Dean O

I figured out what the problem was. I hada manually created a battery with 11kWh of energy but somehow this was only being read as about 4kWh due to incorrect setup. Once I switched to another battery of a similar size in the existing database the battery utilization behaved as expected and I got up to 11.8MWh of self-consumption a year. I should add that setting up your own battery on PVsyst is deeply confusing as it requests detailed information about cell design that is not available on the manufacturers tech sheet. Even though it said the battery had 11kWh of available energy it did not.

I'm trying to run a simulation where a customer has load only ealry in the morning and late in the evening. Normal PV would not be sufficient to cover this so we are using batteries to store the energy during the day, which will then discharge to cover the evening load. When I run the simulation with 20kW PV only it produces 25MWh / year and the self-consumption is 5MWh / year, which is understandable. When I add 33kWh of storage to the system however, it only increases the self-consumption by 1.5MWh / year, which seems very inaccurate. When I look at the houlry graphs I see that the battery charge and discharge is only 3-4kWh / day, which doesn't make sense considering the PV is 20kW, the battery is 33kWh and the customers evening load is in the 30kWh range, being a spike from 0-8kW for about 3 hours from 6-9, then dropping back to 0. With this profile I would expect the battery to fully charge during the day and then be able to discharge around 28kWh in teh evening (given a 90% DoD). Why is this not happening? When I look at the the battery state of charge hourly graph it shows that the battery is fully charging and discharging every day, which should mean this much power is being transfered, so why is it only showing 3-4kWh of energy and not 28? With a full charge / discharge cycle every day all year I should get around 9MWh of use out of the battery so why is it only giving an uptake of 1.5MWh? I've triple checked all the settings and the battery capacity is correcet, the max and min charge valume is correct and the customer load profile is as described. Please can someone help me with this issue as I nee to accurately predict these figures for many clients and I cannot get it to work. I have attached a typical load profile for a day with the system and the battery settings.