How to Read Smart Meters: All Methods Compared

Over 6 million smart meters are installed in Austria. They record electricity consumption in 15-minute intervals, creating a detailed picture of energy usage. Customers are entitled to this data. But how do you actually get your hands on the Viertelstundenwerte (quarter-hourly values)?

There is no single answer. Depending on your use case, at least five different methods are available, each varying significantly in data scope, level of automation, cost, and technical complexity.

This article systematically compares all five options: from manual downloads via the grid operator portal and the P1 customer interface, through the EDA portal, to CT clamp measurements and fully automated API access. Whether you want to check your personal consumption, evaluate client data as an energy consultant, or integrate consumption data into your application as a software developer, you will find the right method here.

What does "reading a smart meter" mean?

A smart meter (intelligenter Stromzähler) records energy consumption at regular intervals and transmits the measurements digitally to the responsible Netzbetreiber (grid operator). In Austria, these are typically Viertelstundenwerte (quarter-hourly values, one measurement every 15 minutes), Tageswerte (daily values), and Zählerstandsgänge (meter reading progressions).

"Reading" a smart meter does not mean looking at the current meter reading on the device itself. It refers to the digital retrieval of historical and ongoing consumption data. This data forms the basis for load profile analysis, energy optimization, billing, and monitoring.

Legal framework: In Austria, customers have the right to their consumption data (regulated by the IME-VO and the ElWOG, which is being replaced by the new ElWG). Quarter-hourly values currently still require an opt-in with the grid operator. Under the ElWG, quarter-hourly values will become standard for most metering points from 2027. Daily values are already available without opt-in.

Depending on the method, data is available in different formats: CSV, XLSX, XML (MSCONS format), or JSON. Which format you get depends on how you retrieve the data.

Method 1: Grid operator web portal (Netzbetreiber-Portal)

How the query works

Each of Austria's 120+ Netzbetreiber (grid operators) runs its own customer portal. Well-known examples include the Wiener Netze Smart Meter web portal, the Netz Niederösterreich service portal, and the Energie Steiermark grid portal. Registration requires your Zählpunktnummer (metering point number) and personal customer data.

After logging in, you can view your consumption as a chart and download the data as a CSV or XLSX file. The available time range varies by grid operator but typically goes back three years.

Advantages and limitations

Advantages: Free, no technical expertise required, and immediately available. For a quick look at your own consumption, the portal is the simplest starting point.

Limitations: The process is entirely manual. You need to log in, select the desired time range, and download the file. Each grid operator has a different portal with a different interface. There is no API and no automated export. Data is available with approximately 1 day delay. If you have Zählpunkte (metering points) with different grid operators, you need to log into multiple portals. Bulk downloads for multiple metering points are not possible.

Suited for: Private individuals who occasionally want to check their own consumption at a single metering point.

Method 2: P1 customer interface on the smart meter

What is the P1 customer interface?

Many smart meters have a physical interface directly on the device: the P1 port (Kundenschnittstelle). This is an RJ12 socket or an optical head through which the meter outputs measurements in real time. Communication uses the DLMS/COSEM protocol via a serial M-Bus interface.

The P1 interface must be activated by the responsible grid operator (opt-in required). Every grid operator is legally obligated to enable the customer interface upon request. However, not every installed meter type supports the interface — in practice, limitations can still occur.

Ready-made products and DIY solutions

Both ready-made products and DIY solutions are available for the P1 interface. Ready-made devices such as energyLIVE (by smartENERGY / Energie Steiermark), the HomeWizard P1 Meter, or the SHRDZM customer interface module attach directly to the meter, connect via Wi-Fi to the home network, and transmit data to the manufacturer's cloud or store it locally. Some manufacturers, such as HomeWizard, also provide a local API.

Alternatively, the P1 interface can be read with a Tasmota-based M-Bus reader and a single-board computer (e.g., Raspberry Pi). This approach offers maximum control but requires technical expertise and your own infrastructure for data collection and storage.

Advantages and limitations

Advantages: Real-time data with very high granularity — instantaneous values such as power, voltage, and current every 1 to 2 seconds. The P1 interface is the only method that delivers second-by-second values. Independent of the grid operator portal. Ready-made products offer simple installation with their own app and visualization.

Limitations: Hardware installation required, physical access to the meter necessary. Only your own meter can be read. Historical data is not provided. Central management of multiple meters is not supported. Hardware costs of 25 to 100 EUR per meter. With ready-made products, there is dependency on the manufacturer (vendor lock-in): if the cloud is shut down, historical data is lost. Not all devices are compatible with all meter types in Austria. In some regions, practical use is nearly impossible: in Vienna, for example, most meter rooms have no power outlet near the smart meter, and the optical interface offers no way to power the smart meter adapter — making continuous operation infeasible.

Suited for: Private individuals and smart home integrators who need real-time monitoring at a single location. Ready-made products are ideal for a quick start, DIY solutions for technically savvy users with specific requirements.

Method 3: EDA portal for energy service providers

What is the EDA?

The EDA (Energiewirtschaftlicher Datenaustausch, Energy Data Exchange) is the central data hub of the Austrian energy sector. Through the EDA network, consumption data, master data, and process data are exchanged between grid operators, suppliers, and authorized third parties.

Registered energy service providers (Energiedienstleister, or EDL) can query consumption data for Zählpunkte (metering points) with an active customer consent via the EDA portal at eda-portal.at. Access requires EDA registration as a market participant with a dedicated participant code (Teilnehmercode).

Data query process

The process follows a fixed workflow: obtain customer consent, register the Zählpunkt (metering point), retrieve data as an XLSX download. The portal is free to use for up to 50 metering points. Available data includes historical quarter-hourly values, daily values, and meter reading progressions (Zählerstandsgangwerte).

Advantages and limitations

Advantages: Access to data from all Austrian grid operators through a single platform. Cost-effective for small volumes. Official, regulated infrastructure.

Limitations: Data retrieval is manual via XLSX download. There is no API and no webhook notifications. The registration process as a market participant typically takes 4 to 8 weeks. The portal interface is not designed for high volumes. Downloaded files are not in a machine-readable format (JSON/XML) and require manual conversion.

Suited for: Small energy service providers with fewer than 50 metering points who accept manual processes.

Method 4: CT clamp-based measurement

How does the measurement work?

Besides the P1 interface, there is another local method: current transformer clamps (CT clamps). Devices like the Shelly EM or Shelly Pro EM are not connected to the smart meter itself but measure current directly on the supply line via current transformers clamped around the phase conductors. The measurement is independent of the smart meter and its interfaces.

The devices connect via Wi-Fi to the home network and transmit data to the manufacturer's cloud or make it available through a local API. Installation requires access to the fuse box and should be carried out by a qualified electrician.

Advantages and limitations

Advantages: Independent of the P1 customer interface — works even if the meter type has no P1 port or it has not been activated. Real-time data. Local API available. Relatively inexpensive (30 to 80 EUR).

Limitations: Measures only current and power, not the official meter values from the smart meter. Not calibration-law compliant and therefore not suitable for billing purposes. Installation at the fuse box requires a qualified electrician. Does not scale for many locations. Historical data depends on the manufacturer and their cloud availability.

Suited for: Private individuals and small businesses who need real-time consumption data and have no access to the P1 interface.

Method 5: Programmatic access via API

Why an API?

All previous methods require either manual work, physical access to the meter, or both. Anyone wanting to integrate consumption data into their own software, dashboards, billing systems, or energy management systems quickly reaches the limits of these approaches. An API (Application Programming Interface) delivers data in a machine-readable JSON format, automated and without portal logins or on-site hardware.

How energiedaten.at works

energiedaten.at connects to all 120+ Austrian grid operators through the EDA infrastructure. The workflow: obtain customer consent digitally, register the Zählpunkt (metering point), retrieve data automatically. Data delivery is via REST API (JSON), webhooks (push notifications when new data arrives), and CSV export.

Available data categories include Viertelstundenwerte (quarter-hourly values), Tageswerte (daily values), and Zählerstandsgangwerte (meter reading progressions). The free tier includes 1 metering point. Paid plans start at 29 EUR per month.

Advantages and limitations

Advantages: Fully automated. All grid operators through a single interface. No hardware effort. Scales from 1 to over 10,000 metering points. Machine-readable formats (JSON, CSV). Webhook integration for push-based workflows. GDPR-compliant consent management.

Limitations: No real-time data. As with all grid-operator-based methods, data is available with approximately 1 day delay. Costs increase with higher volumes. EDA registration as a market participant is required (energiedaten.at supports the onboarding process).

Suited for: Energy service providers, software developers, building managers, and anyone who needs automated data retrieval for many metering points.

All methods compared

Which method is right for you depends on three factors: How many metering points do you need to read? How often do you need the data? And should the process be automated? The following table compares all five methods.

For automated access to quarter-hourly values from all Austrian grid operators, energiedaten.at offers a free starting tier with one metering point.

Frequently asked questions about reading smart meters

Do I need to activate my smart meter to retrieve data?

Daily values (Tageswerte) are available by default on every smart meter. For the more detailed quarter-hourly values (Viertelstundenwerte), you need to opt in with your grid operator. This is typically done through the grid operator's customer portal or by written request. Without the opt-in, only aggregated daily values are stored.

How current is the data?

That depends on the method. Grid-operator-based methods (portal, EDA portal, API) deliver data with approximately 1 day delay. The consumption values from the previous day become available the following day. The P1 customer interface and CT clamps, by contrast, deliver real-time data directly from the meter.

Can I query data for metering points that belong to someone else?

Yes, with a customer consent (Kundenfreigabe). The metering point holder must agree to the data query. This consent management is the foundation for the work of energy service providers. Both the EDA portal and energiedaten.at offer structured processes for obtaining and managing customer consents. More on the topic of automating smart meter data.

What are Viertelstundenwerte (quarter-hourly values)?

Viertelstundenwerte are energy consumption (or feed-in) measurements captured every 15 minutes. This yields 96 data points per day. With this data, you can create load profiles, identify consumption peaks, and perform detailed energy analysis. They are significantly more informative than daily values, which only provide a single aggregate figure per day.

What data formats are available?

Depending on the method: CSV and XLSX (grid operator portal, EDA portal), XML in MSCONS format (EDA network internally), and JSON (API). For software integration and automated systems, JSON is the most suitable format. For an overview of the technical infrastructure, see the smart meter guide for Austria.

What does it cost to read smart meter data?

The grid operator portals are free. P1-based hardware costs between 25 and 100 EUR, CT clamp devices between 30 and 80 EUR. The EDA portal is free for up to 50 metering points. energiedaten.at offers a free starting tier with one metering point; paid plans start at 29 EUR per month and scale with the number of metering points.

Which method fits your use case?

There is no universally "best" method for reading smart meter data. The right choice depends on the use case.

Private individuals who occasionally want to check their own consumption are well served by the grid operator portal. For real-time monitoring at a single location, the P1 customer interface offers the highest granularity — alternatively, CT clamps provide real-time data even without P1 access. Small energy service providers with few metering points can start for free with the EDA portal.

Those who need automated consumption data for many metering points and want to integrate it into their own systems cannot avoid an API solution. Manual retrieval through portals simply does not scale beyond a certain number of metering points.

Try energiedaten.at for free with one metering point — register in minutes, get your first data the next day.