Significant savings through decreased fuel consumption and carbon emissions

Ultracapacitors have been used in heavy transportation for many years. With increasingly stringent regulations around fuel efficiency and emissions controls, their use is set to grow exponentially.

Ultracapacitors have proven to be a superior technology for regenerative braking in hybrid buses and trucks, and cold starting of diesel engines for trucks and trains.


Ultracapacitors can recover energy from a train braking and then provide additional power when a train begins to accelerate again. This facility improves energy efficiency and reduces strain on the grid by removing the spikes in power demand. Ultracapacitors can also be used to provide engine start power for locomotive trains.


Skeleton Technologies heavy transportation ultracapacitor technologyUltracapacitors are well suited to providing the necessary burst of power for starting large diesel engines. Trucks around the world are increasingly replacing lead acid batteries with ultracapacitor technology that is more reliable, guarantees starting in very cold weather and prolongs the engine starting system’s service life.

Trucks can also be fitted with a Kinetic Energy Recovery System that can decrease fuel consumption and carbon emissions by up to 32%.


Ultracapacitors can be used to recover energy from the crane during lowering and braking, and then release that energy during lifting. Ultracapacitors also enable downsizing of diesel engines as the peak power no longer needs to come from the engine.

Turn heat into cost savings

Ultracapacitors capture braking energy in cranes to power lifting, decreasing fuel consumption by 34%.

Skeleton Technologies heavy transportation ultracapacitor technology

Case study - Port of Muuga in Estonia

  • One of the largest container terminals on the Baltic sea
  • An RTG Kalmar E-One was retro-fitted with an ultracapacitor-based Kinetic Energy Recovery System (KERS) to save braking energy when containers are lowered, and to use the captured energy to power the crane when lifting containers.
Port crane KERS Skeleton Technologies

Skeleton KERS for Kalmar 40 000 kg rubber tyred gantry (RTG) crane


Parameter Value
Ultracapacitor voltage 170-340 V
DC Bus voltage (DC/DC converter) 620 V
KERS charging and discharging power 34-68 kW
Usable energy 321 Wh
System weight 230 kg
Reaction time 50 ms
Calendar life 10-15 years
Cycle life 1 000 000 cycles

Advantages of ultracapacitors


  • High power density (50 kW/kg)
  • Long calendar and cycle life (over a million cycles)
  • High temperature tolerance  - operates efficiently at -40°C and up to 70°C
  • Low internal resistance - quick reaction time
  • Charge and discharge in seconds (C-rate of 3000)
  • Safe - can be short-circuited without danger and contain no harmful metals
Port crane KERS Skeleton Technologies

Kinetic Energy Recovery System for port cranes - installation

Ultracapacitor modules and DC/DC converter retrofitted to a Kalmar E-One RTG
Port crane KERS Skeleton Technologies
  Operating hours hh:mm:ss Average fuel consumption l/h
Without KERS 274:20:22 16,67
With KERS 199:58:15 11,00

Fuel consumption decreased by 34%

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Products used in heavy transportation
Industrielle Zellen Module 

Why Skeleton’s ultracapacitors are ideal for this market

Heavy transportation requires high power.

Large vehicles and machinery benefit from the added power density that ultracapacitors can provide.

Operate in cold temperatures.

Ultracapacitors only lose about 5% energy at minus 25 degrees centigrade, compared to a battery’s energy loss of more than 50%. Our ultracapacitor-based Engine Start Module can comfortably operate at -40 ºC.

Diesel is expensive.

KERS based on our industrial modules can help save up to 25% in fuel costs.

Reduced environmental impact.

In addition to not containing any harmful chemicals, ultracapacitor-based KERS modules can help significantly reduce CO2 emissions in heavy transportation.