OpenEMS

Free plan APILinuxSelf-hostedWeb

What OpenEMS is

OpenEMS is a free, open-source platform for monitoring, controlling, and integrating energy storage, renewable energy sources, and related devices and services. Its three-part IoT stack includes Edge for on-site device communication and control, UI for browser and smartphone access, and Backend for connecting Edge systems and enabling internet-based aggregation, monitoring, and control. It supports fast, PLC-like control and reusable algorithms that work across devices.

Its integration list spans batteries, inverters, EV chargers, meters, tariffs, and data services. Supported interfaces include MQTT, Modbus/TCP and Modbus/RTU, InfluxDB, M-Bus, 1-Wire, JSON/REST, and JSON/Websocket. Edge and Backend use the Eclipse Public License 2.0; UI uses the GNU Affero General Public License 3. Production deployment guidance covers Debian/Ubuntu or Docker, and OpenEMS requires Java 21. The getting-started setup is intended for testing, not production. The project describes monthly releases and invites users to seek help through its community forum.

Who it suits

OpenEMS suits organizations and individuals working with energy storage, renewable generation, or related devices, from private owners to grid operators and research institutions. It may also suit teams that can deploy Edge and Backend on Debian/Ubuntu or Docker and meet the Java 21 requirement.

What it does well

Free and open source, with source available online and on GitHub
Provides Edge, browser and smartphone UI, and Backend components
Lists integrations across storage, inverters, EV charging, meters, and tariffs
Supports multiple data interfaces, including MQTT and Modbus

What to know first

Requires Java 21 to run
Getting-started setup is not recommended for production

Getting started

Visit https://openems.io/ and consult the getting-started guide.
Install Java 21 to meet the runtime requirement.
Choose a production deployment of Edge and Backend on Debian/Ubuntu or Docker.
Connect the relevant devices and services using supported integrations and interfaces.
Use the OpenEMS Community forum to get in touch with the project.

Verdict

OpenEMS covers on-site control as well as connected monitoring and aggregation, with a broad list of energy-device integrations and interfaces. Plan for Java 21 and use production deployment guidance rather than the testing setup.

Questions

Does OpenEMS cost anything?

OpenEMS is listed as free and has a free plan.

Is OpenEMS open source?

Yes. Its source code is available online and on GitHub. Edge and Backend use the Eclipse Public License 2.0, while UI uses the GNU Affero General Public License 3.

What platforms does OpenEMS support?

Its listed platforms are API, Linux, self-hosted, and web. Production deployment guidance describes Debian/Ubuntu or Docker for Edge and Backend.

What are the OpenEMS components?

Edge handles on-site device communication and control, UI provides browser and smartphone access, and Backend connects Edge systems for internet-based aggregation, monitoring, and control.

What runtime does OpenEMS require?

The getting-started guide says OpenEMS requires Java 21 to run.

Who started OpenEMS?

The documentation says development was started by FENECON GmbH.

Facts from OpenEMS's own pages

Components: Its IoT stack has OpenEMS Edge for on-site device communication and control, OpenEMS UI for browsers and smartphones, and OpenEMS Backend for connecting Edge systems and providing aggregation, monitoring, and control over the internet. · openems.github.io, 7 Oct 2026
Control: The architecture supports fast, PLC-like device control and reusable, device-independent control algorithms. · openems.github.io, 7 Oct 2026
Control and extensibility: The architecture supports fast, PLC-like device control, modular extension, and reusable device-independent control algorithms. · openems.github.io, 7 Oct 2026
Deployment: The getting-started guide describes production deployment of Edge and Backend on Debian/Ubuntu or Docker. · openems.github.io, 7 Oct 2026
Extensibility: The software uses a modular architecture and modern programming languages to support extension. · openems.github.io, 7 Oct 2026
Founded: 2016 · openems.io, 28 Sept 2026
Integration levels: OpenEMS Ready Basic indicates a device or service is integrated; Silver also requires the manufacturer or service provider to be an Association member; Gold additionally requires integration developed and supported by that manufacturer or provider. · openems.io, 7 Oct 2026
Integrations: The OpenEMS Ready list includes integrations across energy storage, batteries, solar and battery inverters, EV charging stations, meters, tariffs, and data services. · openems.io, 7 Oct 2026
Intended users: The marketplace describes an ecosystem for hardware manufacturers, software developers, research institutes, universities, freelancers, and students. · openems.io, 7 Oct 2026
License: The documentation states that OpenEMS Edge and Backend use the Eclipse Public License 2.0, while OpenEMS UI uses the GNU Affero General Public License 3. · openems.github.io, 7 Oct 2026
Marketplace: The OpenEMS Marketplace connects commercial users and people seeking or offering expertise, including developers, freelancers, students, research institutes, and universities. · openems.io, 7 Oct 2026
Project origin: The documentation says OpenEMS development was started by FENECON GmbH and that the software stack is used in private, commercial, and industrial applications. · openems.github.io, 7 Oct 2026
Protocols: Listed data interfaces include 1-Wire, InfluxDB, M-Bus, MQTT, Modbus/TCP, Modbus/RTU, JSON/REST, and JSON/Websocket. · openems.io, 7 Oct 2026
Purpose: OpenEMS is a modular open-source platform for monitoring, controlling, and integrating energy storage, renewable energy sources, and complementary devices and services. · openems.github.io, 7 Oct 2026
Runtime requirement: OpenEMS requires Java 21 to run, according to the getting-started guide. · openems.github.io, 7 Oct 2026
Security: The documented Backend-to-Backend API supports BasicAuth when a connection is opened. · openems.github.io, 7 Oct 2026
Source and releases: The source code is available online and on GitHub, and the documentation says new versions are released monthly. · openems.github.io, 7 Oct 2026
Support: The project invites users to get in touch through the OpenEMS Community forum and says it is glad to support third parties taking their first steps. · openems.github.io, 7 Oct 2026
Testing limitation: The getting-started setup is intended for testing and is not recommended for production use. · openems.github.io, 7 Oct 2026

Where OpenEMS stands on Freedom251

Energy Management Software#4 of 25