Solar pv price for installation

noncom_2

Yes, I understand the different technologies behind the panels. But isn't it the case that any 185 Watt panel will produce the same amount of electricity from the same amount of sunshine (within a small margin allowing for non-linearity of the transfer curve)?

It's just that the more efficient the crystalline technology is, the smaller the panel will be to produce the same peak Wattage.

So if space on the roof is the limiting factor, then the most efficient panels will allow a higher system capacity. If roof size is not the issue, then you may be able to get a 4kW system using poly-crystalline panels cheaper than a 4kW system using mono-crystalline panels. The output from the systems will be more or less the same. The mono-crystalline one will take up less roofspace, that's all.

Cardew

True, I misread your post.

I take it that ninjaryder was implying that their quote was for monocrystalline.

noncom_2

That would be my assumption - (s)he may have been told that the panels are 10-15% more efficient than another brand, and assumed that means you get 10-15% more power out of them than the less efficient one. Whereas actually you should expect roughly the same output but with a bigger roof footprint.

flashnazia

noncom wrote: »

Where the meter comes into it (the normal domestic consumption meter, not the newly fitted Generation meter) is that if it is an old type, when you are exporting the meter may (mistakenly) run backwards. So when you pay your bill, effectively the number of units you've used in the house will be reduced by the number you've genuinely exported, therefore you will effectively be "paid" your import price per unit for your exports on top of the 3p tariff!

I wonder how long it will take the energy co.s to figure this out and insist on a new meter if you are a generator......

I read on the other section (utilities) that someone is being investigated by utility company because meter is in reverse after solar panel fit. The advice is in contrast to what's here about reversing readings..

noncom_2

Not sure what you mean by this...... I offered no "advice", merely reported the fact that some people who have solar installations already (with the old-style meters) have stated that when they are exporting, the meter runs backwards and therefore their electricity bill decreases.

I don't see how the energy company can "investigate" this?? There is no element of fraud (it's not, presumably, like they're deliberately tampering with the meter) - it is simply up to the energy company to replace the meter with one which is clever enough to count up when power is imported, and do nothing when power is exported.

noncom_2

Having just read the thread in question, I can see that there is some concern arising. But I think it's down to the energy companies to sort it out. One thing I would say though, is that the energy company were alerted to the problem by the fact that one meter reading was LESS than the previous one.

I'm not sure how common this will be. A 4kW installation may produce about 3500 units per year, which is not a million miles from the average annual household consumption. In addition, it will produce most in the summer when consumption is lowest. So I suppose in theory, over a summer quarter at least, the panels could produce more than the house consumes (even if it is not all at the "right time of day" to be used in the house), which means if the meter runs backwards when exporting the figure could be lower by the end of the quarter than it started.

Can't see anyone being prosecuted for this though.

Cardew

noncom wrote: »

Having just read the thread in question, I can see that there is some concern arising. But I think it's down to the energy companies to sort it out. One thing I would say though, is that the energy company were alerted to the problem by the fact that one meter reading was LESS than the previous one.

I'm not sure how common this will be. A 4kW installation may produce about 3500 units per year, which is not a million miles from the average annual household consumption. In addition, it will produce most in the summer when consumption is lowest. So I suppose in theory, over a summer quarter at least, the panels could produce more than the house consumes (even if it is not all at the "right time of day" to be used in the house), which means if the meter runs backwards when exporting the figure could be lower by the end of the quarter than it started.

Can't see anyone being prosecuted for this though.

You could of course argue - especially for firms like ASG - that their installation should be capable of handling this problem such that the meter running backwards situation did not occur?

I suspect the Utility company might think that the installation firm should fund the replacement of a suitable meter???(if no other solution is possible)

The bottom line is that the electricity supply is being tampered with and the company 'defrauded'; albeit without the customer being culpable.

noncom_2

Without more than the briefest of thinking time, I can't be absolutely sure, but I would hazard a pretty well educated guess that there is no solution to this "problem" (or "benefit", depending on which side of the meter you're on!) other than replacing the old-style spinny wheel meter.

The electricity supply is not being "tampered with" in any meaningful sense of the phrase (as the utility companies are part of the scheme which is encouraging people to micro-generate). The company is also not being "defrauded" in any meaningful sense of the word. Unless there is deliberate criminal intervention in the system, the "spinny wheel" which sometimes runs backwards will actually be an accurate "import meter" - in other words it will genuinely measure how much more (or less) electricity is bought in from the Energy Co than is exported to it. Since the purpose of an electricity meter is to measure how much electricity is being bought in from the Grid, it is arguable that this is actually the correct measure.

For example, suppose I generate 3500 units per year, use say 1000 of them directly in the house and export 2500, and my annual household consumption is 4000 units.

My "net" import from the Grid overall is only 500 units (the difference between what I use and what I generate). So arguably this is what I should pay my energy company for. This 500 units is what the "spinny-wheel" would have measured.

Of course, if I then get a 3p per unit export tariff then I am being "double paid" for that, which would not be fair. So perhaps the FIT system should scrap the export tariff and fit everyone with an old-style meter instead!!!!

Just a few thoughts. Bottom line is this: the Energy Co. allow me to install micro-generation downstream of their meter. If their meter cannot handle the "backwards current" when exporting to their satisfaction, they are free to change it, but surely not within their rights to ask me to pay for it (unless that is specified in their T+Cs in advance when I enter a supply contract).

Cardew

By 'tampered' or 'defrauded' I mean the electricity company are supplying electricity for which they are not getting paid. I specifically said that there was no intent by the customer.

The flaw in your reasoning IMO is that the energy company do not own the National grid. Anything someone generates from their PV panels goes into the National Grid and is not for the benefit of any single company. The FITs are also paid for from a 'kitty'.

Taking the example of your house, your electricity company pays the generating company for 3,000kWh which it supplies to(and is consumed in) your house(4,000 less 1,000 from the panels).

Yet the meter is incorrectly altered such that it appears that they have only supplied 500kWh and that is all they get paid for. If a garage put 30 litres of petrol in your car and got paid for 5 litres - I submit the garage would have a justified complaint.

It is more than possible that an electricity company will find that at the end of every quarter the meter reading is lower than at the start of the quarter and they have to pay you a rebate, for electricity they have supplied, and you used.

noncom_2

Sorry Cardew, but I still disagree.

The house is not "consuming" 3000kWh from the Grid, it is consuming 500 - it is importing 3000kWh at some times, and exporting 2500kWh at other times!

I don't really see the difficulty in the fact that the Grid and the house's energy supplier not being the same. The electricity which actually flows into the house probably wasn't actually generated by the company that's selling it to me anyway! But overall, if an energy company sells a certain number of units to consumers, it has to feed the same amount into the Grid somehow. If the house in question "buys" 3000kWh from an energy company, but exports 2500kWh all that is effectively happening is that "the house" has become one of the Generators that the energy company pays to make electricity. Admittedly, if the house's microgeneration is "paid for" by the meter spinning backwards, then the energy company is effectively buying and selling those units at the same price, which cuts out its profit margin. So it would have a grievance on that point, at least.

Anyway, as this debate is now highly speculative (and I have a digital meter so it won't happen to me anyway!) I shall leave it at that: I believe it is the electricity companies' responsbility to change meters for micro-generators if they want to avoid this situation.