Engines Bergen AS Fuel Efficiency and Reliability in LNG propulsion CIMAC NMA Norway Fall Meeting 2014 Hordvikneset 24.09.2014 / Erlend Vaktskjold 2014 Rolls-Royce plc The information in this document is the property of Rolls-Royce plc and may not be copied or communicated to a third party, or used for any purpose other than that for which it is supplied without the express written consent of Rolls-Royce plc. This information is given in good faith based upon the latest information available to Rolls-Royce plc, no warranty or representation is given concerning such information, which must not be taken as establishing any contractual or other commitment binding upon Rolls-Royce plc or any of its subsidiary or associated companies. Trusted to deliver excellence
Topics 2 1. How to save fuel cost and reduce exhaust emissions Fuel prices Engine fuel efficiency Exhaust emissions Power management Variable speed - engine and propeller 2. Reliability Loss of propulsion Limited propulsion control Equipment malfunction or damage 3. Examples of LNG propulsion
Fuel Prices Worldwide 3 Chosen values: LNG 10$/GJ MDO 20$/GJ Sources: MDO: Bunker Index MDO http://www.bunkerindex.com/prices/bixfree_1310.php?priceindex_id=4 LNG: Argus Global LNG: LNG Markets, Projects and infrastructure Volume IX, ISSUE 12, Dec 2013; Volume X, Issue 4, April 2014
LNG vs Diesel Fuel Cost 4 50 Fuel Efficiency [%] 45 40 35 30 25 20 Fuel Cost [$/GJ] 60 LNG 50 MDO 0 25 40 50 75 100 Power Output [%] 30 20 10 LNG MDO 0 0 25 50 75 100 Power Output [%]
LNG vs Diesel Exhaust Emissions 5 250 CO2 emission [kg/gj] 200 150 100 50 LNG MDO LNG 0 NOx emission [g/kwh] 12 0 25 50 75 100 Power 8 Output [%] 4 MDO 0 0 25 50 75 100 Power Output [%]
LNG vs Diesel Exhaust Emissions 6
LNG vs Diesel in the Engine Room 7 Diesel engine 20.000h Gas engine 45.000h
Power Mangement 8 Multiple engines example 4 generating sets 35 30 Fuel Cost [$/GJ] 25 20 15 10 5 0 0 20 40 60 80 100 Vessel power demand [%]
Variable speed 9 35 30 Fuel Cost [$/GJ] 25 20 15 10 80 Variable Speed 5 0 Fuel Cost [$/NM] Fixed Speed 60 0 25 50 75 100 Power 40 Output [%] 20 Variable Speed Fixed Speed 0 0 4 8 12 16 20 Vessel Speed [knots]
Summary Fuel Cost and Emissions 10 Run on LNG Run as few engines as possible Run variable engine speed Run variable propeller speed (Use twin screw) 40-60Hz 60Hz
Reliability Types of Faults 11 Fault type Consquence Mitigation Loss of propulsion «Let go the anchor!» - Very high robustness in critical elements - Redundancy Limited propulsion Equipment malfunction or damage Out of commercial service (off-hire) Maintenance / replacement required - Robustness - Redundancy?? - Robustness - Less equipment / reduced redundancy
Loss of propulsion 12 Major breakdown Minor brakdown Rudder control Pitch control Clutch control Fuel supply Engine shutdown Governor failure Ignition Diesel (conventional) Redundancy on fuel Major supply leak and engine IS required! LNG (lean burn SI) Onboard spares available Pump failure, control failure, leakage, etc Gas leak SD Block valves (4 off, fail to closed) Pressure drop in LNG tank Safety shutdown (prevent major breakdown) Mechanical backup governor on single engines Self-ignition Electronic governor, no backup Ignition sys with spark plugs and pickups
Limited propulsion 13 Rudder backup control Pitch backup control Clutch backup control Air-Fuel control / limit Diesel (conventional) Smoke limiter Black smoke in case of failure LNG (lean burn SI) Electronic governor and actuator Gas pressure control NA Electro-penumatic control Combustion knocking NA Slow down alarm <40%
Reliability Summary Loss of, or Limited, Propulsion 14 Run on LNG Run as few engines as possible Run variable engine speed Run variable propeller speed (Use twin screw) (need frequency converter) (tied to engine speed) 40-60Hz 60Hz
Examples of LNG propulsion 15 Fjord 1 / E39 Halhjem/Sandvikvåg + Arsvågen/Mortavika 5 ferries since 2006, 1 more 2013 Gas electric propulsion, 2 4 main gensets per vessel Diesel backup gensets 10.000 12.000 port calls / year with no incidents Torghatten Nord / Lofoten 4 ferries since 2013 Gas mechanical propulsion 1 main engine per vessel Diesel genset backup through PTI on gearbox An unacceptable number of incidents
Examples of LNG propulsion Fjord Line «Danskebåten» 2 cruise ferrys 2013 Gas-mechanical propusion 4 main engines, 2 propellers Loss of propusion incidents relating to LNG tank pressure drop Bukser and Berging 2 tugs operating at Kårstø gas terminal 2014 Gas-mechanical propusion 2 main engines, 2 propellers No loss of propulsion incidents
Conclusions LNG propulsion 17 Significant fuel cost savings Significant emission reduction - both local and global impact LNG propulsion is more complex - fuel storage, evaporation and pressure control - engine ignition and air-fuel control Individual subsystem is likely to be less reliable System reliability must be restored by overall system design
Questions Comments? 18