Solar PV Useage Query

greyteam1959

Solar Pv all up & running.
Electric meter running backwards during day.
Gas water heating.
Question 1 .....
If I put a timeclock on my electric immersion heater to come on for say 3 hours 11.00 am to 2.00 pm I should be quids in right ??
Question 2
How long is it before the electricity company ( Scottish Power ) come & change your meter ??
Thanks in advance

thenudeone

As long as your electricity meter is capable of running backwards I don't think it matters, because whether you use electricity for your immersion heater when you are generating it or at a different time your meter readings will be exactly the same (unless you have Economy 7, when it gets more complicated)

I think it only matters if you have a digital meter that WON'T go backwards (to prevent fraud). In that case the electricity suppliers will assume that 50% of your generation has gone backwards through the meter into the grid but will not have made the readings go backwards.

My PV system is not yet installed, so this view is not from my experience, just from browsing. Perhaps someone lucky enough to have a backwards-capable meter and PV installed can confirm?

Cardew

Post above is correct.

With a meter running backwards, you heat water with gas at around 3p/kWh, and your generated electricity turns back the meter - saving you around 10p/kWh.

greyteam1959

So when (or if) Scottish Power come & change my meter to a meter that will not run backwards my idea of heating the water using generated electric would be the way to go ??

grahamc2003

mervyn11 wrote: »

Solar Pv all up & running.
Electric meter running backwards during day.
Gas water heating.
Question 1 .....
If I put a timeclock on my electric immersion heater to come on for say 3 hours 11.00 am to 2.00 pm I should be quids in right ??
Question 2
How long is it before the electricity company ( Scottish Power ) come & change your meter ??
Thanks in advance

Can't answer question 2, but the answer to Q1 is NO!

You are quids in at the moment. You are effectively getting the max benefit possible from your solar generation. Each kwh you generate is worth whatever your tier 2 rate is (say 10p) and inaddition, you'll get 3pish for 50% of it (plus the fits of course).

The danger of turning a big load on to soak up the power is that if you have an export of 2kw (there by generating 20p off your bill each hour) and you turn on an immersion heater of 3kw, you'll lose out quite a bit. The heating will be worth about 3kw at your gas price (say 10p/hr), yet you'll be importing 1kw, costing you 10p/hr - so effectively you'll make nothing (instead of exporting and making 20p/hr).

Basically, if you trun your immersion heater on in your situation with a backward running meter
- there'll be no financial difference when you are generating excess power greater than the immersion heater takes
- you'll lose out by varying amounts if your excess is less than the immersion heater takes, and lose out by about 20p/hr if you have no excess when your immersion heater is turned on.

All the above is typical - there may be some circumstances where it may get more complex (e.g. if you're generation results in you using no tier 2 units, and so further generation may be worth your much more expensive tier 1 unit price, but that's unlikely for most people).

landybabe

I am amusing the people that have commented on this post already have solar pv. (so hope this posts dosent seem like we are advising on here) My husbands has a solar company and we have started a facebook page
http://www.facebook.com/home.php?sk=group_177920828921106
The aim for the page is for users to discuss there systems, issues, ect
all welcome thank you

bjohnson

I'm another that has a backward running meter. I notified nPower and they sent a guy to change it but he took one look at our board and said that it was unsafe (there was a flying connection on it that should have been fastened to the board and protected by a plastic connector - since modified).
They will return next week. I am assuming that when they see our minus consumption they will attempt to calculate what the consumption should have been, going from past records. I don't think that they will just give in and offer me a refund! On the other hand since we got the PV panels installed we have deliberately been using less electricity when the panels are not generating (i.e. at night and dull days) so our consumption should have been less.

thenudeone

Why did you want to change your backwards running meter?
Won't you be worse off with a meter that doesn't go backwards any more, when you pump generated electricity back through it?

bjohnson

thenudeone wrote: »

Why did you want to change your backwards running meter?
Won't you be worse off with a meter that doesn't go backwards any more, when you pump generated electricity back through it?

I don't really want to change it but when you fill in the FITS form you have to confess if you have a meter that can run backwards so you would be found out eventually. If you lie they could refuse the FITS payments.

JenR8

We had an installation end of Feb (rent a roof) and Scottish power were informed straight away by me that our meter was going backwards. They phoned a couple of weeks ago to arrange an engineers visit. That date wasn't convenient and they said they'd ring back. Haven't yet.

Assume they will estimate our electricity useage for the period as half our usual, as that is what we are projected to save.

keith_r59

bjohnson wrote: »

I don't really want to change it but when you fill in the FITS form you have to confess if you have a meter that can run backwards so you would be found out eventually. If you lie they could refuse the FITS payments.

The e.on FiT application form doesn't ask that question.

http://www.eonenergy.com/NR/rdonlyres/042AEB55-6474-421A-BF18-BC6042CD4394/0/FITApplicationForm.pdf