LPG marine fuel is now readily available and well placed to support the transition to zero-emissions shipping
Specialists in ship propulsion gathered to discuss the value proposition behind LPG as a maritime fuel at a webinar hosted by Riviera Maritime Media, in association with the World LPG Association (WLPGA). Panellists outlined the benefits of investing in LPG as a marine fuel, discussing its viability and its credentials for future-proofing fleets.
Covering the cost of retrofitting ships, the price of fuel, infrastructure for LPG bunkering and industry uptake, the webinar demonstrated the viability of this fuel type across a wide spectrum of maritime sectors. Panellists also spoke about the safety and technical aspects of the fuel, its energy density and the cost of producing LPG.
WLPGA technical director Nikos Xydas said he expects more shipping companies to retrofit vessels and order new ships with LPG fuel for environmental, technical and commercial reasons.
“LPG is the best choice for bunkers due to its environmental performance to meet IMO 2020 regulations and IMO 2050 strategy,” he said. “Compared with other alternative fuels, LPG needs much lower investment, it is easy to handle and is available now and everywhere,” said Mr Xydas. “It is here today to help clean air. There is no need for high investment, no need for cryogenic technologies – it is a proven technology now available.”
BW LPG is another committed LPG advocate and is becoming a leader in adopting LPG as a marine fuel. It will begin retrofitting up to eight LPG carriers – with another four in the pipeline; 12 vessels in total have been confirmed for conversion.
“LPG has significant economic and environmental benefits,” said executive vice president for technical and operations Pontus Kristofer Berg. “It is tested and works with high energy content. LPG is a sensible investment that is easy to handle and cost-competitive.”
Mr Berg recommended shipowners retrofit ships to LPG fuel instead of ordering newbuildings. “By installing this new technology on the existing fleet, these retrofits generate less CO2, so the environmental payback is six months,” he said. “The carbon footprint of a retrofit is much smaller than a new construction so retrofitting existing ships is our given choice.” BW will install MAN’s LPG-burning dual-fuel engines on its ships.
MAN Energy Solutions promotion manager and business development for dual-fuel engines Peter Kirkeby said MAN has a growing reference list of ships being retrofitted or built from scratch with LPG dual-fuel engines. These engines are based on diesel principles and can burn varieties of LPG chemistry as long as the maximum amount of ethane (with two carbon atoms and a single bond) is 25% and there is no less than 75% of either propane (with three carbon atoms) or butane (four carbon atoms).
“We gained type-approval for our 6G60ME engine in January 2020 and we will retrofit BW’s carriers from August 2020,” said Mr Kirkeby. “The engine technology is here, tested and classed. We are ready to deploy [LGIP engines] in many ship sizes and types,” he said.
Mr Kirkeby explained that in its Copenhagen centre, MAN works primarily on its two-stroke engines, which power large merchant ships. He said the reference list for these ships include LPG carriers, from the very large to the relatively small (5,000 m3).
He said retrofits demonstrate the strength and flexibility of this engine platform, which offers users the opportunity to use their preferred fuel choice. “You do not necessarily need to make that [fuel] choice now,” he said, “But if you are prepared, you can choose LPG at some future point, perhaps when it fits the docking schedule or the particular requirements of a charter deal.”
Mr Kirkeby emphasised that while the ME-LGIP engine operates on the two-stroke diesel principle, it can also run on very low sulphur fuel oils, combined fuels, heavy fuel oil and, of course, LPG.
“You have that opportunity to choose the fuel which is more beneficial for your operations on any given day,” he said.
He went on to note that the thermal efficiency of a diesel cycle remains unchanged, whether it is running oil or LPG. “The diesel cycle we use is very, very stable when it comes to the composition of the fuel,” said Mr Kirkeby. “When it comes to LPG, we can burn pretty much anything we have seen out there. We can also burn volatile organic components. So what is found in crude oil, which crude oil tankers now handle, can actually be recovered and used as a fuel in the LGIP engine.”
He also pointed out that while some gas engines are not necessarily limited in operation, it is important to consider load-up times, acceleration and stability in rough seas. “The LGIP engine does not need a long time to ramp up,” he said. “It will keep the engine load, no matter how rough the seas are. Of course, there is a propeller there, but it is not related to combustion stability.”
Addressing the mechanical benefits of running LPG, Mr Kirkeby said these would quickly compensate for any initial investment in the systems needed to operate the fuel. He said that while investment was clearly required for any dual-fuel engine, replacing “dirty heavy fuels” with a “very clean fuel” would have significant benefits for the mechanical components of the engine. “We have seen on other dual-fuel engines that the piston rings and cylinder condition is extraordinary,” he said. “And actually, we are extending TBOs beyond what is possible with oil operation. You might have an injection valve that requires some maintenance, but you will see other components last longer.”
With the LPG concept coming of age, it is perhaps no surprise that the majority of webinar attendees (71%) thought crude oil tankers would be the next ship type to adopt LPG as a fuel within the next five years. This was largely down to the ability of LPG engines to burn volatile organic compounds. Another 16% of attendees thought chemical tankers would be the next ship type to adopt the fuel source and 13% said container feeder ships were likely next in line for the LPG treatment.
Attendees were asked “what is the main driver for using LPG as the next marine fuel?” Around 63% said it was ease of storage and logistics of LPG over alternatives; next was cost of operation (23%), followed by cost of capital (14%).
Regarding any remaining challenges for the industry to overcome before LPG is more widely used as a marine fuel, attendees were asked for their main concerns for adopting LPG for bunkering: 28% said supply and bunkering infrastructure and another 27% said economics and payback; 19% cited technical and safety challenges, while 17% said engine availability and 9% noted the regulatory framework.
The Riviera LPG webinar was held 3 July 2020. Watch this in full in our webinar library