Innovative energy storage

German startup tackles renewable energy storage and industrial waste heat with single system

Jacqui Griffiths
9 June 2021

5 min read

The world’s shift to renewable energy needs a solution to one central challenge: how to store excess solar and wind power for later use. Meanwhile, energy-intensive industries have a challenge of their own: what to do with all of the excess heat they generate. Kraftblock CEO Martin Schichtel, a chemist by training, believes his German-based company has the answer – a thermal-based storage system.

Chemistry, concrete, curiosity – and a passion for sustainability – inspired Martin Schichtel to develop a groundbreaking thermal energy storage solution.

Martin Schichtel, CEO, Kraftblock

“Years ago I studied chemistry at university, focusing on nanotechnology before taking a couple of jobs in different industries, most in sectors like steel or ceramics, which wasted a lot of energy,” he said. “Then in 2008 I saw a TV report about ‘high temperature’ concrete heat storage. Concrete is cheap, widely available and you can shape it into any form that’s required. But I knew that concrete could store materials up to a maximum of 500 degrees Celsius [932 degrees Fahrenheit], while the industries I had worked in describe 1,000 to 1,500 degrees Celsius as high temperatures. So I caught up with the developers to figure out ways to optimize concrete so it could take a broader range of temperatures.”

What began as an intriguing chemistry puzzle grew into a game-changing sustainable energy system as Schichtel developed his idea and looked at its potential uses. In 2014 he co-founded Kraftblock with economics expert Susanne König, now the company’s CFO. Its mission: to design and build high performance, sustainable energy systems that enable different sectors – including high-temperature industries and power generation – to decarbonize.

“Our ultimate vision is that the world will live with a totally sustainable energy system in the future,” Schichtel said. “Our team and our investors strongly believe that storage systems will be essential to achieving that goal.”


Kraftblock’s story starts with the development of its core technology: a material that combines the thermal conductivity and large capacity needed to capture and reuse thermal energy for high-temperature industries.

“Worldwide, a tremendous amount of energy is wasted in the form of heat,” Schichtel said. “Industries like ceramics or steel require extremely high temperatures. In every furnace, kiln or thermal process there is wasted heat that is usually blown directly into the atmosphere. If that heat can be stored and reused, it becomes a climate-neutral energy source.”

“Our ultimate vision is that the world will live with a totally sustainable energy system in the future. Our team and our investors strongly believe that storage systems will be essential to achieving that goal.”

Existing storage technologies didn’t have the energy density or the ability to handle the high temperatures these industries need – so Schichtel and his team created it.

“Kraftblock’s industrial waste heat ecosystem has been designed to recover energy by capturing excess heat and gases before they are released and recycling them for use in a range of scenarios,” Schichtel said. “Heat can be recycled internally, for instance, to preheat a furnace or generate steam, or it can be used to create electricity. Because our storage is modular and portable, the stored heat can also be transported for use by external third parties. In both cases, it helps businesses to save primary energy and avoid generating CO2.”

High temperatures are not required to create the material – a factor that builds sustainability into the very fabric of Kraftblock’s products.

This virtual twin schematic demonstrates the flow of electricity from a solar array to the Kraftblock storage system, where it is captured as heat. The system releases only cool air to the atmosphere. (Image courtesy of Kraftblock)

“Sustainability for us has different facets,” Schichtel said. “One is to look at how our customers will use our system to become more sustainable in the future, and the other is to bring more sustainable efficiency to an energy system. We use a lot of recycled materials in our system, and it takes less energy to manufacture than competing products because it’s produced at room temperature with simple processes.”


In the long term, Schichtel and his team want Kraftblock to enable totally renewable energies – a path that will see the company storing and distributing excess power produced by large wind and solar farms. Today, Kraftblock is pursuing a “transition path” to that world of energy sharing. Dubbed REET (renewable energies in existing technologies) by the company, the strategy enables customers to create a green energy storage ecosystem using existing infrastructure. 

Schichtel sets the scene: “Imagine a food company that is using gas-fired boilers to produce steam,” he said. “To decarbonize, it must replace the gas for those boilers with green energy. A heat pump cannot deliver enough thermal energy to produce the steam. A renewable power-to-heat system, such as a wind farm, can – but not always when the company wants it. Creating a storage system enables the company to transfer green electricity to heat, with the storage itself becoming a buffer and distribution station for renewable heat at the company’s factories. This is the system we’re creating for a customer, to store green electricity and enable a 24/7 supply. That’s REET: the customer only has to replace its gas-fired boiler and it can keep the rest of its infrastructure alive and working.”

Kraftblock’s storage technology sits at the heart of this green energy story, combined with various technologies to collect energy for storage and distribute it using the customer’s unique infrastructure. “We’ve designed different storage units to provide huge levels of freedom for our customer,” Schichtel said. “The company can charge one unit with energy while discharging another to enable 24/7 operation, or it can join two modules together for higher performance when needed.”


Virtual twin technology is central to Kraftblock’s design process.

“Every company has its own, site-specific requirements for charging and discharging the storage unit,” Schichtel said. “So for each project we must design a complex set of charging and discharging devices that are unique to that customer’s needs and can be linked together in a modular system. Using a business experience platform enables us to combine the various aspects of product development, from thermal and mechanical stress simulation to building a virtual twin of the whole system. We can also use the virtual twin to show interested customers or potential partners different scenarios in a more-or-less live application, including potential issues and how to resolve them.”

This virtual twin schematic demonstrates the flow of stored heat back to the industrial company that generated it, for reuse in its processes. Alternately, the heat can be converted to electricity and fed to the power grid or used to operate the factory’s machinery. (Image courtesy of Kraftblock)

Creating a virtual twin of the system before physically building it has been invaluable to the company and its pilot customer.

“We do a lot of simulations of the system and processes, including predictions of how it will operate,” Schichtel said. “Our system’s efficiency in transferring energy to heat is essential in helping customers improve their sustainability, as even a 1% loss in efficiency could cost them a lot of money. Building a virtual twin has enabled us to keep the efficiency of creating the whole system at a high level. It helps us easily explain and demonstrate efficiency issues and improvements to our customers.

“Using a business experience platform enables us to combine the various aspects of product development, from thermal and mechanical stress simulation to building a virtual twin of the whole system.”

“It has been invaluable in enabling us to demonstrate to customers that everything will work as planned under different scenarios. With virtual twins of the energy system in operation we can also do things like predictive maintenance and building an artificial intelligence control system.”

Kraftblock’s vision of sustainable energy for all may lie in the future, but Schichtel sees opportunities to begin making it real today.

“Renewable energy generation and storage markets are developing rapidly,” he said. “In industrialized countries, more than 50% of the total energy demand across industry and private homes is for heat, and the technologies that deliver it always have to be adapted to the next step. As a result, we are seeing a growing number of requests for REET systems. Being able to monitor market developments through channels like social media is valuable, and virtual twin technology helps us to adapt to those movements.”

Editor’s Note: Kraftblock is supported by the 3DEXPERIENCE Lab through its incubator partner Industrial Future Hub, operated by Deutsche Messe Technology Academy.

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