A Kaya-like identity for decomposing and assessing business models for workplace and public electric vehicle charging

This work explores the business case for public and workplace electric vehicle (EV) charging from the perspective of a site host, such as a workplace, that invests in chargers to support employees, commuters, and visitors. We propose an identity that disaggregates energy throughput, or sales, on a charging network into three constituent measures—the ratio of unique drivers to chargers, the frequency with which drivers initiate charging sessions, and energy use per session. Together, these produce energy delivered per charger per unit time (e.g., per day), a precursor to revenue. The purpose is to disentangle the distinct drivers of energy sales, which enables analysis of drivers, their interactions, and policies that shape them. We demonstrate the value of the identity in a case study, using 95,000 sessions at 338 Level 2 chargers at the University of California San Diego, and show that energy throughput and its precursors are a function of network charging policy. If workplaces have the power to set policy, they may be able to shape energy sales and revenue on the network.