MJ EcoPower Hybrid Systems has awarded a contract to battery manufacturer Saft to supply lithium-ion batteries and battery management systems for four new hybrid rubber tire gantry (RTG) cranes serving Houston Harbor.
RTGs are used to transport and stack shipping containers at port facilities and rail yards. Normally, the electric motors for the movement and hoisting functions are powered by a diesel generator that is often kept idling 24/7. MJ EcoPower’s EcoCrane systems replace the conventional diesel power plant (typically rated at 400-750 kW) with a smaller (100-150 kW) diesel generator combined with a battery-based energy storage unit.
Existing EcoCrane systems based on lead-acid batteries have demonstrated fuel savings of up to 70 percent and emissions reductions of up to 98 percent, according to Saft. Battery-only running also makes the cranes quieter, improving conditions for operators and neighbors.
For the Houston cranes, MJ EcoPower will replace the lead-acid batteries with Saft Li-ion batteries to supply normal operating power as well as regenerative storage for energy captured as the crane hoist lowers containers. The small generator will only be used to recharge the batteries when required, and will be turned off for around 50 percent of the shift.
“The efficient and reliable energy storage provided by Saft Li-ion technology is already well proven in a wide variety of hybrid applications worldwide, including the marine and standby power industries. With this new application for MJ EcoPower Hybrid Systems we are taking an important step into the US hybrid crane market,” said Saft’s Alain Coadou.
Saft notes that there are up to 600 RTG cranes in US harbors that could be retrofitted with hybrid power systems, while around 150 new cranes are built every year for the global market.