Feature ArticleEnvironmental Regulations Spark Power Savings, Reliability and Safety
By Alex Bynum
As the demand for advancements in environmentally friendly maritime operations grows, the defense, commercial and passenger industries face significant hurdles fueled by rising costs in energy and worldwide economic challenges. Increasingly stringent environmental policies are causing sea vessels to look at ways to adapt to reduce emissions. Thankfully, as marine operators explore new ship designs and technologies for achieving cleaner operations, they are also realizing other benefits from hybrid drives and energy storage solutions—including improved safety, reliability and cost savings.
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The development of hybrid propulsion systems has been identified among industry leaders as an ideal avenue for improving sustainable fleet and port operations. Even so, the need for hybrid vessels is not a new concept and has existed for centuries. In ancient times, the Trireme—or Greek three-oarers, used by ancient Phoenicians, Greeks and Romans across the Mediterranean, employed a combination of oars and sails. The oars were used for both primary propulsion and maneuverability in naval combat with the main intent of ramming for defense. The sails provided additional propulsion for transit. Today’s navies have similar needs, including increased propulsion efficiency and improved weapons systems.
Although a major focus, propulsion is not the only need. Today, a process known as cold ironing provides a cleaner operation within the hybrid technology concept. It includes the practice of providing electrical power to a docked ship while its main and auxiliary engines are off—thus achieving strategic gains in efficiency to prime movers and auxiliary systems and further decreasing gas emissions. This has led to the development of hybrid propulsion systems where batteries work with diesel and gas turbine generators and electric motors.
The technology has undergone significant advances across a wide range of marine applications over the past several years.
Within defense applications, the U.S. Navy has led the charge in employing hybrid propulsion systems.
In 2012, the U.S. Navy LHD-8 Makin Island was named a recipient of the 2012 Battle Efficiency (Battle “E”) honor, the Navy’s top performance award, which recognizes sustained superior performance and battle efficiency in an operational environment. The Makin Island is the first modern U.S. Navy ship to deploy with a hybrid propulsion system and serves as an excellent example of the technology’s benefits. The ship can be propelled by gas turbine engines or by auxiliary electric propulsion motors. The system uses GE Aviation (Evendale, Ohio) LM2500+ gas turbines for primary ship propulsion with electric propulsion from the auxiliary propulsion system (APS). During low-speed operation, the more efficient electric propulsion is used in place of less fuel-efficient gas turbines.
An impressive $15 million was saved during the Makin Island’s first seven months of deployment. Moreover, projections estimate that the ship will save $250 million over the course of its 40-year service life.
Energy storage remains of paramount importance for the world’s navies. The U.S. Navy is testing hybrid propulsion for the Arleigh Burke-class destroyers. The modernization of the ship would generate significant fuel savings, but the overall advantages would stem from energy storage. The ability to use energy reserves generated from the new technology would enable modernization with advanced, power-hungry weapons systems.
U.S. Navy sources indicate hybrid-electric drives will increase vessel mission efficiency by allowing increased time at posts. Additionally, the dual-power solution has the potential to create more power for instruments and weapons. The Navy cites 9 percent in possible fuel gains when in propulsion mode using hybrid-electric drive (HED) propulsion, where the load is removed from the main gas turbines and placed onto the gas turbine generators. Adding propulsion-derived ship service, or PDSS, to the HED increases the gains to 12 to 15 percent.
Cost savings and improved function are not the only benefits of the hybrid propulsion applications. Workboats, leisure craft and passenger vessels are facing unprecedented emissions regulations. Recent revisions to the International Convention for the Prevention of Pollution from Ships (MARPOL) standards took hold in early 2013 with the goal of reducing sulfur oxides (SOx), nitrogen oxides (NOx) and CO2 greenhouse gas emissions from vessels by 30 percent by 2030. The amendments are designed to curtail original maritime vessel emissions estimates. If not reduced, the industry’s portion of worldwide emissions will reach 18 percent. To continue this article please click here.
Alex Bynum is the business development manager of Saft’s lithium battery division in North and South America, which focuses on industrial, commercial and defense applications using a range of primary and secondary chemistries. Bynum’s career includes extensive experience in the sales and manufacturing of lithium primary chemistries, as well as complex rechargeable systems. Bynum holds a bachelor’s degree in engineering from North Carolina State University.