Solar PV for a very non standard install

Irish Steve · 01-04-2022 4:40pm #1

So, in a nutshell, for all sorts of historic reasons, the electric system here is very much not a standard single phase domestic installation, I have 3 phase power, and a fully automatic standby generator that's ready to go 24/7, and operates without user intervention. There's also a single phase UPS, though that's not operational at the moment, it originally went in to be available for a server, but that project fell by the wayside as a result of the financial crash, so it was never comissioned again, and the batteries were eventually recycled for scrap value due to their age.

Incoming supply is on a day/night tariff, not smart metered, at present Bord Gais, but that may be changing soon due to the way prices are going. We're on domestic tariff, but technically, because of the extra equipment here, back in the day, the ESB determined us as a commercial installation, due to the generator and changeover system. Either way, Solar could be connected without touching the existing distribution panels, and they can be 100% isolated due to the extra switch fuses needed because of the changeover relays that are required for ESB Network isolation because of the generator.

The interest now is Solar PV, but it's very much a case of trying to work out what would have to be changed in order to be able to ensure that we can keep the house alive in the event of a failure of ESB, from PV batteries, or the generator as appropriate, and ideally, if I can get to the point where we're off grid for long periods, either by charging the batteries from the panels, or by using night rate to top them up, even better, and the fact that we also have the generator as standby is just a bonus, it's not costing me anything significant to keep it there, and it for sure has proved its worth over the last few years when the incoming supply has dropped out for whatever reason.

The existing UPS is not new, and could be replaced by a more modern Solar system very easily, it all depends on exactly how it all has to be set up to get the best return from the whole system. In theory, we have space for up to 30 panels, the dormer flat tiled roof here is 20 Mtrs long x 10 mtrs from eave to ridge, and facing south south east, not shaded.

If we can do it without too much hassle, I'd be also looking at export to the network, but that's going to depend on how the feed in tariff is structured, I'm not overly confident that Minister Ryan has any intentions of making it easy or worthwhile for Solar users to get any advantage from exporting back to the grid, if anything, I can see him penalising solar users for having the sense to upgrade in the first place, and don't get me started on the shambles of his SEAI schemes, they're definitely loaded in favour of the suppliers and installers.

So, the question for all the experts on Solar out there, what's the best way to go forward with this?

The attached PDF is a pictorial representation of the important parts of the distribution system that's in place at the moment.

ESB_supply_map.pdf

the_amazing_raisin · 01-04-2022 9:21pm

Okay, I have to ask, what the heck are you running that needs 3 phase power? 😁

I think it might be worth taking a look at Victron Energy stuff, they've got equipment for bigger installations like what you've got and they have 3 phase options

However, they're not hugely supported in Ireland, I only know 2 or 3 companies that supply their gear

Irish Steve · 01-04-2022 9:36pm

The 3 phase goes back to the early 90's, I had a small mini computer in the garage that used 3 x 300 Mb exchangeable discs, and they needed 6 Kw of power for start up over a 30 second period, and that was for each drive, and the local ESB man said to me when I went in to get things sorted, "Not on single phase you don't", so 3 phase went in and solved the problem. Now, I can have 60 Gb of data on a chip the size of my thumbnail! Times have definitely changed!

The 3 phase has stayed in ever since, even after the computer went, as it means I can do things like run a small Mig welder without surging all the equipment in the house, by using a different phase, and I have a 3 phase pump that was used in emergencies to move large quantities of water to avoid the house being flooded. I also have a small 3 phase lathe, which runs more smoothly on 3 phase than it would on single, and reversing the motor on 3 phase is a lot simpler.

Now, with feed in and electric vehicles coming before too long, I have no intention of letting the 3 phase go, unless it gets horribly expensive to retain it, as that will mean that more than one car can be charged if needed, among other things, and it seems I can also benefit from being able to feed in a lot more power than if I was on single phase.

I can have a look at Victron, and see what they offer, thanks for that, I already know that quite a few suppliers won't have a clue when the standby generator is added into the mix, as that's just not a normal domestic item.

Solar PV for a very non standard install

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