Discussion
Hello thread...
We are looking to install a large solar roof, being edge to edge solar tiles NOT PV panels, for a house we bought earlier this year. House has an almost flat roof, 2.5deg pitch and is only 12 degrees off true south orientation, albeit the northern roof represents 62% of the area and the southern roof 38% of total area due to an asymmetric ridge. Roof is around 340 sqm in total and would generate 56Kwp max ignoring losses. House is around 5000sq ft.
Looking at SigEnergy equipment for the batteries/inverters and controller to manage the storage and import/export, which uses AI to predict the import and export needs and maximise returns. I do not yet know if we would be capped at if we apply for G99, so I am assuming the worst case scenario of a G98 approval at just 3.68Kw per phase, but that still would allow up to 265 kwh a day anyway, which seems is more than we could generate even in summer even with such a large array and forgetting any self consumption.
https://www.sigenergy.com/en
Plan is that supply will be upgraded to 3 phase and 3x 20kw controllers installed with an expandible battery array on each. Initially 3x 8.06kw batteries, but can be expanded to 6 x8kw batteries per inverter (so batteries 145Kw max) if required. Interface to smart compatible appliances such as ASHP and EV car chargers. I think it is very likely we would add at least 3x more 8.06kw batteries within a few months of evaluation of system performance.
After the various losses, the estimates are showing we should generate up to 46Kwp which equates to 6400kwh per month in July and as little as 600kwh in December, totalling 42,500kwh over a whole 12 month period.
I am taking a long term view on this, in that I am not expecting a ROI in any set timescale, its about comfort / future proofing our "forever home" for the rest of our lives (55yrs old now, so ~25yrs use should see us beyond the point of caring), and hopefully ensuring that the new swimming pool doesn't bankrupt us over that time, and may reduce what is currently a serious outgoing on gas/electric into a modest income.
Historic use of gas in the property has been sky-high, its an old 1960's gas boiler in the basement with a U16 meter so that gives an idea of how much it guzzles! ~120,000kwh p/a on gas alone!
I think the big debate in my mind is if the solar roof is worth the full investment, as we have the option of going for 60% / 40% or 100% based on north/south/all splits. I am farily convinced already that the batteries alone make sense. Sure the solar tiles are way more expensive than just PV panels would be, but aesthetically I will not entertain the option of PV panels, so its a solar roof or not at all. The swimming pool is probably the driving factor in the solar decision, aside from the capital outlay of course.
Open to any questions, suggestions or feedback.
We are looking to install a large solar roof, being edge to edge solar tiles NOT PV panels, for a house we bought earlier this year. House has an almost flat roof, 2.5deg pitch and is only 12 degrees off true south orientation, albeit the northern roof represents 62% of the area and the southern roof 38% of total area due to an asymmetric ridge. Roof is around 340 sqm in total and would generate 56Kwp max ignoring losses. House is around 5000sq ft.
Looking at SigEnergy equipment for the batteries/inverters and controller to manage the storage and import/export, which uses AI to predict the import and export needs and maximise returns. I do not yet know if we would be capped at if we apply for G99, so I am assuming the worst case scenario of a G98 approval at just 3.68Kw per phase, but that still would allow up to 265 kwh a day anyway, which seems is more than we could generate even in summer even with such a large array and forgetting any self consumption.
https://www.sigenergy.com/en
Plan is that supply will be upgraded to 3 phase and 3x 20kw controllers installed with an expandible battery array on each. Initially 3x 8.06kw batteries, but can be expanded to 6 x8kw batteries per inverter (so batteries 145Kw max) if required. Interface to smart compatible appliances such as ASHP and EV car chargers. I think it is very likely we would add at least 3x more 8.06kw batteries within a few months of evaluation of system performance.
After the various losses, the estimates are showing we should generate up to 46Kwp which equates to 6400kwh per month in July and as little as 600kwh in December, totalling 42,500kwh over a whole 12 month period.
I am taking a long term view on this, in that I am not expecting a ROI in any set timescale, its about comfort / future proofing our "forever home" for the rest of our lives (55yrs old now, so ~25yrs use should see us beyond the point of caring), and hopefully ensuring that the new swimming pool doesn't bankrupt us over that time, and may reduce what is currently a serious outgoing on gas/electric into a modest income.
Historic use of gas in the property has been sky-high, its an old 1960's gas boiler in the basement with a U16 meter so that gives an idea of how much it guzzles! ~120,000kwh p/a on gas alone!
I think the big debate in my mind is if the solar roof is worth the full investment, as we have the option of going for 60% / 40% or 100% based on north/south/all splits. I am farily convinced already that the batteries alone make sense. Sure the solar tiles are way more expensive than just PV panels would be, but aesthetically I will not entertain the option of PV panels, so its a solar roof or not at all. The swimming pool is probably the driving factor in the solar decision, aside from the capital outlay of course.
Open to any questions, suggestions or feedback.
Edited by AdamV12V on Friday 5th April 21:19
AdamV12V said:
Hello thread...
We are looking to install a large solar roof, being edge to edge solar tiles NOT PV panels, for a house we bought earlier this year. House has an almost flat roof, 2.5deg pitch and is only 12 degrees off true south orientation,
Are the solar tiles suitable for that pitch?We are looking to install a large solar roof, being edge to edge solar tiles NOT PV panels, for a house we bought earlier this year. House has an almost flat roof, 2.5deg pitch and is only 12 degrees off true south orientation,
I know nothing about the solar versions of tiles but would have thought that as they work as a replacement for traditional tiles they would be subject to similar requirements.
Your 2.5deg Pitch would probably be considered a flat roof. roofs are normally a lot steeper in the region of 30deg. there are some tile ranges that go as shallow as 15deg.
With lower pitches than that there is the potential for wind to get under tiles under them and lift the roof. Rain can be blown up and into the roof as well.
We have a single story extension with a 12deg pitch. The tiles we had to have fitted took a good amount of searching to find and had to be ordered specially. They have special interlocking sections that overlap along all edges to direct water down and away, they use special fixings to hold the bottom in place to prevent hold them down in the wind.
(Ps I also don't have any solar at home, but do have a 180Kw system at work)
AdamV12V said:
Hello thread...
We are looking to install a large solar roof, being edge to edge solar tiles NOT PV panels, for a house we bought earlier this year. House has an almost flat roof, 2.5deg pitch and is only 12 degrees off true south orientation, albeit the northern roof represents 62% of the area and the southern roof 38% of total area due to an asymmetric ridge. Roof is around 340 sqm in total and would generate 56Kwp max ignoring losses. House is around 5000sq ft.
Looking at SigEnergy equipment for the batteries/inverters and controller to manage the storage and import/export, which uses AI to predict the import and export needs and maximise returns. I do not yet know if we would be capped at if we apply for G99, so I am assuming the worst case scenario of a G98 approval at just 3.68Kw per phase, but that still would allow up to 265 kwh a day anyway, which seems is more than we could generate even in summer even with such a large array and forgetting any self consumption.
https://www.sigenergy.com/en
Plan is that supply will be upgraded to 3 phase and 3x 20kw controllers installed with an expandible battery array on each. Initially 3x 8.06kw batteries, but can be expanded to 6 x8kw batteries per inverter (so batteries 145Kw max) if required. Interface to smart compatible appliances such as ASHP and EV car chargers. I think it is very likely we would add at least 3x more 8.06kw batteries within a few months of evaluation of system performance.
After the various losses, the estimates are showing we should generate up to 46Kwp which equates to 6400kwh per month in July and as little as 600kwh in December, totalling 42,500kwh over a whole 12 month period.
I am taking a long term view on this, in that I am not expecting a ROI in any set timescale, its about comfort / future proofing our "forever home" for the rest of our lives (55yrs old now, so ~25yrs use should see us beyond the point of caring), and hopefully ensuring that the new swimming pool doesn't bankrupt us over that time, and may reduce what is currently a serious outgoing on gas/electric into a modest income.
Historic use of gas in the property has been sky-high, its an old 1960's gas boiler in the basement with a U16 meter so that gives an idea of how much it guzzles! ~120,000kwh p/a on gas alone!
I think the big debate in my mind is if the solar roof is worth the full investment, as we have the option of going for 60% / 40% or 100% based on north/south/all splits. I am farily convinced already that the batteries alone make sense. Sure the solar tiles are way more expensive than just PV panels would be, but aesthetically I will not entertain the option of PV panels, so its a solar roof or not at all. The swimming pool is probably the driving factor in the solar decision, aside from the capital outlay of course.
Open to any questions, suggestions or feedback.
Firstly, I don't understand the tiles on a flat roof malarkey?We are looking to install a large solar roof, being edge to edge solar tiles NOT PV panels, for a house we bought earlier this year. House has an almost flat roof, 2.5deg pitch and is only 12 degrees off true south orientation, albeit the northern roof represents 62% of the area and the southern roof 38% of total area due to an asymmetric ridge. Roof is around 340 sqm in total and would generate 56Kwp max ignoring losses. House is around 5000sq ft.
Looking at SigEnergy equipment for the batteries/inverters and controller to manage the storage and import/export, which uses AI to predict the import and export needs and maximise returns. I do not yet know if we would be capped at if we apply for G99, so I am assuming the worst case scenario of a G98 approval at just 3.68Kw per phase, but that still would allow up to 265 kwh a day anyway, which seems is more than we could generate even in summer even with such a large array and forgetting any self consumption.
https://www.sigenergy.com/en
Plan is that supply will be upgraded to 3 phase and 3x 20kw controllers installed with an expandible battery array on each. Initially 3x 8.06kw batteries, but can be expanded to 6 x8kw batteries per inverter (so batteries 145Kw max) if required. Interface to smart compatible appliances such as ASHP and EV car chargers. I think it is very likely we would add at least 3x more 8.06kw batteries within a few months of evaluation of system performance.
After the various losses, the estimates are showing we should generate up to 46Kwp which equates to 6400kwh per month in July and as little as 600kwh in December, totalling 42,500kwh over a whole 12 month period.
I am taking a long term view on this, in that I am not expecting a ROI in any set timescale, its about comfort / future proofing our "forever home" for the rest of our lives (55yrs old now, so ~25yrs use should see us beyond the point of caring), and hopefully ensuring that the new swimming pool doesn't bankrupt us over that time, and may reduce what is currently a serious outgoing on gas/electric into a modest income.
Historic use of gas in the property has been sky-high, its an old 1960's gas boiler in the basement with a U16 meter so that gives an idea of how much it guzzles! ~120,000kwh p/a on gas alone!
I think the big debate in my mind is if the solar roof is worth the full investment, as we have the option of going for 60% / 40% or 100% based on north/south/all splits. I am farily convinced already that the batteries alone make sense. Sure the solar tiles are way more expensive than just PV panels would be, but aesthetically I will not entertain the option of PV panels, so its a solar roof or not at all. The swimming pool is probably the driving factor in the solar decision, aside from the capital outlay of course.
Open to any questions, suggestions or feedback.
Edited by AdamV12V on Friday 5th April 21:19
Unless you have a lot of people looking down on you?
In which case you probably have more shading than is apparent tn those numbers?
I guess we are talking about a listed building or something?
Secondly I would be suspicious of 'future proofing' with a niche product like solar tiles.
Solar cells have a failure rate. It's bad enough common solar panels, it seems fairly normal to replace a whole string of panels if one fails, because technology moves on, and if one from a batch has failed, you don't trust the others so much.
You need to read the fine print of any warranties.
When a solar tile fails in 10 years' time, if the supplier is still around, they will probably offer you a new tile at 10/25 price.
They won't be paying for the worlk of dismantling and re-assembling half your expensive lego roof.
i wonder if the popular view of the aesthetics of solar panels will change in the next decade or two?
Maybe in a few years more people will start to point and laugh at 'traditional' rooves with no solar?
I'm actually thinking the tech which interests me now could be a millstone when I'm 70. Loads of obsolete boxes of electronics taking it in turns to fail.
Current house is 20 years old, with lots of 'no maintenance' plastic bits up to and including a double GRP garage door, all starting to look their age...
Even I'm going to outlive most things which are being made today.
dmsims said:
Any particular reason for Sigenergy?
How long has the company behind them been operating?
How long have the batteries been available in the UK market?
How many UK distributors are there?
Is there a UK support contact?
All very good questions.How long has the company behind them been operating?
How long have the batteries been available in the UK market?
How many UK distributors are there?
Is there a UK support contact?
Any particular reason for Sigenergy? - because they are being highly recommended as market leading AI tech that can maximise income from current and future variable rate tariffs, all built in todays controllers. I can consider other more conventional brands too.
How long has the company behind them been operating? - Since 2022
How long have the batteries been available in the UK market? - Initially the 5Kw battery was the only option, now there is a choice of 5kw or 8kw.
How many UK distributors are there? - 4 UK distributers https://www.sigenergy.com/en/order/distributor_map
Is there a UK support contact - 47 UK service outlets.
I will be asking a few more questions about their stability given they have only been trading for 2yrs, but I guess all tech companies have to start one day.
Buzz84 said:
Are the solar tiles suitable for that pitch?
I know nothing about the solar versions of tiles but would have thought that as they work as a replacement for traditional tiles they would be subject to similar requirements.
Your 2.5deg Pitch would probably be considered a flat roof. roofs are normally a lot steeper in the region of 30deg. there are some tile ranges that go as shallow as 15deg.
With lower pitches than that there is the potential for wind to get under tiles under them and lift the roof. Rain can be blown up and into the roof as well.
We have a single story extension with a 12deg pitch. The tiles we had to have fitted took a good amount of searching to find and had to be ordered specially. They have special interlocking sections that overlap along all edges to direct water down and away, they use special fixings to hold the bottom in place to prevent hold them down in the wind.
Indeed, I have had to consider all these issues in selecting a suitable tile that can be locked down. Its currently Asphalt but needs replacing. The Nulok tile system that supplies the solar tiles will work at this pitch and be 95% water tight, but to make it 100% we plan to have a countersunk epoxy coated waterproof layer beneath it, both of which will drain into hidden gutters inside the roof structure.I know nothing about the solar versions of tiles but would have thought that as they work as a replacement for traditional tiles they would be subject to similar requirements.
Your 2.5deg Pitch would probably be considered a flat roof. roofs are normally a lot steeper in the region of 30deg. there are some tile ranges that go as shallow as 15deg.
With lower pitches than that there is the potential for wind to get under tiles under them and lift the roof. Rain can be blown up and into the roof as well.
We have a single story extension with a 12deg pitch. The tiles we had to have fitted took a good amount of searching to find and had to be ordered specially. They have special interlocking sections that overlap along all edges to direct water down and away, they use special fixings to hold the bottom in place to prevent hold them down in the wind.
OutInTheShed said:
Firstly, I don't understand the tiles on a flat roof malarkey?
Unless you have a lot of people looking down on you?
In which case you probably have more shading than is apparent tn those numbers?
I guess we are talking about a listed building or something?
Our house is on a slope so we can very much see the northern flat roof side from our own driveway / top garden area. I have discounted all types of PV Panels as I find them rather ugly. A day1 requirement in sourcing suitable tiles (or BIPV system) was that they would work on such a low pitched roof and give an very attractive finish and must be installed edge to edge, not a clump surrounded by mismatching tiles. Changing the pitch is also not something I want to do as it is very much part of the 1960's design of the house and makes it look very attractive. The roof needs to enhance the building, not detract from it.Unless you have a lot of people looking down on you?
In which case you probably have more shading than is apparent tn those numbers?
I guess we are talking about a listed building or something?
The house is in a conservation area and we are surrounded by ancient woodland, some of which is our own garden, but the house and roof itself is largely in the clear and very little shade. The numbers are simply the conservative numbers the official calcs pump out. Both the fitter and this website gave me almost identical numbers for the whole roof / year based on the number of tiles and output of each. https://re.jrc.ec.europa.eu/pvg_tools/en/#api_5.2
I have another quote coming in next week for SunStyle dragonscale tiles, but they are very expensive indeed, but probably the market leader in aesthetics. They have quoted 350 EUR a sqm for supply and fit, so I strongly suspect they will end up more expensive than the ones in the first quote. I am unsure what inverters and batteries they will suggest with this system, but in theory I could stick with the same suppler fitter and ask them to use the other tiles.
OutInTheShed said:
Secondly I would be suspicious of 'future proofing' with a niche product like solar tiles.
Solar cells have a failure rate. It's bad enough common solar panels, it seems fairly normal to replace a whole string of panels if one fails, because technology moves on, and if one from a batch has failed, you don't trust the others so much.
You need to read the fine print of any warranties.
When a solar tile fails in 10 years' time, if the supplier is still around, they will probably offer you a new tile at 10/25 price.
They won't be paying for the worlk of dismantling and re-assembling half your expensive lego roof.
i wonder if the popular view of the aesthetics of solar panels will change in the next decade or two?
Maybe in a few years more people will start to point and laugh at 'traditional' rooves with no solar?
I'm actually thinking the tech which interests me now could be a millstone when I'm 70. Loads of obsolete boxes of electronics taking it in turns to fail.
Current house is 20 years old, with lots of 'no maintenance' plastic bits up to and including a double GRP garage door, all starting to look their age...
Even I'm going to outlive most things which are being made today.
Yes I am aware of the tile failures and warrenty issues, especially with a new company. But even if the company is still around sourcing a tile to the old spec may well be a problem. The tiling system I have selected can be walked on, and a single tile can be clipped out and replaced without taking the whole roof apart. That aspect is something I have already extensively questioned.Solar cells have a failure rate. It's bad enough common solar panels, it seems fairly normal to replace a whole string of panels if one fails, because technology moves on, and if one from a batch has failed, you don't trust the others so much.
You need to read the fine print of any warranties.
When a solar tile fails in 10 years' time, if the supplier is still around, they will probably offer you a new tile at 10/25 price.
They won't be paying for the worlk of dismantling and re-assembling half your expensive lego roof.
i wonder if the popular view of the aesthetics of solar panels will change in the next decade or two?
Maybe in a few years more people will start to point and laugh at 'traditional' rooves with no solar?
I'm actually thinking the tech which interests me now could be a millstone when I'm 70. Loads of obsolete boxes of electronics taking it in turns to fail.
Current house is 20 years old, with lots of 'no maintenance' plastic bits up to and including a double GRP garage door, all starting to look their age...
Even I'm going to outlive most things which are being made today.
The current house is now 62 years old as was built in 1962, so we already have a good number of things failing that need replacing. This is a part of an extensive scheme of modernisation, whilst retaining and enhancing the original design / charm of the building (hopefully!
) Edited by AdamV12V on Saturday 6th April 09:06
dmsims said:
There is no system on earth that can do this (in the UK) accurately.........
ok my bad choice of words, it uses AI to predict our use patterns and the likely input from solar tiles based on the weather forecast etc.. and uses the tarrifs for the day ahead and then works out the best pattern of export and import from the grid. I am sure I will know more in the weeks to come as I ask more and more questions before ordering with them or anyone else.There's a ton of info on Sigenergy on youtube, so worth a watch for anyone interested in their tech.
AdamV12V said:
dmsims said:
There is no system on earth that can do this (in the UK) accurately.........
ok my bad choice of words, it uses AI to predict our use patterns and the likely input from solar tiles based on the weather forecast etc.. and uses the tarrifs for the day ahead and then works out the best pattern of export and import from the grid. I am sure I will know more in the weeks to come as I ask more and more questions before ordering with them or anyone else.There's a ton of info on Sigenergy on youtube, so worth a watch for anyone interested in their tech.
On the face of it, it sounds like throwing the AI buzz words in to jump on a bandwaggon.
As it happens, I am presently working on a predictive management system for energy (not commercially). No AI - it is simply algorithmic. You could say it 'learns' from previous weeks usage, but in practice that isn't that useful unless you have a very defined usage pattern. Weather forecasts, and solar forecasts are not AI.
Funily enough, it is telling me that the present Agile rate of -0.84p isn't cheap enough and is saving the loads until it drops to -3.93 at 13:30
(The implication being I don't have infinite storage capacity - so want to use minimum cost not just negative cost.)
Look at Victron (an established company)
AdamV12V said:
ok my bad choice of words, it uses AI to predict our use patterns and the likely input from solar tiles based on the weather forecast etc.. and uses the tarrifs for the day ahead and then works out the best pattern of export and import from the grid. I am sure I will know more in the weeks to come as I ask more and more questions before ordering with them or anyone else.
There's a ton of info on Sigenergy on youtube, so worth a watch for anyone interested in their tech.
There's a ton of info on Sigenergy on youtube, so worth a watch for anyone interested in their tech.
AdamV12V said:
Hello thread...
After the various losses, the estimates are showing we should generate up to 46Kwp which equates to 6400kwh per month in July and as little as 600kwh in December, totalling 42,500kwh over a whole 12 month period.
...
Historic use of gas in the property has been sky-high, its an old 1960's gas boiler in the basement with a U16 meter so that gives an idea of how much it guzzles! ~120,000kwh p/a on gas alone!
Excuse the snipping, but remember there's a huge seasonal imbalance between peak solar gen and peak heating requirements. After the various losses, the estimates are showing we should generate up to 46Kwp which equates to 6400kwh per month in July and as little as 600kwh in December, totalling 42,500kwh over a whole 12 month period.
...
Historic use of gas in the property has been sky-high, its an old 1960's gas boiler in the basement with a U16 meter so that gives an idea of how much it guzzles! ~120,000kwh p/a on gas alone!
You didn't say what your plans are for heating the house/pool, but if you go electric 600kwH in December isn't going to touch the sides. (and, current gas price cap is ~7p/kWH vs 28p for electric)
My gut says that long/medium-term, daytime solar export will pay very little. And using batteries to time-shift this (which is what you're basically doing) needs to take into account the round-trip efficiency of the solar-battery-AC conversion (~85%?) and the expected battery life, given you're going to be cycling it almost constantly.
Do you have figures for your current annual electricity use?
silentbrown said:
Excuse the snipping, but remember there's a huge seasonal imbalance between peak solar gen and peak heating requirements.
You didn't say what your plans are for heating the house/pool, but if you go electric 600kwH in December isn't going to touch the sides. (and, current gas price cap is ~7p/kWH vs 28p for electric)
My gut says that long/medium-term, daytime solar export will pay very little. And using batteries to time-shift this (which is what you're basically doing) needs to take into account the round-trip efficiency of the solar-battery-AC conversion (~85%?) and the expected battery life, given you're going to be cycling it almost constantly.
Do you have figures for your current annual electricity use?
Tend to agree with this, also in the medium term, big players will be using batteries to time shift, as will more and more homes.You didn't say what your plans are for heating the house/pool, but if you go electric 600kwH in December isn't going to touch the sides. (and, current gas price cap is ~7p/kWH vs 28p for electric)
My gut says that long/medium-term, daytime solar export will pay very little. And using batteries to time-shift this (which is what you're basically doing) needs to take into account the round-trip efficiency of the solar-battery-AC conversion (~85%?) and the expected battery life, given you're going to be cycling it almost constantly.
Do you have figures for your current annual electricity use?
So I expect the profit from it to drop.
I think the batteries should keep getting cheaper at 'retail' so no rush to buy IMHO, unless you can show a very fast payback.
silentbrown said:
AdamV12V said:
Hello thread...
After the various losses, the estimates are showing we should generate up to 46Kwp which equates to 6400kwh per month in July and as little as 600kwh in December, totalling 42,500kwh over a whole 12 month period.
...
Historic use of gas in the property has been sky-high, its an old 1960's gas boiler in the basement with a U16 meter so that gives an idea of how much it guzzles! ~120,000kwh p/a on gas alone!
Excuse the snipping, but remember there's a huge seasonal imbalance between peak solar gen and peak heating requirements. After the various losses, the estimates are showing we should generate up to 46Kwp which equates to 6400kwh per month in July and as little as 600kwh in December, totalling 42,500kwh over a whole 12 month period.
...
Historic use of gas in the property has been sky-high, its an old 1960's gas boiler in the basement with a U16 meter so that gives an idea of how much it guzzles! ~120,000kwh p/a on gas alone!
You didn't say what your plans are for heating the house/pool, but if you go electric 600kwH in December isn't going to touch the sides. (and, current gas price cap is ~7p/kWH vs 28p for electric)
My gut says that long/medium-term, daytime solar export will pay very little. And using batteries to time-shift this (which is what you're basically doing) needs to take into account the round-trip efficiency of the solar-battery-AC conversion (~85%?) and the expected battery life, given you're going to be cycling it almost constantly.
Do you have figures for your current annual electricity use?
| Mth | Total | Daily Avg |
|---|---|---|
| Jan | 757 | 24 |
| Feb | 1,546 | 55 |
| Mar | 3,329 | 107 |
| Apr | 5,075 | 169 |
| May | 6,352 | 205 |
| Jun | 6,192 | 206 |
| Jul | 6,375 | 206 |
| Aug | 5,405 | 174 |
| Sep | 3,781 | 126 |
| Oct | 2,082 | 67 |
| Nov | 997 | 33 |
| Dec | 593 | 19 |
| Total | 42,482 | 116 |
(all figures in Kwh)
I agree that 600kwh p/m in winter isnt going to touch the sides, and I fully understand that solar will be at its lowest output when I need it most, but that's what the batteries come into play topping up at the lowest tarifs. I suspect we will use 5-6X that amount of electric in reality. Equally maybe that seasons chart is a little pessimistic, seems hard to believe a 56kwp array would only generate 20kw during a typical whole a day in december, thats barely 30mins of generation. ???
Plan is to fit an ASHP and a MVHR to recover heat as circulated, seal up the house to near passivehaus spec. ASHP will likely be in the range of 17-22Kw depending on final room configuration for wet underloor heating, and topped up with some electric matting for the rooms where wet isnt possible. I suspect we are going to be in the 25kw zone for total electric heating, plus the swimming pool., That will likely use around 1,500kwh a month to heat and de-humidfy. All in all, my own current personal estimates put our use of electric being not far off the predictions for the solar generation, and that's without any EV chargers too. If we do nothing and plod on as the house is now, even with the heating turned down to a sensible 18.5C, I suspect we will spend around £8k p/a on gas and electric at current prices, based on our own 2 months of use since we moved in.
Its really hard to give a like-for-like with the historic use of the property. For one we've only lived here since the end of Jan, and the previous owner had 101 appliances left on 24x7 (heated garages, greenhouses etc...) much of which we have switched off and don't plan to put back on, and she used a ton of gas by having the house set to 32C 24x7x265, I suspect it never hit that as it wasnt insulated enough to achieve it. Equally we are adding a lot of insulation, switching all lighting to LED but moving to Electric instead of Gas to heat the property which as you say is a lot more expensive per kwh. That said I don't want gas even if its cheaper, so the gas is going.
Edited by AdamV12V on Saturday 6th April 13:41
OutInTheShed said:
Tend to agree with this, also in the medium term, big players will be using batteries to time shift, as will more and more homes.
So I expect the profit from it to drop.
I think the batteries should keep getting cheaper at 'retail' so no rush to buy IMHO, unless you can show a very fast payback.
Totally agree with this. Batteries are already hugely cheaper than they were just a couple of years ago when I looked at a battery only soln for our previous home. I reckon there is probably 5-10yrs max left in the import-export game before everyone has jumped on the battery storage bandwagon and it then no longer makes sense to offer such differential pricing to everyone. Plus the gov will likely then take away the VAT free installation benefits too I reckon.So I expect the profit from it to drop.
I think the batteries should keep getting cheaper at 'retail' so no rush to buy IMHO, unless you can show a very fast payback.
For this project, payback isn't really something I am overtly focussed on, but of course I am not completely blind to it either. I need to change the roof anyway, so the capital cost of a solar roof installation is purely the incremental over just doing another normal roof again, and more than anything else I dont want to be spending what we are spending on fuel into the future and want to do our bit to make the house self sufficient. I am hoping to at least have zero bills over the whole year, maybe even generate a mild income, albeit I accept probably not as much as the interest would have been from leaving it in the bank!
AdamV12V said:
I agree that 600kwh p/m in winter isnt going to touch the sides, and I fully understand that solar will be at its lowest output when I need it most, but that's what the batteries come into play topping up at the lowest tarifs. I suspect we will use 5-6X that amount of electric in reality. Equally maybe that seasons chart is a little pessimistic, seems hard to believe a 56kwp array would only generate 20kw during a typical whole a day in december, thats barely 30mins of generation. ???
In case it helps you, I have a 26.27kW GSE in-roof and Solion ballasted bin mounted system installed on 2 pitched and 2 flat roofs which are on average 53 degrees off South (according to installer, I think they are more like 30 degrees off South) in Surrey. The pitched roofs are quite steep pitches and the lower pitched roof and lower flat roof have a bit of shading (although the installer classified it as shade factor of 0.98) and my total generation in December was 295.73kWh. Lowest day was 1.72kWh and highest was 22.5kWhEdited by AdamV12V on Saturday 6th April 13:41
The poor generation predicted in Dec/Jan is due to the near-horizontal panels.
Typical data is in the region of 5:1 or even 4:1 for July vs January, with a suitably pitched roof.
You're seeing 10:1, due to the low angle of sun in the winter
But you've got more panels in the equation than most.
Personally, my bills are currenty split roughly evenly between gas and electricty.
Four months of winter dominate the gas bill but the electicity use is only maybe 30% up in Winter?
I am looking to move from this modern house to something older and less efficient.
Typical data is in the region of 5:1 or even 4:1 for July vs January, with a suitably pitched roof.
You're seeing 10:1, due to the low angle of sun in the winter
But you've got more panels in the equation than most.
Personally, my bills are currenty split roughly evenly between gas and electricty.
Four months of winter dominate the gas bill but the electicity use is only maybe 30% up in Winter?
I am looking to move from this modern house to something older and less efficient.
Mr Penguin said:
Why don't you want to use gas?
Do you have the space for a large wind turbine? That is the only way I see you making these numbers even remotely add up with electric.
Gas isnt very ECO and we are trying to be "green" with the house to a large extent, plus Gas is going to get more and more expensive and probably exceed electric at some point.Do you have the space for a large wind turbine? That is the only way I see you making these numbers even remotely add up with electric.
Although we have 1.6 acres theres no space or desire from me for a wind turbine, they are f-ugly, noisy and no place in a residential garden and being a conservation area I doubt we would get permission even if I did ask. Maybe if we had 20 acres of paddock, maybe, but that's a "no" for now.
Why do you think the numbers wont add up? They seem to add up to me...
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