Solar panel FITs and smart meter

mally252

I I have had solar panels for 10 years and receive FIT payments from EonNext. My wife and I are in our bungalow most of the time.
Gas and electricity is provided by Octopus and I am considering getting a smart meter.
However I was told previously that if you spend most of your time at home you benefit by the 50% export calculation and therefore if you move to a smart meter you could lose out because the calculation would show a lower level of export.
Any advice would be welcomed.

Reed_Richards

Get a smart meter and it will tell you how much you export. 

Moving to a smart meter does not force you to move from deemed to metered export.  That does happen with some suppliers but I don't think Octopus forces you to do this.  And even if they did, you would get paid over twice as much per kWh as you get paid for deemed export so you could export only one quarter of what you generate and still show a small profit.  

Petriix

Unless you have a battery or waste loads of energy by unnecessarily heating water with a solar diverter (Eddi, iboost etc.) or maybe have an EV which you charge with a Zappi during the day, you likely don't come close to using 50% of your generation.

At the moment, metered SEG exports are far more lucrative than the FIT scheme export payments. You can always opt back in to the latter should this change but, once metered, you can't go back to deemed. 

Reed_Richards

Petriix said:

Unless you have a battery or waste loads of energy by unnecessarily heating water with a solar diverter ....

I'm struggling with the concept of "unnecessarily heating water".  The only context I can think of where this might make sense is an outdoor swimming pool that is heated but never actually used.  

pete-20-11

Petriix said:

Unless you have a battery or waste loads of energy by unnecessarily heating water with a solar diverter (Eddi, iboost etc.) or maybe have an EV which you charge with a Zappi during the day, you likely don't come close to using 50% of your generation.

At the moment, metered SEG exports are far more lucrative than the FIT scheme export payments. You can always opt back in to the latter should this change but, once metered, you can't go back to deemed. 

I think if you move from FIT export to SEG you can only go back to FIT in the first year? 

Alnat1

Reed_Richards said:

Petriix said:

Unless you have a battery or waste loads of energy by unnecessarily heating water with a solar diverter ....

I'm struggling with the concept of "unnecessarily heating water".  The only context I can think of where this might make sense is an outdoor swimming pool that is heated but never actually used.  

Heating a 300L tank to 70C via a diverter could be seen as unnecessary if the only use is a couple of short showers each day. It's OK if you're a FIT customer but with SEG it's better to export the excess electricity and only heat the water you need.

jennifernil

We had a smart meter installed in November 2022 and eventually moved to metered export in April this year as we were exporting at least 50%,  and are now being paid 15p instead of just over 6p per kWh .   We are with Octopus so have moved everything over to them.  Our first payment for export was £83 for 16/04 to 10/06 and soon we will have our quarterly FIT payment too.  Still waiting for our final payment from EDF.

Definitely better on metered export right now.

Reed_Richards

Alnat1 said:

Reed_Richards said:

Petriix said:

Unless you have a battery or waste loads of energy by unnecessarily heating water with a solar diverter ....

I'm struggling with the concept of "unnecessarily heating water".  The only context I can think of where this might make sense is an outdoor swimming pool that is heated but never actually used.  

Heating a 300L tank to 70C via a diverter could be seen as unnecessary if the only use is a couple of short showers each day. It's OK if you're a FIT customer but with SEG it's better to export the excess electricity and only heat the water you need.

But the laws of physics prevent you from heating more water than you need!  You use X litres of hot water, this is replaced by X litres of cold water which you heat up to the temperature you keep the cylinder at.  You only ever heat the water you use, X litres however much X is.  Plus a bit extra to compensate for heat loss from the cylinder.  

[Deleted User]

Reed_Richards said:

Alnat1 said:

Reed_Richards said:

Petriix said:

Unless you have a battery or waste loads of energy by unnecessarily heating water with a solar diverter ....

I'm struggling with the concept of "unnecessarily heating water".  The only context I can think of where this might make sense is an outdoor swimming pool that is heated but never actually used.  

Heating a 300L tank to 70C via a diverter could be seen as unnecessary if the only use is a couple of short showers each day. It's OK if you're a FIT customer but with SEG it's better to export the excess electricity and only heat the water you need.

But the laws of physics prevent you from heating more water than you need!  You use X litres of hot water, this is replaced by X litres of cold water which you heat up to the temperature you keep the cylinder at.  You only ever heat the water you use, X litres however much X is.  Plus a bit extra to compensate for heat loss from the cylinder.  

The bit extra to compensate for the heat loss from the cylinder can be considerable - even using a well lagged 200l  cylinder heated to 50C I lose about 2kWh a day, increasing the temperature to 70C makes that significantly worse. The laws of physics allow you to be 0% efficient if you choose. Just heat up the water in the cylinder, leave it a few days to cool down without using any and you will have wasted everything......

Reed_Richards

Well yes, keeping a second cylinder containing water that you never actually use and heating it every few days is another way to heat water that you don't need but it's even more pointless than the swimming pool example I suggested.

[Deleted User]

Reed_Richards said:

Well yes, keeping a second cylinder containing water that you never actually use and heating it every few days is another way to heat water that you don't need but it's even more pointless than the swimming pool example I suggested.

I think you're missing the point. Hot water cylinders aren't 100% efficient and there's a big difference in cost between just heating up the minimum amount of water just before you need it and leaving it running 24x7 at the maximum temperature it will go up to. If you have a solar diverter like. Solic 200 or some such device not much incentive to heat the water efficiently (i.e. in a way that minimises heat loss) because it is effectively free. But as soon as you go on to metered export it becomes worth adjusting the timer and thermostat accordingly.