An analysis of vertical axis wind turbines (VAWTs), subjected to flow control by means of steady and pulsed slot blowing, was performed. The analysis was based on blade element theory that included experimental data acquired on a NACA 0012 airfoil. Two methods of control were considered: constant local blade momentum coefficient (oscillatory jet) and constant turbine momentum coefficient (steady jet). The net turbine power output was calculated by accounting for the pumping power required to drive the slot blowing system. The results show great potential for flow control by jet blowing using all methods and approaches. The best net performance increase, namely a factor of 3 in annual energy production, was achieved by means of pulsed blowing using a constant blade momentum coefficient, deployed on both sides of the blade. The simplest of all the methods, namely constant turbine momentum coefficient via a single slot, resulted in 60% increase in annual energy production.