A Comparative Assessment of EV Charging Models: Cost and Environmental Impacts of Firm vs. Managed Loads with Separate Metering

Abstract

This article investigates the economic and environmental impacts of integrating electric vehicles (EVs) into power grids, focusing on a facility that consumes 26,498 kWh daily, has a peak demand of 2,022 kW, and includes a 4,000 kW solar PV system and a 10,079 kWh Tesla storage system, generating 6,918,968 kWh annually. The study emphasizes the advantages of managed charging strategies and separate metering for EV tariffs. Managed charging not only significantly reduces the Net Present Cost (NPC) and carbon footprint compared to firm charging, but it also enhances  grid efficiency by utilizing renewable energy sources. This positions EVs as a transformative element in power grid ecosystems.

Additionally, the analysis presents a methodology for assessing EV battery degradation, providing critical insights for optimizing charging strategies to maximize economic efficiency and environmental sustainability. The findings suggest that institutions like hospitals can achieve significant cost savings through separate metering of EV charging stations under specialized tariffs.

Moreover, the financial evaluation compares the current system, which has a total annual cost of $3,974,455, to the proposed system, which reduces the total annual cost to $3,615,661. These savings are realized through reduced energy purchases, lower demand charges, and revenue from energy sales. Overall, the study underscores the pivotal role of optimized EV integration in reducing costs, enhancing grid stability, and promoting environmental stewardship.