Power meters and Solar Power

The type of meter and whether they are reversible matters little. It's 3p extra export payment compared to 41.5p paid for ANY and ALL generation, 7% extra per kWh is hardly going to be a deciding factor in making the scheme pay or not.

But import/export meters at the boundary are the only fair way. Every other source of generation is metered this way. That metering of generation sources *separately from the boundary* and in addition to that *at the boundary* gives rise to an addtional premium payment that has no place in a competitive market - it's green fudge at its worst.

By the way, the existing digital meters can be configured for measurement of import and export in a matter of minutes.

The type of meter fitted makes a significant difference to the return on a PV investment.

Take the limiting case - ALL consumption outside daylight hours.

This means that, if an export meter is fitted, all PV energy qualifies for the 3p export payment

Reversible meter

Non reversible meter

Net income +32.3p per PV KWh

If an export meter is NOT fitted the assumption is made that half the PV energy qualifies for the 3p export payment.

Reversible meter

Net income +42.8p per PV KWh

Non reversible meter

Net income +30.8p per PV KWh

This is an extreme case but even with the most optimistic assumptions on daylight power usage much of this reduction will still occur.

Jim

One question on my FIT application form was to ask if the import meter had started to run backwards since installing my PV system. It has not as I have a newer digital meter by I expect that If I had said yes, they would have been round like a shot to fit a uni directional meter. I'm sure that they do not want cases 1 and 3 above to occur.

Do you have a PV system installed Jim?

Bob

SNIP

Many of the comments made in the recent posts arise from difficulties I encountered in obtaining accurate costing information on my PV installation.

My PV supplier simply said that the usual assumption was that about half the PV energy resulted in a corresponding direct reduction in the electricity bill. If I needed more detailed information I should take it up directly with the supply company.

This I did. but it took just over a month to get a straight answer to the relatively simple question " how does the timing of consumption affect the electricity bill "

The normally helpful call staff of the supply were not briefed on this subject but I eventually succeeded in contacting the technical department. The following extract from their final email is the basis on which I have made comments to the group.

"With regards to your points below, the following require correction.

The electricity meter registers total power consumption minus total PV power generation.

Your supply electricity meter (that is read for your bills) will record only the excess electricity that you use (buy in from us) when your system is not generating enough for you needs at the time, or not generating at all.

If, in a 3 month period, total PV generation exceeded consumption the meter reading would decrease.

It is illegal for your supply electricity meter to run backwards, therefore the reading should never decrease. The meter should stop and not record any consumption when your generation is greater than any consumption in your property. But if the meter run's backwards you must inform us immediately and we will exchange it for a meter that won't run backwards. " Jim

You could tell them you have blocking diodes to prevent reverse flow, and see how long that delays them.

jsw

Please name and shame them so we all know who this shower of s*it outfit are!

I did not name them as I have no axe to grind with either. Pretty well all PV supply companies make the same optimistic claims on reduced electricity bills and apart from this I am satisfied with my suppliers performance

The electricity supply company is simply implementing nationally agreed supply arrangements.

Jim

Oh dear so you *really* think they are doing that?