Free solar power system. Is it a scam?

Cardew

XRayDave wrote: »

HI Cardew,

Just trying to figure actual savings - but based on just one month's PV oytput, this is somewhat difficult.

Normal yearly electricity consumption (going by last year's bill) was 10800 kWh. Divided by 13 (and here's where the assumptions kick in) that gives 830.7 kWh/4-week period (aka a Rolls-Royce Month).

Panels have produced just about 400 kWh during the 4 weeks of June (2nd - 30th). (400/830.7)x100% = 48.15%

Now my assumptions here are that the electricity usage will be roughly the same throughout the year. We don't tend to use supplementary heating in the Winter as electrical heating is expensive compared to GCH. Granted that in Summer we will use less lighting (longer days) and less heating overall, and probably less cooking using the oven - but probably not by much.

As I stated earlier, this is just a projection to give me a "take" on a typical saving. It remains to be seen how accurate this turns out to be.

Hope this helps,

XRayD

XrayD

Sorry to say your 'take' on saving is just not correct.

You have made the assumption in your calculations that you have used all of the 400kWh generated by the PV panels during June in the house and nothing was exported.

Most people, even with much smaller systems than yourself, will use between 40% and 50% of the generated electricity in the house - averaged across the year - and export 50% to 60%. This post in the other thread from someone with an export meter is quite typical.

Since having an export meter fitted on 14th September 09, I have generated 909 units, 443 of which have been exported (48.7%) - this figure is likely to rise slightly over the next few weeks as we are generating so much more than we need at the the moment. For those electric companies offering to guestimate it at 50% rather than fitting an export meter, they know their stuff!

So he has used 466kWh in the house in 9.5 months and he has a wife(and kids) at home all day. So he can only use about 50kWh a month.

He comments specifically that if he had your ASG system he would only be able to use about 15% of the electricity produced in the house and 85% would be exported.

The problem is that the electricity produced by the panels is low in the mornings and evenings and then rises to nearly 3kW near noon at this time of the year.(as you stated yourself) and you simply cannot use it all.

You would be doing extremely well if you used 100kWh of that 400kWh you generated - and that is twice as much as McFi5 whose example I quoted above.

The only way to know how much you have used in the house(and thus calculate your savings) is to have an export meter to be used in conjunction with your meter. e.g. 400kWh generated, 300kWh exported, so 100kWh used in house.

Look at posts #289 and 290 in this thread.

John_Pierpoint

1. Does anyone have Economy 7 and a Solar PV system?
Presumably having two import meter readings makes no difference (apart from the extra possibility of "clerical" errors- my unlucky (?) experience with the electricity supply industry is that "what can be messed up, will be messed up" sooner or later = make sure you keep all bills and your own meter readings and be prepared to argue the toss, when you get incomprehensible bills. ).

2. Has anyone, already on a FiT contract, tried switching electricity suppliers (am I right in thinking the FiT kickback is received on an annual basis or is it quarterly?)

3. How does "A shade Greener's" claim for the FiT kickback work - are the SMS readings supplied by the meter acceptable for the FiT claim.

XRayDave

Cardew wrote: »

XrayD

Sorry to say your 'take' on saving is just not correct.

You have made the assumption in your calculations that you have used all of the 400kWh generated by the PV panels during June in the house and nothing was exported.

DARN,

You are quite correct of course, I'd overlooked that in my excitement!! I will be bound to be exporting some juice! Thanks for pointing that out Cardew.

The PV System of course includes an export meter (ASG refer to it as a Generation Meter??) - I assume I am correct in this? Trouble is, the readings on this meter are incomprehensible to me - lots of cycling numbers which seem to make no sense at all. I'm sure that the total output generated and the amount exported will be in there.

Because I couldn't make sense of it, I have used an Energy Meter on the live feed from the PV inverter to the domestic electricity meter which seems to give me a fairly accurate figure for the panels.

Looking at the domestic meter itself, either the disc is hardly moving at all - and by this I mean virtually stationary - or just creeping forwards - unless, of course, someone is taking a shower or pops the kettle or washing machine on. Sometimes it even runs backwards - although nit often it has to be said. I'm sure my fascination with the meter will wane after a while.

Kind regards

XRayD

XRayDave

John_Pierpoint wrote: »

3. How does "A shade Greener's" claim for the FiT kickback work - are the SMS readings supplied by the meter acceptable for the FiT claim.

Hi John,

They must be because apart from the "Generation Meter" as ASG call it, they have no way of monitoring how much "Green Electricity" has been generated and so how many kWh at 41.6p they will receive under the FIT scheme.

The meter supplies readings of amount generated (and the amount exported - but not sure about this) directly to ASG - or to someone else and ASG get the figures eventually.

The payments under the FIT scheme are calculated based on the TOTAL amount generated by the panels (@ 41.6p/kWh). ASG do not get (or claim) the extra for exported electricity (an extra 3p/kWh I believe).

Not sure where the readings from the Generation Meter go - perhaps Sarah could enlighten us?

Rgds

XRD

Mcfi5dhc

XRayDave wrote: »

DARN,

The PV System of course includes an export meter (ASG refer to it as a Generation Meter??) - I assume I am correct in this?

Incorrect, sorry

All PV systems will have a generation meter which just shows how much you have generated.

Whoever owns your normal meter (for example mine is Manweb) may replace that meter with an export meter which shows how much you have taken from the grid and how much you have exported. The export meter doesn't have a clue how much you have generated. Likewise the generation meter doesn't have a clue how much has been exported.

(this is my set-up anyway, and all the others I have seen are the same)

If I recall correctly, ASG are not having export meters fitted, they are using the assumed figure of 50% of electric is exported. Considering the size of the systems they fit, this may lose them a not inconsiderable amount of revenue.

PS my fascination with the meter waned as soon as I got the export meter. No longer did the meter go backwards, or stay still.

XRayDave

Mcfi5dhc wrote: »

Incorrect, sorry

All PV systems will have a generation meter which just shows how much you have generated.

Whoever owns your normal meter (for example mine is Manweb) may replace that meter with an export meter which shows how much you have taken from the grid and how much you have exported. The export meter doesn't have a clue how much you have generated. Likewise the generation meter doesn't have a clue how much has been exported.

(this is my set-up anyway, and all the others I have seen are the same)

If I recall correctly, ASG are not having export meters fitted, they are using the assumed figure of 50% of electric is exported. Considering the size of the systems they fit, this may lose them a not inconsiderable amount of revenue.

PS my fascination with the meter waned as soon as I got the export meter. No longer did the meter go backwards, or stay still.

Thanks for clarifying that Mcfi5dhc

As I am not benefitting from the FIT payments or any export payments either (just the "free" electricity generated by the panels), the electricity board (it used to be the YEB) have not fitted an export meter.

So I have the original domestic electricity meter (what I think of as the "Grid Meter" or the YEB Meter) and the Energy Monitor on the PV Inverter feed to the YEB's meter. I have also fitted an Energy Monitor to the live feed to the domestic electricity meter (YEB Meter) and - at the time of writing, the PV Panels are producing 0.76 kW and the Grid Meter is displaying 355W - so, I'd guess that at the present moment, I'm exporting some electricity back to the grid (or is this an incorrect assumption?).

Just looked at the meter and it is creeping backwards - ever so slowly - so this checks out.

Rgds

XRayD

XRayDave

Mcfi5dhc wrote: »

PS my fascination with the meter waned as soon as I got the export meter. No longer did the meter go backwards, or stay still.

Mcfi5dhc,

Are you saying that after MANWEB fitted an export meter - you no longer saw their ordinary meter (a disc type?) go backwards (or did they take the opportunity to replace the meter with a digital or a "smart" meter)??

XRD

Mcfi5dhc

XRayDave wrote: »

Mcfi5dhc,

Are you saying that after MANWEB fitted an export meter - you no longer saw their ordinary meter (a disc type?) go backwards (or did they take the opportunity to replace the meter with a digital or a "smart" meter)??

XRD

Hi XRD

Yes, when Manweb fitted the export meter - they removed the old spinning disc meter completely, and replaced it with a digital meter

Mcfi5dhc

XRayDave

That's a bit of a downer then. I can uderstand why your enthusiasm waned somewhat!

Hmm... maybe I'll not ask for an export meter then. As it stands, if my meter goes backwards, rather than getting a 3p/kWh export "fee" I am getting 13.24p/kWh knocked off my bill.

XRayD

Cardew

XRayDave wrote: »

So I have the original domestic electricity meter (what I think of as the "Grid Meter" or the YEB Meter) and the Energy Monitor on the PV Inverter feed to the YEB's meter. I have also fitted an Energy Monitor to the live feed to the domestic electricity meter (YEB Meter) and - at the time of writing, the PV Panels are producing 0.76 kW and the Grid Meter is displaying 355W - so, I'd guess that at the present moment, I'm exporting some electricity back to the grid (or is this an incorrect assumption?).

If my understanding of your metering arrangement is correct, at that time of writing, your house will be using 355W which will be all coming from the PV panels and you will be exporting 405W(760-355).

Had you switched on a 3kW kettle, at that moment you would be exporting nothing, and using(and paying for) 2.595kW in the house.