The keyword in this segment is ‘variety’. The Joules Project selected a few vessel types, but could not possibly cover all the ground.
(A ) Application Case Harbour Tug
#13.1 Joules Project Harbour tug
The Joules project study addressed the problem that tugs pack a huge amount of pulling power, but spend much of their time in light load condition. That suggests the short term (nominally 2025) options including a hybrid solution, partially utilising shore power to ease the variable power demand, offering a reduction in Global Warming Potential of about 30%.
High powered fuel cells are expected to be available by 2050. Use of biogas to feed the fuel cells is suggested which would be a zero carbon solution. Overall, a GWP reduction of 90% could reasonably be expected.
(B) Application Case Dredger
#13.2 Joules Dredger
This study revealed an unexpected problem and an ingenious solution. It seems dredgers often experience sudden large demands for power because of the uncertain nature of the terrain they are tackling. So the 2025 proposal was to use LNG combined with a hybrid power supply and a flywheel (!) That solution would reduce GWP by 26%
The 2050 proposal relies on a hydrogen based fuel cell, and eliminating the crew. It is estimated that this would reduce installed power by 40% compared to the baseline. Overall, a 75% reduction in GWP is predicted.
This is the only case where automating the ship operation and eliminating crew is considered. Perhaps other projects should be reviewed again to see if further GWP gains could be made by this approach
(C ) Application Case Offshore Patrol Vessel
#13.3 Joules Project Offshore Patrol Vessel.
Patrol vessels spend much of their time at low speeds, or in port, with occasional needs for high speed and power. The Joules Project proposal was for a hybrid system combining two forms of propulsion, use of shore power, and the use of alternative fuels such as LNG. As this type of technology is already fairly common, a modest GWP reduction of 20% is expected by 2025.
The 2050 hybrid propulsion system is enhanced with the foreseen development of high power density electric machines, electric storage systems and fuel cells
Reference is made to use of advanced fuels, but the use of hydrogen derivatives may further improve the projected 65% GWP reduction predicted for 2050
(D) .Application Case Offshore Support Vessel
#13.4 Offshore Support Vessel
There are numerous variations on this theme, including oil rig supply vessels, salvage tugs, standby vessels, and many more. The Joules project chose a seismic survey vessel, which has highly varied power demands, and the need for considerable endurance at sea.
The main proposal for energy saving by 2025 involved using low sulphur marine diesel blended with a Biomass-to-liquid fuel to yield a GWP reduction of 37%
For 2050, alternative ‘drop in’ fuels were considered to yiled a potential GWP reduction of 55%.
With later information it is possuble that a switch to hydrogen derivative fuels could improve this result.
(E) Application Case Mega Yacht
#13.5 Joules Project Mega Yacht
There are a surpising number of megayachts. Typically they spend most of their time in port, occasionally changing location (e.g. Mediterranean in summer, and Carribean in Winter). The Joules Project Team asserted that the need for flexibility means that most recent vessels of this type are already diesel electric, so the scope for reducing Global Warming Potential is strictly limited. The study, inevitably, falls short of considering a switch to hydrogen based fuels, or making better use of renewable shore power.
I recently discovered an amazing article describing the next generation of supryachts. It makes a jawdropping read
#13.6 Typical 36 ft launch tyoe motor yacht
[My personal opinion is that there is a wider problem to be solved. Until 2019 I had owned a motor boat for 5 years. It had 2 turbo charged diesels totalling just over 500 hp. They were basically truck engines. I was regarded as an above average user, and I put on about 100hours per year burning about 3000 litres of diesel. In my opinion these vessels will need to be re-engined. There are thousands of them, and managing that transfer will require political skill.
There are also hundreds of launches, pilot cutters, crew boats and mooring launches used in harbour areas that are broadly the same size. They too will need re-engining, probably with a hybrid fuel cell or ammonia based solution]