About us
About Franz-Josef Feilmeier
Franz-Josef Feilmeier, second of three children, grew up in a home where respect for the environment played a major role.
The parental business, an agricultural warehouse offering GMO-free “food for animals,” is to be made energy self-sufficient with photovoltaic systems. Clean energy is just as important as clean food.
After studying technical business administration at the TH Deggendorf, half a year in China, where he already experiences e-mobility on a grand scale with electric buses in 2005, Franz-Josef moves on to his next professional stations: Diploma thesis on solar technology in Hamburg, construction of solar cell factories based in Konstanz and then building photovoltaic systems with friends back in Lower Bavaria.

2011
Rooftop and ground-mounted systems had grown in size. As full feed-in projects, they were generally investment properties. But the energy transition needs more than just a dumb feed-in when the sun is shining.
The start-up project of FENECON (Feilmeier New Energy Consulting) was a grid-connected PV self-consumption system without excess feed-in on the parental farm to maximize self-supply with intelligent storage and energy management while avoiding any feed-in and the associated grid expansion.
The market was not yet familiar with such products, so we went back to BYD in China, designed appropriate power storage systems together with our Chinese friends, and tested and optimized them in our garage at home. Many an important company has been founded in a garage.

The vision is the 100% energy transition and a better future
for us and future generations.
2012
2013

Days of rain and high water. A dam of the Isar breaks, the whole Fischerdorf is under water and so is the whole camp and our vehicle fleet. Everything is destroyed.
10 strong-willed employees struggle with damage control for more than half a year. We dry, clean, repair without income, because that’s how long it takes until the insurance company transfers the first funds and we can buy new goods. The setback was harsh, but as a time of reflection and development, it also represents the basis for new concepts and later groundbreaking developments.

2014
2015
Together with BYD, we are launching the first series-produced commercial storage system on the European market.
The first test customer is once again the Feilmeier father and the test laboratory is once again the garage, which is now equipped with many test and measurement systems.


BYD is breaking new ground with a compatible battery - and FENECON is combining it with domestic inverters.
The FEMS now controls everything and can do more and more.
2016
Stefan Feilmeier, Franz-Josef’s brother and head of FEMS development, brings his experience from India, from the Linux world into the system. His vision is to make FEMS the ‘operating system for the energy transition’. It is to become open source and accessible to everyone. The OpenEMS platform is created.
The concept is implemented, so we simply make our years of expensive software development available to everyone as open source code. The great effect of a manufacturer-independent and open platform for simplifying and accelerating the decentralized energy transition should only become comprehensively apparent in the next few years.
2017
In the same year, we receive the Handelsblatt Energy Award for our “energy partner model”, which aims to avoid new dependencies and instead achieve a wide range of attractive electricity offers with an OpenEMS storage system. As such a young, small company with just 30 employees, we receive this major, highly regarded award.

In 2017, we are starting to incorporate used vehicle batteries into stationary storage systems and to develop concepts for “living spare parts storage” of vehicle batteries for major car manufacturers.
In the meantime, we have become the technology leader in this segment and have already been able to inspire many manufacturers with our innovative and flexible “full-pack approach”.
2018
OpenEMS is now established at many companies and many research projects work with it, so that together the OpenEMS Association e.V. is founded, which drives the further development of the platform. Stefan becomes chairman of the board of the supporting association.
It’s the time when all storage manufacturers are moving into the next growth phase - which for most means being bought and incorporated by a conventional corporation. That would not be our way. We are a medium-sized

2019
family business and want to remain so in order to Vision of sustainability and decentralized energy transition to be able to move forward freely.
We qualify as an ‘impact company’ and gain BonVenture, an eco-social fund as a partner that supports our social and environmental goals and grants us freedom of choice.
In 2019, more than 40 highly qualified employees are already committed to our mission of energy engineering, some of them also at our first external production site in Künzing.
OpenEMS receives highest recognition as European Energy Storage Highlight.
2020
We grow to over 60 employees and it is still mainly engineers in the team. We can more than double our sales. Many people invest in smart home storage with emergency power during Corona and our products perfectly meet the expectations.

2021
We accept the EES Award, the highest distinction in the storage world, in a
online award ceremony with a loud cry of jubilation. Our industrial series for
Use of electric vehicle batteries in container storage - and once again the
OpenEMS and its many possibilities - have convinced the jury.

To make commercial and industrial storage available to even more customers, we founded FERESTO GmbH (FENECON Rental Storage), which offers large-scale storage for flexible rental. The great demand shows that we have also hit a gap in the market here.

The FENECON Home will be launched on the market in May. A complete system to which we implement future viability as DNA and install energy management as a head on the battery. The learning system loads the electricity storage system in advance and ensures that PV systems are not shut down. The system is nominated for the EES Award but even more important: installers and customers are enthusiastic because the FENECON Home is installed and commissioned in no time and convinces with reliability and openness to the future. Customers can still choose their own electricity provider and integrate suitable heat pumps, heating rods or charging infrastructure.
In June, we will celebrate our 10th anniversary with our team, which now numbers around 80 and is working hard to promote the energy transition. Our partners include storage wholesalers, energy suppliers and general contractors, to whom we would like to express our sincere thanks for the good cooperation and trust they have placed in us, even in difficult times. We look forward to the next many years with all of you.
In October, we are one of only two projects funded in Germany to receive a grant from the EU Innovation Fund. The funding of €4 million will enable us to build Europe’s largest 2nd Life electricity storage factory, the BatteryReFactory in Iggensbach, near Deggendorf. Here, starting in 2024, we will manufacture new products from used e-vehicle batteries and preserve raw materials that are already in Europe here and make them usable again. Our understanding of sustainability and the energy transition makes this step imperative.
In December, we are releasing new FEMS apps for incorporating time-varying electricity rates into FEMS. Hereby the FENECON electricity storage systems can participate even more actively in the energy transition, save cash for our customers and relieve the electricity grids. Ideal for residential, commercial, industrial and loading parks.
We are grateful and pleased that our employees came through the year in good health. This is a great gift.
2022

The theme of the year is Unleashed, as great things will start that were prepared in 2021.
- Thus, the construction of the BatteryReFactory will start in late fall and many other novelties will be on their way.
- In May, we receive The Smarter E Award for Outstanding Projects for the Industrial System, which provides grid services as a living spare parts store for electric car batteries in a former coal-fired power plant.
- We are now 120 committed energy users, with new ones joining every month (as of August 2022).
- New products will enter the market this year. More about that in due course.
2023
The planning and construction work for the new Iggensbach site is progressing rapidly, and the state-of-the-art facility will take on its nearly final form by the end of the year. In 2023, we are launching the FENECON Home 20 & 30, an evolution of the highly demanded home storage system FENECON Home 10, as well as the large-scale storage system FENECON Industrial L.
This year brings us numerous awards, including the ees Award for the FENECON Industrial L and the EM Power Award for our FERESTO rental storage business model. Another major milestone in our company’s history: In November, Franz-Josef Feilmeier and FENECON are honored with the world’s largest and most prestigious award for entrepreneurs—the EY Entrepreneur Of The Year Award 2023. Additionally, we also win the Audience Award. More about these awards can be found further down on this page.
The number of employees continues to grow significantly, making an additional office location necessary alongside the headquarters in the Deggendorf district of Fischerdorf. In the spring, we are able to move into multiple office spaces across two floors in the city center, close to the Technical University.

2024



In 2024, we embrace the motto ‘We Are Growing.’ What began in 2011 in a farming garage at the Feilmeier family home has now grown into something remarkable. We take pride in the fact that we have developed successfully through organic growth, independence, and innovation—driven by satisfied customers. This evolution is now reflected in our updated logo: We now capitalize FENECON in the wordmark and have made further subtle refinements. Our symbol remains true to the combination of battery storage and energy management that defines us.
Our transformation into an established and expanding company is evident in many ways: In 2023, the FENECON team doubled to around 300 employees. March brings a reason to celebrate, as we welcome distinguished guests from politics, business, and science to the official inauguration of our new industrial energy storage facility (press release). At our Iggensbach site, we plan to create around 100 new jobs.
Due to continued growth, our office location in Deggendorf’s city center is expanding. Additionally, in mid-2024, we acquired an existing site near Vilshofen (Passau district) with over 20,000 square meters of production, storage, and office space. By 2025, this location—Albersdorf—will focus on the development and production of our home and commercial storage systems.
New Product Launches
The FENECON Home 6, 10 & 15 enters the market, featuring three hybrid inverters (6, 10, and 15 kW) and a larger battery (2.8 kWh). This evolution of the popular Home 10 provides even greater versatility for single- and multi-family homes. Another innovation is the high-performance commercial storage system FENECON Commercial 92, based on the same battery technology as the Home series and designed as stackable 42 kWh battery towers.
Commitment to a Sustainable Energy Future
To support our mission of a resource-efficient energy transition with cost-effective large-scale storage, we have secured over one gigawatt-hour of high-quality electric vehicle battery packs from CATL. These batteries are already in Europe but were never installed in vehicles, making them unused yet fully functional.
Award-Winning Innovation
At the end of June, we receive two major awards on the same evening:
- The Bavarian SME Award for our future viability, innovation, resilience, sustainability, and responsibility.
- The TOP 100 Award—for the second consecutive year, we secure 1st place in the largest company category, earning the title “Innovator of the Year 2024”.
More about these awards can be found further down on this page.

Our success lies in our team
- A young team of highly qualified and highly motivated colleagues.
- International, open-minded, and tolerant.
- Successful together: flat hierarchies.
- A cooperative partnership with suppliers, customers, and service providers.