If we charge electric cars in the same way in the future as we do now, the peak load on the electricity grid will grow because the number of electric cars increases rapidly. In a pilot project involving 138 households, the peak load was reduced by 40% without users noticing their car was charging slower. The Smart Charging at home was done using an energy management system that received information about the available grid capacity from the Distribution System Operator (DSO).
By smartly influencing the electricity demand of electric cars charging at home, more electric cars can be charged simultaneously without expansion of the electricity grid. The pilot ‘Flexible charging behind the meter’ is a joint initiative of Maxem, Enexis Netbeheer, Enpuls and ElaadNL.
In the pilot, smart charging of electric cars at home was researched in 138 Dutch households that participated in the pilot project. Smart charging was done via an energy management system (Maxem) that controls the energy flows within a house. The aim of the pilot project was to adapt the charging of the electric car to the load on the electricity grid. In the behavioral research we found that the users weren’t experiencing major differences with the normal situation.
During peak hours (between 5 p.m. and 9 p.m.), the power demand in the neighborhood is high and therefore there is less residual capacity for electric vehicles. Therefore, the electric cars were charged slower, unless the user interrupted smart charging by using the override button. This allowed the car to charge at the usual speed during peak hours (the hours with limited available capacity). Electric cars at home are often connected to the charging point all evening and night and only have to charge for a limited number of hours. As a result, avoiding peak hours with the use of smart techniques rarely causes problems in practice.
Having the flex button was considered very important by participants, but this button was hardly used in practice. In addition, it made little or no difference whether users were rewarded for using this button or not.
The pilot shows that charge control can be successfully applied at home charging stations via an energy management system. In the future there will be many home chargers in addition to regular household consumption. The power demand on the grid will be much higher than it is now. In this pilot, the 138 households with an electric car were divided into four virtual neighborhoods and a lower limit of the charging speed of 6 amps was used. Under these circumstances, the peak load already dropped by 40%. In the future, the number of loading cars in a district will be even higher and, technically, the total shifting of the charging duration outside the peak hours is also possible. In that situation even higher percentages are possible. Annabel van Zante, project leader of the pilot project: “We are pleased that smart charging at home can significantly reduce peak loads. The technical possibilities will further increase in the coming years, so we expect the peak load reduction to increase even further. ”
The survey also shows that participants generally have a positive attitude towards smart charging: 84% of the participants indicate that they want to (continue to) use smart charging in the future and 81% recommend other electric drivers to use it.
In order to scale up such a solution, it is important that there is an unambiguous communication protocol that every DSO can use to communicate with any energy management system. In this way, smart charging of home charging points can contribute to a stable electricity grid.
View all research results in the full research report.