Electricity charge falls during the day

As well as a 12-panel roof array, a 5kW inverter and 9.5kWh battery, we also had a smart meter installed - all in the last 6 weeks or so. We've noticed something happening to our usage charges on the smart meter while the PV array is sending to the grid. Typically, by the time the array comes online as the sun gets up higher in the sky, we'll be showing an overall usage for that day of £1.50. From then, while the array has a surplus and feeds the grid, this charge falls, sometimes significantly. How is this happening? We are not signed up for SEG and that would be repaid at intervals of several months anyway, not while we feed the grid each day.

This is not something over which we've made a mistake, it happens everyday the system feeds significant amounts of power to the grid. We are with Scottish Power on a 2 year fixed contract and, with the new system in place, we are consuming very significantly less than our contracted monthly payment - about £80/month against a contract payment of £167.

Can anyone explain this?

My guess would be that the smart meter has not been correctly programmed for solar / potential export and is operating like an analogue meter (ie in reverse)
massive benefit to you while you have no export contract however you should notify your supplier.

Depending on your smart meter display you need to go into it's settings and check the tariff prices. It's possible it has been installed with some default settings and not updated either by the installer or Scottish Power and it has an export price set.

If this is the case you should be able to go in and see the export value separated out. It should still show any export in KwH but if you do not have an SEG in place then the export £ value should be zero.

A little warning, though. The whole industry has made a mess of smart meters and continues to do so. Unfortunately, they learned nothing from the first roll out (SMETS1) when specifying SMETS2. You would expect all SMETS2 meters to be equal and the supply companies to use them consistently. Not so. For example, EON Next (my previous supplier) was not only unable to reconfigure remotely the Smart Meter they had installed for me but their systems continually failed to collect data and bill me incorrectly. I moved to Octopus who, for me, have been brilliant. Oh, and EON next managed to over bill me by a whopping £130 on my final bill which they estimated, for heavens sake.

positor1 It will be a display that is wrong. What is shown on the display has no direct connection to the actual bill generated which will (should) be based on the actual units consumed and the tariff in place.

cluelesscris It will be a display that is wrong. What is shown on the display has no direct connection to the actual bill generated which will (should) be based on the actual units consumed and the tariff in place.

If that's the case, the only mechanism I can see that would cause that incorrectly calculated charge display to fall is if the amount of consumed electricity it uses in the calculation has fallen.

ed-form The display will show the net cost according the the tariff set up in it. If there is an export price it will net this off on the 'home' screen. On my L&G smart meter and display I can view both import and export registers (readings) and values. After I had it installed I had the same issue as the OP. I'm on the original 2011 FIT so no way do I want to go SEG - I therefore reconfigured the display to have zero export tariff value. Not only that but as I moved from EON to Octopus I initially went on to Octopus generic tariff before swtiching to GO. After switching to GO I also had to go in and update the tariff values in the display to match the actual GO numbers I was contracted to.

ed-form you smart meter will account for standing charges, so this could make up a portion of the £1.50 you see, but I'm not sure why it would drop later in the day.

Cdent you smart meter will account for standing charges, so this could make up a portion of the £1.50 you see, but I'm not sure why it would drop later in the day.

Yes! The dump 39p in at midnight. It sounds to me as if Cluelesscris might have the best idea. I'll poke about in the guts of the smart meter to see if I can see what he says.

cluelesscris similar experience with SSE and then OVO. Never read the gas despite it being a smart meter - I kept having to submit manual readings. Their billing was terrible too - every bill was wrong. Given I was already with Octopus for Electricity, I swapped to them - and lo and behold, the gas meter has been read find - and the data at 30 min internals is showing in their app. (I also swapped onto their tracker gas product which is currently cheaper than the cap)