Wärtsilä Corporation, a marine industry solutions and services provider, is to supply the main engines for two environmentally sustainable dual-fuel tugs being built for CNOOC Energy Technology & Services Limited (CETS), a subsidiary of the state-owned China National Offshore Oil Corp. (CNOOC). Wärtsilä says the vessels are the first in a planned series to be fuelled by liquefied natural gas (LNG), and will be the first tugs in China to be operated on natural gas. The contract was signed in the beginning of July 2012 and the order is included in the third quarter 2012 order book.
The strategy of CNOOC is aimed at achieving more clean energy in its operations. The low emission levels made possible by Wärtsilä dual-fuel engines is particularly beneficial for vessels operating close to population centres, as tugs frequently are, while the high fuel efficiency enables lower operating costs. These 6500 bhp tugs will operate along China’s coastline, and will be fuelled from the company’s own bunkering terminals.
“We are delighted to be co-operating with CNOOC in supplying the main engines for these gas fuelled tugs. It is a landmark project that is very much in line with the marine sector’s key targets of achieving greater sustainability with better fuel efficiency. We endorse CNOOC’s strategic move towards cleaner energy and the use of LNG as a marine fuel, which is precisely in line with Wärtsilä’s own strategy,” says Aaron Bresnahan, Vice President Wärtsilä Ship Power Specials.
The vessels will each be powered by two 6-cylinder Wärtsilä 34DF in line dual-fuel engines. The engine can switch smoothly between fuels whilst operating. The Wärtsilä 34DF is manufactured in configurations of from 6L up to 20V giving 435/450 kW per cylinder and a total maximum mechanical output of 9000 kW. The engine speed is 720 or 750 rpm for use with 50 or 60 Hz applications.
The engine is fully compliant with the IMO Tier II exhaust emissions regulations set out in Annex VI of the MARPOL 73/78 convention.
Delivery is scheduled at the beginning of 2013, and the first of the tugs is expected to be delivered in June 2013.
Wärtsilä has recently achieved the notable milestone of supplying dual-fuel propulsion engines to 100 Liquefied Natural Gas (LNG) Carrier vessels. As of end May, Wärtsilä has sold some 720 DF engines, and has accumulated more than 5 million running hours of experience with this technology.
(This article compiled using information from a Wärtsilä Corporation press release)
Editor Note: Two LNG powered tugboats with Rolls-Royce engines were ordered by Norwegian company Buksér og Berging AS in January 2012 and will enter service in Norwegian waters late 2013.