Adding battery to PV System Help (EDF)

jasonhenley

Hi all
I have a PV System on an old FIT tariff (27p and 50% at 7.5p) and looking to possibly add a battery. 

I am chasing my tail with EDF trying to get an answer if I will loose my FIT tariff (go onto a newer one) or if I keep my existing tariff. 

EDF don’t know, told me to call MCS who said it’s down to EDF. Spoke to EDF again today to be told again they’re not sure, but once the system has been installed to send the schematics in for them to make a decision🤔 

So, has anyone done this or know the answer. 

Thanks

Qyburn

What sort of solar installation, and what sort of battery?

Reed_Richards

Are you looking to add a battery with its own dedicated inverter?  If so, i don't think that would have any effect on your FIT payments but you would need approval from your DNO because the solar panels and battery together are capable of exporting more power that the solar panels alone.

mmmmikey

Hi - I receive my FIT payments from EDF and added a battery without it having any effect at all on the FIT payments so it can certainly be done. Everything was done properly with all the proper notifications and completely hassle free. It's just a question of correctly installing an appropriate battery system. Have you selected the battery system yet and if so do you have a schematic showing how it would be installed? If so, if you post that here we should be able to give some info on whether it's likely to be a problem. If not, do you want recommendations on what battery system to buy?

ThisIsWeird

Hi Jason.

I presume you are on a FIT which pays you for everything generated, but also gives you a fixed rate for export to the grid? Ie, they don't actually measure how much you actually export, but have an 'assumed' %-age, for which they pay you at a much smaller rate than the FIT?

(More recent PV arrangements do actually pay you for everything you actually export, so that would likely be affected by you pinching this for storage.)

So, assuming this is the earlier FIT arrangement, then installing batteries shouldn't affect anything. This is because you are allowed to use every drop of generated electricity in any case, and still get the wee %-age of 'assumed' export.

mmmmikey

ThisIsWeird said:

Hi Jason.

I presume you are on a FIT which pays you for everything generated, but also gives you a fixed rate for export to the grid? Ie, they don't actually measure how much you actually export, but have an 'assumed' %-age, for which they pay you at a much smaller rate than the FIT?

(More recent PV arrangements do actually pay you for everything you actually export, so that would likely be affected by you pinching this for storage.)

So, assuming this is the earlier FIT arrangement, then installing batteries shouldn't affect anything. This is because you are allowed to use every drop of generated electricity in any case, and still get the wee %-age of 'assumed' export.

Hi - my apologies for contradicting you but I don't think it is correct in all cases that batteries shouldn't affect anything. By way of explanation....

If you connect batteries direct to the inverter (called a DC configuration in some places), which is upstream of the generation meter, there is an additional consideration. The issue is that if you charge the batteries from the grid, when you discharge them the energy used will be measured as generation so in effect you would get a FIT payment for charging and discharging the batteries. You either need an approved and certified meter that runs backwards when the batteries are charged (to cancel out the FIT payment from the discharge), or the batteries need to be installed downstream of the meter using their own inverter (an AC configuration). Both configurations are, as far as I know, allowed (or at least they used to be) but you do need to be aware of the metering implications if you connect the batteries to the same inverter as the solar panels.

So it can be done but it may require installation of a different approved meter.

jasonhenley

mmmmikey said:

Hi - I receive my FIT payments from EDF and added a battery without it having any effect at all on the FIT payments so it can certainly be done. Everything was done properly with all the proper notifications and completely hassle free. It's just a question of correctly installing an appropriate battery system. Have you selected the battery system yet and if so do you have a schematic showing how it would be installed? If so, if you post that here we should be able to give some info on whether it's likely to be a problem. If not, do you want recommendations on what battery system to buy?

Hi. Thanks for the reply. 

At the moment not fully looked into what system etc. at the stage knowing if it can be done and looking at investment to ROI. 

If you’ve got any recommendations, that would be great. Thanks. 

Petriix

Whatever you do, go for an AC coupled battery that's entirely separate from your existing installation. Don't interfere with anything on the other side of your existing generation meter. 

If you do as I say there's no danger of messing up you FIT payments. 

Reed_Richards

mmmmikey said:

If you connect batteries direct to the inverter (called a DC configuration in some places), which is upstream of the generation meter, there is an additional consideration. The issue is that if you charge the batteries from the grid, when you discharge them the energy used will be measured as generation so in effect you would get a FIT payment for charging and discharging the batteries. You either need an approved and certified meter that runs backwards when the batteries are charged (to cancel out the FIT payment from the discharge), or the batteries need to be installed downstream of the meter using their own inverter (an AC configuration). Both configurations are, as far as I know, allowed (or at least they used to be) but you do need to be aware of the metering implications if you connect the batteries to the same inverter as the solar panels.

So it can be done but it may require installation of a different approved meter.

You don't need a meter that "runs backwards", you just need a meter that measures energy in both directions, import and export and tells you the net result, one minus the other.  Thar's what I have; it's an Eastron SDM230 Modbus https://www.eastroneurope.com/products/view/sdm230modbus 

mmmmikey

Reed_Richards said:

mmmmikey said:

If you connect batteries direct to the inverter (called a DC configuration in some places), which is upstream of the generation meter, there is an additional consideration. The issue is that if you charge the batteries from the grid, when you discharge them the energy used will be measured as generation so in effect you would get a FIT payment for charging and discharging the batteries. You either need an approved and certified meter that runs backwards when the batteries are charged (to cancel out the FIT payment from the discharge), or the batteries need to be installed downstream of the meter using their own inverter (an AC configuration). Both configurations are, as far as I know, allowed (or at least they used to be) but you do need to be aware of the metering implications if you connect the batteries to the same inverter as the solar panels.

So it can be done but it may require installation of a different approved meter.

You don't need a meter that "runs backwards", you just need a meter that measures energy in both directions, import and export and tells you the net result, one minus the other.  Thar's what I have; it's an Eastron SDM230 Modbus https://www.eastroneurope.com/products/view/sdm230modbus 

Coincidentally I installed an Eastron SDM230 this afternoon as a way of getting solar generation data into Home Assistant - my solar inverters are about 13 years old and there's no convenient way of getting data from them.

Just a point of interest but are you using it to claim FIT payments, and which supplier do you use? My FIT payments use readings from a regular looking Landis and Gyr meter which has a tamper proof seal like a normal supply meter. Given the ease with which you could fiddle the payments with the Eastron I'm surprised it's approved for claiming FIT payments? I didn't notice but does it have a serial number for identification purposes?

mmmmikey

jasonhenley said:

mmmmikey said:

Hi - I receive my FIT payments from EDF and added a battery without it having any effect at all on the FIT payments so it can certainly be done. Everything was done properly with all the proper notifications and completely hassle free. It's just a question of correctly installing an appropriate battery system. Have you selected the battery system yet and if so do you have a schematic showing how it would be installed? If so, if you post that here we should be able to give some info on whether it's likely to be a problem. If not, do you want recommendations on what battery system to buy?

Hi. Thanks for the reply. 

At the moment not fully looked into what system etc. at the stage knowing if it can be done and looking at investment to ROI. 

If you’ve got any recommendations, that would be great. Thanks. 

I have a PowerVault that I would highly recommend. It has a very easy to use web interface with specific options to allow it to optimise itself for a number of different tariffs and schemes like the National Grid switch off and save. It's designed and supplied by a UK company using standard components. I found them in easy to deal with during the sales process and their technical support team are excellent, important to me as I'm a bit of a geek.

There are certainly cheaper solutions out there, though, so worth comparing prices. I can't really speak for other systems though as I've only dealt with PowerVault.