Integrating electric vehicles (EVs) into vehicle fleets deployed by transportation network companies (TNCs; e.g., Uber and Lyft) is a particularly promising way to realize the benefits of vehicle electrification, due to the greater average miles traveled and passenger occupancy of TNC fleets. In this report, the researcher examines EV use in TNC fleets from 2016 through 2018. They leverage novel datasets from TNCs as well as from charging service providers (e.g., Chargepoint and EVGo) to analyze charging and use patterns of EVs within TNC fleets. These insights allow the researcher to quantify the emissions benefits of EV use within TNC fleets, assess the capability of EVs to perform TNC services, and understand the effects of EV use within TNC fleets on the charging behavior of non-TNC EVs. Findings show that the emission benefits of electrifying a vehicle in a TNC fleet are nearly three times greater than the benefits from electrifying a privately-owned vehicle.