Solar Power Storage -The battery to power your home

The fast-growing Leipzig-based company SENEC is spreading its wings, expanding from Germany to Europe and beyond. To facilitate current and future growth, SENEC is expanding and updating its portfolio of energy storage solutions for private homes, to fit new customers and markets.

Since 2009 SENEC has been in the business of developing sustainable energy solutions integrating solar panels, energy storage, and charging stations for electric vehicles. Currently, 75.000 SENEC storage systems are operating across Germany. That number is expected to increase sharply, not least due to the current energy crisis emphasizing the advantages of homeowners producing and consuming their own energy.

More than a battery

The centerpiece of the SENEC portfolio is the SENEC.Home energy storage box, of which the newest version named SENEC.Home 4 can store up to 25,2 kWh. But a battery is not just a battery, and it’s not only defined by its storage capacity. To deliver value to the customer it must integrate with other systems and infrastructures, like billing software, installing and maintenance systems, backends, data bases and much more.

Since 2019, IT Sonix has developed a large part of the software doing that job. With currently, around 45 consultants engaged in various SENEC projects, it’s one of the largest engagements in the IT Sonix portfolio.

The IT Sonix solar power platform team is working on the newest version of the energy storage, the Home4, as well as on its predecessor, the Home3, and on various other connected devices and services. For instance, the software to configure the storage unit, the solar panels connected and the wall box for charging an electric vehicle. Also, the system has to be configurated when connected to the energy grid. And not least, the installers selling and installing the system have their own web interface with all the technical information, calculation tools etc. they need.

Began with billing

It all began, back in 2019, with billing. The year before, SENEC was acquired by the 3^rd largest energy company in Germany, EnBW, and subsequently hired IT Sonix to help migrate to the EnBW billing system, named PowerCloud.

That accomplished, IT Sonix began updating the web portal used by the more than 1.200 installers selling and installing the SENEC products. The PIP (Partner Installateur Portal) helps installers find the right solution for the customer, dependent on the energy needs of the household, the position of the solar panels on the roof etc. The new PIP is making life easier for installers, for instance allowing them to configure the storage unit via the cloud instead of connecting directly to the unit via cable. The PIP is designed with modern technology, including the latest Angular tools.

Splitting the monolith

The next assignment was to modernize and scale the backend of the system. One of the key people in that work was Sven Thiergen, Senior Backend Developer covering parts like backend business logic, database handling, real-time message processing and cloud deployments (Kubernetes).

• The old version was built as a monolith. It was reaching its limit and starting to get into problems to scale, Sven Thiergen explains.
• So, it was decided to split the monolith into sub-parts and to deploy a microservices architecture instead. Also, new additions and features were to be done as microservices deployed in Kubernetes. With a modern cloud approach the backend is now ready to handle much more data than before.

Peter Hoffmann, one of IT Sonix’ two project leads, elaborates:

• It has been an interesting challenge to design a backend that can scale, while also being able to store large amounts of data. SENEC gives a 10-year guarantee on the storage capacity of its batteries, and as the batteries are the most vulnerable part of the whole system, all battery related data is stored. In fact, more or less any data from the system will be stored for a long period of time, to improve the design and to develop predictive maintenance tools. We’re working on that project as well, helping develop machine learning tools to reduce defects and crashes in the future.

Real-time communication

Describing the technology, Sven, and Peter point to one specific feature in the new, updated SENEC.Home4 device they find especially important: real-time communication.

Currently, the embedded control system of the device transmits data every 5 minutes. The new version has switched to real-time communication, with Kafka being introduced as event streaming and central messaging platform to make the SENEC.Home 4 a truly real-time system. This allows for much quicker ways to control, supervise and prevent, for instance to avoid overcharging of the battery or other sub-optimal issues that could affect the performance and lifetime of the storage unit.

However, ensuring scalability is probably the most crucial contribution IT Sonix has brought to the table in its cooperation with SENEC. To give an impression of the potential, SENEC has grown to 500 employees in just 3 years, and the company is currently expanding into Italy and Australia.

Both countries require additional developments. For instance, Australian homeowners want to sell excess energy out of their storage directly to their local energy grid. To do that, the system needs to support VPP (Virtual Power Plant), a software tool that bundles the output from small energy producers and sells it to grid operators.

Looking into the future, in a few years there may not be 75K storage units, but 500K or even 1 million installed in private homes across the globe. Without scalability issues, thanks to the careful work of IT Sonix solar power platform team.