Energy Storage: Five New European Innovators

Ensuring a steady supply of clean, efficient, and renewable energy is a challenge felt worldwide. Thermal energy storage, a technology that retains heat to be utilised or transfered later, can play an essential role in this mission – helping us make the most of fluctuating renewable energy sources like wind and solar. 


As a testament to global ingenuity, we’re seeing a wave of companies innovating in this field. In this article, we shine a light on five of them – Polar Night Energy, Kraftblock, Brenmiller Energy, EnergyNest and Magaldi MGTES – each reshaping the landscape of thermal energy storage in its own unique way.


Polar Night Energy: from a coffee shop idea to ‘sand batteries’

Polar Night Energy is a Finnish company that started with a quirky idea in a Finnish coffee shop, and soon turned it into an effective energy solution. They’ve developed a ‘sand battery’ – a novel way to store excess wind and solar energy as heat in sand.

This sand battery helps tackle the inconsistency of renewable energy sources. It serves as a high-capacity storage unit for surplus renewable energy, ready to convert it back into heat for most efficient typical application or electricity via ancillary turbines when needed. Having their first operational heat storage in Kankaanpää, Finland, Polar Night Energy exemplifies how we can create stable, affordable, and clean thermal energy storage.


  • Sand based storage medium / approx 600c / air discharge
  • Current Models – 2MW / 300 MWh and 10 MW / 1000 MWh, modular scale
  • 1GWh modular build – 2 week cycle @ 95% efficiency


Kraftblock: turning waste heat into a resource

Kraftblock believes in a two-fold approach to renewable energy: harnessing new sources and reusing the ones we often waste. Their innovative energy storage systems encourage industries to shift from fossil fuels to renewables and recycle waste heat.

They’ve used advanced technology to devise a storage system that effectively captures waste heat and renewable energy. This system can significantly reduce industries’ reliance on fossil fuels. Kraftblock’s solution presents a viable path to the global goal of carbon reduction, providing a scalable, affordable, and flexible system for both heat and electricity.


  • 85% recycled storage medium / up to 1300c / multiple heat transfer medium discharge
  • Containerised modular transferable units, up to 1.2 MWh m3
  • 4-60 MWh units, stackable with charge and discharge stations


Brenmiller Energy: gigafactory goals and rock-solid storage

This Israel-based company successfully combines innovation with ambition. They recently opened a factory with a target of 4GWh annual production capacity by the end of 2023. Brenmiller’s bGen solution uses rocks to store power, heated to high temperatures, and then discharged by releasing the stored heat to create steam for electricity or industrial heating.

The factory, mainly powered by solar energy, exemplifies the company’s commitment to sustainability. Brenmiller Energy’s dedication to developing long-duration energy storage could be a game-changer in addressing the energy and climate crisis, and in reducing carbon emissions from electric grids and factories.


  • Crushed rocks storage medium / up to 750c / steam or air discharge
  • Thermal charge via biogas, flue-gas, heat recovery, or via excess renewable generation
  • Modular system with multiple input/output performance and integration options


EnergyNest: efficiently storing energy for on-demand use

EnergyNest offers businesses robust thermal energy storage solutions that convert off-peak electricity, waste heat, or excess steam into on-demand energy. Their scalable ThermalBattery technology can reduce operating costs, open up new revenue opportunities, ensure a reliable clean energy supply round the clock, and support companies in their carbon reduction efforts.

Each EnergyNest system is tailored to the client’s specific needs, ensuring maximum energy efficiency and financial benefits. Their solutions can assist businesses in reducing their dependence on fossil fuels and shield them from energy price fluctuations and carbon offset costs.


  • Thermal concrete storage medium / up to 400c
  • Heat Transfer Fluid charging / steam or hot water discharge
  • ISO shipping container modules – 20ft / 1.5MWh, 40ft / 3MWh


Magaldi MGTES: fluidised sand beds

Approximately 70% of the energy demand in the industrial sector is primarily in the form of heat, mostly as steam to power various industrial processes, and approximately 90% of this demand is met by fossil fuels.  A huge opportunity here to repurpose waste heat in particular and move the heat to other uses.

MGTES uses a fluidised sand bed to store clean energy for up to several weeks, before being released as steam.  Its main target markets are industrial processes [food, paper, chemical, plastics] alongside backup thermal power to generation facilities, or even direct generation via turbines.


  • Modular sand solution in 125/250/500t capacities
  • 20MW per module / approx thermal Loss – <2% per day
  • Round Trip Efficiency – >90%


The future of energy innovation

As we push towards a renewable energy future, thermal storage is pivotal in balancing energy production and usage. Breakthroughs led by companies like Polar Night Energy, Kraftblock, Brenmiller Energy, EnergyNest and Magaldi can significantly expedite the energy transition, nudging the world towards a greener, more sustainable future.

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