EPRI Explores the Costs and Benefits of Electrifying Materials Handling Equipment
By: Andra Rogers
(Excerpt from EPRI State of Technology 2013)
Electric transportation includes much more than just electric cars and trucks. EPRI’s Non-Road Electric Transportation program covers a range of technologies, from cranes to lift trucks. In one project, EPRI partnered with the Georgia Ports Authority and Georgia Power Company to assess the impact of replacing diesel gantry cranes with electric cranes in the Port of Savannah.
As the Port of Savannah expands to meet the needs of greater shipping traffic on the East Coast, Georgia Ports Authority has evaluated moving from combustion-powered machinery to electric. Electric cranes have several advantages. They reduce air and noise pollution and cut operating and maintenance costs. They’re also more efficient: “When the crane is going up it’s pulling energy, but when it’s going down it’s regenerating energy,” said Andra Rogers, senior project manager in EPRI’s Power Delivery & Utilization sector.
As it grows, the Georgia Ports Authority plans to replace all diesel-powered gantry cranes in its Garden City Terminal with electric gantry cranes. Plans call for 170 cranes in 2022. The port’s mobile cranes, called rubber-tired gantry cranes, move shipping containers off trucks and into the stacks. As a first step, Georgia Ports Authority installed four electric cranes and allowed EPRI to equip them with sensors and equipment to collect data on engine performance, generator outputs, and location. EPRI researchers and Georgia Power will use this data to evaluate the additional electricity needs and demand profiles of an expanded electric gantry crane fleet. “We’re looking not only at the power and theenergy of the crane, but also what this crane looks like to the grid,” Rogers said. The research will also assess the costs and benefits of electric cranes versus diesel. Data collection began in 2012 and will continue through September 2013.
Although many industries rely on electric lift trucks for indoor work, few companies use them outdoors. EPRI is producing a case study on their performance outdoors. Some users perceive electric trucks to be underpowered and unsafe in wet weather. They also worry that the batteries will lose their charge quickly. However, electric lift trucks operate as well as or better than their internal combustion counterparts in many of the same applications. They also deliver benefits in life cycle cost, emissions, and operation. “They’re a very viable option that can be implemented today,” Rogers said.
One EPRI study highlighted the performance of electric lift trucks at a metal processing plant in Pittsburg, California. The company replaced 8 of its 10 propane lift trucks with 80-volt electric lift trucks able to operate for two 8-hour shifts on a single charge. The plant also installed high-frequency charging technology that can charge a truck in about 5 or 6 hours. Electric lift trucks cost 20% to 30% more than propane or diesel models, but they have lower operating costs. According to EPRI’s lift truck cost calculator, which determines the cost savings and environmental benefit of electrics compared to internal combustion models, each electric lift truck will save the plant $54,418 over five years and reduce its exhaust emissions by 220,754 pounds.