5 Min Survey at Customer's House

[BruceB]

They go into a tripower and I have not been recording performance of each side separately. It is on my list of things to do if I wind down work and take up hobby electronics! I suspect the MCS tables are reasonably accurate to compare performance.

 

[Ian-LS]

Just done a quote for a customer which will save him around £425 off his electric bill, his electric bill is around £3000 mind but its all electric heating so massively higher bills than normal. This is on a west south west roof and a east north east roof.

 

[SRE]

I'm a bit confused - is that a 4kwp system, how can he save so much? Surely he's not running the central heating in the Summer? Has he got something that uses a lot of electric in the summer? Working on 15p/kwh cost that's 2,833 kwh but the majority of that will be generated during the Summer months when there won't be any heating on. Have I missed something?

 

[T0RN4D0]

I don't know how these things work up there. Down here, they are viable because we're all paying for them. You sell all the energy you make at about three times the price you buy it back and then use it. Which means it costs 5 times as much to make then the one from the dreaded nuclear plants.

Im sure north side panels are economically feasible, especially for the guys selling and installing them.

 

[Ian-LS]

Its a 6 kWp system limited to 3.68 kW with less than 1% losses due to the differing orientations and 30 degree angle of the roof. The peaks of the two arrays will be early-mid morning and mid afternoon lending itself well to self consumption.

Its difficult to be precise on the expected savings but with annual consumption of 20,000 kWh a good chunk of the PV system will be used on site.

Usually I would expect savings to be in the £150-£200 mark with customers with average size electric bills.

 

[Ian-LS]

This is the expected performance of PV at different orientations and roof angles. Bit of education for you TORN4DO

 

[SolarCity]

I don't know how these things work up there. Down here, they are viable because we're all paying for them. You sell all the energy you make at about three times the price you buy it back and then use it. Which means it costs 5 times as much to make then the one from the dreaded nuclear plants.

Im sure north side panels are economically feasible, especially for the guys selling and installing them.

Please stick to subject.

Feel free to start another thread if you want us to correct you on your common misconceptions about solar power.

 

[SRE]

Interesting, what sort of kwh are you projecting?

We always quote lower savings, that's not to say others aren't right but I work from home and use about 30% of what I generate and I try hard to match consumption with generation. My consumption pattern just doesn't match generation. Mine is bumped up a bit with underfloor heating in the kitchen but I've yet to be able to get pv covering it's cost and a glass kiln - I'm too busy in the Summer with solar to utilise the kiln during generating hours.

I explain this to our customers - for them it's real world data, in their area and if they save more they just get a quicker payback.

 

[Ian-LS]

4,530 kWh per year so its only 755 kWh/kWp but design is based more on spreading the generation throughout the day than getting the highest kWh/kWp possible.

Its perhaps an area that needs further data for people to use. I know one of the rent of roof companies surveyed all the customers with 4 kWp systems on south facing roofs to see what percentage of the PV was being used. Think it varied between 25-50% from memory.

 

[SRE]

Yea, EST's survey found 25% was the "norm". Found it quite interesting that on a certain Facebook page a certain Rent a roof company has quite a few posts from customers about how much their fuel bills have been cut. There's nothing wrong with this (and I'm not for a minute saying it's the company's fault) but having dealt with fuel bills and debt for almost 25 years I understand how few people actually understand their bills.

When I see that someone has reduced their bills by £50 a month it's clear that the customer doesn't understand that this is because they have either over paid their electric or the meter readings have been over estimated. Looks great for electric savings but doesn't reflect the reality.

 

[Worcester]

It's a small commercial swimming pool rather than a luxury private one - it's part of a farm diversification project. Problem is it's competing with the cost of biomass which will save more, quicker and then he'll have the cash for pv - that's what I've advised him to do, along with voltage optimisers for the pumps. He's got other projects he's doing as well so he's having to prioritise.

I'm pleased he's now got some decent information to make his decision with even if it means we don't get work from it. I haven't done the full quote but it probably does pay off with a low interest loan but to as quickly as biomass - he's cutting his oil bills by 40% even without the RHI.

Gavin - I'll have you know we had a whole hour of sunshine today! It was a record though lol.

Biomass for the swimming pool is a no-brainer, the (Commercial) RHI he'll get for that will easily pay for it, on top of that he could get paid to heat the homes as well. (Glad we diversified when we did) He should / could also consider solar thermal for the pool.

 

[Worcester]

Its a 6 kWp system limited to 3.68 kW with less than 1% losses due to the differing orientations and 30 degree angle of the roof. The peaks of the two arrays will be early-mid morning and mid afternoon lending itself well to self consumption.

Its difficult to be precise on the expected savings but with annual consumption of 20,000 kWh a good chunk of the PV system will be used on site.

Usually I would expect savings to be in the £150-£200 mark with customers with average size electric bills.

Hi Ian, remember based on the new MCS and Ofgem interpretations even limited to 3.68kW he'll only get the 4-10kWp tarrif (I know it's not a big difference these days)

 

[Ian-LS]

oh yes I know that Worcester. We've been quoting on the 4-10 kW feed in tariff rate with anything over 4 kWp since mid 2012 due to OFGEM. With the small difference in feed in tariff rates it makes sense to go over 4 kWp more

 

[Gavin A]

Hi Ian, remember based on the new MCS and Ofgem interpretations even limited to 3.68kW he'll only get the 4-10kWp tarrif (I know it's not a big difference these days)

for high energy users we tend to work on it becoming economically viable above about 4.5kWp, with 4-4.5kWp being the no go zone, and most being 5kWp for south facing, or 5.5-6.5kWp for east / west, roof space allowing, all within the 16amp AC output limit.

The drop from 21p to 16p FIT for 0-4kWp systems really meant that theses systems became economic from that point onward, which was partly why we gave up on our attempts to get ofgem to see reason on the TIC issue.