Flow-Based Market Coupling (FBMC) is an advanced Capacity Calculation and Congestion Management
methodology introduced in Europe for the efficient coupling of market zones. The methodology accounts
for physical limitations of transmission lines more accurately than the net transfer capacity (NTC) approach.
The results however depend heavily on the underlying assumptions concerning the state of the grid at the
point of market coupling. To identify the available transmission capacity, the future generation and load
distribution needs to be known, which in turn also depend on the available transmission capacity. To escape
this problem the base case is derived to describe the probable conditions. Especially in long-term market
models, this is subject to high uncertainty and the future distribution of renewables is subject to assumptions
of the modeller, which might deviate significantly between different models. This paper analyses the effect
different distribution of renewables have on the available transmission capacity and thus the outcome of
Flow-Based Market Coupling.