• Energy Research

The envisaged large penetration of electric vehicles (EVs) in the near future, brings new challenges to low voltage (LV) and medium voltage (MV) grids. For uncoordinated EV charging, the impact on the LV grid may be significant, due to the simultaneity between the residential power peak and the charging of EVs. The amount of EV chargers that can be connected to the grid without endangering the reliability or voltage quality for other customers is called the hosting capacity. This paper presents the analyses of the hosting capacity of a realistic LV residential network with 160 households for EV chargers. A stochastic approach is used, assuming that the EV chargers are randomly distributed over the households and the phases. For different EVs penetration rates in the network, the hosting capacity for slow chargers is determined. The results show that the EV penetration rate that the network can safely accept is 45%.

This paper presents some of the results from an international working group on voltage-dip immunity. The working group has made a number of recommendations to reduce the adverse impact of voltage dips. Specific recommendations to researchers and manufacturers of power-electronic equipment are: considering all voltage dip characteristics early in the design of equipment; characterize performance of equipment by means of voltage-dip immunity curves; and made equipment with different immunity available.

The paper analyses the measured emission from four individual modern turbines of about 2MW size equipped with power electronics. The four turbines show different long term spectra and their spectra also show different variations with time. The harmonic emission from individual turbines consists of harmonic and interharmonic spectra. This emission was shown to be low, with the exception of certain non-characteristic frequency components. The measured emission from individual wind turbines has been compared with emission limits. When IEEE Std 519 is applied, for two of the turbines the limits are exceeded for higher odd harmonics. At the same time, these turbines comply with the national French emission limits. Next, a study of the primary harmonic emission of a wind park as a whole was performed. It is concluded that the emission from a park can be higher as well as lower than the emission that would be obtained by adding the harmonic magnitudes of the individual turbine emissions.

Abstract Due to the potential for deploying distributed generation, improving energy efficiency and adopting sustainable energy-related practices, consumers provide significant value in the energy sector transformation. If their interests and goals are similar, they can group together and form energy communities. Energy communities enable consumers to jointly pursue their individual and collective economic, environmental and social goals, while simultaneously contributing to the decarbonisation of the energy system. Considering the growing interest in this field, this paper aims to enhance the understanding of the social arrangements, the technical designs and the impacts of energy communities. The social arrangements of energy communities are discussed in relation to the different actors, their roles and interactions. Then, the paper reviews the technical aspects of designing various local energy systems, while taking into account the goals of energy community members and outside actors. The reviewed literature is benchmarked with respect to the methods, modelling objectives and the constraints used in the design process. Finally, the paper quantifies the economic, environmental, technical and social impacts of energy communities, reviews the numerical indicators used to quantify these impacts and provides a critical discussion of the findings. Based on the findings, future research directions are highlighted.

Electric cars in the worldwide vehicle stock have reached sizeable growth since 2010. Besides proven benefits to the sustainable development and wheel-to-wheel efficiency, electric cars can provide side benefits to car owners and to power system utility. Plug-in vehicles can behave either as loads or as a distributed energy and power resource in a concept known as vehicle-to-grid (V2G). This paper reviews the main grid services that can be provided by the V2G technology. V2G system used to regulate the frequency of a microgrid has been analyzed. The analyzed microgrid is comprised of base power generation, a mixture of renewable energy sources, load and an EV aggregator. Different possible scenarios are taken account, for different shadings of renewable energy production in the grid, different sizes of residential load and different number of EVs. The results show that V2G concept can provide efficient primary frequency regulation in islanded operation of a microgrid with lower spinning reserve.