So, I had a client request the CO2 savings figures for systems with PV vs. the same systems with battery storage included.
Of course, I had assumed that the systems with batteries included would have greater CO2 saving figures (or "CO2 emissions avoided" figures).
However, the CO2 emissions avoided figure is slightly lower for the systems with battery. An example (not actual figures but there about!):
* 170kWp Solar PV system with no battery: 150,000kWh/year production, 60,000kg/yr CO2 emissions avoided
* 170kWp Solar PV system with battery storage: 150,000kWh/year production, X amount stored in battery, 58,000kg/yr CO2 emissions avoided
How can this be? The only things I can think of are:
> Perhaps it is not including the battery storage figures, and so the CO2 avoided stays roughly similar. However, I think this is unlikely as each time I did this on different systems, the CO2 avoided seemed to decrease by roughly the same amount each time I added batteries, and it never increased.
> Perhaps it takes into consideration the CO2 in the production of the battery?! This also seems unlikely.
I just don't want to say to a client: "You will save more CO2 if you don't have a battery installed", as then the client is likely to not have the battery installed, when in fact this will help their energy bills etc far more than just the Solar PV.
Thank you
