Last GREEN4SEA Forum explored nuclear power as an alternative source of power. Now that there are very promising 4th generation reactors for advanced atomic, ships will not be releasing any emissions, as it there are no SOx, NOx, CO2 or particulates. In fact, considering the full energy cycle, atomic is millions of times more power-dense and cleaner compared to either fossil fuels or popular alternatives in the likes of methanol, ammonia and hydrogen.
Taking a deeper look into the advantages of nuclear power, the panel explained why atomic power should be considered for shipping’s decarbonization. More specifically, Panos Zachariadis, Technical Director, Atlantic Bulk Carriers, made an analysis of the emissions from current to fuels to highlight the difference with nuclear power. “For the first 5-10, one kilo of methane is worse than 110 kilos of CO2. What we hear is that methane is 25 times worse than CO2, when in reality it is 86 times worse. When an engine burns LNG, it does not produce less CO2 than commercial fuels, but the same or worse”, he said
Mr. Zachariadis added that new studies constantly come out saying that “LNG is not as good as we though it was. On the latest study, the most popular LNG ship engines, actually emit 70 to 82% more GHG, than distillate fuels.”In fact, he mentioned that big companies, like Maersk have ruled out LNG as transitional fuel, while the “green lobby now says that switching ships to LNG is worse than doing nothing.”
As far as hydrogen and ammonia are concerned, Mr. Zachariadis mentioned that they come from natural gas, and 95% of hydrogen production comes from natural gas through a process called steam methane reforming which is very carbon intensive. “Just for producing hydrogen, the emissions would be 830 millions tons CO2 per year, which is the same as all of shipping. Also, hydrogen production is only 75 million tons”
Methanol is the same thing, as it also comes from the same process as hydrogen, and its world production is about double that of hydrogen, at about 150 million tons. However, that means that the numbers of its carbon intensity are also double. “We are not there yet with all those alternative fuels, to address global warming’’, believes Mr. Zachariadis, adding that batteries cannot be considered as a viable option. As he stated: “One ton of diesel has an energy capacity of 11,700 Wh per kg. The best lithium battery is 300 Wh per kg. So a containership sailing at its most economical speed would need 100,000 tons of batteries for a trip to Asia from Europe”
Another reason for shipping to choose nuclear power, is the energy density of uranium and thorium, which is 1,539,842,000 and 929,214,000 respectively. In comparison to current fuels, their energy density is 40 million and 23 million times more. Taking all of the above into consideration, Mr. Zachariadis concluded to the following reasons as to why 4th generation mini reactors should be considered by maritime:
- No possibility of meltdown;
- Natural cooling;
- Reduced radioactive remains.
- Use current spent radioactive waste or nuclear weapons as fuel;
- 25 year life, totally enclosed, no maintenance;
- Much cheaper than diesel engine and fuel;
- Can produce green hydrogen without electrolysis.
Complementing on how can shipping achieve decarbonization, Edmund Hughes, Director, Green Marine Associates Ltd, noted that: “The IMO Initial strategy sets out the parameters in which we have to work and in particularly the third level of ambition where we want to peak GHG emissions from shipping as soon as possible and to reduce the total annual GHG emissions by at least50% by 2050”
As he mentioned, this is leading to the 4th propulsion revolution, but now we are aware of all the various types of fuel and technologies that are being considered.“All these factors are there and they have to be discussed but they all bring risks. There is not going to be zero risk option, especially when talking about deep sea ships”. As Mr. Hughes further explained, shipping understands the risks of nuclear very well, “but the fourth generation of advanced nuclear reactors they have essential inherent safety over what are the pressure water reactor technology which is currently seen in power generation in large power stations ashore.”
“These reactors can be built in modular and they can be smaller and can be much more economic. In the UK for example it has set a green program of investment including the development of these advanced nuclear reactors”
For this reason, Mr. Hughes believes that shipping cannot ignore nuclear, despite its obstacles, some of which are:
- The volumes required and availability to support deep sea shipping;
- The energy to produce and feedstock;
- Lifecycle considerations: Tank to wake or well to wake?
Continuing on the same wavelength, Giulio Gennaro, Technical Director, Core-Power, stated that: “Shipping has to decarbonize, and the strategy to do this is to electrify all that can be electrified and to produce electric power with green sources. Advanced atomic will a play a fundamental role in this clear electric power generation”
However, he noted that there are segments of the economy that cannot be electrified and the industry should use advanced atomic to produce power. One option would be the use of molten salt reactors (MSR), whose advantages are:
- They are modular and can be fitted in ships and floating installations;
- Passive walk-away safe;
- Cheapest, most efficient way to produce green hydrogen, ammonia, methanol;
- Liquid fuel, 2 million times more energy dense than diesel;
- 95 times more fuel efficient than conventional nuclear;
- 15-50 MWe power for up to 30 years fuel lifecycle.
Another important factor for shipping’s decarbonization, according to Mr. Gennaro would be the floating production of green fuels. This technology should be considered as a solution as:
- MSR technology powers green synthetic fuels’ floating production for shipping and for on shore use.
- Raw materials input is electric power and heat from m-MSR water, air, and CO2. Operating in domestic waters or near ports.
- Model demand for green synfuels is 250 mill MT per annum by 2035.
“If we consider ship propulsion alone, we have to understand that the possibility of installing 4th generation advanced atomic initially will be restricted to the large segment of the fleet, which is also the hardest to be decarbonized”
Mr. Gennaro emphasized, adding that there are also other options that can be tapped into when using nuclear power, and these are the floating plants.
“This could provide electric power from sea to shore. The drawback is the need for a heatsink, because when we use a diesel engine we use the atmosphere as a heatsink. If we move to the sea we have an infinite heatsink, which makes things very practical and safe”
Finally, another option according to Mr. Gennaro would be floating mobile desalination plants, as they:
- Produce 200-250 million gallons potable water per day;
- Could provide electric power to shore;
- Provide rapid response vessel for disaster relief.
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