The e-laad.nl foundation was initiated in 2009 by the Dutch grid operators and from the start the focus lay on the smooth introduction of an electric vehicle charge infrastructure in the Netherlands and, by doing so, facilitating the emergence of electric vehicles (EVs). The Dutch grid operators initiated this because they recognized that electrification of transport would start sooner or later and they should investigate the impact electric vehicles will have on the grid. This way they could prepare to mitigate the effects, for instance by introducing demand response in the charging cycle; so called smart charging.
To accomplish this e-laad.nl worked together with partners on the standardisation of plugs, charging cards and started the development of the Open ChargePoint Protocol (OCPP), in which the communication between charging station and backoffice system was standardised. Later on smart charging profiles where also added to the OCPP protocol.
To make sure all the charge stations owned by e-laad.nl had correctly implemented the standards and could (smart) charge the different Electric Vehicles, several tests procedures and test where created and executed. This was continued when the e-laad.nl foundation was split into two parts; EVnetNL as charge point operator, and ElaadNL as charging infrastructure knowledge centre. The testing activities where positioned within ElaadNL and new tests, mostly related to more advanced smart charging and power quality, where created afterwards.
During the years of testing various issues came to light, related to interoperability, smart charging and to the impact of EVs on the grid. Cases where observed of EVs not listening correctly to the stations signals and of EVs creating harmonic distortions and short current peaks, see figure 1 and 2, which can have a big impact on the functioning of the charging station and possibly even on other equipment and on the electricity grid itself.
Figure 1: Harmonic distortion of the current
Figure 2: Current peak (˜90A) during start of charging process
The outcome of several tests made ElaadNL realize that more tests and more types of tests would be needed to ensure a smooth large scale introduction of charging infrastructure and EV in the Netherlands. The expectation is that in 2025 The Netherlands will count about 1 million electric vehicles, of which most will be charged in the evening in residential areas. To be able to accommodate this cars will need to be able to smart charge and, if the car supports it, able to return electricity to the grid. This way the amount of energy that is supplied by (renewable) energy generators and can be transported by the grid can be optimised with the energy needs of the customers. During our tests we came across several cases where smart charging let to issues on the EV or charging station side, which strengthened our belief in the need of testing EVs, charging infrastructure and the different combinations before market introduction.
Also, EVs and charging infrastructure might have another effect on the electricity grid which is less visible than the capacity. During the previous tests cases where found where the power quality of the grid was negatively influenced when charging., which could influence the charging station itself. As standalone cases these would not have a significant impact on the grid yet, but if several of these products would be in a same location, like on a charging plaza, the influence on the grid might add up and have a significant effect on the grid. This might increase energy loss and damage or reduce the lifespan of grid assets and/or household equipment.
To be able to test the different EV and charging station combination, the smart charging behaviour of the products and their impact on the power quality, ElaadNL is currently improving his testlab facilities.
ElaadNL testing ground
To allow EV manufacturers to test the functionality of their car on the different charging stations in the Netherlands the parking lot surrounding the ElaadNL office building will become one big charging plaza where all public charging stations found in the Netherlands will be installed. All stations will be able to smart charge and the energy flows in this charging plaza will be managed by a central system which can send specific testing charge profiles to the stations. These energy flows will not only be measured on size, but by the use of special equipment also on power quality. In the testing ground several high frequency power quality meters are implemented, which monitor the effect the electric vehicles have on the electricity grid.
If anything out of the ordinary is found, more detailed tests can be run in the ElaadNL testlab which is already in place and equipped with advanced measuring equipment. Here the tests can be run more controlled and the data can be logged more precise.