  The possibilities to involve small-scale prosumers for ancillary services in
the distribution grid through aggregators and local flexibility markets
question whether it is profitable for prosumers to oversize proactively. In
this analysis, a Python model is developed to identify the cost-optimal
operation plan of the PV-battery system and to evaluate the device flexibility.
An economic assessment is carried out to derive the cost-benefit of sizing
based on the mean electricity price. A sensitivity analysis is performed with
the above results to study the profitable sizing of PV-battery systems with
flexibility services. The results show a promising advantage of oversizing
although limitations prevail with the extent of flexibility services offered.
