Electric vehicle charging costs and power losses under the energy price crisis: shifting dynamics in Norway

Electric Vehicle (EV) users benefit from smart charging strategies, which schedule the times of charging to minimize charging costs. While smart charging strategies are widely researched and employed in real-world applications, little is known about how their benefits hold up with a changing market environment over time. In Norway, the electricity market changed dramatically between 2019 and 2023 due to the energy price crisis and an expansion of interconnectors between the Norwegian and European grid, which led to higher and more volatile prices. This paper investigates how EV users' charging costs and grid operators' power losses are influenced by the use of smart charging strategies during that time. We use real-world residential EV charging data to develop a simulation model to generate diverse charging sessions. A mathematical model is used to compute cost-optimal charging schedules under flexible (smart) and non-flexible charging strategies. Our results show that the benefits of flexible charging strategies increased over time, i.e., with price volatility. The magnitude of the benefits depends strongly on when users connect their EVs to the grid. Although flexible charging can increase power losses by shifting demand to new peak times, we find that the monetary value of these losses remains low. Thus, from a societal cost perspective, flexibility still leads to lower overall costs. We also test our model in scenarios considering imperfect foresight of prices, a weakened time-of-use price, and battery degradation as part of the EV users' costs. The main findings remain robust in all three scenarios.