LNG Tankers with Electric Propulsion Systems Equipped with RENK Gear Units, Couplings and Slide Bearings
17 January 2007
Experts predict that natural gas will be the fastest growing type of energy over the next two decades and by 2020 it will cover at least 25% of the global energy demand.
When natural gas is cooled down to -163°C, it will liquefy and reduce to six hundredths of its volume. Thus, 600m³ of natural gas converts to 1m³ of Liquefied Natural Gas (LNG). The demand for oil is currently growing by 2% per year while demand for that for natural gas increases by 3% per year. Based on studies conducted by energy market analysts, the market for LNG will double by 2010 and the long-term growth rate is expected to increase by 10% per year or more. With progressing globalisation, about half the natural gas trade will be handled with liquefied gas within the next 25 years. Currently, it is less than 5%. The logical consequence of this progress is huge investments in harbours, liquefying facilities and ships. At present, approximately 200 LNG tankers are cruising the oceans. By 2010, their number is expected to climb to 300 as a result of the LNG boom. Currently, more than 100 LNG ships are under construction or on order.
RENK AG, a member of the MAN group, is one of the leading manufacturers of marine gear systems. The RENK plant in Rheine, Germany, has specialised in manufacturing single and twin-engine gear units and propeller shaft clutches, and is a much demanded partner in the booming LNG tanker business.
At the moment, a remarkable number of newly-built South Korean and Japanese LNG tankers, with a capacity of up to 165,000m³, are equipped with electric propulsion systems and RENK twin gear units. The centre distances are up to 4,000mm. Two electric motors are combined by one twin gear unit delivering a power output of 30,000kW to the fixed-pitch propeller.
The orders recently placed for several LNG tankers of the latest generation also feature two independent propulsion systems which significantly contribute to an increase in redundance, with RENK single-engine gear units assuring a reliable conversion of electric power into propulsion.
The strong presence of RENK in this field is also evident in the regular supply of the neccessary bearings for generators and electric machines on board, delivered by the Hannover plant.
