4-5kw solar PV: advice please!

Martyn1981

ahw23 wrote: »

So what I'm going to do is chase the contractor who ran away without quoting and contact the one recommended by Tunnel, but first of all email the one with the best quotation, explaining that now my OH has crunched the numbers over the weekend, we think we can't justify that price per kw, and in any case would benefit from a larger system. That puts the ball in his court and the worst he can do is say no.

Hiya, all good thoughts. To help with your haggling, I've done a very quick PVGIS check. I didn't do it properly, just put in your postcode, then put 5.1 in the PV size box, 30d in the pitch, and -90 in the orientation. I slapped it all as due east as it will mostly balance out, so gives a decent starting point.

That came out as 3,980kWh pa. The current FiT is 4.18p/kWh and the export is 4.91p/kWh (50% deemed), so a total of 6.635p/kWh.

So income of 3,980 x 6.635p = £264
Leccy savings of around (£80 to £160) = £120
Total £384 pa

£6,295 / £384 = 16yrs

Inflationary uplifts will balance out lost interest, but there could be a replacement inverter (£800?), so economically (alone) not brilliant, and that's if you can get 5.1kWp for the old 4kWp price. Upgrading the SE inverter warranty from 12yrs to 20yrs is about £200 I think.

So long as you're happy that it won't be a gold mine, and you appreciate the green & ethical bonuses* then £5.5k would be a decent price, perhaps?

*Over the first 20 years you'd hopefully displace 80MWh of gas generation, and could be running for 30-40yrs.

ahw23

He called back this morning to explain that we should expect the price to be higher because of (in no particular order): premium panels & inverter, Brexit having made American/German imports more expensive, using two sets of scaffold (front and back), the knock taken by the industry since domestic demand collapsed in the wake of the FIT cuts. He is going to go and consider whether the 17th an 18th panels have to be as expensive as the 15th and 16th (for which we apparently required an inverter upgrade, even without going for one above 3.6kw).

ajbell

You can do better than £80 - £160 a year savings.
I save about £300 a year on elec and may be £50 - £100 a year on gas with my solar panels.
I save on gas as I have a diverter that sends excess power to the immersion and then an oil filled radiator.
I try to export as little as possible.
Only exporting now in the summer.

Martyn1981

ajbell wrote: »

You can do better than £80 - £160 a year savings.
I save about £300 a year on elec

It's important to make sure you don't mislead though. Personally we save about £170, but I'm careful and do have a largish system.

The full paragraph from the PV FAQs that I quoted from is:

3. Savings on your electricity bill. Consuming electricity that is being generated by the PV at that specific time, will save you importing as much electricity from your energy supplier. The amount of savings will depend on the size of the PV system installed, how much electricity you use, and importantly, whether there is much electrical consumption during the working day, when the PV is generating. Savings will vary from household to household, but could be approx. £120 (probably in the £80 to £160 range). Larger savings are possible, but will require higher daytime consumption.

If you have a big system as ahw23 is considering, are home during the day, and have relatively high leccy consumption, then larger savings are of course possible.

But if nobody is home most days, and leccy consumption is more average (ours is about 3,000kWh, or 1,500kWh import after PV consumption), then savings of £200+ will be pretty hard, even with a big system or big generation.

Martyn1981

ahw23 wrote: »

He called back this morning to explain that we should expect the price to be higher because of (in no particular order): premium panels & inverter, Brexit having made American/German imports more expensive, using two sets of scaffold (front and back), the knock taken by the industry since domestic demand collapsed in the wake of the FIT cuts. He is going to go and consider whether the 17th an 18th panels have to be as expensive as the 15th and 16th (for which we apparently required an inverter upgrade, even without going for one above 3.6kw).

Hiya. UK PV is a bit of a mess now.

However, most of the cost of scaffolding is in the two journeys. Whilst they will want more for a second setup, it won't double the cost.

PV panel prices are falling, however the weakening pound has probably had an effect. Panels represent about 30% of the install cost for domestic PV. Hopefully the MIP (minimum import price) which has set a price for Europe (to protect it from cheap Chinese panels!!!!!!) will end soon, as prices outside Europe are tumbling, making our protectionist measures look daft.

Yes their business has fallen, and the supply chain has probably lost market scale, but surely they now have fully trained staff who need work?

Lots of pros and cons, but hopefully you'll find something. It's just a shame that things have been messed up so badly this last year, all for the sake of having a sensible FiT of perhaps 6 to 6.5p/kWh, allowing the industry to reach maturity.

ahw23

Quotation just in from Tunnel's recommended supplier:
£6429 for 18 Solarworld panels + SE. They also offer some cheaper panels, but that takes production down below 5kw, without taking price down much below £6k, so there doesn't seem to be any proportional gain. I haven't time to do a proper comparison right now but I'll try to review it this evening. This does sound a better offer, although I feel more comfortable with a company who've actually looked at the house and had a good talk about it before quoting.

tunnel

Martyn1981 wrote: »

PV panel prices are falling, however the weakening pound has probably had an effect. Panels represent about 30% of the install cost for domestic PV. Hopefully the MIP (minimum import price) which has set a price for Europe (to protect it from cheap Chinese panels!!!!!!) will end soon, as prices outside Europe are tumbling, making our protectionist measures look daft.

It's a shame we're not shot of the EU just yet, imagine their faces if we could buy panels at a fraction of the cost that the rest of Europe have to pay.....

tunnel

ahw23 wrote: »

This does sound a better offer, although I feel more comfortable with a company who've actually looked at the house and had a good talk about it before quoting.

Obviously it's a fair trek down to you and they will probably initially quote from your postcode and house number. Get a dialogue going with them first and then ask if someone could come out,
Just tell them you want the house surveying properly before proceeding.

ajbell

Martyn1981 wrote: »

It's important to make sure you don't mislead though. Personally we save about £170, but I'm careful and do have a largish system.

The full paragraph from the PV FAQs that I quoted from is:



If you have a big system as ahw23 is considering, are home during the day, and have relatively high leccy consumption, then larger savings are of course possible.

But if nobody is home most days, and leccy consumption is more average (ours is about 3,000kWh, or 1,500kWh import after PV consumption), then savings of £200+ will be pretty hard, even with a big system or big generation.

Yes I understand.
I have made a point of trying to maximise the gains by reducing the Base load of my house to the minimum, A rated appliances, led, etc and using a diverter to heat my water and a radiator.
Also charge everything during the day and use laptops on battery at night.
Got my comsumption down from 13000 gas, 3500 elec to 8000 gas and 900 elec.
My fit payment is now greater than my dual fuel bill.
£600 fit and £456 dual fuel.
Could probably do better as in the summer I still export and pay standing charges when I don't consume any gas and electricity from the grid.
I need a lower standing charge in the summer and something to do with the excess electricity, any ideas? .

ahw23

I think I'll get on the phone to them again tomorrow and see if they can come out to visit. I don't think we can come to any conclusions about how much electricity we'd save, as there are too many variables. Our current usage is higher than I'd like- about 14-15kwh/day, not all of which I can account for (as our monitor broke at some point during the move). Hopefully, some of it is the electric shower, which wouldn't be so much in demand if we had iBoost and a mixer, and some of the rest comes from the insane incandescent/halogen bulbs left by the previous inhabitant. At the moment, there's someone around all but 2 days of the week, with plenty of cooking (all electric) and laundry (ultra-efficient brand-new machine) going on. We should also be getting an electric car pretty soon but would need to charge it on weekday evenings some of the time. It's possible that I will up my work schedule in 2 years time when the family member generating the dirty laundry and eating the hot meals heads off to school, but it's not definite. Even if that happens, we can probably still set dishwasher and washing machine on timers.