The leaner, greener LNG carrier of the future

Gas is enjoying soaring growth. Plentiful and comparatively low carbon, it is expected to make up an increasingly large share of the global energy mix in 2050. As a result, its transportation is scaling up too. Never have so many LNG (liquefied natural gas) carriers crisscrossed the planet's seas. But, shipping still accounts for a big chunk of the final cost of a cubic meter of gas — too big, in fact. Both to whittle that down and for environmental reasons, Total has designed and begun construction of two LNG carriers offering improved energy efficiency, in large part because they will use some of the gas they carry for their own needs. Jacques Besse, vice president of LNG shipping at Total, explains the challenges and potential of these LNG carriers of the future.

There are two ways to move gas. One is by land, via gas pipelines; the other is by sea, aboard LNG carriers. Maritime shipping accounts for more than 31 percent of all the natural gas transported in the world1 and is expanding fast for two main reasons. The first is that major producing regions2 are located far from consumer markets.3 The second is that shipping is more flexible, making it easier to balance supply and demand. Geopolitical considerations and the advantage of reliably safe carriers are other key factors.

Natural gas must be liquefied before it can be shipped: In this way, 600 cubic meters of natural gas can be reduced to 1 cubic meter of liquefied natural gas (LNG). It's a four-step process, from purification, which removes carbon dioxide and sulfur compounds, to liquefaction, which cools the gas to -161 degrees Celsius at atmospheric pressure. The LNG is then ready to be loaded onto LNG carriers.

An exclusive tour of the South Korean shipyards that are building the LNG carriers of the future.

Cargo that doubles as fuel

However, LNG shipping is also subject to strong environmental and financial constraints, which are driving change and innovation. These requirements have spurred Total — which currently has around 40 LNG carriers under charter and 26 on order — to take the lead on energy efficiency innovation. Jacques Besse is vice president, LNG shipping at Total. His long career makes him an invaluable source of information about how these giant ships have changed in the last two decades. "When I started out back in the 1970s, the capital cost of the carrier represented 60 percent of total shipping costs. Now the cost of fuel oil is 60 percent," he says. "For both cost and environmental reasons, we've changed the propulsion method by using the gas we carry," he added.

It's a bit as if oil tankers were to use what they have in their cargo holds. That would be complicated, because the product hasn't been processed. But liquefied natural gas has been "a perfect fuel since 1964," states Jacques Besse. Because of the way it's processed, it contains no sulfur, emits less carbon dioxide (CO2) than fuel oil and produces little in the way of nitrogen oxides (NOx4). It is also odorless, colorless, non-corrosive and non-toxic.

But transported at a temperature of -160 degrees Celsius, liquefied natural gas boils off. Instead of being allowed to dissipate in the air, the boil-off gases, primarily methane, are recovered and burned in engines or turbines to power the LNG carriers at a minimum speed of 17 knots. An average of 0.10 to 0.15 percent of the total cargo volume is available for use each day.

The new propulsion method used by Total ships — a dual-fuel (diesel and gas) engine — both improves the carrier's efficiency and brings it into full compliance with the stringent environmental regulations set to take effect in 2020.

A Nantes start-up works on the carrier of the future

Even with this mode of propulsion, shipping still makes up a big share of the final cost of natural gas. There are many ways to optimize energy efficiency. "We've ordered two carriers that incorporate dual-fuel propulsion, but we wanted to go farther and build the LNG carrier of the future," says Jacques Besse. "So we've also looked at hull design to optimize hydrodynamics." A small business in Nantes, France, HydrOcean, was given the job of evaluating the best design for the carrier. "Until now engineers measured hull efficiency in a tank," says the Total manager, "using scale models that had to be built and tested in the water. It took a fairly long time, so testing capacity was limited." However, HydrOcean, a start-up spun off from the École Centrale de Nantes engineering school, is a showcase of French know-how in mathematical modeling. The company can measure dozens of variations in hull shapes and models using computer simulations. You can't do that in a tank due to cost and time constraints. "We were able to test around 150 different designs, both loaded and without cargo. Our shipyard, Samsung Heavy Industries in South Korea, was very impressed."

The industry's digital transformation, often said to be slow, is under way. SK5 Audace and SK Resolute, two LNG carriers that have a cargo capacity of 180,000 cubic meters, are prototypes. Currently under construction in South Korea, they are scheduled for delivery in July 2017 and January 2018, respectively. They still require adjustments, especially to their software. But other features can also be fine-tuned. "There are still some aspects of the hull's design we should be able to upgrade. We didn't have access to all the technical information, but what we've done so far is being watched very closely by everyone in the industry. For good reason — our work on hull design and propulsion, combined with better insulated LNG tanks, has yielded an 11 percent drop in carbon emissions, a 3.8 percent gain in propulsion efficiency and shipping cost savings of 13.5 percent," concludes Jacques Besse.

• For more on the subject: Lubricant, the Unknown Factor In Energy Efficiency

A host of ways to improve

The hull can still be improved and propulsion can also be optimized by creating a combined cycle. Recovering heat from engine exhaust is an option under study, "even though the exhaust is low pressure and the volumes obviously spread out, which would require large treatment areas, never a good thing on a boat," warns Jacques Besse. Adding more energy systems also means making life more complicated for crew, who are a scarce commodity on an LNG carrier and whose technical capabilities are limited because of their isolation at sea. "At some point we'll probably have to put people on board to manage carrier energy."

But, he says in a final comment, "We haven't maxed out our options. The technologies aboard these LNG carriers, which cost $200 million each, are simple and have a lot of room to be upgraded. Optimizing routes based on weather, communications, energy management — we still have a lot to learn, especially compared to our aerospace colleagues."

But airplanes can't fly on LNG, at least not yet!

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1 In 2013.



4 Combined with volatile organic compounds (VOCs) and exposed to sunlight, NOx promote the formation of ozone in the atmosphere's lower layers (the troposphere). They play a role in the formation of acid rain and in soil eutrophication. They also factor into the formation of fine particulate matter in ambient air. From a health standpoint, nitrogen dioxide (NO2) is an irritant gas that reaches the tiniest airways of the respiratory tract. It can cause respiratory problems or bronchial hyperresponsiveness in at-risk people and make children's bronchi more susceptible to infection. NO2 is 40 times more toxic than carbon monoxide (CO) and four times more toxic than nitric oxide (NO).

5 SK are the initials of the South Korean ship owner, SK Shipping.

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