Abstract

the awareness of energy security and global warming is increasing, alternative technologies are being developed such as electric vehicles. In addition, the integration of a more sustainable energy system with renewable resources put a lot of pressure on the electricity system in terms of regulation power. This thesis has investigated and developed proposals of business models with electric vehicles, which by their construction can raise value for both customers and electricity companies. The development of the business models have been done using a model, which was based on the complexity of the frequency control market, the charging of vehicles and the behavior of the drivers. The proposed models address two types of customer segments; business and private customers. In addition, applying a perspective that includes active and non-active customers has segmented these further. Based on the assumptions in the thesis, the most promising area of interest is the non-active business customer, in this case, a car pool. This proposal was based on the simulation results together with an analysis of advantages and disadvantages with active and non-active customers. This proposal assumed that customers preferred to be non-active in order to maintain flexibility and freedom, which could be studied further by customer surveys. 

Abstract

the use of electric vehicles grows there is a greater possibility of using aggregated sets of electric vehicles as a large flexible unit to assist with the control of the power system. In this paper, the possibility of using electric vehicles as a flexible load for frequency control is investigated. The investigations are performed in a Pan-European interconnected grid with varying wind power penetration and different operational scenarios. Within this grid, the paper focuses on primary frequency control provision from electric vehicles and how the system behaves as the vehicles are being controlled within their respective areas. The investigations show that electric vehicles can be used for primary frequency control with different wind power penetration. By controlling the vehicles, the steady state frequency is improved and, since the vehicles react fast enough to the frequency changes, also frequency nadir and rate of change of frequency are positively affected.

Abstract

This paper assesses the impact of electric vehicles (EVs) providing primary frequency regulation via vehicle-to-grid (V2G) technology. The aim of the work is to define a set of recommendations in order to guarantee a stable large-scale deployment of EV fleets as primary reserve providers. A realistic fleet model is proposed, which emulates the aggregated response of a number of EVs characterized by V2G hardware response times derived in laboratory tests. The effects of primary frequency control via EV fleets replacing conventional generating units are assessed with a sensitivity study in a single-bus power system with growing fleet sizes and response times. Two recommendations are derived to guarantee safe and stable operation: Recommendation 1 requires the share of EVs providing primary reserve to be smaller than the reserve from conventional units; Recommendation 2 requires response times below a given limit value, calculated as a function of the following power system parameters: the system inertia, the total primary reserve over the rotating generation capacity, and the employed droop gain. The full 60 kV power system of the Danish island of Bornholm is then employed to evaluate the validity of the proposed requirements on a real system with complex dynamics, non-linearities and voltage dependencies.

Abstract

Electric Vehicles (EVs) can, when they are not used for driving, create value for the EV owner, by delivering ancillary services to the transmission system operator. Calculating potential earnings from grid services and charging strategies highly depends on the driving time, driving distance, and time spent at different locations. While few datasets describing EV usage exist, this work is based on one of the most extensive datasets gathered from 7,163 Nissan LEAFs. Using the real driving and charging data it was possible to calculate the value of a specific charging strategy for the individual EV. The EV dataset was used in a simulation based on British electricity transmission network operating codes and frequency measurement data. The outcome is the profit from frequency regulation for each EV in the data-set, which is found to range between 50 and 350 £/year, because of the large difference in the EV usage.

Abstract

Electric vehicle (EV) chargers can be controlled to support the grid frequency by implementing a standard-compliant fast primary frequency control (PFC). This study addresses potential effects on power systems due to control discreteness in aggregated EVs when providing frequency regulation. Possible consequences of a discrete response, as reserve provision error and induced grid frequency oscillations, are first identified by a theoretical analysis both for large power systems and for microgrids. Thus, an EV fleet management solution relying on shifting the droop characteristic for the individual EVs is proposed. The PFC is implemented in a microgrid with a power-hardware-in-the-loop approach to complement the investigation with experimental validation. Both the analytical and the experimental results demonstrate how the controller performance is influenced by the response granularity, and that related oscillations can be prevented either by reducing the response granularity or by applying appropriate shifts on the droop characteristics for individual EVs. This is an open access article published by the IET under the Creative Commons Attribution -NonCommercial License (http://creativecommons.org/licenses/by-nc/3.0/) Document type: Article