As more and more seaports power their operations from electrical grids, a new set of assumptions about cost and reliability have been created. Operating costs and efficiency are important considerations for all seaports, but for the Georgia Ports Authority (GPA) which overseesthe ports of Savannah and Brunswick, the issues are especially front and centre. With no private marine terminal operator responsible for terminal infrastructure or cargo handling, GPA has a direct and immediate stake in the way its cargo handling equipment performs and the costs associated with running it.
How GPA ‘plugged-in’
Rich Cox was GPA’s general manager of equipment and facilities maintenance for more than 18 years before he retired last autumn. It was he who highlighted that all of GPA’s cranes were fuelled by diesel and were experiencing a 3.8% downtime rate. His aim was to get that downtime to less than 1%. When GPA began investigating electric-powered cranes, it ran into constraints, as cranes that utilised 480 volt power could only travel approximately 900 feet from the power source. When another power option became viable – in the form of a 13,800 volt feed to cranes – the mathematics started to change, as the cables for the higher voltage could allow travel of up to 2,300 feet from the power source. Mr Cox noted that after the ports authority purchased two electric cranes, the reliability got better and the maintenance costs began to significantly decrease.Consequently, GPA made plans to convert seven more cranes from diesel to electric, implementing the change in 2000. Today, all ship-to-shore cranes at GPA facilities are electrified, and the authority is now turning to electrifying rubbertyred gantry (RTG) cranes. In 2011, GPA carried out a demonstration project using a Conductix-Wampfler mobile energy supply system which proved so successful that GPA now has an additional eleven electrified RTGs. Though they can still run on diesel, the cranes use electric power approximately 95% of the time. According to Mr Cox, the payback period is just over five years considering capital and diesel savings. He found that by not running diesel all the time, GPA has significantly reduced its maintenance costs. However, while the change has yielded many benefits, it has created some new challenges as well.