Before revision:  We provide a characterisation of the optimal strategy using the stochastic maximum principle and develop a numerical algorithm to solve this control problem , Based on this numerical solution, we provide detail and intuition for the optimal strategy for a regulated firm .
After revision:  We provide a characterisation of the optimal strategy , and develop a numerical algorithm to solve this control problem , Based on this numerical solution, we provide detail and intuition for the optimal strategy for a regulated firm .