# Smart Meter Gateways: Options for a BSI-Compliant Integration of Energy Management Systems
## 3 Key Aspects of the BSI Technical Guideline with Relevance for Energy Management
### Processing of Measurements  
Meter measurements are either received or requested based on the _Meter Profile_. Even though we focus on electricity and mention deviating requirements for gas, an SMGW can also support other types of meters, such as meters for water and heat. After collecting the measurements, the SMGW must assess their correctness, check the status information sent by the meter and check its own status. If an issue is detected, the SMGW pushes a message to the _SMGW Administrator_ and additionally, depending on the type of issue, to the respective EMP. The values most recently collected from the meters according to the configured _Meter Profiles_ are stored internally and treated as latest meter readings. These data are then processed according to the _Examination Profiles_ and the configured tariff use cases. An overview of the tariff use cases and the temporal resolution of the available data is given in Table 1. To create transparency for the consumer, the measurements are collected in a list and stored for later access. The tariff specific data that are derived by the SMGW are then collected and eventually sent to the EMP configured in the respective _WAN Communication Profile_. Table 1 lists the triggers for transmitting derived metering data to an EMP. All registered measurements, processed input data and derived metering data can be accessed by the consumer via the _Consumer Interface_ (\"Letzterbraucher-Schnittstelle\", see Section 3.4). Although the technical guideline mentions an interface for CLSs to access metering data, it does not contain a definition of such an interface. Only interfaces for the consumer and the service technician are specified in document version 1.0 [7]. Therefore, local systems can only access metering data handled by the SMGW using the _Consumer Interface_. Since the SMGW is able to handle meters and tariffs for multiple consumers simultaneously, e.g., in the case of apartment buildings with different households, consumers are only able to access the data concerning themselves (see [16] for more details). All processing profiles are created and managed by the _SMGW Administrator_. Figure 1 depicts the process from registering the measurements to providing the data to local and remote entities. Concerning the availability of current meter readings provided by the SMGW, it is necessary to distinguish between entities within the WAN and entities within the HAN. An external party must act as an EMP in order to receive metering data. Inside the HAN only consumers can access the data relevant to them. A local EMS may use the _Consumer Interface_ of the SMGW in order to fetch the latest registered measurements. \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Trigger** & & **Tariff Use Case** & **EMP/WAN** & **Consumer/HAN** \\ \hline \multirow{4}{*}{time (internal)} & TAF1 * & Data parsimonious tariffs & \(\geq\)1 month & \(\leq\)15 min (60 min) \\  & TAF2 * & Time variable tariffs & billing period & \(\leq\)15 min (60 min) \\  & TAF7 * & Recording meter reading progression & billing period & \(\leq\)15 min (60 min) \\  & TAF8 & Registration of extreme values & billing period & registration period \\ \hline \multirow{4}{*}{threshold (internal)} & TAF3 & Load variable tariffs & billing period & \(\leq\) 15 min (60 min) \\  & TAF4 & Consumption variable tariffs & billing period & \(\leq\)15 min (60 min) \\  & TAF12 & Prepaid tariffs & on event & \(\leq\)15 min (60 min) \\ \hline \multirow{2}{*}{internal or external event} & TAF5 & Event variable tariffs & billing period & \(\leq\)15 min (60 min) \\  & TAF10 & Fetching of grid state data & on event & on event \\ \hline \multirow{4}{*}{external event} & TAF6 * & Fetching of measurements & 1 day & 1 day \\  & TAP9 & Fetching current feed-in & current data & current data \\ \cline{1-1}  & TAF11 & Direct control of local units & on event & on event \\ \hline \hline \end{tabular}  
* must be supported by the SMGW.  
\end{table}