Solar Panels

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kerrya1
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Solar Panels

Post by kerrya1 » Thu Nov 04, 2021 1:55 pm

Given the current situation with gas and elec prices and my desire to reduce our use of these regardless of price. I'm looking into getting solar panels installed on our roof, the front aspect is south-facing, and unobstructed with no roof lights or other unuseable areas. I think the roof area is large enough for a 4kWp installation based on this calculator https://www.pvfitcalculator.energysavingtrust.org.uk/.

Does anyone here have experience of getting these installed recently? How much indoor space did it need to acommodate all the bits and pieces (technical terms), did the installation cause a lot of mess and disruption? Was it all worth it?

I'm in Scotland so have access to government backed interest free loans to help pay for this and other things we plan to do like insulation and draught-proofing.

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Re: Solar Panels

Post by lpm » Thu Nov 04, 2021 2:28 pm

There are specialist forums for this topic, with experts offering advice.

My immediate suspicion is that you'd get a better financial payback by installing a battery in the cupboard under the stairs, filling it up at cheap overnight electricity rates and running it down during the day. Adding solar to this will be a hard sell from a financial perspective.

You might find it a nice dream to have CO2 reductions from solar panels, but the CO2 payback is probably going to come from the less glamorous insulation plans.
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Re: Solar Panels

Post by IvanV » Thu Nov 04, 2021 5:27 pm

kerrya1 wrote:
Thu Nov 04, 2021 1:55 pm
Given the current situation with gas and elec prices and my desire to reduce our use of these regardless of price.
How well insulated is your house? Are all your bulbs LED already? Do you have an induction hob? Unless you are already very thorough on this kind of thing, then this is the first best thing you can do. Though you can go too far. Retrofitting underfloor insulation rarely shows a return.

In places in places in Scotland without piped gas, and so using more expensive tanker-delivered gas, then air source heat pumps are becoming an installation of choice, but only really if you are in one of those mild westerly areas where freezing temperatures are relatively rare. And grants are available. They can be annoying, but I know someone in SW Wales who is very happy with his. He does have a back-up heat source, but almost never needs it.

The difficulty you have is that domestic roof-top solar in this country produces most of its electricity when you don't need it. In the middle of the day, in the brighter months. So you'll shave very little off your bill, and most of the electricity you generate it you'll sell into the grid at a price much less than you pay for electricity. The generous schemes in the past when you could, to all intents and purposes, run your meter backwards when you exported, and even get a reward on top, have come to an end. That's why the installation of domestic solar cells has practically ground to a halt. It doesn't wash its face financially. Better to put the solar cells in Morocco and run a cable under the sea...

It's a different matter in, say, Australia where everyone is putting solar cells on their roof. They want the electricity on sunny days to run air conditioners. And their electricity is more expensive than here, or was a few years ago when I looked into it.

I know people who have solar installations. The objects inside the house are small. Whether it is much fuss depends upon the precise arrangment of things in the house, where cables can run, where meters are, etc. Batteries are another matter, they are large. Tesla PowerWall is designed to be installed outside alongside an external wall.

If you were not so far north, I'd be pretty sure you'd get a better return and greater carbon reduction by solar water heating. But you'll need advice on whether that will work usefully so far north. I once stayed in a house in southern Greece in that had solar water heating, and on the couple of days it rained from dawn till dusk, we got no hot water. That was in mid-April when the sun is probably as high as much of the summer in Scotland. Solar water heating captures a higher proportion of the sun's energy than solar cells, and you can store the hot water easily in an insulated tank till you need it. But you need a compatible hot water tank, and plumbing and all that, so it definitely is a serious job to install. Nearly everyone in that part of Greece had solar water heating, it was a no-brainer. But they could locate the hot water tank externally, stuck up on a pole above the roof, as they never have sufficient frost that far south in Greece. Different matter in Athens, which does occasionally suffer a heavy snowfall.

I'm far from convinced installing a battery to charge using cheap overnight electricity washes its face financially, anywhere near. If it did, everyone would be installing them. Batteries only make money by supplying specialist grid reinforcement services, which you'll need a grid-scale battery for. You can of course include a battery with your solar installation. That instantly increases the money saved, as the export rate is so poor these days. But the extra money you make is unlikely to pay for the battery. And for a Scottish user where the solar elecricity season is rather short, it wouldn't be earning its keep much of the year. But you could still arbitrage night to day electricity in the winter if you did that. But I'd still be surprised if it washed it's face. I have met renewable energy geeks who have solar arrays, Tesla PowerWall, electric car and everything. And they know very well how best to arrange it. But they recognise that it's kind of their hobby, and doesn't actually save them money. Aside from solar cells installed in the days when there were generous incentives.

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Re: Solar Panels

Post by Imrael » Thu Nov 04, 2021 9:15 pm

I recently did solar plus battery. (Plus EV). Interior disruption was pretty minimal and the process was painless, except financially. Optimistically the payback is at least 10 years. I am just rolling into insulation, air pump and UFH. I am doing stuff in the wrong order somewhat because heating broke at an inconvenient time and putting in a gas boiler to replace it, only to remove it comparatively soon seems a bit nuts.

On ivans point about the battery he may be correct. Adding the EV (and a water heater that uses surplus power) to the picture make a bit of a difference. On the other hand when the villagte had a 4 hour power cut recently we ran through it from battery and didnt even notice for the first 2 hours.

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Re: Solar Panels

Post by Grumble » Fri Nov 05, 2021 8:39 am

EV Man recently did a breakdown of home battery costs showing payback in less than ten years, without solar panels. https://youtu.be/_T0vahG6JPU
A bit churlish

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Re: Solar Panels

Post by Troubled Joe » Fri Nov 05, 2021 9:10 am

One for the hive mind !

How tricky would it be to self install a set of panels/charging point for an electric car - independent of the mains?

We’re thinking of replacing Dr Mrs TJ’s car which is getting like Trigger’s broom in the number of original parts left. She only pootles to the hospital and back in hers (I have a company car which we drive the crap out of for family stuff on the basis of not-our-problem) so we currently only fill up once a month if that - so fast charging isn’t a massive issue, just trickle charging to top up.

Is this feasible or 3.141 in the sky ?
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Re: Solar Panels

Post by kerrya1 » Fri Nov 05, 2021 9:25 am

IvanV wrote:
Thu Nov 04, 2021 5:27 pm
kerrya1 wrote:
Thu Nov 04, 2021 1:55 pm
Given the current situation with gas and elec prices and my desire to reduce our use of these regardless of price.
How well insulated is your house? Are all your bulbs LED already? Do you have an induction hob? Unless you are already very thorough on this kind of thing, then this is the first best thing you can do. Though you can go too far. Retrofitting underfloor insulation rarely shows a return.

In places in places in Scotland without piped gas, and so using more expensive tanker-delivered gas, then air source heat pumps are becoming an installation of choice, but only really if you are in one of those mild westerly areas where freezing temperatures are relatively rare. And grants are available. They can be annoying, but I know someone in SW Wales who is very happy with his. He does have a back-up heat source, but almost never needs it.

The difficulty you have is that domestic roof-top solar in this country produces most of its electricity when you don't need it. In the middle of the day, in the brighter months. So you'll shave very little off your bill, and most of the electricity you generate it you'll sell into the grid at a price much less than you pay for electricity. The generous schemes in the past when you could, to all intents and purposes, run your meter backwards when you exported, and even get a reward on top, have come to an end. That's why the installation of domestic solar cells has practically ground to a halt. It doesn't wash its face financially. Better to put the solar cells in Morocco and run a cable under the sea...

It's a different matter in, say, Australia where everyone is putting solar cells on their roof. They want the electricity on sunny days to run air conditioners. And their electricity is more expensive than here, or was a few years ago when I looked into it.

I know people who have solar installations. The objects inside the house are small. Whether it is much fuss depends upon the precise arrangment of things in the house, where cables can run, where meters are, etc. Batteries are another matter, they are large. Tesla PowerWall is designed to be installed outside alongside an external wall.

If you were not so far north, I'd be pretty sure you'd get a better return and greater carbon reduction by solar water heating. But you'll need advice on whether that will work usefully so far north. I once stayed in a house in southern Greece in that had solar water heating, and on the couple of days it rained from dawn till dusk, we got no hot water. That was in mid-April when the sun is probably as high as much of the summer in Scotland. Solar water heating captures a higher proportion of the sun's energy than solar cells, and you can store the hot water easily in an insulated tank till you need it. But you need a compatible hot water tank, and plumbing and all that, so it definitely is a serious job to install. Nearly everyone in that part of Greece had solar water heating, it was a no-brainer. But they could locate the hot water tank externally, stuck up on a pole above the roof, as they never have sufficient frost that far south in Greece. Different matter in Athens, which does occasionally suffer a heavy snowfall.

I'm far from convinced installing a battery to charge using cheap overnight electricity washes its face financially, anywhere near. If it did, everyone would be installing them. Batteries only make money by supplying specialist grid reinforcement services, which you'll need a grid-scale battery for. You can of course include a battery with your solar installation. That instantly increases the money saved, as the export rate is so poor these days. But the extra money you make is unlikely to pay for the battery. And for a Scottish user where the solar elecricity season is rather short, it wouldn't be earning its keep much of the year. But you could still arbitrage night to day electricity in the winter if you did that. But I'd still be surprised if it washed it's face. I have met renewable energy geeks who have solar arrays, Tesla PowerWall, electric car and everything. And they know very well how best to arrange it. But they recognise that it's kind of their hobby, and doesn't actually save them money. Aside from solar cells installed in the days when there were generous incentives.
Thanks Ivan, this is all helpful. My husband and I both work from home at least 4 days a week so we would be using the energy generated during the day - I wouldn't be considering it if the house was empty all day. We do have all LED bulbs and an induction hob, all our applicances were as efficient as possible when bought and new enough not to need replacing soon. The house does need cavity wall insulation and better loft insulation, but that is also part of the plan and would be done before or alongside any solar installation. We also have an attached garage where we could install a battery.

My brother lives in the Borders and has recently replaced their oil fueled central heating system with an air source heat pump but as we are in a suburb of Edinburgh I don't think we'd go down that route. I have looked at solar water heating but I'm not convinced, yet, our electricity usage is much more significant than our gas as it only provides the heating and hot water, everything else is electric. Do you have any thoughts on the combined Solar PV and water heating panels?

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Re: Solar Panels

Post by jimbob » Fri Nov 05, 2021 9:49 am

Troubled Joe wrote:
Fri Nov 05, 2021 9:10 am
One for the hive mind !

How tricky would it be to self install a set of panels/charging point for an electric car - independent of the mains?

We’re thinking of replacing Dr Mrs TJ’s car which is getting like Trigger’s broom in the number of original parts left. She only pootles to the hospital and back in hers (I have a company car which we drive the crap out of for family stuff on the basis of not-our-problem) so we currently only fill up once a month if that - so fast charging isn’t a massive issue, just trickle charging to top up.

Is this feasible or 3.141 in the sky ?
Just checking my FIT statement

My 3 bed semi has its roof covered with solar panels and for 2020 I generated

Q1 288 kWh
Q2 191 kWh
Q3 1102 kWh
Q4 388 kWh

1969 kWh for the year

Which for a Nissan leaf 265Wh/mile is about 7000 miles but only about 1000 miles in Jan-March
Have you considered stupidity as an explanation

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Re: Solar Panels

Post by lpm » Fri Nov 05, 2021 10:46 am

Troubled Joe wrote:
Fri Nov 05, 2021 9:10 am
One for the hive mind !

How tricky would it be to self install a set of panels/charging point for an electric car - independent of the mains?

We’re thinking of replacing Dr Mrs TJ’s car which is getting like Trigger’s broom in the number of original parts left. She only pootles to the hospital and back in hers (I have a company car which we drive the crap out of for family stuff on the basis of not-our-problem) so we currently only fill up once a month if that - so fast charging isn’t a massive issue, just trickle charging to top up.

Is this feasible or 3.141 in the sky ?
These are separate decisions, I'd say. Electricity is fungible so there's no point in reserving some for one product.

The most eco answer for Dr Mrs TJ is probably bike or eBike if the journey is only a couple of miles. Or a little Fiat or Zoe or Leaf with small battery and limited range if a car is needed.

For recharging you'd get a proper home charger sooner or later (assuming you have a drive or garage) and plug in once a week at cheap overnight rates. This would then be ready for when your second car is electric.

Solar panels are hard to make work financially. The calculator in Kerry's opening post gave me a saving over the lifetime of the installation of £1. Self install would presumably save a lot of cost but could you do it? Are you a trained roofer and a trained electrician?
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Re: Solar Panels

Post by lpm » Fri Nov 05, 2021 12:35 pm

Grumble wrote:
Fri Nov 05, 2021 8:39 am
EV Man recently did a breakdown of home battery costs showing payback in less than ten years, without solar panels. https://youtu.be/_T0vahG6JPU
That video shows home battery is a dud investment.

The return from shoving £3,900 into your pension scheme is the highest, second would be into a ISA or other tax efficient investment. Home batteries trails far behind, though better than leaving £3,900 in the building society.

Away from financial calcs, do batteries do much for CO2? Not really, because the night rate is going to belong to the nation's fleet of EVs in the 10 year time frame.

These things always seem to come back to insulation, for both financial and CO2 reasons, well ahead of the interesting stuff like solar and heat pumps.
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Re: Solar Panels

Post by Grumble » Fri Nov 05, 2021 1:03 pm

lpm wrote:
Fri Nov 05, 2021 12:35 pm
Grumble wrote:
Fri Nov 05, 2021 8:39 am
EV Man recently did a breakdown of home battery costs showing payback in less than ten years, without solar panels. https://youtu.be/_T0vahG6JPU
That video shows home battery is a dud investment.

The return from shoving £3,900 into your pension scheme is the highest, second would be into a ISA or other tax efficient investment. Home batteries trails far behind, though better than leaving £3,900 in the building society.

Away from financial calcs, do batteries do much for CO2? Not really, because the night rate is going to belong to the nation's fleet of EVs in the 10 year time frame.

These things always seem to come back to insulation, for both financial and CO2 reasons, well ahead of the interesting stuff like solar and heat pumps.
I don’t agree with your reasoning for dismissing the impact on CO2. There are already times when the output from wind farms is curtailed overnight when demand is low and supply is high. This situation will only happen more often. A nighttime tariff may or may not be the best fit but a tariff that allows low CO2 power to be stored in the home will help drive down CO2, whether the battery is hung on a wall or sitting on a driveway.
A bit churlish

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Re: Solar Panels

Post by Brightonian » Fri Nov 05, 2021 1:12 pm

In calculating the costs I would want to factor in the utility value or whatever the term is of having one's own power back-up in case of a zombie apocalypse and/or the French cutting the interconnector.*

* A Brexiter friend reckoned the fire the other month was "a bit suspicious".

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Re: Solar Panels

Post by lpm » Fri Nov 05, 2021 1:17 pm

Grumble wrote:
Fri Nov 05, 2021 1:03 pm
I don’t agree with your reasoning for dismissing the impact on CO2. There are already times when the output from wind farms is curtailed overnight when demand is low and supply is high. This situation will only happen more often. A nighttime tariff may or may not be the best fit but a tariff that allows low CO2 power to be stored in the home will help drive down CO2, whether the battery is hung on a wall or sitting on a driveway.
There's the CO2 cost of the battery to consider as well.

Generally financial cost and CO2 cost align, close enough for our purposes. An object that costs £3,900 will have cost 10x as much CO2 in manufacture as something that costs £390. Sure, electronics and batteries tend to be more expensive CO2-wise than average, insulation might be less. But broad brush you're ballpark OK taking just the £ number.

If batteries are meh financially you can be pretty sure they're meh for CO2 as well. Using up North Sea night time winds doesn't seem particularly noteworthy, the time to payback the initial CO2 outlay is going to be pretty long.
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Re: Solar Panels

Post by Grumble » Fri Nov 05, 2021 1:50 pm

lpm wrote:
Fri Nov 05, 2021 1:17 pm
Grumble wrote:
Fri Nov 05, 2021 1:03 pm
I don’t agree with your reasoning for dismissing the impact on CO2. There are already times when the output from wind farms is curtailed overnight when demand is low and supply is high. This situation will only happen more often. A nighttime tariff may or may not be the best fit but a tariff that allows low CO2 power to be stored in the home will help drive down CO2, whether the battery is hung on a wall or sitting on a driveway.
There's the CO2 cost of the battery to consider as well.

Generally financial cost and CO2 cost align, close enough for our purposes. An object that costs £3,900 will have cost 10x as much CO2 in manufacture as something that costs £390. Sure, electronics and batteries tend to be more expensive CO2-wise than average, insulation might be less. But broad brush you're ballpark OK taking just the £ number.

If batteries are meh financially you can be pretty sure they're meh for CO2 as well. Using up North Sea night time winds doesn't seem particularly noteworthy, the time to payback the initial CO2 outlay is going to be pretty long.
But the payback is less than half the battery’s estimated life which would indicate a reasonable CO2 saving. I agree that the lower cost things should be pursued first, but that’s more of a low hanging fruit argument. Doesn’t mean that we shouldn’t employ a high climbing monkey to get the harder to access fruit.
A bit churlish

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Re: Solar Panels

Post by lpm » Fri Nov 05, 2021 2:18 pm

I'm not sure about that.

How much CO2 can the world invest in 2022, to get reduced CO2 emissions in 2023 onwards? Don't we need to maximise that return on investment for absolutely everything, by putting those solar panels in Morocco not Edinburgh and insulating Britain instead of installing batteries? Low hanging fruit means a quicker and less expensive upfront CO2 hit, as well as a better £ economics.

On the other hand I'd like to have solar/batteries, because it would be interesting and fun more than because it makes any financial sense, and so maybe I should compare it to another fun thing like spending £3,900 on a Caribbean holiday. Obviously spending my £3,900 on batteries is vastly better. Intuitively, if as a society we spend all our money this year on insulation we can't as a society take as many flights and can only afford a car that's cheaper to run.

Then again, there's a shortage of electricians in the UK and if they're installing batteries for me they're not installing EV chargers or building new homes or working on fibre broadband or wiring up HS2 signalling. Which brings it back to measuring the resource requirement in £.
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Re: Solar Panels

Post by Troubled Joe » Fri Nov 05, 2021 2:52 pm

Thanks guys, much appreciated. I’m not an electrician, but always like a challenge, even if it ends up being nothing more than a thought experiment in the end (“I fitted a solar panel on a boat to trickle charge a 12v battery, how much more complicated can it be?”)

We are looking into panels for the house itself but given it is a 120 year old mongrel with the roof built at least 6 different stages, only one of which faces south it is - as someone once said - a bit more complicated than that; hence looking at a standalone for the car.

Also thanks to lpm for the pumpkinny tribute in your avatar - much appreciated!
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Re: Solar Panels

Post by dyqik » Fri Nov 05, 2021 3:29 pm

Here, at least, I think a lot of the battery backup installations are based on cells retired from EVs and hybrids, which has a different effect on the embodied CO2 than for new or remanufactured batteries.

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Re: Solar Panels

Post by jimbob » Fri Nov 05, 2021 3:39 pm

dyqik wrote:
Fri Nov 05, 2021 3:29 pm
Here, at least, I think a lot of the battery backup installations are based on cells retired from EVs and hybrids, which has a different effect on the embodied CO2 than for new or remanufactured batteries.
One of the application engineers where I work (currently on power transistors for high voltage traction inverters for EVs) said that once the retired hybrid batteries are put into such an installation, because the current is far lower than the hundreds of amps needed (even for a Nissan Leaf at full power) the battery capacity doesn't deteriorate noticeably any further with charging and discharging cycles.
Have you considered stupidity as an explanation

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Re: Solar Panels

Post by lpm » Fri Nov 05, 2021 4:22 pm

Grumble wrote:
Fri Nov 05, 2021 8:39 am
EV Man recently did a breakdown of home battery costs showing payback in less than ten years, without solar panels. https://youtu.be/_T0vahG6JPU
This guy assumed 12 kWh per day for a "family house". I've checked and I'm at 9 per day. That's with working from home.

I'm pretty sure I could get to 8 per day by finishing the switch to LEDs, fiddling with the eco settings on the dishwasher/washing machine and defrosting the freezer. Plus picking AAA appliances when current ones break. I've no idea where 9 kWh per day fits in the scheme of things, what do other people use? And then there's using timer functions to get washing machines etc to come on in the night.

And our fella seemed to think we were paying 25p to 30p per kWh. I'm (currently) on a flat rate of 20.5p with Bulb, which was at his lowest savings point. Sure, prices are currently crazy high and Bulb could be bust, but over the next few years his prices seem way too high.

Using his maths, my savings would be £401 p.a. for an upfront cost of £3,900. I'd rather try for £75 p.a. saving from trimming my usage. I'm going to need to shift to an Octopus Go type tariff of 5p night, 23.4p day so time shifting is going to give bigger opportunities.
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Re: Solar Panels

Post by Grumble » Fri Nov 05, 2021 10:17 pm

lpm wrote:
Fri Nov 05, 2021 4:22 pm
Grumble wrote:
Fri Nov 05, 2021 8:39 am
EV Man recently did a breakdown of home battery costs showing payback in less than ten years, without solar panels. https://youtu.be/_T0vahG6JPU
This guy assumed 12 kWh per day for a "family house". I've checked and I'm at 9 per day. That's with working from home.

I'm pretty sure I could get to 8 per day by finishing the switch to LEDs, fiddling with the eco settings on the dishwasher/washing machine and defrosting the freezer. Plus picking AAA appliances when current ones break. I've no idea where 9 kWh per day fits in the scheme of things, what do other people use? And then there's using timer functions to get washing machines etc to come on in the night.

And our fella seemed to think we were paying 25p to 30p per kWh. I'm (currently) on a flat rate of 20.5p with Bulb, which was at his lowest savings point. Sure, prices are currently crazy high and Bulb could be bust, but over the next few years his prices seem way too high.

Using his maths, my savings would be £401 p.a. for an upfront cost of £3,900. I'd rather try for £75 p.a. saving from trimming my usage. I'm going to need to shift to an Octopus Go type tariff of 5p night, 23.4p day so time shifting is going to give bigger opportunities.
12kW is what he claims is an average, clearly the best thing to do is get below that if you can. Personally I’m at just over 9 and I have 3 kids who like to use the PlayStation. Don’t know where his 12 comes from. If you have an EV it’ll go up though, clearly.

The 25-30p/kWh is what you’ll be paying for a new contract when your current one runs out. That’s not supposition it’s the current reality. There is some supposition involved in thinking that prices will stay that high, and I don’t know if I’m as sure as him that they will, but I haven’t really looked into it and it’s forecasting anyway so there’s bound to be some handwaving going on.

The fire brigade don’t recommend running your appliances at night - and there are plenty of sad examples why.
A bit churlish

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Re: Solar Panels

Post by Millennie Al » Sat Nov 06, 2021 1:47 am

lpm wrote:
Fri Nov 05, 2021 12:35 pm
the night rate is going to belong to the nation's fleet of EVs in the 10 year time frame.
Since the sun shines reliably in the daytime, the sensible way to manage EVs is to charge them during the day. For a commuter, this means arriving at work with low charge, leaving it on charge in employer-provided parking, and going home fully charged. The power can, of course, be fed into the grid from solar cells on your home while you draw it out at work.

Accommodating wind is more difficult as it does not follow a predictable pattern, but price changes could reflect availability, and perhaps computer-controlled appliances (such as washing machines) which need to be used any time up to a deadline can use cheaper wind power when available, reducing load at other times.

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Re: Solar Panels

Post by lpm » Sat Nov 06, 2021 8:43 am

For the UK, significant solar isn't going to happen in a 10 year time frame. The very low night rate should last a long time, I think.

Home EV chargers are future proofed for automatic switch on during high wind generation, because the current govt subsidy requires a smart charger with an app rather than a dumb plug. But this seems pointless because for now everyone charges at 5p between 0:30 and 4:30.

Just like home solar panels seem to be in the wrong place, should be in Morocco, home batteries seem in the wrong place. If we all band together and put our batteries next to a wind farm in Wales we'd instantly get economies of scale. Installation costs in hundreds of separate homes is what kills the economics.

Which would lead to the equivalent of Grumble's Ripple wind farm cooperative. I had a quick look at that but didn't have time to get stuck into numbers. Sharing a wind farm makes sense, sharing a battery installation should also make more sense than distribution in individual homes.

Psychologically we all want to act in our own homes and do our bit. Acting collectively is rarely available to us. But it's probably worth trying.
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Re: Solar Panels

Post by Grumble » Sat Nov 06, 2021 9:46 am

lpm wrote:
Sat Nov 06, 2021 8:43 am
For the UK, significant solar isn't going to happen in a 10 year time frame. The very low night rate should last a long time, I think.

Home EV chargers are future proofed for automatic switch on during high wind generation, because the current govt subsidy requires a smart charger with an app rather than a dumb plug. But this seems pointless because for now everyone charges at 5p between 0:30 and 4:30.

Just like home solar panels seem to be in the wrong place, should be in Morocco, home batteries seem in the wrong place. If we all band together and put our batteries next to a wind farm in Wales we'd instantly get economies of scale. Installation costs in hundreds of separate homes is what kills the economics.

Which would lead to the equivalent of Grumble's Ripple wind farm cooperative. I had a quick look at that but didn't have time to get stuck into numbers. Sharing a wind farm makes sense, sharing a battery installation should also make more sense than distribution in individual homes.

Psychologically we all want to act in our own homes and do our bit. Acting collectively is rarely available to us. But it's probably worth trying.
Depends what you count as significant I guess, but we already have peak solar of over 9 GW in the U.K., which I would call significant. I do think sharing in a wind farm is better for an individual though. I haven’t actually bought shares yet, just reserved the chance to do so for the next build. Ripple have already built one shared ownership wind turbine so it’s not pie in the sky. I’d welcome critical analysis of the numbers before I actually put significant money into it, I’ve been convinced by their sales pitch but I’m no economic expert.
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lpm
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Re: Solar Panels

Post by lpm » Sat Nov 06, 2021 11:52 am

Grumble wrote:
Sat Nov 06, 2021 9:46 am
I do think sharing in a wind farm is better for an individual though. I haven’t actually bought shares yet, just reserved the chance to do so for the next build. Ripple have already built one shared ownership wind turbine so it’s not pie in the sky. I’d welcome critical analysis of the numbers before I actually put significant money into it, I’ve been convinced by their sales pitch but I’m no economic expert.
The Ripple co-op has similar economics to the other schemes, I think. But a hell of a lot easier than getting solar or batteries - 5 minute task instead of the pain of roofers and scaffolders and electricians.

For context, battery guy was talking about a £3,900 investment and solar would be something like £6,000.

For the second project they estimate approx £1,500 investment to get approx 8kWh per day. So in CO2 terms that would basically cover my background house usage. That's much more appealing CO2-wise than paying for solar.

In financial terms you don't get the 8kWh per day for free, however. If I understand it right, you sell your bit of the generation to Octopus or Co-op for about 5p per kWh. Then you choose Octopus or Co-op as your supplier and take one of their usual tariffs on offer, say 25p. They apply your generation back on to your bill as a 5p discount. You get your own electrons back, sort of, but buy them back at less than you sold them.

5p per kWh discount translate to £145 saving p.a.

Which isn't great, compared to investing £1,500 into my pension. But it's almost identical to battery guy's £401 p.a. saving for a £3,900 investment.

Currently it looks like the discount is more like 8p, due to the sky-high electricity prices, while the first project had an assumption of 4p. Owning a fragment of a wind turbine is a bit more profitable when prices go up, obviously, but hard to make a guess on where they'll be for the next decade or two. If you own a wind farm you pray for windy days but then moan because the wholesale price on windy days is so low. Assuming 5p seems OK as a base case.

One slight issue is that (currently) it compels you to take Octopus or Co-op as your electricity supplier. Maybe alternatives will be added in the future. Octopus is actually what I want right now, because they're the ones that offer 5p night rate for EV charging. But this might all change in five years, with alternative suppliers becoming cheaper or Octopus going bust or whatever. Tying yourself down isn't attractive.

A big plus is that you can move house and take the investment with you, unlike solar. So ideal for anyone planning to move. You can also invest into Ripple itself, for a modest sum, but the exit strategy for ever selling this investment again is a bit shaky.

They don't seem to mention tax on their website. I bet the £145 p.a. saving would be treated as a dividend and taxable. Although the personal dividend allowance, if it still exists, would typically cover it.

When my EV finally shows up I'll be going from an average of 9kWh per day to about 14. Covering the CO2 would require an investment of approx £2,650 for annual savings of about £260. The car itself would be about £900 of this investment. To be honest I've paid £650 for a nice colour. And £650 for stupid alloy wheels because the standard ones were so ugly. And the home charger will cost £600. And I might spend an extra £400 on the charger to get a really pretty one. Amidst this frivolity refusing to spend £900 to increase the UK's wind generation seems a bit perverse.

I'm thinking the financial investment calcs are just about enough to justify Ripple, because CO2-wise it's so much better than batteries, and so much less building hassle than solar. It would be good fun to see how it plays out over the next couple of decades, plus smug-points for knowing exactly where your home's renewable energy comes from.

Sling around your referral code, Grumble, it seems worth the £25 reservation fee.
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sheldrake
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Re: Solar Panels

Post by sheldrake » Sat Nov 06, 2021 1:24 pm

Troubled Joe wrote:
Fri Nov 05, 2021 9:10 am
One for the hive mind !

How tricky would it be to self install a set of panels/charging point for an electric car - independent of the mains?

We’re thinking of replacing Dr Mrs TJ’s car which is getting like Trigger’s broom in the number of original parts left. She only pootles to the hospital and back in hers (I have a company car which we drive the crap out of for family stuff on the basis of not-our-problem) so we currently only fill up once a month if that - so fast charging isn’t a massive issue, just trickle charging to top up.

Is this feasible or 3.141 in the sky ?
Tesla sell everything needed for this (panels, big home batteries and chargers that run off them), at least in the US. I’ve seen people in California and Florida very chuffed about running their Teslas on sunlight. I dont’t know the cost or whether they insist on their technicians installing though. It probably makes more economic sense in a sunny climate.

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