Optimizing EU power grids for the electric vehicle
Major cross-industry collaboration including key automotive, power and related sector partners, academia and regulators
MERGE, which stands for ‘Mobile Energy Resources in Grids of Electricity’, is a €4.5m, 16 partner consortium project that includes utilities regulators, commercial organizations and universities with interests in the power generation, automotive, electronic commerce and hybrid and electric vehicle sectors across the entire European Union. This major two-year research initiative aims to prepare Europe to take full advantage of future significant increase in both the use of EVs in EU towns and cities, and the increasing proportion of the region’s electrical power generating mix composed of intermittent renewable resources such as wind, solar and wave energy. MERGE commenced in early 2010 and the results of a number of crucially important studies announced today relate to the early model development exercises that will enable the power grid operators to carry out more in-depth and detailed grid-scale modelling and simulation activities through the remainder of the project.
Commenting on the announcement of the first results of the MERGE project, Prof. Neville Jackson, Ricardo group chief innovation and technology officer, said: "Ricardo is particularly pleased to have been able to play a central role together with our partners in the MERGE consortium. We believe that there is much to learn about the impact and potential usage patterns of electric vehicles. Analysis of re-charging requirements for six European countries shows that, whilst there are some national variations, a 10 percent penetration of plug-in vehicles corresponds to a 10 percent increase in peak electricity demand using a “dumb” re-charging scenario where users plug-in their vehicles returning home in the early evening. Analysis from the survey has shown that 70 percent of potential users would prefer to charge their vehicle at home and 20 percent at work. It also revealed that despite the relatively low cost of re-charging, users were still highly motivated to make use of any low cost tariffs that may be available during off-peak demand. The full results of these studies will provide extremely robust data and models for later and more in-depth analysis by the MERGE project partners."
The results of the reports published are available for download from the MERGE project web site www.ev-merge.eu.
Defining requirements for plug-and-play charging
The first of the four studies for which reports have now been published was carried out by Ricardo and Technische Universität Berlin (TU Berlin). This research was an investigation of the requirements for both the power and information and communication technology (ICT) aspects of the required future plug-and-play interface between EVs and their charging infrastructure. In terms of power infrastructure the project team investigated the requirements for charging connector standardization and power level requirements ranging from simple single phase charging to multi-phase AC or high voltage DC fast charging and interactivity scenarios with grid services. The ICT aspects of the study examined user authentication, communications protocols and payment methods. In forming recommendations from this work the team in particular considered the requirements of standardization of charging methods and infrastructure in order to enable the type of effective ‘roaming’ services that would be needed to provide freedom of EV use comparable to that enjoyed today from vehicles powered by liquid fuels.
The role of smart metering technology
The second study – carried out by Iberdrola and Red Eléctrica of Spain, INESC Porto of Portugal, Power Public Corporation of Greece, TU Berlin, Electricity Supply Board of Ireland, and InSpire of Norway – was intended to specify smart metering systems for EVs. Smart metering solutions provide a potentially effective means of enabling EV charging functions on a universal basis including, for example, vehicle to grid (V2G) communication for the purpose of optimizing energy management. The smart meter can be onboard the EV or integrated with charging points. The study reviewed existing smart metering solutions under development by European industry and aimed to provide guidance enabling future EV smart metering solutions to be fully integrated with other emerging technologies and solutions in the field of electricity and remote control. Notable amongst these was, for example, the adoption of local home management schemes dealing with micro-generation, responsive loads and the potential of EV batteries as a source of grid energy storage.
Smart grid opportunities
The third study for which results were announced today was carried out by INESC Porto, Cardiff University, the National Technical University of Athens, Public Power Corporation of Greece, Ricardo and Red Eléctrica. This work examined how micro-grid concepts could be used together with advanced control technologies in a smart grid implementation of EV charging, both individually and in clusters of vehicles. The key difference with the existing stationary micro grid resources is that the EVs are mobile devices which are not always present, which requires a new approach if their presence is to be fully exploited. Management of the charging process is a key issue and three scenarios were addressed including ‘dumb’ charging (where each EV charges its battery without reference to external grid restrictions), charging based on a specific fixed dual tariff scheme, and a smart charging scheme that adjusts according to network restrictions in order to balance generation and load against, for example, the prevailing availability of renewable power.
The MERGE project has already scientifically demonstrated the potential of the smart grid as a key enabler for integrating electric mobility. In Germany for example, an EV market penetration of 10 percent would increase the country’s peak electrical load by 9000 MW to 72000 MW at 8pm each day based on a ‘dumb’ charging scenario of users charging their cars when returning from work. The smart control envisaged by MERGE would enable these 9000 MW additional loads to be moved into off-peak overnight periods, thus leaving peak demand unchanged. In this way overloads would be avoided and the existing power infrastructure would benefit from more efficient utilization.
Consumer attitudes and behaviours
The final study for which results have been published today focuses on the identification of traffic patterns and human behaviours relating to the use of EVs. Carried out jointly by e-business intelligence provider IMR World, Ricardo and the TU Berlin, this study investigated how conventional vehicles are currently used and the potential impact the widespread introduction of EVs would have on the grid. A detailed consumer attitudes questionnaire was distributed in eight languages to a range of distribution lists by all partners in the MERGE consortium. Over 1600 responses were obtained representing a cross-section of the European population and focussing in particular on Germany, Great Britain, Spain, Greece, Portugal and Ireland. The questionnaire responses provided statistics on the proportion of responders that would participate in multiple-tariff electricity rates, as well as potential usage patterns. These data have been used in basic models of the energy requirements of EVs under different ‘dumb’ and ‘smart’ charging scenarios. The models will be used in more detail as the work of the MERGE project continues.
Modelling grid connected EVs
In addition to the work published by the consortium today, an additional report will shortly be released based on a study carried out solely by Ricardo within the MERGE project, which aims to establish a methodology to enable grid operators to model the energy storage performance of grid connected EVs. This work will include a review of current and probable future EV battery technology, battery simulation model development, and assessment of implications for charging stations and vehicle battery management systems design and operation. Possible EV market penetration scenarios will also be developed and the combined outputs of this study will therefore enable the grid operation partners of the MERGE project to use the models developed in assessing the impact of EV use and the potential of future interactive services such as grid demand management and balancing. The report of this work is expected to be published in the next few weeks.