Centralised Smart EV Charging in PV-Powered Parking Lots: A Techno-Economic Analysis

Abstract

Highlights: Results: A centralised smart EV charging algorithm for workplace parking lots is proposed. The algorithm is able to perform cost- or emissions-based EV charging, including a PV system in the optimisation. An innovative “benefit-splitting algorithm” is also proposed, to make sure EV owners receive fair compensation for participating in smart charging activities. Our results show possible reductions of up to 11% in EV charging costs, 67% in electricity provision costs for the CPO, and 8% in CO2 emissions if making use of an existing 35 kWp PV system. Contracted EV charging capacity for the parking lot can also be reduced, along with EV impact on the power grid. Implications: Centralised smart EV charging is already implementable in public charging with current technology, and it represents a powerful tool to reduce EV charging costs and their impact on power systems and to deliver grid balancing services as well. EV owners’ fair compensation should be addressed when designing advanced smart charging algorithms, especially when delivering services where substantial discomfort can be perceived, e.g., Vehicle-to-Grid (V2G). The increased uptake of Electric Vehicles (EVs) requires the installation of charging stations in parking lots, both to facilitate charging while running daily errands and to support EV owners with no access to home charging. Photovoltaic (PV) generation is ideal for powering up EVs, both for environmental reasons and for the benefit it creates for Charging Point Operators (CPOs). In this paper, we propose a centralised V1G Smart Charging (SC) algorithm for EV parking lots, considering real EV charging dynamics, which minimises both the EV charging costs for their owners and the CPO electricity provision costs or the related CO2 emissions. We also introduce an innovative SC benefit-splitting algorithm that makes sure SC savings are fairly split between EV owners. Eight scenarios are described, considering costs or emissions minimisation, with and without a PV system. The centralised algorithm is benchmarked against a decentralised one, and tested in an exemplary workplace parking lot in Denmark, that includes includes 12 charging stations and one PV system, owned by the same entity. Reductions of up to 11% in EV charging costs, 67% in electricity provision costs for the CPO, and 8% in CO2 emissions are achieved by making smart use of a 35 kWp rooftop PV system. Additionally, the SC benefit-splitting algorithm successfully ensures that EV owners save money when adopting SC.