Solar panels - or not?

[[XAP]Bob]

Yes, the somewhat specialised inverter/chargers needed for V2H seem to be offered at ridiculously high prices; and are few at present. Yet the benefits of V2H seem, potentially, large in an e-car flooded world so perhaps there'll be "price corrections" before long? We can only hope.

As and when car makers manage to decide that V2H is a good thing to add even a dumb EVSE unit should technically support 7kW V2H/G, since they're basically a glorified light switch. It just needs the inverter on the car to be bidirectional, synchronous, and for the car to have some information about the household needs (that could be a flat export for a programmed time, or it could be a car specific wireless CT clamp on the meter tails.

Perhaps that Miliband could cancel the ridiculous carbon capture subsidies in favour of stimulating and supporting V2H inverters of a wide capability, possibly including subsidies to buyers? He's already yapping about putting up solar panels all over the place (warehouse roofs and on any new-build) so who knows?

Yep - getting all new builds to be efficient is certainly the lowest hanging fruit and hasn't been done yet. CCS is thoroughly unproven at the moment, and I have my doubts. There aren't that many industries that can't electrify their operations...

The advantage of subsidising solar, inverters, batteries et al for individual households (and perhaps businesses) is that a highly distributed yet also localised e-production and distribution facility could be build with far less expense than nuclear power stations and similar, with householders and businesses providing a goodly portion of the costs.

I'd also want to be funding micro nuclear plants. Container sized generation with ~10MWe output, small enough to be centrally processed, large enough to be really useful - put a couple at every motorway service station across the country and you've an additional 10GWe, with free heating for all the service station buildings (and potentially any other local facilities). That enough to supply a significant number of DC EV chargers, as well as export to the grid the vast majority of the day.

If enough storage capacity is included by way of not just household, car and business premises batteries but also thousands of local sub-station batteries and large facilities such as those that pump water up and down to/from very large water-bodies (via turbines) there might be so need for nuclear, gas or other damaging and expensive facilities to support the low solar and wind production periods. Add in tidal-flow generation (which is predictable and regular) as a further always-there generator and ......

Storage capacity is always a difficult one - what's the longest period you reckon we need storage for? Pumped storage is relatively hard to locate, most battery tech isn't suited to long term storage... Flow batteries might make a serious impact at substations etc.
Tidal flow is pretty challenging to harvest as well - you either build a massive barrage, wreaking havoc on the same ecosystem everywhere you build one, or you use turbines in an extremely hostile environment.
I *think* we will continue to use nuclear (albeit we need to stop custom designing every time we built a facility, and start commoditising the process), but you're right in terms of gas etc.

[[XAP]Bob]

Thanks for detailed reply.
I have never suggested "these things" are empty gestures.
I am glad it works for you.

Issues that I do have are that you don't really export anything, but simply consume! (2.4 kw not enough)

'twas Cudgel who mentioned empty gestures, I just didn't quote the one liner

If my roof lent itself to more generation I would put it in - the east facing aspect is broken by an overhang over the bay windows beneath, the west facing aspect is actually a flat roof, the south is maxed out, and the north is untouched. I could put a few additional panels facing east, an a few facing west at low pitch on the roof. But their value is fairly compromised by shading/inclination.

The payback time scale is dependent on you buying cheap off-peak and reselling at a profit I imagine?
(I do have a problem with that as I consider it pushes up costs for other standard tariff low consumption houses.)

The payback period is comparing my current costs/usage with my costs/usage on previous time of day tariff.
The timescale isn't so much dependent on buying cheap and reselling - that's a negligible portion of what I do. Approximately I export all my generation, and live on energy which is bought at cheap rate and supplied to my house via a battery. There is some subtlety around this, and obviously it changes slightly summer to winter, but that's the approximate process.
I would disagree wrt Time of Day tariffs: they don't push up the price for other households, because they incentivise the use of very low (even negative) priced wholesale energy - I have the agile price tracker on my system, and it's pretty interesting to see the price pattern through the day. In fact, I'm not just incentivised to use the cheapest power, it's enforced by the fact that Octopus control my EV charger, they also reward (though I don't track these very small rewards) using the cheapest nights to charge the car, rather than nights when the wind out in the north sea is relatively calm. I can force the car to charge, but I'll get charged at full rate for that - still cheaper than most public charging, but not ideal for saving money.

I don't see nuclear as particularly clean, but rather as a necessary evil.

And around 50% of the grid isn't carbon neutral still- I don't buy into green tariff stories- if you get it from the grid you get the same proportion CO2 as everybody else.

It's certainly clean in operation, but it's got significant potential benefits.
There are two ways of looking at grid usage. You can buy from someone who invests in renewables, or not. The actual electrons which get mildly inconvenienced are indeed the grid average, but the investment from your payment for them need not be.

Home Assistant looks at the grid average as I import electricity, so it's a fair representation of my "actual electrons" carbon cost, irrespective of either of our opinions about REGO certificates (and I'm guessing neither of us particularly like them). By moving my power usage to times of lower demand, and higher renewable generation, I can use significantly less than the national average, and by doing so I can actually lower the national average (by a teeny, tiny amount), and save everyone money, because there is fractionally less requirement for peaker plants, so they can be brought online slightly later.
No I don't think I measurably move the needle on my own, but I am pushing it in the right direction - and with millions of other households we can, and do, move the needle each winter. That's what demand flexibility is about.
There was a DFS session earlier this week, and I got paid 60p/kWh for lower than normal usage, or higher than normal exports at peak time, when the grid would otherwise have had to fire up another power station (and it's that heating and firing which is really expensive), as it is those of us with batteries can take a lower (but still worthwhile) payment for our electricity, saving the grid, and therefore you, money.
This year they're doing regional DFS, hopefully that will allow us to push for regional pricing as well, so that the scots don't have to turn off wind turbines and pay more for electricity because the south east needs a peaker plant active.

I would be interested in total cost (just ball park) for the whole show though.
Car, panels, battery and all the necessary clever management technology.
One day.....

All the home stuff (i.e. excluding the car) was about £10k. That's panels, inverters, battery, having it all installed (scaffolding etc).
I also bought a second hand EV charger for ~£200 because of compatibility with the better tariff.
The automation is completely optional, I use HA to do much more than just automate this stuff, and it's running on a server that I have for other things as well. It does make a few things slightly easier, but it's not required by any stretch. The biggest automation I have is to stop the battery discharging into the car, and that could also be done by a slightly different wiring setup (as it is at my parent's house)

The car is a motability lease, and that's much more difficult to quantify. I did the calculations more than four years ago now, and at the time with diesel at £1.10, and my off peak electricity at 10p (both of which have shifted in my favour) the cost of owning and looking after an older car (typically ~70-100k miles) was the same as leasing an EV (leasing an ICE was way too expensive). That came with an EVSE installation at home, and whilst it claimed to be a smart charger, it was as smart as a bag of rocks. I now have that on an automation, but don't use it all that much.

It looks as if the Govt is going to force the leccy companies to offer a "no standing charge" tariff option.
The devil will be in the detail of course, but if really low consumption houses don't get some small benefit then it will be just so much more hot air.
We shall see.

Yeah - I'd rather the SC was just brought down significantly, there are a few things it should pay for (like the meter network, and billing systems), but it's currently got *way* to much loaded onto it. Network transmission costs for example should be part of the unit rate.

I am not holier than thou.
I consume more fossil energy than I should.
The house is very good, but transport is fossil fuel.
I still cycle as much as I can though.
The last two months for example, have seen very low car miles and fuel consumption, perhaps 20 litres.

Not trying to be holy about this at all.
I am very engaged in our energy usage, with both financial and ecological motivation, as well as being a physicist and genearl data nerd .
We burn way too much gas for heating and hot water, and I do want to upgrade to a heat pump... our boiler is twenty years old, so I'll be looking at that hopefully next year. I really hope I can get someone to make a reasonable calculation about the house. The MCS result I've been given would have the house interior at over 50 degrees with an outside temperature of negative four (based on multiple years of gas consumption and weather data). I think there has to be an arithmetic or more likely a measurement/assumption mistake, but they won't show me the calculations, so I can't see where the mistake is.

When we do that I'll be getting in a small propane tank to run the hob (because that will need running for some time (MrsBob hasn't yet come across an induction hob she likes, and we have access to a few), and some additional battery storage to help out through the winter.
If i'm right the propane will be cheaper than the standing charge for gas - so worth switching to, particularly since the hob manufacturer was kind enough to send me the nozzles for free (yes they'll need a corgi registered engineer to fit them).

[PDQ Mobile]

^^
Kind of you.
I will ponder when I get bit of space.

[Biospace]

Just having a battery combined with a smart meter & a flexible tarriff would enable you to shift load so you mainly/only use power from the grid when it's cheap (including sometimes negative).

Looking at the itemised quotes, just installing the battery and all its accessories etc comes to more than 50% of the whole quote including 14 solar panels. Which makes the panels themselves appear less expensive!

What’s more important though is to see what utility you’ll get out of the two different spends. It may turn out that the bulk of the utility gain is in the battery storage, cheap power from buying it in off-peak rather than generating stuff that you get next to nothing for when you sell. I’m wondering if big batteries is the better way to go - nearly never sell or give away your generated power - and note that in the winter months (when we most use electricity) solar panels generate very little so give no benefit. It doesn’t matter how cheap something is if it gives either no or only small benefit.

Should I have the misfortune to be disconnected from the mains due to a winter storm then having a large battery powering lights and (non-electric fuelled) central heating would be much nicer than a large solar array producing next to nothing.

Spending £10k on a battery and related equipment simply so you can cook on electricity and have hot water for two or three days seems questionable logic to me when lighting, communication and more would cost a fraction of the price (plus have a fraction of a carbon footprint) and last even longer. In a power cut when a smaller battery covers everything bar electric cooker and electric heating, if there's no wood stove then use a portable stove for cooking and an extra layer of clothing plus heated element throws, if a house is so poorly insulated and there is so little heat storage it doesn't stay warm for much over a couple of days.

There's a tendency for people to be convinced there is a need for many kWh of battery storage, which I believe is part of our consumption culture. Under £1000 of battery and inverter equipment is perfectly capable of powering lighting, internet, charging for mobile devices, laptops, a tv screen or two, a boiler and its pump for a considerable time.

As electric cars replace those with engines, there will be even less of a need for huge domestic batteries.

[[XAP]Bob]

If the sole aim is keeping networking/lighting in a power cut then yes you can deal with far less storage.

If you want to shift all your usage to a possibly variable time of day that helps the grid then… you’ll need more
And avoiding burning stuff is part of the point, so the boiler pump isn’t enough, the heat pump needs power..

[Cugel]

If the sole aim is keeping networking/lighting in a power cut then yes you can deal with far less storage.

If you want to shift all your usage to a possibly variable time of day that helps the grid then… you’ll need more
And avoiding burning stuff is part of the point, so the boiler pump isn’t enough, the heat pump needs power..

There's a range of motives in driving an acquisition of so-called "green" energy tech. They often get all jumbled up together so that the acquirer gets rather confused about what they're buying and installing; and why.

There's the desire to:

*not contribute to global warming;
* not contribute to particulate and other health-damaging atmospheric pollutions;
* avoid supporting the import or use of fuels that are inherently nasty-dirty but also support dirty-nasty regimes;
* be as resilient as possible against bought fuel/energy loss or unavailability by making one's own;
* save money by avoiding high (or any) fuel bills from often greedy and uncaring suppliers.

To serve all these motives in full, any fuel other than electricity generated "cleanly" and with as few (preferably no) middlemen as possible needs to be avoided. Relying on suppliers makes us a hostage to fortune. Relying on one's own non-e fuel gathering & use is damaging if the fuel is burnt, especially if what's burnt isn't renewed either (wood burning is as bad as burning oil or gas, in practice). ICE cars are killers in more way than one, via prang but also from the tailpipes.

Clean green tech costs money. But so does a set of new clothing or some furniture, neither of which will see a return if sold after long usage. A car costs a lot of money (more than a full set of heat pumps, insulation, solar panels, batteries and inverters) but few baulk at buying a £50,000 car, if they have the dosh for it, despite it depreciating to value nowt in a decade or a little more, with nothing to show but a fatter stomach, feeble-leg and perhaps a few scars from the "accidents".

Buying and installing clean green tech that costs little or nothing to run seems like a no-brainer, since the spend will be clawed back, one way and another, by the fuel savings compared to oily-gassy stuff no longer used. In many cases, a full clean-green tech installation will end up making the buyer-user financially better off than they would otherwise have been, with the same lifestyle as would've been run by oily-gassy, after only 6 - 10 years.

As ever, the bugbear is finding the capital to spend on a clean-green tech installation. But most who own a house can probably find a loan based on the house value they own that'll be inexpensive enough to still make it worth it. Or just stop renewing the SUV every year.

Landlords should be legally forced to make such improvements; or sell to those who can. Builders of new housing should also be obliged to include clean-green tech as the only option, since alternatives are now not just an economic choice but the source of a potential existential crisis that'll do immense damage to everyone and everything before very long.

Personally I feel quite totalitarian about the matter. The dominant and commonplace fuel usages now current are effectively a serious pandemic. Not inoculating ourselves with clean-green tech will soon see a death rate far in excess of that from a bit of bubonic plague, with no chance of a come-back if we don't change our ways reet-quick.

On the other hand, we humans are inherently incapable of being anything but self-centred little skinbags determined to have what we want right now. Nothing significant enough to change our impending doom seems likely to happen. For details, see stats concerning the still increasing extraction and use of oily-gas world-wide, not to mention the increasing acreages of non-productive land, degraded-beyond-recovery biosphere and several other doom-bringers..

[[XAP]Bob]

I would also be utterly totalitarian on new builds.

There is no excuse for any new build to be less than excellently insulated, designed to get as much solar as possible, and utilise it via heat pumps…
If you’re by a river or stream then hydro is well worth thinking about as well.

[Cugel]

I would also be utterly totalitarian on new builds.

There is no excuse for any new build to be less than excellently insulated, designed to get as much solar as possible, and utilise it via heat pumps…
If you’re by a river or stream then hydro is well worth thinking about as well.

Them builders do like to build of flood plains. Perhaps every front and back door should have a small hydro-electric plant in it?

My neighbour (a rather good builder, none of that ticky-tacky from him, no) has a large field that's part of the Teifi flood plane, along with various river rights. The Teifi passes only 50 or so yards from the bank above the flood plane field on which his house (and three sheds full of exotic building machines) are situated. He often talks of installing a small hydro gubbins of some sort in the Teifi flow, as that would give 24 hour generation albeit at a relatively low rate if the gubbins is to be small and unobtrusive enough to avoid interfering with the river's behaviour. But just one kw per hour, for 24 hours a day every day of the year, would soon mount up to a lot of e-juice.

He has solar on his large shed roofs but no batteries - yet. I've been working on him, by showing him the effects of being able to download and store overnight e-juice at a quarter of the daytime rate. His hesitation is because he has bottled gas and wood burning cooking/heating/ hot water, so to it would cost him a lot to replace all that with a heat pump and so forth to use free electricity electricity instead.

This is perhaps emblematic of a part of the wider issue about lack of adoption of clean-green energy generation & storage tech - it doesn't just cost to buy and install - you also have to install the stuff to use it and waste the oily-gassy-woody stuff that's replaced.

[ChrisF]

Hi, OP back again here. Thank you for all the replies, it's been an entertaining thread! I haven't seen much to dissuade me from going ahead with the purchase. And I've learnt a lot in the process (in particular, one reply led me to an excellent channel on YouTube - https://www.youtube.com/@GaryDoesSolar - which I'd say is essential viewing for anyone considering solar).

There is one reason in favour that I hadn't thought about when I wrote the first post. We have the capital. If it isn't spent, and both my partner and I die before the payback time (we are 71 amd 72 now) , that capital will go to our children, who will probably spend it on less green things (they aren't as green as us, surprisingly). If we survive until after the payback time then everyone's a winner

[[XAP]Bob]

Hi, OP back again here. Thank you for all the replies, it's been an entertaining thread! I haven't seen much to dissuade me from going ahead with the purchase. And I've learnt a lot in the process (in particular, one reply led me to an excellent channel on YouTube - https://www.youtube.com/@GaryDoesSolar - which I'd say is essential viewing for anyone considering solar).

There is one reason in favour that I hadn't thought about when I wrote the first post. We have the capital. If it isn't spent, and both my partner and I die before the payback time (we are 71 amd 72 now) , that capital will go to our children, who will probably spend it on less green things (they aren't as green as us, surprisingly). If we survive until after the payback time then everyone's a winner

There are a bunch of good channels, Gary is certainly one of them.

[roubaixtuesday]

I would also be utterly totalitarian on new builds.

There is no excuse for any new build to be less than excellently insulated, designed to get as much solar as possible, and utilise it via heat pumps…
If you’re by a river or stream then hydro is well worth thinking about as well.

Strong agree.

River hydro however has very low potential.

I walked past the National Trust scheme at Quarry Bank Mill today. That's on a decent sized river, in a gorge, utilising an already constructed mill race, so about the best possible location for such. It still only peaks at 50kw and averages not much more than half that, and cost nearly a million.

https://vinchad.blogspot.com/2015/04/qu ... cheme.html

So not a huge amount of power, and very few places will have anything like such a favourable location.

[Cugel]

I would also be utterly totalitarian on new builds.

There is no excuse for any new build to be less than excellently insulated, designed to get as much solar as possible, and utilise it via heat pumps…
If you’re by a river or stream then hydro is well worth thinking about as well.

Strong agree.

River hydro however has very low potential.

I walked past the National Trust scheme at Quarry Bank Mill today. That's on a decent sized river, in a gorge, utilising an already constructed mill race, so about the best possible location for such. It still only peaks at 50kw and averages not much more than half that, and cost nearly a million.

https://vinchad.blogspot.com/2015/04/qu ... cheme.html

So not a huge amount of power, and very few places will have anything like such a favourable location.

Small tidal generators could well become models for river-flow generators. They'd work in exactly the same way but with one rather than bi-directional flows. Of course, the amount of river flow locations that would be feasible would be very small. Still, those like my Teifi flood-plain neighbour could probably benefit.

How viable are small tidal generators? Probably much more do-able than large scale tidal barrages and the like .....

https://en.wikipedia.org/wiki/Tidal_stream_generator

https://interestingengineering.com/ener ... nerator-uk

The UK has a vast amount of tidal flow potential. And the energy density of a tidal flow is probably much greater than that of wind flow for the same cross-section of flow at the same speed. Tidal flow generators (underwater windmills) would also be much more protected from bad weather events and predictable in output than are windmills. They may also be more environmentally friendly - no fish-strikes; invisible to bah-humbug ole reactionaries who like their views of the countryside to be without the windmill - although they don't mind a zillion acres of green sheep-dotted desert.

[roubaixtuesday]

Small tidal generators could well become models for river-flow generators.

The rather small scale generator I posted uses a drop of 4m head, it's not a flow generator.

I would be quite astonished if the potential for river flow power is anything but utterly trivial.

The UK has a vast amount of tidal flow potential.

Quoted as 11 GW potential, but not yet demonstrated beyond low MW.

https://www.offshore-energy.biz/tidal-e ... ysis-says/

[[XAP]Bob]

River hydro however has very low potential.

You don't need all that much potential if you've got a reliably flowing river...
I've got 6 solar panels, which is about 10m^2 of panels - So in a year each m^2 generates ~200kWh, since there are 8760 hours in a year that's ~25W/m^1 average. The whole array is only 250W, and I certainly consider that worthwhile.

Ideally you want a drop somewhere, because that really gets some energy into the water, but an undershoot water wheel on a reasonably flowing river is an option (though not a subtle one).

[simonineaston]

I’ve just bought an inexpensive pocket multimeter with a view to testing the modestly sized panel up at the farm (0.5m x 1.5m) - any advice before I do it?
btw, anyone on the lookout for a good value multimeter, its a TIS 258, available online for under £20 and appears to be liked by sundry reviewers.

picture of multimeter