Challenges such as gas storage, space optimization in vessels and the lack of liquefying plants are some of the themes approached.

A team of engineers connected to the Research Centre for Gas Innovation (RCGI) has been studying the need for adapting the design of vessels so that they operate fuelled by natural gas. The goal is to combine knowledge that allows designing a ship adapted to the national conditions, within the restrictions imposed on Brazil for using natural gas as fuel. The study also intends to provide an overview of the natural gas market in Brazil and a perspective of the use of Liquefied Natural Gas (LNG) as marine fuel.

“The idea is to devise scenarios for natural gas and for LNG, considering the possibilities that these scenarios would create for the shipbuilding industry and for the conditions that would allow the sustainable development of them. At a second moment, we will concentrate more on LNG as the fuel for vessels”, summarises Professor Cláudio M. P. Sampaio, naval engineer at Poli/USP and coordinator of the project “Conceptual feasibility project of energy- and environmentally-efficient natural gas-fuelled ships.” There is a team working with him, composed of four other naval engineers.

Sampaio states that, in countries with stricter environmental regulations, the use of natural gas as fuel for vessels has already been stimulated, considering that it emits less sulphur oxide and nitrogen oxide, besides possible reductions on CO2 emissions as compared to the traditional vessel fuel, bunker oil.

“A law is being enforced in the USA, which bans the use of bunker oil up to 200 miles from the coast. Due to this very strict emission regulation and also to the cost of gas, which is low as the USA is currently one of the major world producers, thereis a boom of natural gas to fuel cars, lorries, vessels and some adapted vessels in that country. The North Sea and the Baltic Sea are also emission control areas, in which the sulphur oxide levels have to be kept low. The use of gas is thus entering the agenda, especially in those countries.”

This is a three-year project, each dedicated to a stage:  in the first year, a LNG road map will be elaborated. “The aim here is to understand the Brazilian market and its restrictions. For example, we don’t have such strict environmental regulations, therefore, is there an advantage of exploring gas and, particularly, LNG? An option could be acting as a fuelling point for transoceanic vessels that might be refuelling with natural gas. But where should it be stored? What is the best place? Santos Port? What are the safety conditions around this unit? What is the interest of Brazilians in using gas? If we, Brazilians, opt for using natural gas fleets, how will the fuelling procedure?”

According to him, an important point in the analysis is the pre-salt. “A large portion of the natural gas from the pre-salt layer is known to be reinjected underground. We should, therefore, ask ourselves whether we are going to reinject the gas forever. If we had an infrastructure to explore the pre-salt gas, we would probably extract a much larger amount than the one we are actually using. How could it be sold. Would it have to be liquefied. However, we only have a small liquefying plant in Paulínia. Then we would have to incur on costs for building a liquefying plant. All of this has to be evaluated and weighed. These are possible scenarios, ideas”, sums Sampaio.

In the second year, the engineers will be concerned with the naval design of a vessel of the platform supply vessel type (PSV), which supports oil production on the coast. They will develop the preliminary design of a liquefied natural gas-fuelled PSV. “We are interested in the vessel configuration, the technologies to improve the hull lines, the materials to be used. What has to be changed regarding the bunker oil-fuelled vessel? How to make a design of this type? Even using liquefied natural gas, which allows a greater stored volume, the LNG tank will be larger than that of the common fuel and, consequently, there will be a loss of space in the vessel. It is then necessary to assess whether it is worth it.”

He highlights that, besides requiring a larger storing space, natural gas demands greater control. “Whereas bunker fuel is stored at ambient temperature, LNG is stored at 160º C/ 320º F. This content requires specific care.”

Lastly, in the third year, a simplified analysis of a shuttle tanker and a FSRU system (Floating Storage Regasification Unit), which is a unit receiving LNG, regasifying and forwarding it to the gas pipeline system; in the Brazilian case, mainly to supply thermopower plants. “Finally, we will weight the two technologies – bunker oil- and natural gas-fuelled vessels – and make a comparison”, says Sampaio.