that feeds an immersion heater has got to be better than water pipes, and steaming antifreeze in your loft....
Don't do it.

While that is your choice, solar thermal is effective. Electricity is worth 5 times that of thermal energy. There should not be any ‘steaming antifreeze’ in the attic, if the job is done properly but, yes, it is easier (not necessarily ‘better’) to use a PV diverter, such as a Solic 200, for domestic water heating.

What exactly do you have against solar thermal? Not a competent plumber? I have vacuum tubes ready to go up, but they will be below the heat exchanger coil (simply fitted on the south facing facade) so will not need a pressurised system or a substantial circulation pump. I like free energy and care less about the initial capital expense - as energy prices will continue to rise for the foreseeable future.

Same as heat pump technology. I won’t install an air-sourced system as the COP is not very good in the UK for most installations (unless one has space for extra PV and a suitable storage system, of course). I will wait until boreholes, for ground source, are a more economic choice. No artesian water flows, at a sensible depth, around our house.

 

[EEEK]

Saw a guy mention the other day a plan to use solar to charge storage heaters during the day.... sounded like a decent plan to me.

Would it work ?

 

[Trevorleach]

While that is your choice, solar thermal is effective. Electricity is worth 5 times that of thermal energy. There should not be any ‘steaming antifreeze’ in the attic, if the job is done properly but, yes, it is easier (not necessarily ‘better’) to use a PV diverter, such as a Solic 200, for domestic water heating.

What exactly do you have against solar thermal? Not a competent plumber? I have vacuum tubes ready to go up, but they will be below the heat exchanger coil (simply fitted on the south facing facade) so will not need a pressurised system or a substantial circulation pump. I like free energy and care less about the initial capital expense - as energy prices will continue to rise for the foreseeable future.

Same as heat pump technology. I won’t install an air-sourced system as the COP is not very good in the UK for most installations (unless one has space for extra PV and a suitable storage system, of course). I will wait until boreholes, for ground source, are a more economic choice. No artesian water flows, at a sensible depth, around our house.

I fitted an evac tube set up in 2014, and apart from one wiring issue which was my fault as I had not crimped the extension correctly it has been pretty much fault free, during the summer we use little to no gas at all.

At the time I used the Navitron forum for info and advice, sadly now gone.

 

[bump]

Not much use for me unless I can rotate the house 90 degrees. As we have an east west facing roof I'd need to have both covered to get a reasonable output.

 

[Gareth J]

Saw a guy mention the other day a plan to use solar to charge storage heaters during the day.... sounded like a decent plan to me.

Would it work ?

Absolutely, and "dumb" heater can be used as a dump for excess generation.... however, would that really be that useful? The peak of generation coincides exactly with the time of year you least need heat in the house!

Not much use for me unless I can rotate the house 90 degrees. As we have an east west facing roof I'd need to have both covered to get a reasonable output.

Not necessarily, an East- West setup can provide more useable electric than a due south one, despite a lower overall output. Important to consider now there are no feed in tariffs.

 

[minimutly]

Absolutely, and "dumb" heater can be used as a dump for excess generation.... however, would that really be that useful? The peak of generation coincides exactly with the time of year you least need heat in the house!



Not necessarily, an East- West setup can provide more useable electric than a due south one, despite a lower overall output. Important to consider now there are no feed in tariffs.

Hmmm, been wondering about this for a while - my garage has it’s own supply, so I could fit 3.8kW of solar either side of one of the ridges east- west, 2 strings. Need a load for it though, maybe a battery bank and inverter?

 

[minimutly]

While that is your choice, solar thermal is effective. Electricity is worth 5 times that of thermal energy. There should not be any ‘steaming antifreeze’ in the attic, if the job is done properly but, yes, it is easier (not necessarily ‘better’) to use a PV diverter, such as a Solic 200, for domestic water heating.

What exactly do you have against solar thermal? Not a competent plumber? I have vacuum tubes ready to go up, but they will be below the heat exchanger coil (simply fitted on the south facing facade) so will not need a pressurised system or a substantial circulation pump. I like free energy and care less about the initial capital expense - as energy prices will continue to rise for the foreseeable future.

Same as heat pump technology. I won’t install an air-sourced system as the COP is not very good in the UK for most installations (unless one has space for extra PV and a suitable storage system, of course). I will wait until boreholes, for ground source, are a more economic choice. No artesian water flows, at a sensible depth, around our house.

I have nothing against wet systems or plumbing. The point is though, if you go electric, you have flexibility to do with it what you want. Go wet and all you can do is heat water.

 

[AVI_8]

My son came to visit today, he’s a sales rep for a company who install these installations, he’s being saying to me for a while about getting this, I do have a good size roof which is south facing, but I live in Scotland, so there’s a lot of perma cloud, he seems to think that I could get 2\3 of my electrics from solar, I’m currently around 6000 KW/h of elec, if the electricity prices rise much further I’m starting to think it might be worthwhile, He told me that the best I’d get for selling it back to the grid is only 3.9 pence per KW/ hour with octopus but that’s not where the savings are, if I wanted a battery, it would hold 8.2 KW and would cost £2692, he also told me that the Tesla batteries were very over priced just now, and that battery prices were likely to reduce over time.
He told me that I could do a good DIY installation considerably cheaper than getting a company in to do it,
For example and If my memory serves me correctly 9 LG panels an inverter and an 8.2 KW battery would be £6000, to get a supply including install would be £10K
Id have to get a roofer to install the panels so that would be in addition to the 6K price for the components, which would just leave me to run the cables and get an electrician to do the final connection.…. food for thought especially with electricity prices going where they are.
The main point I took from our conversation was that 40% of the cost of getting a solar system is installation.
And I know a lot of you guys are good at DIY, so there’s a significant saving there, it’s a fairly simple installation once you get a roofer to fit the panels, just running cables to an inverter, battery, then a spark to do the magic to your house system, This is third party info though from a brief conversation with my son, I’d be interested to hear from an electrician if there’s any further complications in connecting this to a house CU

 

[DAPPH]

The bit I don’t understand is this exporting. I know if the panels generate more than is being used there will be an excess, but how does this go back into the grid? Is it just the case that the meter runs backwards?

It's al to do with a bloke called eddy currents & potential differences

 

[DAPPH]

All the guestimates of energy output can be sourced from the net. You need to provide location direction the panels face and the angle they will be installed at. Panel output (efficiency), any shading and the type of inverter will make small adjustments to the expected average annual leccy production.

My advice is to avoid the temptation of free panel installation with a contract for the income (they do still exist, I think). Think what happens if/when you might want to move house. That could/would/should cost you thousands off your selling price!

Always get several quotes. Not all companies are truthful, many have gone bust to start up again afresh, so no long term guarantees for them to fulfil. Some may promise far more output than available in reality.

Leccy costs will only rise. You need to be able to work out the practical pay-back period - dont just trust the installer salesperson!

3.68kW is the normal current allowance to be fed into the grid from a single phase property. Permission may be available for more than that at the discretion of the utility.

There are options to consider - like battery storage. Would you use the leccy yourself, if it is not stored. Are you envisaging a battery electric car in the future is yet another thing to consider.

On top of all that, do remember that solar likely produces 8 times as much leccy in the summer than during the winter months. Yearly outputs are not always the best way to plan a system.

What about hot water? Solar thermal panels, while only harvesting heat energy, might be better than using higher grade energy for that purpose, although solar PV panels are relatively cheap, these days, and leccy is a high grade energy source.

Not so sure about having panels knocks money off the value of the house .. not many months ago people were clamouring for them if it was a sale from a covid death as I think they saw which way things were heading .

 

[skotl]

I just walked through this calculator (YMMV) and it suggested I'd save £147 over seven years. That's a nope then.

Home | Solar Panel Calculator

www.pvfitcalculator.energysavingtrust.org.uk

 

[Gareth J]

My son came to visit today, he’s a sales rep for a company who install these installations, he’s being saying to me for a while about getting this, I do have a good size roof which is south facing, but I live in Scotland, so there’s a lot of perma cloud, he seems to think that I could get 2\3 of my electrics from solar, I’m currently around 6000 KW/h of elec, if the electricity prices rise much further I’m starting to think it might be worthwhile, He told me that the best I’d get for selling it back to the grid is only 3.9 pence per KW/ hour with octopus but that’s not where the savings are, if I wanted a battery, it would hold 8.2 KW and would cost £2692, he also told me that the Tesla batteries were very over priced just now, and that battery prices were likely to reduce over time.
He told me that I could do a good DIY installation considerably cheaper than getting a company in to do it,
For example and If my memory serves me correctly 9 LG panels an inverter and an 8.2 KW battery would be £6000, to get a supply including install would be £10K
Id have to get a roofer to install the panels so that would be in addition to the 6K price for the components, which would just leave me to run the cables and get an electrician to do the final connection.…. food for thought especially with electricity prices going where they are.
The main point I took from our conversation was that 40% of the cost of getting a solar system is installation.
And I know a lot of you guys are good at DIY, so there’s a significant saving there, it’s a fairly simple installation once you get a roofer to fit the panels, just running cables to an inverter, battery, then a spark to do the magic to your house system, This is third party info though from a brief conversation with my son, I’d be interested to hear from an electrician if there’s any further complications in connecting this to a house CU

I'd forgotten about smart export payment! Good point. Only applies if you get it MCS installed though, rediculously.

Regarding DIY installs, seen people here do significantly more impressive things. I put 4kW on a tin roof, was pretty straightforward.

 

[Gareth J]

Hmmm, been wondering about this for a while - my garage has it’s own supply, so I could fit 3.8kW of solar either side of one of the ridges east- west, 2 strings. Need a load for it though, maybe a battery bank and inverter?

Is the garage connected to the house too? The more places you can potentially use the electric before it escapes out to the grid the better

 

[AVI_8]

I just walked through this calculator (YMMV) and it suggested I'd save £147 over seven years. That's a nope then.

Home | Solar Panel Calculator

www.pvfitcalculator.energysavingtrust.org.uk

That’s a handy website, it says I’d save £304 per year with a 4 KW system, but that’s based on elec costing 16p per KW/H
I‘m pretty sure it costs a bit more than that just now and with talks of it getting even more expensive.

 

[minimutly]

Is the garage connected to the house too? The more places you can potentially use the electric before it escapes out to the grid the better

The garage has its own supply........
Let me add that I run a dehumidifier in the winter occasionally, the lighting load is a few hundred watts still (slowly swapping in leds), and then there is whatever tools I use. So it would need a battery system I think.

 

[Gareth J]

The garage has its own supply........

Unless you can amalgamate house and garage supplies, you're potentially missing out on a lot of savings. Or an electric car in the garage I guess.

Obviously have no idea of the geography of your estate but maybe you could consider feeding the house from the garage supply or vice versa. If it were logistically possible, you'd save on a second connection fee too.

 

[mike os]

what are thoughts on ground mounted panels

also do the rules differ significantly?

My roof is not well suited so thinking of an alternative

Mind you the above calculator only saves me 270 a year and a loss of 200 over the life of the system?????