Innovation provider

Energiatehnika OÜ


Jüri Joller, Dr
+372 50 24 303
Männiku tee 123
11216 Tallinn
+372 655 1312
Skype: energiatehnika_Llt


The ultracapacitor energy recovery system is available up to voltage 3 x 460 VAC, 10 kW, 25 kW, 40 kW, 63 kW and 100 kW (URS 460AC-10 ... URS 460AC-100). The systems for 600 VDC ... 1000 VDC for application in electrical transport are under development.
The Ultracapacitor energy recovery system consists of module with ultracapacitors, special power converter and control unit with measuring sensors fitted into common modular enclosure. Ultracapacitor energy recovery modules with different power and energy ratings up to 2,5 MW and 35 kWh are planned. The Ultracapacitor energy recovery system can use different charge and discharge methods, create pulse power, (e.g. for starting or braking heavy loads in weak grid), and operate as UPS feeding the load during power interruption until the reserve generators will be started (it needs 10...20 seconds usually) in production lines, hospitals, hotels, etc. It can compensate peak loads of the power supply and charge rapidly the batteries of electric vehicles.
Energiatehnika Llt. has experiences with ultracapacitors since year 2001, when one of its owners Jüri Joller wrote his doctoral thesis in Tallinn University of Technology. Dr. Joller is author of different patents in the fields of ultracapacitor and power electronics applications.


Since the braking energy is stored and reused, consumption of electrical energy is reduced to minimum. In some applications energy saving is up to 30%...50%. The system not only saves money but also helps to cut peak demands of electricity during load acceleration or peak demand (e.g. during charging battery of electric vehicle). In UPS applications the system can reduce production losses and increase yield.

The ultracapacitor doesn’t have moving and maintenance requiring parts like flywheel accumulator. In comparison with  electrochemical batteries, the number of loading and emptying cycles is approximately 1000 times higher reaching million complete loading and emptying cycles. In addition to that, ultracapacitors are maintenance-free and the guaranteed lifetime in storage device reaches 25 years.

Innovative aspects (ecologic, social and economic)

Environmental Aspects
In some applications, e.g. trams, hoists and elevators, the energy saving is up to 30%...50%. In broad application it will influence CO2-emissions. As the operating costs of the electrical transport will be reduced, there will be potential of applying more vehicles to improve environment especially in cities. Reduction of waste in production facilities due to uninterrupted power supply.

Social Aspects
Ultracapacitor energy recovery system has certain impact on work environment, because of reduction of production breaks due to power interruptions. In some processes, e.g. hot cincing the rollsteel, the process restoration after power interruption may require hours of dirty and dangerous manwork.

Application examples

Hoists, conveyors and elevators
Mixers and pumps in critical processes
Lubrication and hydraulic pumps
Cooling systems and fans e.g. of trams and trolleybuses
Smoke exhaust systems
Steam generators for autoclaves
Energy storage unit for central DC link
Fast battery charging stations for electrical vehicles
Traction drives of trams and trolleybuses
Substations for public electrical transport


The ultracapacitors are still quite expensive in comparison with flywheel and backup power systems based on electrochemical batteries, which is limiting the applications to those, where the most economic saving can be achieved.


Current stage of development

Development phase – laboratory tested

Intellectual Property Rights

Trade mark

Country of origin


Country of application



National Contact Point

Antti Roose
Tartu Ülikooli, Geograafia Osakond
Vanemuise 46
51014 Tartu

Tel: +372 737 6841
Fax: +372 7375825