Export Cap - is there a way to set it?


In the UK those of us who installed solar early are paid a subsidy for every KWh we generate whether it is exported or not (in the basis that we save the country from having to build a new power station). We are also paid a small fee for each KWh exported, where in most cases to save the cost of an export meter it is assumed that the house uses 50% of what it generates and the rest is exported.

There is a catch. if like me you installed the maximum 4KW solar array to begin with, and later add more panels (as I have just done), the subsidy only applies to the original 4 KW setup.

Is there a simple way for me still to have PVOutput calculate the money side (which it does so well) while limiting the amount on which there is a subsidy to either the ratio of 4 KW to my new total system capacity (ie pro rata it) or alternatively using the Solar Edge inverter which only supports the original 4KW panels?


Its no possible since the debits/credits are calculated from the generation / consumption numbers received.

Is this a hard limit of 4kW or a percentage of the new system capacity?

New system is 5kW and exports 10kW, it is limited at 4kW or 4/5*10 = 8kW


It’s a hard cap of 4 KW for domestic customers. 8 years ago when we were awarded it (for 25 years) it was a generous subsidy, much needed as the cost of panels etc was more than twice what they are today and they were 10% less efficient.
We recently added to our 8-year old system of 4KW a further 9 KW of new panels. we get zero subsidy for them.
I guess I just need to approximate it by taking the subsidy cost and as you suggest, pro rata the real rate to have a number which will be near the amount being earned.
Thank you.


I simply add the FiT level to 50% of the export as my credit per kWh - as the export is not metered but “deemed” this works fine.


That works fine if your configuration is up to 4 KW. If over, as in my case, one has to pro rata as the FiT isn’t available of the additional capacity sadly.


Strictly speaking, the limit is 50kW for deemed export but I get your point. Mine is a G.59 approved system of 5.4kW …