I love my solar panels but…
- This topic has 4 replies, 2 voices, and was last updated 5 years, 9 months ago by Tom Peckham.
2013-12-30 at 21:30 #12869Tom PeckhamGuest
Please can you tell me the thinking regarding the main electricity meter which supplies the mains power to a residence which goes backwards when the PV panels on the roof provide power in excess of that being used in the house at any one time?
The average use of electricity over a year is more than what is generated by the PV solar panels by a factor of two at least. However, my provider tells me that the main supply meter must be changed for one which does not go backwards.
As I see it, if I am using all of the power generated by the Photovoltaic installation, then the meter is stationary. If I use less power than I am actually using, then the meter should go backwards because I am exporting power into the national grid. There does seem to be some confused thinking on this point!
Your comments would be appreciated.
2013-12-30 at 22:41 #12870NormanGuest
Its the Law of Unintended Consequences.
When they FIT scheme was devised there was no requirement for systems up to 4 KPW to have an export meter.
It was agreed that the exported amount would be deemed to be 50% of that generated.
So the Energy companies built this into their FIT payment systems.
Now what is happening with the old magnetic meters is when their is a flow of electrons out of the house it moves the magnetic dial in the opposite direction reducing the KWH reading.
An “Untended Consequence” of installing a pv system
If the Energy Companies leave the old meter in the customer is getting 50% export allowance PLUS his meter reading is being reduced. A double benefit.
That’s why the Energy companies will change the meter asap.
There is a legal requirement on all FIT applications for the FIT recipient to inform the Energy Company immediately they notice the meter turning backwards.
Hope this helps.
2013-12-31 at 10:13 #12871Tom PeckhamGuest
Thank you for your explanation about meters going into reverse. I follow your argument to some degree, but I feel that there is a fallacy. I am thinking about what you have said.
If I use say 10 Kwh of power in one day and my PV panels produce 5KwH of power, then the power that I buy from my energy supplier is 5 KwH less that the total power used. That means that I have effectively saved myself 5KwH of power which I do not have to pay the energy provider for! That is a benefit financially to me.
If on a similar day the PV panels generate 5 KwH of power and I use 5 Kwh of power, then that is 5Kwh of power that I do not have to buy and I have had a days electric power for free. I have a financial benefit.
Now, if on another day my PV panels generate 10 KwH of power and I only use 5KwH, I am exporting to the grid 5KwH of power. According to your reasoning I am suddenly penalised for actually exporting unused power, whereas if I use it I benefit.
It does seem to me that if what you say is correct, there is an inducement to me to use everything that I generate on summer sunny days. I should do all my cleaning with the vacuum cleaner, boil water and do lots of washing of clothes, have lots of baths and so on. This would seem to defeat the idea of the PV panels on my roof feeding power into the grid system! It is a very rum argument in my opinion.
Over the year I do use well over twice the amount of power generated by my PV panels, and so I do save myself effectively over 1200KwH of power.
Thank you for your thoughts on the subject. I will think more.
Best regards in advance,
2013-12-31 at 12:38 #12877Stuart LovattKeymaster
Not sure I understand, but you have a generation tariff which you will be paid for surplus energy you don’t use. Many people put them on second homes because they get paid for the unused energy exported out while the house is not in use, the same is true with your home. You don’t have to use the energy to benefit from the energy they generate as you can import/export as opposed to just importing as per standard homes. The amount you get paid for exporting is dependent on the tariff rate you signed up too.
Another option is to heat your hot water with your PV for free using this system:
Hope this helps.
2013-12-31 at 15:35 #12881Tom PeckhamGuest
Thank you for the reply. I think that my argument in the previous reply was logical. I agree that I get paid for the units of power that are generated by the PV solar panels.
As I said,over the full year I use at least as much as I generate and over 100% more besides.
Trying to simplify my earlier argument, all that I can say is that if I generate, say for example, 1000 KWh in a full year, I receive payment on that amount of power generated under the FIT scheme.
If I use in my house over the year say 3000 KWh of power, because I have generated 1000 KWh of power I do not have to pay the supplier for that amount of power. Theoretically I have exported it by not consuming it. That is, if your argument is correct, provided that at no time in the year my incoming power meter does not run backwards. i.e. I am using all that my photovoltaic panels generate.
According to your argument, if at any time in the year my incoming power meter does run backwards because for a few days the PV panels generate more than I use, then it would appear to me that I will be penalised if a meter is fitted that will not run backwards, thus recording the actual power sent to the grid. As I said earlier, if I use it all, then I am not thus penalised. The incentive is for me to use the power deliberately rather than to export it!
My argument is I am sure logically correct!