Solar things

Lordhippos

Stand User
Following on from my post in the stuff bought thread, I wanted to post more detail without horribly de-railing the main thread.

This is primarily for @Geriatric hedgehog but info/discussion welcome with anyone. Hope you have a nice cuppa tea (I'd highly recommend Twinings Strong English Breakfast or Lady Grey) and some biscuits to accompany reading this post, it could be a long one.

Is it worth getting solar?
In my opinion - yes, if you:
  1. Have the money, or can borrow it via something like a personal loan without stretching finances.
  2. Use at least a moderate amount of electricity. I'm talking an average of about 10kwh per day or more.
  3. Install a system no less than about 3.6kwp in size. The more the merrier.
  4. [Bonus/Optional] If you are at home and can load shift certain things into the day when solar generation is above home consumption.
  5. [Bonus/Optional] Don't mind spending extra for home battery storage or something like an Eddi that can divert excess solar to hot water immersion heater.
To understand this more fully, I would highly recommend getting your specific actual usage for electric for approximately a year if you can, this may be possible to find out from your suppliers website, or you can take some meter readings yourself and extrapolate out, readings 7 days apart gives you a weeks worth of usage, multiply by 52 gives you a rough value for a year.

To make it really worthwhile I'd recommend only when your usage is approaching, or above, 3650kwh of electric per year.

How is the generation used?

Any incoming solar generation will power devices currently consuming power. After that, if you have a battery it will store excess there. If that is full, and you have an Eddi or similar for hot water, it will power that, and finally, if the prior list has no capacity, it will send excess to the grid.

So the order of operations is:

Solar Generation => House Consumption => Battery Storage => Eddi/Hot Water tank heater => Grid Export

Is selling Energy to the grid profitable?

Currently, no, not really. This is like the energy crisis in reverse, solar net exporters are essentially being stitched up by poor rates.

The old Feed In Tariff (FIT) system was abolished some years ago, and has been replaced with Solar Export Generation (SEG). SEG payments from most providers are in the region of 4p - 6p per kwh exported to the grid. For this reason it's best to use whatever you can. They then turn around and sell that for 28p/kwh to someone else, presently.

Octopus Agile Outgoing is fairly good though, and I'd recommend it if you have a smart meter over basically any other export tariff.

Interesting side note: you can have SEG with any provider, you don't need to use your current one.

Are any planning permissions required or other applications?
Installing a reasonable system on a pitched roof at home is typically going to fall under "permitted development" in the UK. There are some rules for that, but I'd recommend discussing with installer. Any install on a flat roof is likely going to need a planning application.

If your system is capable of exporting more than 3.68kw to the grid, you'll need a G99 DNO (District Network Operator - in my case SSE) application, which installer should handle. This took SSE 3 months to approve, and work can't be done until it's approved.

If your system is less than 3.68kw export capacity then a G98 is required, which is auto-approved and needs to be notified by the installer to the DNO after the fact.

How much does solar cost/what is expected ROI?
A basic panel only system for approximately 4kwp (4KW peak) is likely to set you back in the region of £5K at the moment. Panels are pretty good these days, a 400W panel (x 10 for 4kwp) would be fairly common on new installs.

If you add extra likes batteries or hot water diverters, these can add to the cost. I've seen quotes for larger systems with a battery or two, and they can be approaching £15K with extras above and beyond. Such expensive systems are more tailored to larger dwellings with more demand though.

I would budget £5K - £15K depending on requirements.

ROI is likely still measured in years, I'm estimating 5-8 year ROI for my system, in my circumstances. There is also an opportunity cost here, you could instead pay market rates for energy and invest the money, so spending all at once on solar means you lose that compounding investment potential.

How much does the roof matter?
The very best roof direction for solar is South facing. East or West can also work OK, but North is not recommended.

Commercial solar farms actually often prefer E/W because it gives a longer duration of generation, with less peak output, but allows for panels to be set back to back like this (but with less of an angle): \/\/\/\/\/\/\/\/\/\/

The roof condition is also important. If your roof is falling apart, I would not recommend adding panels, they weigh a lot, and are not meant to be moved for years.

The rail kits actually bolt through the tiles to the roof trusses, so if your roof is in good condition, the panels shouldn't be going anywhere.

What about shading or limited good weather?
The cheapest/most common panel installation mode is string, this means all of the panels in the same string operate as one unit, one panel getting shaded will impact the output of all of them in the same string. I have two strings (one of 6 panels, one of 7).

If your roof has some degree of shading, you may need to add optimisers for some of the panels. These allow shaded panels to operate shaded without impacting performance of other panels. These will up the cost per panel slightly, and it's also one more thing that can go wrong or break.

It's worth noting that panels operate pretty well even in good ambient light, the intensity of light is a factor, and being in sunlight is best, but as long as it's bright outside, the panels will generate something.

Will Solar panels pay for all of my Electric costs?
The long and short answer is no. If you work out how much power you need per year, and get a system that can reasonably meet that requirement, the problem becomes one of timing. In the summer you will generate additional power, potentially to a point where you can't use it quick enough. In the winter, a poor day will basically do nothing.

Estimations on this basis would suggest that for 8 or 9 months of the year, it should produce a good level of energy if sized well.

Standing charge is also required, which is a fixed cost, you can't really go off-grid with just Solar because you need the grid in the darker months.

Is a battery a good idea?
Right now, Solar installations are 0% VAT rated. If you buy a battery with a solar install it's also 0% VAT.

If you get panels for now and decide to buy the battery later, the battery would be charged at 20% VAT.

A large enough battery to reasonably tide your usage over between "solar shifts" can be a good idea, as you can store excess energy instead of exporting to the grid. Battery adds some flexibility into things as you don't need to turn that washing machine on the moment the sun comes out.

You can theoretically install a battery without solar panels, or panels with no battery, or both. There are some scenarios where the battery alone is a better idea than panels, for example if you have an EV and are on the Octopus Go tariff, you can charge the battery up overnight for as little as 7.5p/kwh.

Cons of a Solar system
Some cons I think I may come across include:
  1. Any changes to the panels may include getting more scaffold put up to get onto the roof again.
  2. Inverters are the most likely part to fail, and they are not necessarily cheap to replace.
Summary
I'll try and sum up some important points here:
  1. I would only recommend solar if you use a lot of electric, in the region of 10kwh per day or more on average.
  2. Installation is likely to run £5K - £15K depending on shopping cart.
  3. When selecting installer, try and get 3 quotes if possible. Check for reputation, examples of previous work etc. Word of mouth is great here.
  4. Ensure installer is MCS registered, which is the standard for any regulated Solar installation.
  5. Solar does not entirely pay your electric bills for the year but if used well, should reduce them a lot.
  6. I'd not recommend installing anything less than a 3.6kwp system due to fixed installation costs.
  7. G98 or G99 DNO application will be needed depending on export capacity from inverter (G98 for < 3.68kw, else G99).
  8. Consider adding battery and/or hot water diverter depending on your own figures on repayments.
  9. Export rates on SEG kind of suck right now. Hopefully it will improve along with retail energy costs.
  10. Pitch and direction of roof matters, as does condition, and shading from trees/chimneys etc.
  11. Panels are fairly large for the 400W~ versions, roughly 1.7M x 1.1M, so roof space will also matter.
  12. Panels lose about 0.5% effectiveness per year, so after 20 years they'll still be around 90% as good as they are on day 1.
  13. You don't really need to clean them, rain should take care of most things.
If I think of anything else to add I'll edit this list.

My stats
These have only been running for about a week, but some headline stats to show impact so far, for 7 days.

Parameters
My average expected/typical usage: 12-16 kwh per day
Stats period (7 days): 31/08 - 06/09
Current cap pricing: £0.28 per kwh

Consumption
Total Consumption: 110.77 kwh
Average Consumption: 15.82 kwh per day

Generation
Total Generated : 86.52 kwh
Total Exported: 7.7 kwh
Total Used: 78.82 kwh
Average Generated: 12.36 kwh per day
Average Used: 11.26 kwh per day

Grid Demand
Total Grid demand: 29.48 kwh
Average Grid demand: 4.21 kwh per day

Savings & Efficiency
Generation (Used) to Consumption %: 71.16%
Consumption Cost without Solar: £31.01
Consumption Cost with Solar: £8.25
Savings made: £22.76
Average saving: £3.25 per day

Because we all like charts, can see how the system works with the battery charging on a day like today, where the weather was fairly good if a little rainy at times.

At the start of today, it was at 4% (reserve capacity it ran out late last night). Between 00:30 and 04:30 it charged to 65%.

From there, it powered the house through until the solar kicked in around 07:00. By 09:00 solar was powering the house and also charging the battery. By 15:00 the battery was fully charged and I was unable to find enough things to use the excess power.

18:30 and the solar dies down, battery has been powering everything since then and is down to 73% as of now.

c3FTi3l.png
 
Last edited:

ayase

State Alchemist
That is quite the comprehensive guide @Lordhippos! I would add though that, with a few caveats, it is possible to do it cheaper and go entirely off-grid. I say this because my dad has done it, and I was fairly involved with the whole process.

Caveat No. 1: You need plenty of sunlight, probably the biggest issue in the UK. My dad is lucky in that he managed to escape the UK for sunnier climates, something brexit has now made considerably more difficult for the average person. Which is very unfortunate given how much more reasonable property prices are in many parts of Europe, particularly the sunnier Mediterranean ones perfect for solar. But as you mention, the panels are getting much more efficient and capable of generating even in relatively low light, and this will probably continue to improve.

Caveat No. 2: You're okay with purchasing and installing everything yourself, and doing it very much on the cheap. While you don’t necessarily need to have studied electrical engineering, since these days it’s entirely possible to learn everything you need to know online, it probably helped that my dad did. The panels, regulator (which stops the power output from the panels overloading the batteries) and inverter (which ups the 12v dc output of the batteries to 240v ac) all came from ebay. Until recently, when we replaced them with a large bank of 2v deep cycle batteries which are designed to cope with being charged and discharged regularly (wired together into banks of 6 producing 12v each), my dad’s house was running entirely off old lead acid car batteries. I think overall, the cost of the entire system was less than £2000. Your time has a value of course, but when you're spending it on something that will ultimately benefit you financially it's probably time well spent.

Caveat No. 3: You forego appliances with very large power draws. Basically anything that uses over a kilowatt (unless you can afford to buy a lot of batteries) because it will drain the batteries very quickly. That’s no microwave or electric oven, no electric kettle and no (standard) fridge or washer. My dad uses a low power twin tub washer and a large 12v cool box as a fridge, wired directly to the batteries' 12v supply. I think another thing that has made a major difference to his energy consumption is that he put lighting on a separate 12 volt dc circuit, which also operates directly from the batteries without the need for an inverter. 12v LED bulbs are very easy to come by now and are really no different from modern LED bulbs, which contain a capacitor to step-down the voltage anyway because you don't want to put 240v directly into LEDs. This means the 12v to 240v inverter only needs to be switched on to power plug sockets, essentially acting as a master power switch for all electrics in the house besides lighting (and the "fridge"). The reason this is useful is because the inverter itself uses power when it is on, which is essentially just wasted power if none is actually being drawn from it. Obviously this approach isn't going to work for everyone, but it is possible. It's certainly possible to still have a laptop computer, given the lower power consumption and the fact they can run off battery power whenever the inverter is off.

Overall I think I can say that disconnecting entirely from the power grid is a fantastic idea. Not only does it make you immune from the kind of price hikes we’re seeing now, but you also don’t have to pay that most ridiculous of utility costs: The standing charge. I can’t think of a single other business that operates on the understanding you have to pay to maintain their infrastructure regardless of how much of their product you actually use. Imagine being charged £10 to simply look around a shop whether you end up spending £1 or £100. Every other business factors their overheads into the cost price of their products, I see no reason utility companies shouldn’t be expected to do the same. Standing charges actively penalise people who use less resources.

SEG payments from most providers are in the region of 4p - 6p per kwh exported to the grid. For this reason it's best to use whatever you can. They then turn around and sell that for 28p/kwh to someone else, presently.
What an absolute joke that is, you can tell the energy companies don't want people to stop being dependent on them. All the more reason to do so.
 
Last edited:

Lordhippos

Stand User
Thanks so much for the detailed reply @ayase - I enjoyed reading it! :)

I have a few more trains of thought that I didn't include in the last post, partly for length reasons, and partly to see what kind of replies I had and what people were interested in. I may add some of those here.

Generation through the Months of the Year
I am not sure how many kwh I can generate per day for every month of the year on average yet, but I have a friend who has a 4kwp or so system and they have some stats, and I distinctly remember December in particular being fairly low generation, with some days basically being 0 kwh or near enough they may as well have been,

In order to cover for reasonable generation during even the very worst days of the year, potentially you would need an exponentially larger system than 4kwp, at least in the UK. I think being off-grid would also somewhat necessitate being a fairly light user in general, so just not really running background stuff much, and not using power hungry things much either.

Off grid vs On grid
I am of the opinion that being On Grid can be a net positive, but it depends how much you like the idea of cutting the grid out, and what sort of contingencies you have in place should you get a particularly bad series of days.

I have an ex-work colleague who built a small house on an acre of land and went off-grid. They had solar, a battery (probably lead acid at the time) and they had a backup generator as well. I know from speaking to them that they needed the generator quite often in the winter, and at that point you wind up burning fossil fuel to cover solar shortages in the worst months.

The main reason I am for being on the grid though, is because I don't just think solar is a good thing for me, I think it's a good thing for the entire grid, excess energy doesn't get wasted, it gets sent somewhere to be used. For these reasons I think being On Grid is potentially better, and then just minimising the grid import as much as possible. It's a good safety net, and you don't need any extra equipment, or to change appliances or anything.

Standing Charge
Standing charge is a bit ridiculous though I agree, it's also covering the failed energy company balances so it's excessively high right now. The only comparison I can draw for standing charge is the old phone line rental for broadband, even though I have FTTP now, I'm still kind of paying the same sort of figure so they've just rolled it into the cost.

Why did I get Solar installed?
There are a few reasons but ultimately I've wanted it for a while, I just couldn't make it work financially. Electric was too cheap, and the payback period was 15-20 years for any solar system. The current ratio is more like 5-8 years for me, with my benchmark figures at least.

So on top of having a pretty good ROI, I also help out the planet (OK we ignore the impact of actually making panels and things for now), and potentially other people on the grid. I can load shift mostly out of peak rates.

In some ways, having more heavy grid users with solar helps everyone, because the peak demand is lower, so the grid doesn't need to burn extra gas to meet demand. If enough people had similar setups, then prices for everyone should be improved, though it would need a lot of solar existing to make a big dent.

What is the actual cost?
Many thanks to @RadFemHedonist for replying to the comment in the other thread yesterday on my behalf, I didn't really want to because there were so many holes I could pick up in any reply I made, that no good would have come of doing so. Sometimes people can be irrational about things when they compare them to their own situation. I've resigned myself to the fact that many people are smarter, richer, better looking, and more successful than me, so instead of worrying about them, I do my own thing! :)

I'm lucky to be in a good position financially but it's not been without sacrifices, I've always driven really old cars that cost very little (currently in a 2010 VW Diesel) whilst my friends and colleagues spend £300/month on PCP vehicles, I've saved and put a lot of my cash into the mortgage/home ownership front because I wanted to own my own home, and I don't like to spend money on frivolous things, I buy quality > quantity, and in general I will save up first rather than getting things on credit to avoid paying interest.

I've not been handed anything on a platter, and have worked hard to get to where I am, my salary is currently a little above average for the UK, but it wasn't always the case, and it's not well above average really now. I just work hard to keep my living costs down so I have more room to use savings to buy things I want, or to invest into things like solar that help more later.

This is just my logic behind finances, my pension is likely going to be kind of rubbish, so I'm investing into my own future as much as I can. Keeping my fixed costs down really helps with peace of mind, and means I could lower my salary in a pinch without fundamentally collapsing in on myself.

Cost differential
I haven't really discussed this, but yes DIY solar exists. If you are grid connected you can probably do 95% of the work yourself and then pay a sparky to sign off the work, but you need an MCS accredited one to get grid export approved, and you'd need to submit your own G98 DNO application. You can cut a lot of costs by doing much of it yourself. Going onto a typical roof though is not for the faint of heart I think.

It's also possible to ignore the home rooftop and use for example an outbuilding, or ground mounted if you have a large garden, these make for far easier DIY jobs, and also make maintenance easier :)

I will however add that, right now, parts are up in price. Demand for solar is up a lot, so that £2K roughly quoted could well be a fair bit higher now, though I don't disagree you can save a bunch if you trade time/learning instead of money.

Why not DIY for me?
There's a few reasons I decided not to look at DIY myself, but largely boils down to:
  1. I don't want to fall off my roof and die.
  2. If a system I install burns my house down, the home insurance people may not be all that sympathetic.
  3. I can better use my time earning the money via job and paying professionals to do it.
 
Last edited:

RadFemHedonist

Death Scythe
What is the actual cost?
Many thanks to @RadFemHedonist for replying to the comment in the other thread yesterday on my behalf, I didn't really want to because there were so many holes I could pick up in any reply I made, that no good would have come of doing so. Sometimes people can be irrational about things when they compare them to their own situation. I've resigned myself to the fact that many people are smarter, richer, better looking, and more successful than me, so instead of worrying about them, I do my own thing! :)

I'm lucky to be in a good position financially but it's not been without sacrifices, I've always driven really old cars that cost very little (currently in a 2010 VW Diesel) whilst my friends and colleagues spend £300/month on PCP vehicles, I've saved and put a lot of my cash into the mortgage/home ownership front because I wanted to own my own home, and I don't like to spend money on frivolous things, I buy quality > quantity, and in general I will save up first rather than getting things on credit to avoid paying interest.

I've not been handed anything on a platter, and have worked hard to get to where I am, my salary is currently a little above average for the UK, but it wasn't always the case, and it's not well above average really now. I just work hard to keep my living costs down so I have more room to use savings to buy things I want, or to invest into things like solar that help more later.

This is just my logic behind finances, my pension is likely going to be kind of rubbish, so I'm investing into my own future as much as I can. Keeping my fixed costs down really helps with peace of mind, and means I could lower my salary in a pinch without fundamentally collapsing in on myself.

Why not DIY for me?
There's a few reasons I decided not to look at DIY myself, but largely boils down to:
  1. I don't want to fall off my roof and die.

No worries - I'm pretty leftwing economically/politically and see no point in being needlessly uncivil/shooting the messenger-type stuff so was happy to offer a little help (also thanks again for helping me to convince Amazon to refund the money on that tablet that got stolen in transit after I sent it back to them cuz it didn't work - I'm honestly still grateful for that) :) I'm at a turning point in my life trying to sort out my financial situation and be more responsible with money (also I'm disabled and on benefits so it's a curious sort of witches' brew I'm dealing with here!) I don't know if I could manage to switch to solar panels but I am reading this thread as it's very interesting learning about what you are doing! (Also I am thinking about moving house so I will ask my mum if any of this sort of renewable energy stuff would be possible in a place I could realistically afford, both for financial and ethical reasons) :)

Also big same on the whole not dying thing :p
 

Lordhippos

Stand User
No worries - I'm pretty leftwing economically/politically and see no point in being needlessly uncivil/shooting the messenger-type stuff so was happy to offer a little help (also thanks again for helping me to convince Amazon to refund the money on that tablet that got stolen in transit after I sent it back to them cuz it didn't work - I'm honestly still grateful for that) :) I'm at a turning point in my life trying to sort out my financial situation and be more responsible with money (also I'm disabled and on benefits so it's a curious sort of witches' brew I'm dealing with here!) I don't know if I could manage to switch to solar panels but I am reading this thread as it's very interesting learning about what you are doing! (Also I am thinking about moving house so I will ask my mum if any of this sort of renewable energy stuff would be possible in a place I could realistically afford, both for financial and ethical reasons) :)

Also big same on the whole not dying thing :p

There are sometimes council run solar schemes, there are some conditions I think but depending on house efficiency and stuff, I think some even offer some panels for free!

Not sure what is required though, would need to read up on it :)

Bit like this scheme for nearby Portsmouth: Free Solar Panels - Switched On Portsmouth

It sounds like it's based on home EPC rating being E or lower (which is very bad) but also only for owned homes I think. Your council might have something though worth a google.

As a general note though, it makes sense, you need to own the roof to add the panels to it!

I've heard of a mini-DIY setup you can do that doesn't require much skill or knowledge, where you essentially plug a couple of panels and a mini-inverter into an outdoor water-rated plug socket. Not sure how good it is though, but not being fixed in place is great for portability! :)
 
Last edited:
Thanks a lot everyone for the very useful info, especially @Lordhippos for the very detailed summary and usage info. It's really helps to know whether an investment like that will be cost-effective and the shorter ROI period certainly helps make solar a more worthwhile endeavour than it was previously. I will use your info to sit down and work out my usage but suspect it should help with my bills overall, even if not when you need the energy including gas the most ie winter!!

You also made a very important point on batteries potentially being worthwhile on their own, by using EV tariffs for example, and stocking up on the Lecky at the cheaper rate to use during the expensive rate hours. I had been thinking about the feasibility of that and would you think that a battery system on its own would be easy enough to upgrade, were one to get solar panels at a later date?

The info on councils is also very useful but it's such a shame there's no clear cut info and links on government websites or even council ones for that matter - when I looked it up, the one for my council was utterly hopeless. Are there any websites you'd suggest to compare installers or companies for this?

I'm probably confused on this point, but you mentioned a linked device for your heating boiler? Would this negate or help with your gas usage then? And I read something elsewhere about systems like that being more expensive as the costs aren't subsidized??

On the other points, being off the grid would be the dream, there's nothing like being self-sufficient! Though I know for a fact our household could not do without the power-hungry white goods. And I'm utterly hopeless on DIY and can envisage numerous looney tuney death scenarios just thinking about it...
1662806486406.png
And you're spot on with your philosophy @Lordhippos, everyone has to look at their own lot in life and find happiness and contentment as much as possible. It's not even politics when you think about those working backbreaking hours and multiple jobs and still barely breaking even, that's just life and always has been. But it's no reason not to do the best you can whilst trying not to look over your shoulders and getting depressed or trapped in status-anxiety hell...
 

RadFemHedonist

Death Scythe
On the other points, being off the grid would be the dream, there's nothing like being self-sufficient! Though I know for a fact our household could not do without the power-hungry white goods. And I'm utterly hopeless on DIY and can envisage numerous looney tuney death scenarios just thinking about it...
View attachment 26101
And you're spot on with your philosophy @Lordhippos, everyone has to look at their own lot in life and find happiness and contentment as much as possible. It's not even politics when you think about those working backbreaking hours and multiple jobs and still barely breaking even, that's just life and always has been. But it's no reason not to do the best you can whilst trying not to look over your shoulders and getting depressed or trapped in status-anxiety hell...

Without wishing to derail this thread too much, I would say that I don't think the way things are is right or fair but I don't want people (myself included) to end up giving up hope of happiness because of that especially since it's very hard to make that much change to the system even collectively, and while happiness is not altogether unrelated to one's material socioeconomic conditions I want to at least try and help support myself and others to cultivate what happiness I/they can have that is not dependent on/less dependent on that kind of stuff. No one is an island and we should look out for each other but at the same time there are individual rights/boundaries/limits and some responsibility for oneself. Plus in my view at least this is an instance of someone with a bit more money using it in a relatively constructive fashion to benefit the environment and also in the shorter term may mean there is more left for those who must depend on fossil fuels. There is a project from Sum of Us right now where they are raising money to help solar power a village that is dependent on kerosene lamps, and I found it interesting to read about, here is a link for anyone who is interested:


(I have nothing to comment about the Looney Tunes part I just like Looney Tunes and the image you posted and your comment made me laugh) :)
 

Lordhippos

Stand User
You also made a very important point on batteries potentially being worthwhile on their own, by using EV tariffs for example, and stocking up on the Lecky at the cheaper rate to use during the expensive rate hours. I had been thinking about the feasibility of that and would you think that a battery system on its own would be easy enough to upgrade, were one to get solar panels at a later date?

The magic ingredient here is essentially the inverter, this is the hub that the panels and/or battery connect to, and it's primary function is to be the brains behind the system (i.e. when to do what with the power) but also to convert DC input from solar into AC current that your home/battery can use.

If you get a system of just panels, or just a battery, you will need the inverter all the same. The most cost effective is going to be both at the same time potentially, because you can then get the whole system currently for 0% VAT rated.

If you buy just a battery/inverter, then you're likely to be paying 20% VAT, unless the installer just pretends it's coming with panels and fudges the numbers a bit.

With any configuration, panels, battery, or both, you can generally expand the system later and attach the missing things to the same inverter. So you could start with just panels, and later attach a battery.

It's generally suggested to get a Hybrid inverter if you ever want to add an EV down the line. Also to plan installation location to allow room for a battery later for example (they are big/heavy!).

Are there any websites you'd suggest to compare installers or companies for this?

I started out on Checkatrade looking at local installers, but in the end wound up using a company based nearby that a forum member suggested from a different forum than this one.

Possibly some resources like local facebook groups you could use if you use that (I don't use it not sure), or otherwise word of mouth if you have anyone living nearby who has had them installed in your road for example?

Whatever you decide, I'd recommend trying to get in 3 quotes, and generally you want to maximise how many panels are installed because once they're on the roof, adding additional panels is fairly cost effective, and more helps with the winter dip.

I'd also encourage to look at previous gallery of works if they have one to see what kind of job they do, and also any testimonials or reviews (being careful for fakes as usual). I would be disinclined to go with a newer company without much history.

I'm probably confused on this point, but you mentioned a linked device for your heating boiler? Would this negate or help with your gas usage then? And I read something elsewhere about systems like that being more expensive as the costs aren't subsidized??

My previous home had a water cylinder and a gas boiler. The water cylinder could either run off the standard gas boiler, or it had a backup immersion heater that basically turned it into a giant kettle.

What the hot water diverter does here is send excess solar generation into the immersion heater effectively, so if you currently heat a water cylinder with a gas boiler, it can save you some money there. I will however note that you can also get a cheap EV tariff and fire it up in the cheaper window instead, so it's a cost that you can mitigate in other ways.

And I'm utterly hopeless on DIY and can envisage numerous looney tuney death scenarios just thinking about it...

Me: Time to do some DIY solar panels
Electrics: So you choose death, then?
Me: ☠️

Yep not big into DIY either! :)

And you're spot on with your philosophy @Lordhippos, everyone has to look at their own lot in life and find happiness and contentment as much as possible. It's not even politics when you think about those working backbreaking hours and multiple jobs and still barely breaking even, that's just life and always has been. But it's no reason not to do the best you can whilst trying not to look over your shoulders and getting depressed or trapped in status-anxiety hell...

Without wishing to derail this thread too much, I would say that I don't think the way things are is right or fair but I don't want people (myself included) to end up giving up hope of happiness because of that especially since it's very hard to make that much change to the system even collectively, and while happiness is not altogether unrelated to one's material socioeconomic conditions I want to at least try and help support myself and others to cultivate what happiness I/they can have that is not dependent on/less dependent on that kind of stuff. No one is an island and we should look out for each other but at the same time there are individual rights/boundaries/limits and some responsibility for oneself.

Same question for both you and @RadFemHedonist - have you seen Parasite the movie? the South Korean one?

There is a line in it which is so true (paraphrasing here): money can't buy happiness, but it sure can make everything smoother.

It's got a really interesting view on society and the haves and the have nots. I'd highly recommend giving it a watch if you've not seen it, the film is really good.

In general, I think we have a fairly good standard of living in the UK, it's not perfect, but for the most part people can get a roof over their heads, and if driven, can excel. Background or upbringing is not necessarily a blocker to success, but like most things wealth and the ability to generate more of it help a lot. I'd like a system where everyone can get by, but I also think we need one that rewards extra effort as well, there are still quite a few who struggle going paycheck to paycheck.

A common issue seems to be people stuck in rentals long term, where you pay so much out on rent and basics that you can't save or ever afford a house (if you can even keep up with the rising prices over time!). This kind of thing could do with being addressed somehow.

A counter-problem that I think a lot of people do ignore though, is how do you prevent the opposite of this issue? Some people are given a free place to live because they can't afford it and they have a family, whilst others are eligible for nothing but wind up spending all of their money on necessities, in both cases neither are wealthy, but one has had to work, and the other hasn't.

Actually what I'd really like to see properly implemented is a UBI system, Universal Basic Income. Everyone gets a "salary" from the gov, and then you can choose to work on top for additional. The UBI should cover a relatively basic existence, but comfortable enough. That would encourage people to seek employment to cover spending money, but would not punish people who work by taking anything away. Additional income support could be given to people who then most need it beyond UBI.

UBI would simplify a lot of things for a lot of people, and would leave some smaller challenges to solve.

There is a project from Sum of Us right now where they are raising money to help solar power a village that is dependent on kerosene lamps, and I found it interesting to read about, here is a link for anyone who is interested:

Initiatives to solve these kinds of problems elsewhere are interesting, The entire world needs more green energy as well, eventually the oil and gas will run out so we need to transition away from them. Wind and Solar are part of that strategy, along with Nuclear being pretty good at baseline generation with releasing carbon into the atmosphere (though Nuclear waste needs careful attention).

Tom Scott did a really interesting and fairly short video on green energy production in Scotland:

 
Last edited:
Thanks for the info dude, very much appreciated, especially the bits on the inverter and also how things are subsidized, i.e. by no VAT on the whole package but not on individual components alone.
There is a line in it which is so true (paraphrasing here): money can't buy happiness, but it sure can make everything smoother
That is certainly the most memorable line from the movie and so very true indeed. Great movie. The whole money doesn't make you happy thing is a denial fallacy to an extent, as not having to worry about creature comforts does help, but perhaps that is a state of mind depending on one's definition of creature comforts, and having too much time and money may not help from development of existential dread. Human society generally oscillates between extremes and achieving a balance and utopian state wouldn't likely work with how we're wired, we will find some way or the other to wreck it. And it does feel these days like we're swapping places with the developing world with the increasing inequality in society. But I can already feel myself getting irritated thinking of politics, so will end with my coping mechanism is to try to think more in terms of being in the pursuit of contentment, which is more likely to lead to happiness hopefully, whatever one's level of material possessions or lack thereof may be.
 

Lordhippos

Stand User
That is certainly the most memorable line from the movie and so very true indeed. Great movie. The whole money doesn't make you happy thing is a denial fallacy to an extent, as not having to worry about creature comforts does help, but perhaps that is a state of mind depending on one's definition of creature comforts, and having too much time and money may not help from development of existential dread.

Yep I really think money can help make you happy, but it can't solve everything by itself. it smooths out worries and concerns a little. That's my take away from the sentiment anyway.

Human society generally oscillates between extremes and achieving a balance and utopian state wouldn't likely work with how we're wired, we will find some way or the other to wreck it.

Ah yes, that is true, for the most part we are great at adding chaos into order! :)

Oh I forgot to add, what's kind of fun is the game within the game, if you can reasonably predict solar generation on the next day, and you know your rough usage/base load, you can try and top up the battery on a cheaper overnight rate to a point where the solar has the most headroom to charge in the day, get it wrong and you wind up buying in from the grid, but get it right and there will be very little waste from over-generation/export that you don't use.

Also some months will natively be better than others, the rough outline of a 4kwp system in my neck of the woods generates 3750kwh per year, you can see this on this chart that expected generation varies through the year, assuming approximately 300 kwh used per month (for simple maths we'll call a month 30 days, and 300 kwh per month is 10kwh per day):

ewd4RCn.png


December and Jan will only produce about 1/3rd of what you need. Feb and Nov about half, but the remaining months are either above, well above, or slightly below usage figures.
 
Last edited:
Thinking again of the utility of solar whilst sitting in my car using it to charge my wife's phone before mine thanks to the powercut in our area since 5am.... Just the day to have not bloody charged my phone overnight as well D'OH!! Was speaking to a mate yesterday living in the same area who was planning to install solar panels before covid hit, and now the solar installers are so busy they don't even respond to his emails and calls!
 

Lordhippos

Stand User
Thinking again of the utility of solar whilst sitting in my car using it to charge my wife's phone before mine thanks to the powercut in our area since 5am.... Just the day to have not bloody charged my phone overnight as well D'OH!! Was speaking to a mate yesterday living in the same area who was planning to install solar panels before covid hit, and now the solar installers are so busy they don't even respond to his emails and calls!

One thing they don't do by default is take over power flow in a power cut, you can make them do it but likely needs a bit of tweaking, and probably a manual switchover or similar.

If I lose the grid my system will shut down, I believe I can pay to have the behaviour changed, but so far haven't felt the need to.

If you did flip to battery backed UPS on the home, then you'd be a little limited on how much you can use at once, so no kettles and things! my battery can do 2.6kw charge or discharge, so that's a limit before it would shut off.

Saying all of the above, I know it's possible to do it. You'd want a big enough battery installed to handle load for say half a day. These battery systems are pretty beefy, the fact it can run the whole house more or less off grid is amazing.
 
Last edited:
Aaah that's interesting. My layman self assumed that it could just pick up the slack in the event of a powercut from the grid. The UPS is a good thought, in the age when powercuts were unheard of I'd completely forgotten about those but we live in funny times now so maybe that is also something to look up also!
 

Lordhippos

Stand User
Aaah that's interesting. My layman self assumed that it could just pick up the slack in the event of a powercut from the grid. The UPS is a good thought, in the age when powercuts were unheard of I'd completely forgotten about those but we live in funny times now so maybe that is also something to look up also!

You can turn the battery into a UPS for the home but yeah normally you have to pay to do it.

Can be done though, although negative of that is you always want to keep some charge in the battery and not run it flat.
 

Lordhippos

Stand User
I'm not going to update this thread constantly but after having 2 weeks worth of data (01/09 - 14/09), I have some more stats to share about the performance and savings on such a system as this.

Firstly looking at consumption, I have used 226.41 kwh in 14 days.

Average consumption per day being 226.41 / 14 = 16.17 kwh per day.

K9dt20c.png


For generation, I have generated 168.45 kwh in that same time window.

168.45 / 14 = 12.03 kwh generation per day.

5D8OWDk.png


For grid usage, this counts both current usage and also charging the battery overnight when needed. Same time window again.

I have drawn 78.14 kwh from the grid.

78.14 / 14 = 5.58 kwh per day drawn on average.

VT7DNBZ.png


Conclusions

Bearing in mind the headline stats shown above, I have used 226.41 kwh of electric, of which solar generation (directly or to battery for later consumption) accounts for 155.39 kwh saved (solar to home + solar to battery figures).

Saving an average of 11.10 kwh per day. which differs slightly from raw generation count because of export to grid for some excess.

The new cap price for electric is soon going to be £0.34/kwh for most of us, but currently it's £0.28. At £0.28 that 155.39 kwh saves £43.50 in total. At £0.34 it's saving £52.83 in total.

Taking the lower figure for now (£43.50), that means it's saved £43.50 / 14 = £3.10 per day. At the higher upcoming figure that would be £3.77 per day on the same usage basis. This is the cost of the average saved per day (11.10 kwh) negated from the usage figures.

Ignoring cheap off-peak rates, essentially my costs with solar and without but same consumption would be as follows:

No Solar: 226.41 * £0.28 = £63.39
With Solar: 78.14 * 0.28 = £21.87

It's worth bearing in mind that my actual savings are a little higher because I have cheaper off-peak Electric with Octopus Go, I pay £0.075 per kwh of electric between 00:30 - 04:30, and most of my grid power consumption fits into that window of time.

The worst day for solar was 13/09 at just under 3kwh for the whole day, that was a miserable cloudy/rainy day with no sun at all, but even on that day, being careful I was able to avoid drawing anything from the grid more or less outside of the off-peak window.

U9vYw9N.png
 
I'm not going to update this thread constantly but after having 2 weeks worth of data (01/09 - 14/09), I have some more stats to share about the performance and savings on such a system as this.

Firstly looking at consumption, I have used 226.41 kwh in 14 days.

Average consumption per day being 226.41 / 14 = 16.17 kwh per day.

K9dt20c.png


For generation, I have generated 168.45 kwh in that same time window.

168.45 / 14 = 12.03 kwh generation per day.

5D8OWDk.png


For grid usage, this counts both current usage and also charging the battery overnight when needed. Same time window again.

I have drawn 78.14 kwh from the grid.

78.14 / 14 = 5.58 kwh per day drawn on average.

VT7DNBZ.png


Conclusions

Bearing in mind the headline stats shown above, I have used 226.41 kwh of electric, of which solar generation (directly or to battery for later consumption) accounts for 155.39 kwh saved (solar to home + solar to battery figures).

Saving an average of 11.10 kwh per day. which differs slightly from raw generation count because of export to grid for some excess.

The new cap price for electric is soon going to be £0.34/kwh for most of us, but currently it's £0.28. At £0.28 that 155.39 kwh saves £43.50 in total. At £0.34 it's saving £52.83 in total.

Taking the lower figure for now (£43.50), that means it's saved £43.50 / 14 = £3.10 per day. At the higher upcoming figure that would be £3.77 per day on the same usage basis. This is the cost of the average saved per day (11.10 kwh) negated from the usage figures.

Ignoring cheap off-peak rates, essentially my costs with solar and without but same consumption would be as follows:

No Solar: 226.41 * £0.28 = £63.39
With Solar: 78.14 * 0.28 = £21.87

It's worth bearing in mind that my actual savings are a little higher because I have cheaper off-peak Electric with Octopus Go, I pay £0.075 per kwh of electric between 00:30 - 04:30, and most of my grid power consumption fits into that window of time.

The worst day for solar was 13/09 at just under 3kwh for the whole day, that was a miserable cloudy/rainy day with no sun at all, but even on that day, being careful I was able to avoid drawing anything from the grid more or less outside of the off-peak window.

U9vYw9N.png
Thanks for the detailed analysis, very useful indeed! I'm with Octopus and really need to get in touch with them to get a better tariff but I saw they had some discounts with some solar providers - these any good in your opinion, or are Octopus just giving reductions on overpriced providers?
 

Lordhippos

Stand User
Thanks for the detailed analysis, very useful indeed! I'm with Octopus and really need to get in touch with them to get a better tariff but I saw they had some discounts with some solar providers - these any good in your opinion, or are Octopus just giving reductions on overpriced providers?

Most things like this are over-inflated to begin with, if you ask me. Definitely worth getting at least 2-3 quotes in.

Octopus Go is meant to require an EV, but it didn't always require one, so far they haven't stopped me using it (you can sign up online, I don't have an EV). Without a fairly large load shift it's not a great tariff to be on though.

In general if interested, I would run your own numbers, check your roof is in a good state of repair, you're not planning to move in 2-3 years etc, got space etc, only then would I pull the trigger on a system like mine.
 
In general if interested, I would run your own numbers, check your roof is in a good state of repair, you're not planning to move in 2-3 years etc, got space etc, only then would I pull the trigger on a system like mine.
Yeah this is the difficulty for me in that I'm not sure quite what we will be doing with the roof. Need space so a loft conversion is required, before which there is no point doing the panels, but don't have the funds for the conversion so stuck in a rut... Got to work harder and have even less time for anime boooo!
 
Top