Too much power

Casper55

I understand that it is more efficient to use all the power generated rather than loose it to the grid and then run things like washing macchines later on when energy production is at a low and will be charged for the usage. So at peak times when say a 4kw system could be producing 3.5 kw or more what happens to the mains supply meter does it actually go backward for a short period of time. As I would like to use all the power I generate.Therfore would I be better with a smaller system. Or does the larger system give the better return due to the Feed in Tariff
best regrda Casper

penrhyn

You can never have too much power!!

zeupater

Casper55 wrote: »

I understand that it is more efficient to use all the power generated rather than loose it to the grid and then run things like washing macchines later on when energy production is at a low and will be charged for the usage. So at peak times when say a 4kw system could be producing 3.5 kw or more what happens to the mains supply meter does it actually go backward for a short period of time. As I would like to use all the power I generate.Therfore would I be better with a smaller system. Or does the larger system give the better return due to the Feed in Tariff
best regrda Casper

Hi

If you can use and control appliances during the day when the sun is shining then do so. For high power electric devices there will be a point where, depending on how much electricity a pv system is producing, it could be cheaper to run them at night on cheap rate electricity if it is available, but if not available it will always be cheaper to run the appliance at peak generation times. It will almost certainly average out over a period of time to be be more expensive to run a standard immersion heater during the day using power from a domestic sized pv system below 4kWp than using either off-peak electricity or gas.

There are very few, very old electricity meters which will run backwards when exporting, most analogue meter have a ratchet which stops the system reversing. Having a larger system will definately enable you to increase the FiT payable as long as you don't move the system into the next tariff band, but the amount of generated electricity which you will be able to use yourself will not be much different between say a 4kWp system and one half the size, both will probably provide an energy import saving of somewhere around £100/year.

The main defining restriction on the system you can have is the roof area which is available. A 4kWp system, depending on panels, is likely to cover somewhere around 30sqm of roof, therefore with a requirement for clear roof all around the array you'll need around 40sqm of southerly facing unshaded roof .....

HTH
Z

zeupater

penrhyn wrote: »

You can never have too much power!!

Really ???? ...... Are you sure ???????


:beer:

Casper55

zeupater wrote: »

Hi

If you can use and control appliances during the day when the sun is shining then do so. For high power electric devices there will be a point where, depending on how much electricity a pv system is producing, it could be cheaper to run them at night on cheap rate electricity if it is available, but if not available it will always be cheaper to run the appliance at peak generation times. It will almost certainly average out over a period of time to be be more expensive to run a standard immersion heater during the day using power from a domestic sized pv system below 4kWp than using either off-peak electricity or gas.

There are very few, very old electricity meters which will run backwards when exporting, most analogue meter have a ratchet which stops the system reversing. Having a larger system will definately enable you to increase the FiT payable as long as you don't move the system into the next tariff band, but the amount of generated electricity which you will be able to use yourself will not be much different between say a 4kWp system and one half the size, both will probably provide an energy import saving of somewhere around £100/year.

The main defining restriction on the system you can have is the roof area which is available. A 4kWp system, depending on panels, is likely to cover somewhere around 30sqm of roof, therefore with a requirement for clear roof all around the array you'll need around 40sqm of southerly facing unshaded roof .....

HTH
Z

Thanks for the reply, much appreciated. I take it then that more modern ditgital meters run backwards. In this case, would the Grid not act as astorage device ie. The meter running revearse when more energy is produced than needed and running the correct way when more power is needed than produced. Surely this would do away with the need to run appliances when solar energy is produced at its peak.I can see that it would be best to use it all and save 13p per unit rather than make the 3 p which would be assumed anyway
best Regards Casper

celerity

Casper55 wrote: »

I take it then that more modern ditgital meters run backwards.

Nope, digital meters won't run backwards, (as far as I know anyway).
My understanding is that power companies don't ever want meters to run backwards - the only reason some older ones do is due to their mechanical nature.

/\dam

Casper55

celerity wrote: »

Nope, digital meters won't run backwards, (as far as I know anyway).
My understanding is that power companies don't ever want meters to run backwards - the only reason some older ones do is due to their mechanical nature.

/\dam

Thanks Now it begins to make a bit more sense to me

jetski690

I had mine installed a few days ago and guess I'm one of the lucky one's as my meter is running backwards when producing power, my installer said every meter he's seen of the non digital type have all run backwards, of course I'm now going to inform my energy supplier

zeupater

jetski690 wrote: »

I had mine installed a few days ago and guess I'm one of the lucky one's as my meter is running backwards when producing power, my installer said every meter he's seen of the non digital type have all run backwards, of course I'm now going to inform my energy supplier

Hi

Most FiT application forms query whether the meter runs backwards, but if yours didn't it might be wise to query this with your nominated FiT company .... don't want it playing on your conscience and keeping you awake at night .... :cool:

HTH
Z

bjohnson

I reported my meter running backwards to nPower in March and they are going to replace the meter (which is done by a separate company) next week so I don't think that they are in too much of a hurry.

jetski690

zeupater wrote: »

Hi

Most FiT application forms query whether the meter runs backwards, but if yours didn't it might be wise to query this with your nominated FiT company .... don't want it playing on your conscience and keeping you awake at night .... :cool:

HTH
Z

My energy supplier and the Fits application form was with EDF and there was deffo no mention of the meter running backwards on the form and I certainly have no trouble sleeping