Enabling Technologies for Smart Grid Integration and Interoperability of Electric Vehicles

Abstract

Conventional, centralized power plants are being replaced by intermittent, distributed renewable energy sources, thus raising the concern about the stability of the power grid in its current state. All the while, electrification of all forms of transportation is increasing the load on the transforming power grid and potentially only contributing to the problem. However, an intelligent integration of EVs into the grid, could not only alleviate potential self induced problems, but also make EVs a vital resource for providing grid services. This thesis investigates the technical requirements for successful EV integration into the smart grid, as a smart, mobile distributed energy resource. The work is split into three key topics: enabling technologies, grid service applications and interoperability issues. The current state of e-mobility technologies is surveyed. Technologies and protocols in the full e-mobility architecture, enabling the synthesis between EVs and smart grid, are analyzed for potential gaps. A test system, inspired by the core of the e-mobility architecture, is implemented toenable testing of EVs providing grid services. The grid services identified in the NIKOLA project, as potentially viable to be provided using EVs, are tested in laboratory- and field experiments. The work shows that EVs can provide a varietyof grid services on the distribution- and transmission level, such as improving voltage quality, preventing transformer overloading and frequency regulation. The issue of interoperability in the field of e-mobility, investigated in the COTEVOS project, is explored. It is concluded, that collective testing of the OEM equipment in testing symposiums, is the best way to ensure interoperability between different OEMs, and to discuss as well as fix the issues in the standard itself. Altogether, it is demonstrated that the provision of different grid services, using EVs, is technically feasible. While some gaps in standards/protocols still exist, standardization committees are actively listening to inputs from e-mobility research projects to cover them in the new versions. This enables EVs to not only mitigate their own effects on the grid, but also provide value to grid operators, locally as well as system wide. Finally, it is shown that active integration of EVs into the smart grid, is not only achievable, but is well on its way to becoming a reality