The Solar Thread

interest free loan over 10 years supposedly. “Home Energy Scotland application” … – but their email has energy savings trust…. takes a bit of digging on google and then a nonsense half hour phone call with someone asking if you have energy saving lightbulbs etc – they then send you a code and a link by email, which you need to do the application.

Application needs a quote from an MCS approved installer – they have a list of people…

i invited 4/5 of them to quote – still trying to work out if the quotes are good value or if they are pricing to max out the spend of the loan.

one sent a “quote” = £6k for solar and £6k for batteries to get ball rolling and said they would send a propoer quote once we had desired spec in mind for battery and panels etc

thanks, will have a look! EDIT: looks like Scotland only for that one.

Will batteries continue to make sense for next 10 years? More chance of rates rising than falling or will wholesale market adjust to renewables?

the questions i asked my self is – what has the goverment done to secure lowering of energy prices – our infrastructure is ageing and sufficient replacement capacity is not yet in the pipeline it seems.

They have cemented in plans to increase consumption by significant multiple of current values ( electric cars and phasing out of gas heating replacements)

adjustment to renewables will likely take form of time adjusted pricing to suit the volatility of the generation.

the reading on all of those said batteries were a no brainer in my risk vs reward – and if im wrong – so be it – I’m still getting more use of my solar panel power than i otherwise would have.

one sent a “quote” = £6k for solar and £6k for batteries to get ball rolling and said they would send a propoer quote once we had desired spec in mind for battery and panels etc

I can see why, it filters out anyone who isn’t in the right ballpark. Our system cost £12k and was pretty much split 50:50 between solar and batteries (panels are cheap, but labour intensive to install and need scaffolding etc). Batteries are easy to install, but are expensive.

They also need to filter out anyone who doesn’t have suitable roof space and orientation e.g. if you’re North facing, there’s bugger all point installing anything…

Octopus users, has anyone tried switching between outgoing octopus and octopus go on a summer/winter basis. Wondering if I can have my cake and eat it. So get the better export during the high production months then force charge the battery for less in the winter.

Yep, you just need to stay on your tariff for 30 days. The gamble you take is that your good tariff is gone when you try to move back, but Octopus are surprisingly un-evil when it comes to this.

Just joined and gone more or less straight onto Agile. Waiting for an MPAN to start exporting. Will probably go onto flux when it comes through as the export prices outweigh the higher import prices i think.

My understanding is not that you have to stay on the tariff for 30 days, but that once you switch to a smart tariff, you cant switch to another within 30 days. you can go back to the standard tariff whenever if that’s better for some reason.

I hadn’t come across flux before this morning but it looks to fit better for us than go or outgoing. I think we can easily avoid the peak charges and the day time export rate is much nicer. Have signed up to that for now to see how it goes.

Hi solar thread peeps! I have to confess I haven’t read all 20 pages, or would understand about 50% if I did. However I come with a question and I am sorry this has already been done. I live on a council estate in sunny south london. We are blessed with shallow south facing roofs and a row of garages with flat-ish roofs that get sun. What I need, on behalf of our tenants management firm, is a proper itemised quote and consultation, ideally for free, for installing panels and a worked out program fr how to manage the energey we produced. I have tried one or two local community enterprises but they aren’t on it. There’s around 350 residences, but even if we powered the office for free that would be a start. Please get back to me if you can help or know who can

I think there’s so much demand for solar at the moment it’s unlikely you’ll find an installer with the goodwill and time to do something more complicated than a standard quote. Although I’m not really sure from your post what you are looking for. Feels like there are complications like who owns the building, who pays for the installation, who benefits from the electricity generated etc.

Yep, you just need to stay on your tariff for 30 days

100% not the case when you port to them. It’s just if your switching between their smart tariffs

I moved from OVO to octopus on April 4th. I was on flux incoming by the 8th once they had fully ported my smart meter.

Went live on flux outgoing last week also according to their emails.

April figures: 5.4kWp array, SSE facing, 30deg incline, 19kWh of battery storage, little to no shading.

597kWh generated. 510kWh used. 44kWh imported (3/4 of this was car charging), 157kWh exported. Power cost £13. Standing charge £15. No export payment 🙁

Currently moving to Flux, which for the amount exported this month would have netted ~£34 so we’d have been cash positive.

Bar for the 3 days of partial car charging and little bits each day (~0.2-0.7kWh from power switching) we’ve been off grid for the whole of April. Win!

We’ve exported 275kWh (of 514 production) this month and got paid 0 for it! Flux outgoing still processing (though to be fair the new smart meter was only fitting half way through the month).

Beginning to wonder if we should have specified a bigger inverter as been seeing clipping and also short periods where we have battery charge but still pull from grid as load is over 3.6kW. Still trying to get battery profile control. I think this could help with the clipping as I think I could set it up to prioritise export more on sunny days so the battery charges slower.

Looking at the graphs the battery is worth it. Around 45% of our consumption comes from the battery, a greater portion than direct consumption!

Does anyone know of devices other than batteries that can be installed on the DC side (solaredge system).

Beginning to wonder if we should have specified a bigger inverter as been seeing clipping and also short periods where we have battery charge but still pull from grid as load is over 3.6kW.

It’s why some people fit things like the Zappi charger and Eddi hot water diverter. Otherwise it’s an education thing – don’t run the washing machine / dishwasher / oven simultaneously. I decided that spending £1,500 on them was a bit of a waste and bodged together something with Home Assistant and a Sonoff 20A remote switch, especially now that oil has fallen to 60p/litre.

Apart from using an electric hob it’s quite difficult to exceed 3.7kW continuously, especially as the inverters are allowed to spike up to 4kW for short periods?

It’s the oven + 5 ring induction hob that causes the spikes. In fact the hob in its own can pull more than that. Doing quite well at the other bits, have switched most dishwashing and all clothes washing to quiet usage periods.

Beginning to wonder if we should have specified a bigger inverter as been seeing clipping and also short periods where we have battery charge but still pull from grid as load is over 3.6kW

bigger inverter would likely have been clipped by the batteries.

remember that if your making sun then most decent hybrids can do 3.6 from the solar and 3.6 from the batteries.

”

It’s why some people fit things like the Zappi charger and Eddi hot water diverter. Otherwise it’s an education thing – don’t run the washing machine / dishwasher / oven simultaneously. I decided that spending £1,500 on them was a bit of a waste and bodged together something with Home Assistant and a Sonoff 20A remote switch, especially now that oil has fallen to 60p/litre.

”

Not gonna lie – was having slightly cold feet over my Solar thermal install with the oil prices but at the end of the day – it will still be cost neutral one da + the tanks now in place.

got my batteries updated mid month so my utilisation is up now – with 5kwh only i found i had to charge in the 19pence period or i was out before the sun could catch up. New firmware and my batteries have stopped throwing errors and self limiting to 500w – solved by shutting down the second battery short term.

We got 406Kwh from our 3.6Kwh array for April – not had to import other than for our electric shower since my batteries were updated.

remember that if your making sun then most decent hybrids can do 3.6 from the solar and 3.6 from the batteries.

Is that with AC coupled batteries? Our battery is DC coupled, the AC output is limited to 3.6Kwh whether that is coming from the array or battery. It can output 3.6 with everything else going to the battery but that is only good till the battery is full. With very little load the battery appears to be able to take charge at whatever rate the array produces (have seen 6+).

I imagine we could get better consumption and generation with different settings but the solaredge all does not yet give that control.

Bar the 1st April, which was really dark, we’ve been 100% self sufficient last month. 372 kWh from a 3.8 kW array.

Still owed Octopus £5 though as our export didn’t wipe out the standing charge fully. Had we been on their fixed 15p rate, we would managed to, so will change as soon as I can figure out how to – can’t seem to find the option on their webpage.

@footflaps. The flux tariff may be even better for you as well export can be 20 or 30p

ah yes – mines AC coupled via a hybrid inverter.

I probably shouldn’t be able to do 3.6 + 3.6 but im not going to complain about it……

Hmm maybe be a useful future enhancement to add a smaller ac coupled battery for the spike loads.

I decided that spending £1,500 on them was a bit of a waste and bodged together something with Home Assistant and a Sonoff 20A remote switch, especially now that oil has fallen to 60p/litre.

Ah, that’s first on my list when we get panels.  Dumping energy into our hot water tank is a clear winner.  Will need to look up that switch

We don’t have a hot water tank currently so dumping to water would have a high upfront cost.

Ah, that’s first on my list when we get panels. Dumping energy into our hot water tank is a clear winner. Will need to look up that switch

We haven’t bothered.

The kit is nearly £1000, which is a lot of hot water and the fact it’s going to be quite random and require us remembering it’s been overcast, so we have no HW, so have to switch on the boiler to have a shower after a ride, would be a bit of a PITA.

Unless you have a massive solar array and live somewhere with no clouds, in which case I can see it working….

Flux has really changed the economics of solar/storage/thermal. Before it was almost a given that you should use as much power as possible, now it’s practically even to simply export/import unless at peak times.

Interesting tidbit. Yesterday, at its peak, solar power was contributing 9GW of power to the grid. Almost 30% of demand. Power was so cheap that we were essentially buying it from France at the cost of transmission.

yes ive just moved from bulb to octopus and they are giving me 15p per kw export. Im really happy with that. Not sure how long it will last though. How come its so much more than the usual 3-5p?

I fancy a water heater as the battery is full by 1pm so it would be used. however it seems expensive.

The kit is nearly £1000, which is a lot of hot water and the fact it’s going to be quite random and require us remembering it’s been overcast, so we have no HW, so have to switch on the boiler to have a shower after a ride, would be a bit of a PITA.

Unless you have a massive solar array and live somewhere with no clouds, in which case I can see it working….

It’s not random to be honest.  At one house we have a 4kwh E?W system and I’ll soon be turning off the boiler completely as it easily does all the hot water for two of us throughout the summer period.

We’ve just been away for 6 days and the boiler didn’t come on once.

At the other place we have just 3Kwh but it’s S facing and it too does all the hot water from April to October – in fact there’s isn’t even a boiler there!
I may have to boost it twice each summer but that’s only when we have a house full.

But £1000…Really?  That’s insane!!

ive just moved from bulb to octopus and they are giving me 15p per kw export. Im really happy with that.

Awww, sweet.  My export is currently 60.25p/Kwh…… 😛

Sorry 😉

whats your on peak import?

whats your on peak import?

22p – still on a fixed rate until October.

Flux has really changed the economics of solar/storage/thermal. Before it was almost a given that you should use as much power as possible, now it’s practically even to simply export/import unless at peak times

Given we have many wet dank days with poor solar I can’t get this to add up for me, currently on tracker tariff for E&G and 15p export.

Elec tracker is 18.74.

Flux is around the 32p are you relying on export to offset the the higher import over the longer term?

import

export

thats fab, What will it go to after October and what tariff are you on?

Oh probs 50p !!!

Flux is around the 32p are you relying on export to offset the the higher import over the longer term

That is the idea. Use battery through the peak period and then hopefully the export will pay for any import when averaged out. Use cheaper period to fill battery in the lean months. I’m not getting paid for export yet which is annoying now we are generating much more than we are using (paperwork apparently).

what tarrif are you getting that export from as id like to move to it 🙂

Average generation in April was 22kWh, average use (for us) was 15kWh. That’s 210kWh of additional power. Later Spring and Summer the generation will be better, but still, this is worst case. The difference between import and export on Flux is around 11p/kWh. So, assuming a small battery to avoid the peak, the difference in price from small to large battery is £3500-£4500. Assume you do generate 22kWh average, store 5kWh of that, use 5kWh of that (directly) and export the remaining 12kWh. That’s an export generation payment of £80, but you’d then need to import 7-8kwh at other times, so that’d cost you £72. So you’re cash positive AND you’ve saved £3k-£4k on on battery. This makes the ROI on a bigger battery only really making sense in the duller months by charging off peak. In those months you’ll maybe need 20kWh, you’d generate maybe 5-6kWh, so you’d need to import 14kWh, doing that off peak saves you £1.60 a day, for 90 days, that’s £150 of additional cost a year. That’s 23years to pay back the investment on a bigger battery!

Can someone more knowledgeable than me help me out with this one? I’m currently in the process of buying a new house which has a gas boiler and a hot water cylinder. My instinct would be to rip it all out and put a combi in as i hate the thought of using gas to heat a whole cylinder of water just to wash my hands (it has an electric shower). I do like baths though.

So would it be better for me to put a combi in or should i get solar PV on the roof and connect it to the cylinder to keep the water temp topped up? I think the costs of installing either system would be broadly similar (I’m not thinking of batteries at this point).

At the moment, you’ll have an indirect cylinder and for PV heating, you’d want direct, or better still, both. I’m not sure if the cylinder can be adapted to take an additional coil. @Trailrat might know?

Regardless, solar PV + Diverter + new cylinder (maybe) will be more expensive and the ROI will be poor. It will be more future proof, but expensive.

We have an oil combi, solar PV and are going to be putting in a hybrid direct/indirect unvented cylinder this year. But the solar + the tank (ignoring batteries) will be £8-10k.

My simplistic notion was that the PV could run the immersion heater somehow (I’m assuming its got one)?

an insulated hot water tank loses very little heat, so whilst you are heating the entire tank you’re heating it more slowly (which is more efficient), from an efficiency perspective there’s not much in a combi vs tank.