Energy storage illustration

In energy storage, chemistry restricts the potential of physics.
So we moved away from chemistry and invented a unique, high performance, pure electrical energy storage technology.
Powerful, with an incredible high energy density. At low cost. Safe, with low impact on environment.

We believe time has come for a much-expected revolution in energy storage…

Download the presentation / play the video.

Meet the Vacuum Capacitor !
Various calculations show that the introduction of a high share of renewable, intermittent sources of energy, as well as tens of millions of EVs, show that it cannot be achieved without genuine, very-large-scale energy storage. Typically, tens of TeraWatt.hours are needed at the scale of only one medium-size country like France, if we want to reach a close-to-100 % level of electricity from renewable sources of energy.
We will be still quite far from the world’s needs in terms of energy storage, if our energy mix is to become genuinely 80 % decarbonated by 2050, as suggested by the latest UN reports on climate change.
So we are in urgent need to have better, higher-density, safer, cheaper and more sustainable solutions for energy storage.
Meet the Vacuum Capacitor, a technology that will definitely change the game in energy storage !

The Vacuum Capacitor:

Our Vacuum Capacitor technology for energy storage brings the solution :

  • Environmental friendly, easily recyclable
  • No dangerous, toxic, rare or expensive raw materials
  • Highly resilient under various temperatures
  • No electrochemical storage : direct storage of electrons
  • Very high energy density (≈ 100 times higher than Li-Ion)
  • The lowest cost

No electrochemical storage : direct storage of electrons

Very high energy density (≈ 100 times higher than Li-Ion)

The lowest cost

Environment-friendly, easily recyclable

No dangerous, toxic, rare or expensive raw materials

Highly resilient under various temperatures

Prototype image

One of our early prototype
It can store approximately 1 kWh.

Prototype image

One of our early prototype
It can store approximately 1 kWh.


Our storage device, the Vacuum Capacitor, is a very high-density energy storage system, similar to a supercapacitor, but with substantial differences. Thanks to its patented structural features, and to a special charging system, we ensure proper conditions for volumic energy storage, inside vacuum, using new physical principles.
What we store inside our devices can be called “high-density charge clusters”, or “high-density clouds of electrons”. These charges (electrons) are then retrieved when needed, through the same electrode than for the charge (cathode).
This is a highly efficient and direct electricity storage, without transformation into electrochemical, or chemical energy.


One such prototype Vacuum Capacitor (“VC”), approx. 50 g and 7 cm height, will typically be able to store 1 kWh of energy. The electron clusters, or clouds, are stored under the top, white ceramic cap.
Charge and discharge are achieved through the bottom copper cathode (anode not shown here). Round-cycle efficiency of the whole system (charging system + Vacuum Capacitor) is currently being tested and undergoing improvement, in order to reach an overal efficiency not less than 95 %.

THE LOWEST COST : well under 100 USD per kWh, right now !

With its simple structure and long service life, our technology offers the most cost-efficient and reliable energy storage solution for most applications. While Li-Ion technology (the battery pack itself) is expected to reach the $100 per kWh mark on or before 2030, with current prices closer to $200 / kWh, the cost price of our Vacuum Capacitor (including the associated charging system) is already well below this figure, and will become even lower when its massive production begins.
Li-Ion, other electrochemical, Redox Flow, Hydrogen, Power-to-gas, CAES, TES and other technologies will hardly remain competitive against our technology, once introduced on an industrial scale.


Our Vacuum Capacitor is made of relatively common, non expensive and durable materials (metals, ceramics, …) : it can easily be produced in large quantities, manufacturing gigawatthours of energy storage capacities at much lower price than in existing or planned factories of Li-Ion batteries.
Our technology also allows us to avoid relying on supplies of rare or expensive materials, such as cobalt or lithium, whose prices are currently rising due to their scarcity or near monopoly extraction conditions. It is also known that the exploitation of these raw materials poses serious environmental and sustainability issues, without taking into account the total carbon footprint linked to the manufacturing and supply chain.


Our electrodes are designed to withstand a very large number of cycles. Our current target is to reach 100,000 cycles, which we hope to confirm soon with our current testing program.


Our Vacuum Capacitors will each individually encapsulated in a specific, reliable physical and dielectric barrier, to prevent current leakage, or damage in case of VC misfunction. If a Vacuum Capacitor fails inside a storage system, its physical protection barrier, earthing (or emergency discharge system) and the system’s PMS shall ensure that it will not prevent other units from functioning properly and safely.
The free-from-electrolyte Vacuum Capacitor won’t catch on fire. Damaged units will simply be replaced during the next scheduled maintenance.
Thanks to the use of common raw materials and to their simple structure, discarded vacuum capacitors can be easily dismantled and their components recycled.


The Vacuum Capacitor itself is resistant to the harshest weather conditions, such as cold or extreme heat, while most other storage technologies require air conditioning to function properly.
In our case, the appropriate temperature range must only be guaranteed for the surrounding electronic components (PMS, I&C, inverters, ...), while the compactness and the energy density of our Vacuum Capacitor make it possible to save money on the significant energy used for air conditioning.


Grids & Microgrids


Home & off-grid

Commercial & Industrial

Electric transportation


About Us:

President picture, Gunther Irgang

Günther IRGANG,

CEO picture, Michael Irgang

Michael IRGANG,


FREEL TECH AG. is a Luxembourg-based innovative start-up, established in 2017, which is developing and testing the Vacuum Capacitor technology, covered by several patents since the early 2010’s.

Since 2018, the company is in early talks about cooperation for large-scale development of the technology with interested industry players.


  • Vacuum Capacitor presentation
    March 2019

    Energy storage illustration Download our updated presentation here to have more details about our technology.

  • FREEL TECH video
    December 2018

    Play the FREEL TECH presentation video

  • Preselection to INNOENERGY Contest
    December 2018

    FREEL TECH is preselected as one of the top 30 most innovative companies in energy storage in 2019 (INNOENERGY Contest "Global electric storage call for Startups")

    Energy storage illustration

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