ET24SWE0025 - Performance Evaluation of DC EVSE

As California continues to take a global leadership role in building and transportation decarbonization by aggressively pursuing energy efficiency and electrification measures to meet its climate goals, including its 2022 Scoping Plan to Achieve Carbon Neutrality (updated and released in November 2022 as required by California AB 32), the addition of electrically-powered equivalents to replace historically fossil-fueled appliances will have a serious impact on California’s total energy needs and its relative load shapes/profiles. A major California decarbonization activity currently underway is electrification of the light-duty vehicle fleet. Currently, plug-in electric vehicles (PEV) adoption remains low due to its relatively recent (2010) market introduction. However, adoption rates have increased significantly in recent years with estimates for PEV sales as high as six percent of all new vehicles purchased in 2022. As of 2022, the size of the light-duty fleet in California was 28.2 million vehicles. If just five percent of the gas-powered fleet were to electrify, the total annual energy required to meet California’s needs would be ~5563 GW-Hr annually. For this project, the research team will focus on two distinct electric vehicle service equipment (EVSE) categories; EVSE with an Alternating Current (AC) output, and EVSE with a Direct Current (DC) output. The PEV battery ultimately requires a DC source for charging and when connected to an AC charger the PEV’s on-board charge converter hardware is active. Using available published performance data, the research team estimates on-board charge converter hardware to be 80-92 percent efficient (www.ev-database.org). To date, power charging equipment under 30 kW is offered as AC Level 2, and it has relied on the vehicle’s charge converter to complete the total charging pathway to the battery. Recently industry has begun to develop and offer DC chargers in this power range. While most DC charger offerings in the <30 kW range are very new to the market and not yet Energy Star certified, there are a few DC systems that report a total system efficiency of 94-95 percent in the Energy Star Database. Assuming DC chargers are ~95 percent efficient and AC chargers including on-board losses are ~86 percent efficient, then if all of the PEVs currently in California opt to use DC charging, California could save up to 377 GW-Hr annually. This project will quantify the differences in EVSE charging efficiency between DC and AC chargers via a robust laboratory evaluation utilizing actual PEV components and commercialized EVSE. The project will also include analysis to quantify the state-wide impacts of DC charging including annual energy saved, demand reduction, and reductions of greenhouse gas emissions.