The new ERTG system was developed with the help of Konecranes, Conductix-Wampfler and Georgia Power, which provided the cranes, the new power system and the electrical infrastructure, respectively.
While relying on cleaner, shore-based power to handle containers, the ERTGs feature the ability to automatically switch to diesel generators when moving from stack to stack. All functions are controlled by the ERTG crane operator.
Long-term plans call for retrofitting Savannah’s Garden City Terminal’s fleet of diesel-powered RTGs to use shore power via retractable arms which will link to a conductor rail system, bringing the total number of ERTGs to 169 by 2022. Repowering the RTGs will be a multi-year initiative, requiring new cranes to be ordered with electric power capabilities, and some older cranes to be retrofitted. When complete, the ERTG fleet will allow the port to avoid the use of an estimated 5.97m gallons of diesel each year. This will result in a net savings of nearly US$10m each year, even after the purchase of electricity is factored in.
GPA Director of Engineering Chris Novack said ERTGs are more reliable than diesel-powered versions with less downtime. In addition, fewer hours of diesel-powered operation will mean reduced maintenance costs and extended diesel life.
The ERTGs will switch via an auto-engage system between diesel and the electrical grid with the cranes operating on electrical power about 90% of the time. The RTG-mounted electrical equipment and retractable arm are compact and lightweight – important factors for subsequent ports considering a transition to electric power.
“This means it can be used for any ERTG, even those with little room for additional components,” said Jerry Koetting, district sales manager at Conductix-Wampfler. \”We therefore assume that the product can set entirely new benchmarks in the ERTG electrification market.\”
The ERTGs are powered through 480-volt conductor rails installed on the container yard at the rear of Container Berths 4 and 5. They will capture power when lowering boxes – energy which is currently lost under diesel power. For comparison, the GPA’s electrified ship-to-shore cranes reduce their power demand by about 35% by capturing energy from lowering boxes.