be able to clean this exhaust, but the technology is not proven.” Small amounts of unspent ammonia may also be emitted, Chryssakis says. “Anything over 30 ppm locally can be dangerous, and as little as 5 ppm can be smelled.”


Chryssakis mentions the option of ammonia tankers burning their cargo as fuel, much the same as modern LNG tankers do. But this technology will first gather momentum in newbuilds, he maintains, while regulations and contracts favouring sustainable power will drive retrofits. The cost of producing ammonia will also influence decisions.


A host of green ICE alternatives


Burning hydrogen in combustion engines is another option, says Chryssakis. And though hydrogen contains no carbon atoms, and thus emits no CO2


when


consumed, it is often produced using natural gas. Hydrogen can be used to partly replace LNG in combustion engines, thereby reducing their carbon footprint.


Biofuels have long been considered an alternative to petroleum-based fuel, but producing them at scale remains an issue. “Large-scale production, including facilities, has not performed well enough to justify realization, either economically or technically,” says Chryssakis. “For example, if it takes 50 years for a forest to mature, and only two per cent can be harvested annually if we are to ensure regeneration, that would limit access to sustainable feedstock.”


Synthetic fuels can use the same infrastructure and engines as petroleum fuels, but they will need to be produced from renewable energy in order to qualify as green. “The issues right now are scaling up production, and identifying suitable energy sources,” Chryssakis says. “For example, it has been estimated that we would need 8 km2


to produce enough ammonia to operate one large container vessel for a single year.”


The case for bridge fuels


Despite its status as a fossil fuel, LNG should not be discounted as a short and medium-term solution, Chryssakis maintains. “LNG can contribute a 15–20 per cent greenhouse gas emissions reduction, and it can also serve as a basis for using other fuels in the future. Evolving engine technology could also reduce methane slip from LNG.” All engine makers are working to resolve this issue, he points out. “No one wants to risk stranded assets of ships unable to sail because of emissions restrictions.”


If so-called bridge fuels are abandoned, he says, the alternative is to continue burning oil while in pursuit of the “perfect” solution. “But we cannot bet safely today on a solution that will not be available until 2035 or 2045. It is better to work with what we have, and concentrate on building a future- proof infrastructure that can match future ships.”


With internal combustion technology providing the highest efficiency for decades to come, LNG is a key bridge fuel as the search for a feasible carbon- neutral alternative continues.


Competition to ICEs


With internal combustion technology providing the highest efficiency for decades to come, LNG is a key bridge fuel as the search for a feasible carbon- neutral alternative continues.


Chryssakis notes that batteries with currently available chemistries are approaching the physical limits of energy storage. “New storage chemistries may emerge that can offer tenfold improvement, but they are still not proven on a commercial scale, and probably the first applications will be seen in automobiles, not large units like ships.”


of solar panels


Fuel cells are more suited than batteries when size is an issue, he says. “But they perform


62 | The Report • September 2020 • Issue 93


better under constant loads, so they need batteries to even out consumption.” Then there are the issues of fuel access and storage to resolve, as well as fuel production methods. Fuel cell life expectancy also remains a significant variable, he notes.


The relative attractiveness of different power solutions will vary between segments as well, Chryssakis says. “For example, cruise passengers might be willing to pay a premium for cleaner ships. But how quickly are consumer attitudes changing in the same direction?” That being said, charterers and owners in the transport trade are becoming more attentive as consumer sentiment shifts towards green alternatives, and they are actively seeking alternatives, he confirms.


“We have a zero-emission strategy, but we must also be prepared for markets to evolve. Many in the industry want to follow their hearts in one direction or another, but we do not know enough about the right direction yet.”


Keeping ICE options open


“Right now we are still in the phase where we need to explore all available options for ICEs. The most important thing is not to close doors too early. We can experiment today with what is available until the best alternative emerges,” says Chryssakis.


ICEs can accommodate nearly all types of fuel, he says, but the market must be ready or manufacturers will not be able to justify committing their design capacity. “There are so many balls in the air now that stakeholders are facing very complicated decisions,” Aabo acknowledges. In such an environment, engine manufacturers believe they can offer a robust option. “We know that ICEs will provide the highest efficiency possible in the foreseeable future. Unless something completely unexpected turns up, ICEs will be around for many years.”


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44  |  Page 45  |  Page 46  |  Page 47  |  Page 48  |  Page 49  |  Page 50  |  Page 51  |  Page 52  |  Page 53  |  Page 54  |  Page 55  |  Page 56  |  Page 57  |  Page 58  |  Page 59  |  Page 60  |  Page 61  |  Page 62  |  Page 63  |  Page 64  |  Page 65  |  Page 66  |  Page 67  |  Page 68  |  Page 69  |  Page 70  |  Page 71  |  Page 72  |  Page 73  |  Page 74  |  Page 75  |  Page 76  |  Page 77  |  Page 78  |  Page 79  |  Page 80  |  Page 81  |  Page 82  |  Page 83  |  Page 84  |  Page 85  |  Page 86  |  Page 87  |  Page 88  |  Page 89  |  Page 90  |  Page 91  |  Page 92  |  Page 93  |  Page 94  |  Page 95  |  Page 96  |  Page 97  |  Page 98  |  Page 99  |  Page 100  |  Page 101  |  Page 102  |  Page 103  |  Page 104  |  Page 105  |  Page 106  |  Page 107  |  Page 108  |  Page 109  |  Page 110  |  Page 111  |  Page 112