While engine manufacturers, equipment manufacturers and equipment manufacturers strive to market next-generation technologies that will reduce greenhouse gas emissions in the future, shipowners today need practical solutions to improve the environmental performance of their fleet and save on fuel costs. This is particularly critical with the impending implementation of the Energy Efficiency Index for Existing Ships (EEXI) and Carbon Intensity Indicator (CII) and Ultra Low Sulfur Fuel Oil (VLSFO) exceeding the 1,000 USD per ton in Rotterdam.
Turbocharger efficiency is one of the main drivers of specific fuel oil consumption. In the case of an ultra-large container ship, Dirk Balthasar, head of global services sales at Accelleron (formerly ABB Turbocharge) said marine propulsion“If you have a turbocharger with higher efficiency, you can save several hundred tons of fuel and also CO2 on an annual basis.” Discussing turbocharger developments on a podcast, Balthasar observed, “It’s a technology that is already available.”
And although the turbocharger has been around for over 100 years, it has benefited from constant refinement.
During the discussion, Mr. Balthasar noted several trends in the marine market, including two-stage turbocharging. Over the past decade, Balthasar said two-stage turbocharging has become increasingly popular in the marine market for high- and medium-speed four-stroke engines. “It’s a big step up from single-stage turbocharging,” he said, allowing “engine builders to increase engine power density and reduce fuel consumption.” Compared to single-stage supercharging, two-stage supercharging, combined with Miller timing, offers significant improvements in engine performance.
“A turbocharger saves several hundred tonnes of fuel and also CO2”
Two-stage supercharging uses two turbochargers, a low-pressure stage and a high-pressure stage, as a means of overcoming the need to reduce NOx emissions to comply with stricter IMO Tier III emissions regulations, without increasing fuel consumption. fuel.
Mr. Balthasar also pointed to the possibilities of increasing engine performance by replacing a legacy turbocharger. “You are replacing an old, low-efficiency turbocharger with a modern turbocharger. You can increase efficiency and reduce fuel consumption with a newly tuned engine,” he said.
With an eye on decarbonization, turbocharger designers are working with engine builders to develop prime movers that will burn low and zero carbon fuels such as methanol, ammonia and hydrogen. Bi-fuel engines capable of running on methanol have been in service for years and the first hydrogen engines have just been released on the marine market. Two-stroke and four-stroke marine engines will be released over the next three years.
Mr Bathasar said the turbochargers are working on engines in service and on test beds running on methanol, ammonia and hydrogen. This involves adjusting turbocharger design and product materials for different power densities and fuel characteristics. Ammonia, for example, has a low burn rate, is highly corrosive and highly toxic. However, its energy density is greater than that of liquid hydrogen.
Looking further into the future, Bathasar predicts that turbocharger technology will continue to play an important role in decarbonizing shipping, underpinning a new generation of “supercharged fuel cells” for ships.