Network peak load reduction by home charge management of electric vehicles

Objective

Electrification of the energy use of households is an undeniable trend nowadays. This trend introduces home appliances with a significant electricity consumption, such as home charge points for electric vehicles. Many studies have shown that simultaneous use of home charge points will lead to high peak loads in the local grid. Also ‘smart charging’ methods or algorithms could prevent high investments in reinforcement of the low and medium voltage grids. Enexis Netbeheer, ElaadNL, Enpuls and Cohere have initiated a pilot to research to what extent the peak load of the distribution network can be reduced by direct home charge management while minimizing inconvenience to end-users.

Approach

Households with battery electric vehicles (BEV) and a home charge point were invited to participate in the pilot. The participants (approx. 140) agreed to hand over the control of their charge point to an aggregator (Cohere) on behalf of the network operator (Enexis Netbeheer).

Because the participants were scattered all over the Netherlands, they were modelled as if they were virtually connected to the same low voltage network. When overloading of this (virtual) network is imminent, the power consumption of the charge points can be reduced by remote control. To this end, the network operator sends a control signal to the aggregator and the aggregator distributes this signal to all participants. The participants possessed a home energy management system (HEMS) that supported the control of their charge point. In case the charge speed of the car was affected too much, participants had the possibility to manually override the control of their charge point at any time, using an app on their smartphone.

During the pilot period, which lasted approximately one year, the degree of constraint of the charge points was changed regularly by varying the assumed available network capacity.

Different control strategies were examined (static vs. dynamic) and the influence of financial incentives on the behavior and acceptance of households. The acceptance of households was furthermore measured by two surveys and in-depth interviews, making this a unique pilot in which collected data is complemented with behavioral research.

Outcome

The outcome of this research is that the peak load of a grid with high penetration of charge points can be reduced by several tens of percent without causing significant inconvenience to end-users.

The application of home charge management can therefore provide considerable savings on grid reinforcements, lowering societal costs related to the energy transition.