  In recent years, the market for frequency containment reserve (FCR) has
become a relevant source of revenue for stationary battery storage systems in
Germany. During this period, prices for FCR have decreased, while the market
has become increasingly flexible with shorter service periods and lower minimum
power requirements. This flexibility makes the market attractive for pools of
electric vehicles (EVs). Their idle times are now often longer than FCR service
periods, providing the opportunity to earn additional revenue. In this paper,
multi-year measurement data from 22 commercial EVs are used to develop a
simulation model for FCR commercialization. In addition, the driving logbooks
of more than 460 vehicles from different commercial fleets are analyzed. Based
on our simulations, the impact of FCR flexibilization on the economics of an EV
pool is analyzed using the German FCR market design from 2011 to 2020. It is
shown that depending on the fleet, especially the recent change in service
periods from one week to four hours generates the largest increase in available
pool power. Further reductions in FCR service periods will like produce minor
benefits, as idle times are often longer than service periods. Overall, the
increase in flexibility greatly offsets the decreasing FCR prices and leads to
higher revenues for most fleets analyzed. According to our model, revenues of
about 250 EUR/a to 400 EUR/a could have been achieved per EV in the German FCR
market in 2020.
