Developments in the natural gas and liquefied natural gas (LNG) industries are putting new demands on LNG shipping, triggering new specialized LNG carriers. Lars Petter Blikom sets out why.
Aside from tanks and machinery, they are all generally the same. Size-wise they also follow the standards of the indus- try, which have evolved somewhat over the past 40 years as the “standard” size has grown from 125,000cu. m, through 137,000cu. m and 145,000cu. m, to today’s size of about 160,000cu. m.
|Photo from DNV GL.|
A ship built in accordance with a standard size and specification has many benefits. For one thing, it makes the ship itself a commodity. When every ship is the same and it can do the same job, it allows for the trading of the ships themselves—an activity ship owners are quite fond of. There is also an operational benefit to having standard ships; all the ships can load and unload at all the world’s export and import terminals. This creates flexibility in shipping, opens up opportunities for portfolio optimization and cargo diversion, and establishes a “cargo size” as a tradable volume.
Yet, changes in the natural gas and LNG industries will inevitably lead to a rethink of LNG ship design. It seems clear that the standard ship is not always the best option, and often it is not even a viable option.
Take, for example, the long term trend in the LNG industry for LNG export plants and import terminals to move to offshore locations. In benign waters, these plants and terminals can still be served by standard ships, but as soon as wave heights exceed a couple of meters, special purpose vessels will be necessary. They may need dynamic positioning capability for safe berthing and station-keeping, and they may need special connection arrangement for tandem offloading systems.
LNG supplies are also needed now in new, more challenging areas, such as the Arctic. LNG carriers serving LNG plants here will have to be built according to ice class rules. This means reinforced steel plates in the water line, more engine power, propellers able to break ice, special hull shape, and various other properties not offered by the standard LNG carrier.
Another driver for new ship design comes from the shift in LNG being used historically mainly for power plants, industry, and domestic heating and cooking in areas, with dense gas distribution grids, to off-grid applications in the future. Such applications include power generation in areas with no distribution grid, isolated industrial complexes, islands, and also transportation, where LNG and com- pressed natural gas (CNG) are being widely adopted in many markets. For all these applications, natural gas eliminates most local emissions, contributing significantly to improving air quality—a growing problem for emerging Asian cities. Making natural gas available to these consumers requires a different supply chain than exists in the natural gas industry today, and there will be new requirements also to the ships serving this supply chain in the future. We will see a greater demand for small- and medium-size ships. We will see increased use of flexible hoses for loading and offloading, which again drives a need for new connection systems, and we will see use of a wider selection of LNG containment systems, driving new operational requirements to pressure and temperature control, gas quality, etc.
LNG is gaining traction as a marine fuel, and within a few years we expect to see LNG bunkering going on in all the big ports around the world. This bunkering process will have to be served by special-purpose LNG bunkering ships and barges. These bunkering ships will not be very different from small LNG carriers, but they will have some additional features, such as dynamic positioning capability for efficient mooring, a special bunkering arrangement with either flexible hoses or loading arms, and additional systems for vapor return and cargo pressure control.
As a lot of the future growth in natural gas demand comes from power production, both small and large scale, it doesn’t come as a surprise that floating LNG power barges/ships emerge. By having LNG storage tanks, re-gasification capability, and a power plant onboard, the unit can supply electricity instead of gas to shore, a great advantage in many areas, e.g. those that have limited land area available for accommodating future power sources.
There is also increased focus on providing ships in port with power from shore—referred to as cold-ironing—and LNG power barges could be a good alternative to this practice in many ports. Again, a standard LNG ship can’t be used for this, as it will face a whole set of new requirements, spanning regulatory, operational, technical, and commercial aspects.
Over the coming years, global energy markets will change and adapt to meet future requirements for reduced car- bon footprints and less local pollution. Natural gas is the cleanest of the fossil fuels, and is expected to constitute a significant share of the global energy mix for years to come. But in order to make sure we maximize the environmental effects of natural gas, it is important to utilize natural gas in applications where even cleaner options are not available.
|Photo from DNV GL|
For the industry to reach these customers, it will be necessary to redesign business models and supply chains for natural gas and LNG. This means new concepts in ship design. These are already materializing and the shipping industry is responding by designing and ordering new types of ships. So the question is not really whether this will happen, but how quickly?
Lars Petter Blikom is Segment Director for LNG at DNV GL, with global responsibility for business development within the LNG industry, covering both classification of ships, and advisory services. Lars Petter studied for an MSc degree in marine technology from NTNU before joining legacy DNV.