Smart Charging of Electric Vehicle Fleets: Modeling, Algorithm Development, and Grid Impact Analysis, with Emphasis on Fleets of Transit and Heavy-Duty Freight Vehicles

Electrification of the transportation sector has the potential to significantly reduce greenhouse gas emissions from internal combustion engine vehicles. However, with increasing penetration of electric vehicles (EVs) and their associated power demands, there is a need for charging strategies which minimize the cost for operators, maximize the usage of carbon-free electricity, and most importantly, minimize the peak demand on power distribution infrastructure. This is particularly important for large fleets of freight and people carriers (e.g., as used by Amazon, FedEx, public transportation systems, and a myriad of local transporters, as well as long-haul, over-the-road freight transportation) of high energy capacity EVs, which concentrate charging power demands both spatially and temporally. Smart charging represents a promising, near-term, and inexpensive approach to addressing these challenges. Based on input data such as time-of-use pricing, grid energy mix, and operator preferences, the investigators have shown previously that smart charging in residential settings can intelligently choose charging time windows and power profiles that minimize the EV owner’s cost to charge, and maximize
the usage of carbon-free energy, while exploiting non-uniqueness in power profiles to decrease the impact on the grid and utilities. In the research, smart charging will be explored in the larger context of electric vehicle fleets carrying freight and/or people to assess its potential to again decrease charging costs, increase carbon-free energy usage, decrease spatially-concentrated peak demands on the grid, and lower infrastructure investment. Notably, the approach will exploit ‘greedy’ algorithms which accomplish the research goals without the requirement of coordinated charging, and thus can be readily adopted in the near-term at low cost. Assessment of the smart charging strategies as applied to freight and people carriers will also be conducted to determine their efficacy and to quantify benefits of interest to decision makers, such as utility operators and government regulators, who must decide on future infrastructure improvements and fleet regulations based in part on potential benefits derived from smart charging. Lastly, a partnership with Atlanta Public Schools (a minority-serving entity) will be explored to test smart charging algorithms for decreasing peak power demands in their upcoming deployment of 25 new electric buses in the fall of 2024.