A large number of ships built since 2013 comfortably exceed the Phase 3 requirements set by IMO’s energy efficiency design index (EEDI) formula, which is due to come into effect from 2025. “If the regulation’s purpose is to force technological [change], it’s not doing its job,” said Faig Abbasov, shipping policy officer at the environmental think-tank, Transport & Environment.
He was speaking at the ShipInsight conference earlier this month (13 February) as a member of a panel looking at energy efficiency. Although EEDI is termed an efficiency index, “it is actually a CO2 design standard,” he said, displaying data covering what he said are the five ship types responsible for most CO2 emissions – bulkers, container ships, tankers, general cargo vessels and gas carriers.
Transport & Environment is a member of a correspondence group that is analysing this data, which has been collected by the IMO. With one exception, it showed that the best 30% of ships in each category were well ahead of the Phase 3 EEDI requirements. The exception was bulk carriers, although the best 30% of those surpassed the EEDI Phase 2 target, due to come into effect next year.
For a standard such as EEDI to be effective, he said, it should be set at the level where current technology is just good enough to comply. Only then will there be an incentive for technological innovation to meet the next phase, he said. He drew an analogy with someone who has been given a calorie control programme to follow by a dietician. If that advice sets a level that is more than the person is already consuming, “will that regime help them lose weight?”
Klaus Vänskä, global business development manager for marine systems at ABB also said that EEDI “is not working very well”. One reason for that is because a ship’s operational conditions are likely to be very different from those predicted at the design stage so he welcomed MARPOL Annex VI Regulation 22A, which came into force on 1 March 2018 and requires fuel consumption data to be collected and reported, starting this year. This “will give us an understanding of the real CO2 emissions of those vessels,” he said.
Speaking from the floor during later discussion, the director of environment sustainability for DFDS Poul Woodall asked whether tightening EEDI requirements would increase newbuilding prices and therefore make it attractive to keep older ships running.
Mr Abbasov argued that,initially, it would not do that because new ships would be more efficient, offsetting their increased cost. However, once new and more expensive fuels start being used, the logic will reverse, he suggested. Mr Vänskä advocated taking account of the carbon footprint from building new ships. Even if they were more efficient to operate, from an overall greenhouse gas perspective, it may be better to continue using an older ship rather than replacing it, he said.
During his presentation, Mr Vänskä said that operational factors could help improve a ship’s efficiency. Once fuel savings from such options as route optimisation and weather routeing are taken into account alongside technical developments, efficiency could be improved by 30-35%, he suggested.
Double-digit efficiency gains can also be achieved by using alternative fuels, suggested René Laursen, mechanical engineer at MAN Energy Solutions. For example, using LPG as the primary fuel can deliver a 20% increase in power from an engine or a corresponding decrease in CO2 emissions, he said. To achieve larger CO2 reductions than that, “you need to look at carbon free-fuels,” but assessments would have to take account of what he called the ‘well-to-wake’ emissions produced to make such fuels.
One of those could be ammonia, he said, mentioning a cooperation agreement between MAN Energy Solutions and the windfarm developer Siemens Gamesa, which has looked into the relative efficiencies of using renewable electricity to produce ammonia, hydrogen, ethanol and methane. It found that ammonia can be produced as efficiently as hydrogen, once the energy needed to cool the hydrogen for storage is taken into account. IMO will eventually have to decide how to calculate the CO2 emitted while future fuels are being produced, Mr Laursen said.
But there are still efficiency improvements to be gained from engineering improvements, he said, in particular by using an improved design of power-take-off gear and waste heat recovery systems that together could add 4-7% to an engine’s efficiency. He also showed a diagram of a system the company is researching that would combine a diesel engine and a gas turbine – powered by engine’s exhaust and additional fuel – with a steam turbine that would recover waste heat energy. In combination, these would deliver 60.67% of the fuel’s energy, he predicted.
Other significant energy savings can be achieved by ship design improvements, said Jan-Erik Räsänen, head of new technology at the naval architecture and marine engineering specialist Foreship. The company mainly works on cruise ship concepts and he illustrated his point by comparing a class of ships it had worked on in 2008-9 with new vessels it is designing for the same customer that will use 25% less fuel than those of just a decade ago.
“Energy efficiency is an alternative fuel,” he said. “Be efficient in your design [and] be really efficient in your operation,” he said, and “you can afford to pay the $200 premium on cleaner fuel because you will be so much more efficient.” He recommended using alternative fuels rather than scrubbers because of the energy they need, but he also spoke in favour of LNG, saying that its use plays a big part in the energy improvements he is expecting in the company’s new cruise ship design. For example, not using HFO removes the need for tank heating.
He also believes that effective waste heat recovery can pay dividends; “Diesel engine efficiency is just less than 50%, but the net energy utilisation rate should be way over 70%.”