Modeling Demand Response of Charge Point Operators to Consider Flexibility in Grid Planning

Electric Vehicles (EVs) are creating new challenges to power system planning and operation such as grid over-loads and voltage deviations, particularly at the distribution system level, while simultaneously offering new opportunities in congestion management through their ability to provide flexibility. Traditional planning methodologies consider the trade-off of investment costs against improved system reliability and energy efficiency. However, to embed EV flexibility into grid planning, models that estimate the flexibility of Charging Point Operators (CPOs) managing EV charging stations are necessary. For that, CPOs need to be characterized, allowing estimation of their flexibility, in particular, their ability to reduce grid overloads (congestions) and voltage deviations, as well as their operational costs when providing such flexibility. In this paper, a new flexibility model for CPO flexibility is proposed, which characterizes CPOs based on their charging and occupancy rates. The model is then embedded into the grid planning problem by defining a new flexibility cost function. An illustrative example is presented to show how the proposed model is embedded into optimal planning. The obtained results show an example where the best investment is an hybrid solution between traditional reinforcement investment and the use of flexibility.