The spread of e-mobility can be accelerated if private charging infrastructure could be put to wider and more flexible use. Technical, legal and tax restrictions currently prevent the simple and seamless charging of different users or different cars at private charging points in Germany. For example, when a private user charges a company car at home, an additional meter and an additional electricity supply contract are required to separate the electricity consumption of the company car from the private consumption. If an employer allows employees to charge their private vehicles at work, or when multiple users share a private charging station, the different charging processes also have to be billed separately. This usually requires a charging service operator doing the back-office billing calculation. The communication and processes used for this are not standardized by the Federal Office for Information Security (BSI). Use case 16 (German “Energiewirtschaftlicher Anwendungsfall ‘EAF-16’) of the BSI therefore describes the use of charging points in non-public environments with separate metering of energy consumption. However, no commercial application of the use case 16 exists so far.

In this paper, we present a new technical solution for the separate metering and billing of EV-charging at private charging points (use case 16). Our solution is based on an advanced smart meter infrastructure and event-driven tariffs. An event-driven tariff is characterized by the ability to switch between tariff levels based on internal or external events. Such an event might be the identification of a specific user or specific EV. The energy consumption of each charging process is measured by a digital electricity meter connected to a Smart Meter Gateway (SMGW). At the beginning of each charging process, the charging infrastructure triggers a tariff event to allocate the electricity consumption to the specific tariff register of each user or EV. The accumulated energy quantities of each user are then transmitted via the SMGW to the electricity vendor using standard and secure BSI-processes.

The concept has been successfully tested in our EV-field-laboratory using a prototype of an enhanced SMGW of EMH Metering. (EMH Metering is one of five certified manufacturers of smart meter gateways in Germany). It reflects the results of a joint development project, funded by the German Ministry of Economic Affairs.

The paper describes the technical infrastructure, including the enhanced SMGW, (sub-)meters, and a standard charging point. We will present the required processes and signalling between the stakeholders, e.g. the electricity vendor, the gateway administrator and the technical components. Results of various tests conducted in our EV-field-laboratory are also shown. Additionally, we will give a brief outlook on how the same event-driven tariff concept can be used for further applications, such as dedicated electric vehicle charging tariffs in private households.