Dillsue

Where did you get the 2023 figures from? I've just looked at the N Scotland graph for the last 365 days and they don't go above 24p/kwh and the average looks to be low 20s??

For our MCS system only the MCS number for the panels is listed with no mention of the inverter so I suspect an inverter change won't matter to your MCS registration. Your DNO will definitely be interested in the new inverter to ensure its compliant with their grid standards, if its a change of inverter make/model. If the replacement inverter is the same make/model then you don't need to do anything. If its a change of make/model then you'll need to let them know the new inverters details and the new inverter will almost certainly need to be listed on the ENA database and be G98/G99 compliant. Check before you buy a new inverter! What's the original Inverters rated output? 16 amp/3.68kw or less? Changing the inverter is the same as changing a socket in the house ie anyone can legally do it. You only need a part P spark if you are adding or altering a circuit. If you were going to change the MCB for the inverter, change the supply cable size or increase the inverters power output, then you'd need a spark but a like for like change doesn't need a spark. Obviously work safely.

If your install has been done under G98, it's a notification that you need to do(have done) rather than an application- you tell them what you've done rather than ask their permission to do it. If your DNO is referring to a G98 submission as an "application", they're getting their wires crossed! If you Google G98 commissioning form, you'll find the commissioning form that you need to send them but it sounds like you've already sent it? Certainly for our DNO, SPEN, they don't seem to issue an export MPAN until all the paperwork is in place, they didnt for me at least! Last I heard from Octopus If you want them to buy your non MCS export you have to- pay them a £250 fee, get building control approval for the install, get a part P electrical installation cert, get a smart meter installed, get a confirmation letter/email from your DNO. With a 1.7kw system there's a fair chance its not worth it for the amount you'll export at 15p/kwh

Yep if you've got you're own and want to use it for luxuries like AC then fill your boots. But if you think the grids got plenty of spare solar on a sunny summers day that's a bit away from reality sadly

Unfortunately not. Have a look at gridwatch.co.uk to see how thin the yellow solar sliver is.

Google "Octopus tracker rate" and there's at least one website with the last year's rates.

You only know the future price 1 day ahead so you'll not know what a particular nights rate is until the day before. Historically I believe the tracker tariff has worked out cheaper than their standard variable price capped rate, but you take the risk that it doesn't stay that way!! I'm guessing that if the OPs use is only/mainly in the summer then there could be some quite low rates to be had??

If your going for a moveable array make sure you consider wind load when it's gusty. Maybe accept that you'll never protect from the odd tornado but consider stormy weather that may be getting worse through the life of the array

In fairness if they've not finished it may be abit premature to be critiquing the job?? Obvious things that stand out are- No/limited pipe clips to support pipework- it shouldn't be relying on the fittings for support No limited support for cabling- it shouldn't be dangling from the control box No pipe insulation Hopefully they'll sort everything out when they come back

The coffee cup left on the floor says it all

I have no idea if such a thing exists but have you looked to see if a Radwell type of sealant is available that may keep you running till the spring? A dose in the ground loops may seal things up temporarily??

With a multistorey house I'd definitely zone it based on occupancy. If your first and second floors are bedrooms only, there's likely no point in heating them during the day. We have the upstairs split from the downstairs and only heat the upstairs late evening and occasionally early morning. Rest of the time upstairs only gets what trickles up from the ground floor. You may need to slightly oversize ground floor emitters to account for bigger losses to the cooler upstairs??

OPs asking what he needs to run HP, EV and house which is likely way more than 10kwp for the period he'll likely need the HP running

Alot of money to extend your roof so you could have enough space for a small solar farm. Winter production is pretty poor when you need the juice the most so you'd likely need a massive array to keep pace with an EV, HP,living etc. Work out the load you want to power then look at PVGIS to see how big an array you'd need to power things for the time periods you want. Then see if that will fit on your roof

I didnt read the linked doc, but 4kwp for £8400 sounds very expensive even with data from MCS.

It's possibly getting "rerouted underground to the houses" so whilst it's almost certainly tingly it's unlikely to be jumping anywhere at normal domestic voltage.

I guess that was from an uninsulated HV cable at 132/400 thousand volts and not really comparable to the OPs domestic supply at 230/400volts. We've got 33000volt cables feeding our transformer and the DNO has recently renewed them giving only a couple of metres clearance for farm machinery to pass under them.

If you want to retain the HW circulating pump you could fit PIR movement sensors in the bathrooms and use those to start the pump as soon as someone walks in but definitely need to insulate the flow and return. You also want to get all that pipework around the cylinder insulated particularly all the tappings other than cold feed. For the tappings you want the thicker walled insulation butted right up to the cylinder casing and ideally shaped so its in contact with the insulation inside the casing. If any or all of your tappings are warm, youre losing heat 24/7!!

Could well be cheaper but may force you to have the shed/ pergola where you don't want it?? Other thing to remember is you're always better mounting panels as high as you can to stop/ minimise shading and lengthen the time the panels are in direct sun.

TBH if the cables are safe to work under I'd just get on and fit your panels. Panels aside, your DNO isn't going to restrict you accessing your roof to maintain it/fit a Velux etc so there's no justification to object to access for panel install. The bottom line is if the DNO is concerned about your proximity to the cables they shouldn't have run them so close over the roof. If the integrity of the insulation isn't certain, let your DNO you're planning to fit panels and ask them to shroud the cables whilst you work. Once they are aware there's panels under their cables they might prioritise shifting the cable??

It is, but best talked about quietly as Great Britain didn't get great by doing environmentally friendly things. I'd hazard a guess that if the UK was tasked with putting right it's wrongs we'd be bankrupt overnight.

Don't be too disappointed as PVGIS predicts 3470 kwh/Yr for us and our actual is 35xx - 37xx/Yr since 2015. The post you were commenting on was quoting a 1.9kwp system which is a modest system and pretty small if you're wanting to go off grid.

I wasn't aware of a time limit on our G99 approval but that's not to say there isn't something buried in the small print! It took our DNO a good 9 months to change a transformer so there's no rush on their side. If your part system is powered up and commissioned then the installer should have already sent the commissioning docs to your DNO so there'll be no clock ticking for you to add the remaining panels. If your roof under the power line is the best place for your panels then probably worth persevering with the inspectors visit on the off chance he gives approval for your extra panels

Assuming the original installer notified/applied to your DNO, then the only red tape/certs you need to bother with are getting a part P spark to check the wiring before you connect it to the inverter. You can install it all and just get your spark to check it if that's what you want. You don't say whether the coiled up cables are connected to the inverter via an isolator? If they are connected directly just be aware that they may be live with several hundred volts on them depending on how things are wired. If there's no isolator you might want to get one fitted before you start working with the coiled cables.

Google EPA section 82. Normal route is via your local authority and section 80, but it can take an age and the LA have to witness the nuisance. As they only work office hours you'll not get far with smoke from a neighbour that lights their fire at 6pm or has a bonfire every Sunday morning. Section 82 is the DIY route.