We had PV panels fitted in November 2011 and so enjoy the original high FIT. But without the FIT I'm less convinced they are of any real value. Today we have generated all of 968w/hr. We do have a 3kw battery pack, but again its value is marginal.
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Solar Panels UK - is it worth it?
- Thread starter jdwuk
- Start date
Solar batteries certainly help but there isn’t a genuine cost justification, it’s just nice to have in that sense.
the problem with charging EV’s from solar is that a kettle/oven/tumble drier and so on will steal the power unless you have a decent size array and then it’s usually only good in spring/summer/autumn. i don’t charge the Tesla from the Powerwalls (I could) but do charge the Outlander sometimes. Otherwise, I leave them to run the home or provide a little extra when the clouds roll by
MrBadger
Badger out
Quite frankly, buy solar panels and maybe even a battery, but only because you like the idea of using some of your own electricity. Don't go buying them because you think that you are being environmentally friendly, will be getting any worthwhile financial savings or will be able to run your car on significant proportion of home generated energy.
Also watch out for @Dilly
He has an extraordinary amount of PV compared with what most mere mortals will have so his experiences will not necessarily translate to those that others will experience. I hope he doesn't mind me saying that.
If you are tempted, look at PVGIS, bash in the numbers for your location and an achievable size array (often these are constrained by roof space and/or DNO limits) and look at the estimated figures. Then bear in mind that charging a car at 10A (so less than a third of the speed of a 7kW charge point) will require 2.6kW of excess solar generation or battery inverter capacity then extrapolate the numbers from there.
Also watch out for @Dilly
He has an extraordinary amount of PV compared with what most mere mortals will have so his experiences will not necessarily translate to those that others will experience. I hope he doesn't mind me saying that.If you are tempted, look at PVGIS, bash in the numbers for your location and an achievable size array (often these are constrained by roof space and/or DNO limits) and look at the estimated figures. Then bear in mind that charging a car at 10A (so less than a third of the speed of a 7kW charge point) will require 2.6kW of excess solar generation or battery inverter capacity then extrapolate the numbers from there.
Yachtsman
Member
I’ve been quandering over the same issue. I contacted MAC (my second contact) both contacts used Google earth? to view my property and subsequently provide a proposal.
The first company I contacted (very local to me with awards!) stated 12 panels max, 4.6kWh.
Mac came back with 22 panel (ok slightly less output per panel) which is rediculas so I didn’t invite him to a full site survey, not impressed at all.
Not at all @VanillaAir_UK most domestic installations are likely not to exceed 16 panels. When I bought, that’s what they wanted to supply. 16 of today’s average panels will probably peak at 4.8kWh. I have several roofs and peak at almost 11KWh.Quite frankly, buy solar panels and maybe even a battery, but only because you like the idea of using some of your own electricity. Don't go buying them because you think that you are being environmentally friendly, will be getting any worthwhile financial savings or will be able to run your car on significant proportion of home generated energy.
Also watch out for @Dilly
If you are tempted, look at PVGIS, bash in the numbers for your location and an achievable size array (often these are constrained by roof space and/or DNO limits) and look at the estimated figures. Then bear in mind that charging a car at 10A (so less than a third of the speed of a 7kW charge point) will require 2.6kW of excess solar generation or battery inverter capacity then extrapolate the numbers from there.
the one thing I have learnt is that there is a point to solar batteries both as a source of cheap power, but perhaps more useful as a buffer to even out solar peaks and troughs And in some cases a backup for grid outage. That said, cheap they ain’t!
As a warning, for all my panels, today being as dull as dishwater, they produced just 810Wh
I guess I should add that 16 panels will probably charge a car in summer but much of the time you’d be seeing just 2-3kWh and the house gets first call.
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And you're in the dark orange part of the map. Goodness knows what we'd getAs a warning, for all my panels, today being as dull as dishwater, they produced just 810Wh
Llama.
Lurking somewhere up North
To the OP, I’d say getting solar PV is definitely worth it, provided you can fit enough panels on your roof. But a storage battery is now an essential part of the installation due to the end of FIT and anticipated continued electricity price rises.
I had my solar PV installation in March 2020
This included 14 panels producing 4.2kw max output. Also 7.2 kWh of battery storage. Including the inverter this instal cost £8500 from EEC Solar.
This enables me to run my 4 bed house completely free of grid usage for about 6 months of the year, with the remaining 6 months becoming more dependent on battery storage of £.05 per kWh off peak.
On the sunniest days I’m making about 30 kWh per day, but on the darkest days I’m making only 1 KWh per day.
I’m on track to break even in about 10 years. But with off peak charging of the battery storage this comes down to about 7 years.
A couple of observations having had the system for 18 months:
1) I wouldn’t bother getting Solar PV without a battery. The batteries are expensive. But the ability to store cheap off peak electricity is a key part of the cost benefit. I’d say 7kwh if battery capacity is about right four our family of four.
3) I think my solar array of 4.2 peak output is a bit small for my family. I would say a 5kw PV system is the minimum that a family of four would need. Stretch to 7kw if you can afford it.
2) Don’t bother with Tesla battery storage. They really don’t offer the benefit to justify the significantly higher cost. But I have no requirement for off-grid usage having never had a power outage. This may be important for some.
3) I have a Zappi to charge from solar. This is useful for about 6 months a year when my storage battery gets charged by solar by about 2.00 PM which leaves excess solar production to charge the Tesla until sunset. Otherwise I just charge off peak at night. I think the extra cost of the Zappi is just about worth it.
4) This may make some of you cringe but I added the £8500 cost of my solar panels on my mortgage at the point of renewal. This added £35 per month to my mortgage on 2.5% interest. I judged this to be a capital investment that would outlive my home ownership. So even though my panels will pay for themselves in 10 years, they are part of a 25 yr mortgage.
I hope all that helps.
Llama
I had my solar PV installation in March 2020
This included 14 panels producing 4.2kw max output. Also 7.2 kWh of battery storage. Including the inverter this instal cost £8500 from EEC Solar.
This enables me to run my 4 bed house completely free of grid usage for about 6 months of the year, with the remaining 6 months becoming more dependent on battery storage of £.05 per kWh off peak.
On the sunniest days I’m making about 30 kWh per day, but on the darkest days I’m making only 1 KWh per day.
I’m on track to break even in about 10 years. But with off peak charging of the battery storage this comes down to about 7 years.
A couple of observations having had the system for 18 months:
1) I wouldn’t bother getting Solar PV without a battery. The batteries are expensive. But the ability to store cheap off peak electricity is a key part of the cost benefit. I’d say 7kwh if battery capacity is about right four our family of four.
3) I think my solar array of 4.2 peak output is a bit small for my family. I would say a 5kw PV system is the minimum that a family of four would need. Stretch to 7kw if you can afford it.
2) Don’t bother with Tesla battery storage. They really don’t offer the benefit to justify the significantly higher cost. But I have no requirement for off-grid usage having never had a power outage. This may be important for some.
3) I have a Zappi to charge from solar. This is useful for about 6 months a year when my storage battery gets charged by solar by about 2.00 PM which leaves excess solar production to charge the Tesla until sunset. Otherwise I just charge off peak at night. I think the extra cost of the Zappi is just about worth it.
4) This may make some of you cringe but I added the £8500 cost of my solar panels on my mortgage at the point of renewal. This added £35 per month to my mortgage on 2.5% interest. I judged this to be a capital investment that would outlive my home ownership. So even though my panels will pay for themselves in 10 years, they are part of a 25 yr mortgage.
I hope all that helps.
Llama
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MrBadger
Badger out
Something to watch with batteries is their limited lifespan. Its all very well working out a theoretical payback period for them, but most of the time that does not take into account that they will have worn out significantly by that point in time so that payback period is significantly longer or even unobtainable.
Anyone thinking of having batteries installed need to ask what the expected life expectancy of the battery is. For example a battery life will be rated at a number of full charges, then you can calculate the theoretical maximum of kWh that the battery will store and (after taking into account the round trip efficiency, another question to ask) and the real usable kWh of the battery (it may well only be 80-90% of installed capacity). Multiply that number by an average electricity saving and you will have a figure for the maximum electricity saving achievable over the usable lifetime of the battery.
So for instance, a 7.2kWh battery with a lifetime of 4500 full cycles, 90% usable storage (6.48kWh) and 90% round trip efficiency will have a usable storage of around 26244kWh. Say you average energy price is 10p/kWh (you get some offset by solar so it will not be full wholesale price) and you can buy off peak at 5p/kWh, then you have a potential saving of 5p for every kWh roundtripped through the battery. So £0.05 x 26244 gives a grand lifetime saving of around £1300 on what was probably a £3000 outlay - it will never pay itself back. Now of course, average energy prices have gone up, but I personally think its just a blip and whilst they may not return to previous levels, even a future average of 20p/kWh (no guarantee that off peak will remain low either) is going to be marginal on breakeven on a £3k battery setup over its lifetime if solely time shifting grid energy through a battery and tbh, not a huge amount better if offsetting free solar on a modest sized array - we generate around 3000-3500kWh per year and self use well over half that, so you can throw back into the mix that ~1000kWh/year will offset the off peak purchase (you will not be able to store every spare kWh of solar generated electricity), so a further saving of £50-70/year by not buying at electricity at 5p off peak pricing.
Said from someone with 4kW PV and 7.2kWh of battery storage who jumped into this with eyes wide open.
IMHO, battery storage may well become one of those mis-selling things. From the financial perspective, the ROI on a pure solar setup will be far greater than a Solar + battery setup. Its easy for an installer to offset/hide the poor ROI of a highly profitable upsell of battery storage amongst the PV figures. If you can get away with it (not always possible), a larger PV array will be financially the better solution. And with 10% or more losses through a battery system, it can hardly be called green.
Anyone thinking of having batteries installed need to ask what the expected life expectancy of the battery is. For example a battery life will be rated at a number of full charges, then you can calculate the theoretical maximum of kWh that the battery will store and (after taking into account the round trip efficiency, another question to ask) and the real usable kWh of the battery (it may well only be 80-90% of installed capacity). Multiply that number by an average electricity saving and you will have a figure for the maximum electricity saving achievable over the usable lifetime of the battery.
So for instance, a 7.2kWh battery with a lifetime of 4500 full cycles, 90% usable storage (6.48kWh) and 90% round trip efficiency will have a usable storage of around 26244kWh. Say you average energy price is 10p/kWh (you get some offset by solar so it will not be full wholesale price) and you can buy off peak at 5p/kWh, then you have a potential saving of 5p for every kWh roundtripped through the battery. So £0.05 x 26244 gives a grand lifetime saving of around £1300 on what was probably a £3000 outlay - it will never pay itself back. Now of course, average energy prices have gone up, but I personally think its just a blip and whilst they may not return to previous levels, even a future average of 20p/kWh (no guarantee that off peak will remain low either) is going to be marginal on breakeven on a £3k battery setup over its lifetime if solely time shifting grid energy through a battery and tbh, not a huge amount better if offsetting free solar on a modest sized array - we generate around 3000-3500kWh per year and self use well over half that, so you can throw back into the mix that ~1000kWh/year will offset the off peak purchase (you will not be able to store every spare kWh of solar generated electricity), so a further saving of £50-70/year by not buying at electricity at 5p off peak pricing.
Said from someone with 4kW PV and 7.2kWh of battery storage who jumped into this with eyes wide open.
IMHO, battery storage may well become one of those mis-selling things. From the financial perspective, the ROI on a pure solar setup will be far greater than a Solar + battery setup. Its easy for an installer to offset/hide the poor ROI of a highly profitable upsell of battery storage amongst the PV figures. If you can get away with it (not always possible), a larger PV array will be financially the better solution. And with 10% or more losses through a battery system, it can hardly be called green.
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PITA
Model 3 Performance
Our setup at home includes :-
18 x Sunpower Maxeon 3 - 400w Panels with Optimizers (7.2 kWp on 3 roof aspects)
1 x Solaredge 5 kW Inverter installed outside on North Facing wall.
2 x Tesla Powerwall 2 storage batteries (27 kWh / 10 kW). Installed outside on North Facing wall.
North facing wall installation gives good ventilation and out of direct sunlight... and easy access for powering down / fire hazzard issues.
1 x Tesla Gateway 2 with EV Charger wired into it directly, not from the consumer unit.
The Gateway 2 unit has several fused connection points, some grid-tied, some not grid-tied. Very clever bit of kit and perfect for wiring in EV Chargers.
2 x Smart Meters (Gas & Electric). Octopus Go smart tariff, and Octopus SEG export tariff.
1 x MyEnergi Zappy 7 kW Car Charger.
1 x MyEnergi Eddi & Harvi 3 kW emersion water heater
1 x Toshiba 8 kW Heat Pump (Air to Air). Hot & Cold climate control with 4 x Internal room Wall Units (2.5kW cooling each, 3.5kW heating each).
1 x Tesla Model 3 Performance EV.
During Summer, our Solar Array produces about 43 kWh on the best days. Which is enough to power the house. Excess is stored in EV.
During Winter, our Solar Array produces 1 kWh per day, but Battery Storage holds 27 kWh of cheap rate overnight download power. Which isn't enough, but is a good contribution. At 10 kW continous power capability it allows for all house demands during day without needing peak-rate grid support. So all of the cheap rate electric gets used.
EV holds about 70 kWh storage which is charged 30% capacity overnight on cheap rate tariff. We download cheap power at about 15 kW during the 4 hour cheap-rate £0.05 window. So get about 60 kWh at a cost of £3.00 per day. Enough to fill the Powerwalls and 30% top-up the car.
Our Gas Boiler Central Heating system is still in situ, so that heats the house in the mornings, towel rails, bathrooms, ensuite, toilet rooms, kitchen etc... then our Heat Pump keeps the house warm for the rest of the day.
Our Gas usage in October 2020 was 60 hours worth. In October 2021 it was 16 hours worth. The Heat Pump is making a huge difference, and can be used completely independantly, or together on REALLY cold days. Not that our house is cold, as it's been rated as EPC A+ (Scored 107). But it's nice to have a dual heating system for failover (Gas or Electric)
18 x Sunpower Maxeon 3 - 400w Panels with Optimizers (7.2 kWp on 3 roof aspects)
1 x Solaredge 5 kW Inverter installed outside on North Facing wall.
2 x Tesla Powerwall 2 storage batteries (27 kWh / 10 kW). Installed outside on North Facing wall.
North facing wall installation gives good ventilation and out of direct sunlight... and easy access for powering down / fire hazzard issues.
1 x Tesla Gateway 2 with EV Charger wired into it directly, not from the consumer unit.
The Gateway 2 unit has several fused connection points, some grid-tied, some not grid-tied. Very clever bit of kit and perfect for wiring in EV Chargers.
2 x Smart Meters (Gas & Electric). Octopus Go smart tariff, and Octopus SEG export tariff.
1 x MyEnergi Zappy 7 kW Car Charger.
1 x MyEnergi Eddi & Harvi 3 kW emersion water heater
1 x Toshiba 8 kW Heat Pump (Air to Air). Hot & Cold climate control with 4 x Internal room Wall Units (2.5kW cooling each, 3.5kW heating each).
1 x Tesla Model 3 Performance EV.
During Summer, our Solar Array produces about 43 kWh on the best days. Which is enough to power the house. Excess is stored in EV.
During Winter, our Solar Array produces 1 kWh per day, but Battery Storage holds 27 kWh of cheap rate overnight download power. Which isn't enough, but is a good contribution. At 10 kW continous power capability it allows for all house demands during day without needing peak-rate grid support. So all of the cheap rate electric gets used.
EV holds about 70 kWh storage which is charged 30% capacity overnight on cheap rate tariff. We download cheap power at about 15 kW during the 4 hour cheap-rate £0.05 window. So get about 60 kWh at a cost of £3.00 per day. Enough to fill the Powerwalls and 30% top-up the car.
Our Gas Boiler Central Heating system is still in situ, so that heats the house in the mornings, towel rails, bathrooms, ensuite, toilet rooms, kitchen etc... then our Heat Pump keeps the house warm for the rest of the day.
Our Gas usage in October 2020 was 60 hours worth. In October 2021 it was 16 hours worth. The Heat Pump is making a huge difference, and can be used completely independantly, or together on REALLY cold days. Not that our house is cold, as it's been rated as EPC A+ (Scored 107). But it's nice to have a dual heating system for failover (Gas or Electric)
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This almost exactly mirrors my situation and setup. I can only see energy prices heading one way. The RoI on installs is coming down all the time, if that's an important consideration for you.
I had prevaricated for years. Always wanted solar but didn't have the spare capital lying around. The E.On interest-free deal was the clincher for me and because they were selling them with a battery it seemed like the right time to take the plunge.
Pink Duck
Active Member
If wanting to receive green energy, it may be better to allow the large scale grid operators to achieve that while using a 100% renewal electricity tariff, rather than materially rolling out solar to millions of homes. I've yet to see a true EV-specific energy offering where my own net annual saving is any better than ~£100 (4%). If you already have solar, a battery system is useful if power cuts are relatively frequent. Currently solar adds little to home valuations, but that may change as new buyers value this more over time. Solar panels themselves can be detached/reattached during a house move, but by that time there'll likely be newer, more efficient panels. There is one positive aspect though, in that if you are able to afford both then you can personally contribute to a cleaner grid that bit sooner, but still likely at lower cost effectiveness than grid-scale providers can achieve in the near term.
It's not a zero sum game is it though? You present your argument as if it's an either/or question.
Pink Duck
Active Member
I wanted an EV, I could have waited longer, instead I bought a Tesla Model S, which was a trade-off between time and pricing to achieve an objective sooner. So ultimately it's down to individual viewpoint, hence just my various thoughts for the OP on 'is it worth it?'
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Gatsojon
Member
I didn’t get PV and a Powerwall 2 to save money, anymore than I bought a Tesla to save money; I did it for the experience and the project. Very much enjoying it so far.
PITA
Model 3 Performance
Exactly the same here... did mine during Pandemic Lockdown while things were cheaper and available.
