“Half of all energy the Navy uses will be non fossil fuel by 2020”.
US Navy Secretary Ray Mabus interviewed by Thom Hartmann.
Interviewed elsewhere, Mabus underlined –
In the 1850s, we went from sail to coal. In the early 19th century, we went from coal to oil, and in the 1950s, we pioneered nuclear.
Every single time, there were people that said, “Can’t do it. You’re changing one very certain means of transportation for one that is not that certain,” and every time, those naysayers were wrong.
We just launched the first hybrid ship. A big ship, a big deck amphibious ship. Built in Pascagoula, Mississippi. Went around South America to its home port in San Diego. Saved $2 million in fuel costs, first voyage.
The company I work for designed and installed the hybrid propulsion on the LHD-8, the first hybrid ship that Secretary Mabus mentions (as well as other hybrid and full electric ships). We were called Converteam at that time, but we were acquired by GE Energy recently.
For hybrid and full electric ships, it is all about intelligently selecting which power sources to put online such that the ship’s needs are met. A ship that is propelled by an electric motor can combine the propulsion power and the electrical service power, which can allow several percentage points reduction in fuel use compared to traditional ships that split up the propulsion and electrical service loads. Electrical energy storage could potentially save even more fuel in the future, kinda like the Prius with its energy storage capability. Flywheels and next gen battery modules may be capable for this purpose on large ships. Loading gas turbines and diesel engines at their best efficiency point can reduce fuel consumption, operating hours, harmful emissions, and maintenance.
The real kicker is being able to source all this power from sustainable biodiesel or other biofuel. Being able to scale up sustainable biofuel production (algae based, maybe) is really the only thing on the drawing board that can allow air and ship travel to continue in its present form. It is good to hear Secretary Mabus mention an industry RFI for up to $510 million to foster a biofuel resurgence. Really, we should have been working on that since the Carter administration, but better late than never, I suppose. It is also good to hear that the Navy is going solar as well.
Thanks for sharing this, Peter.
there’s actually a much better video on this out there that I was looking for. will post when I find it.
Otter17, I don’t understand how a hybrid system would be of any utility on a ship. The value of hybrid systems, as I understand it, is twofold: 1) they recapture a portion of the energy when the vehicle decelerates; and 2) they provide high torque at low velocities. Neither advantage seems to be of much use on board a ship. I would expect that a large ship would accelerate from start just once on a voyage: at the outset. I would further expect that it would not deliberately decelerate until it nears port. And I certainly wouldn’t expect the engine to run at anything other than optimal power through the bulk of the journey. Inasmuch as there’s always some energy loss in converting from the kinetic energy to electrical energy, it seems that it would be more efficient to just use a big diesel engine and use it at constant velocity throughout the voyage.
So what am I missing here?
You are right, many ships do operate as you describe. For example, a transportation tanker would have almost no use for a hybrid propulsion system since it simply travels at a constant speed all the way from port to port. A full electric propulsion system would also have marginal or even negative fuel efficiency utility.
In certain applications, particularly in the naval and tugboat realms, the utility becomes apparent since the propulsion and ship service loads can be quite variable. Thus, having multiple power sources (diesel or gas turbine gensets) that can provide power that is well-matched to the total load requirements can be of great advantage. Furthermore, we can expect gains in power conversion efficiency with new power semiconductor materials in the pipeline.
Hybrid and full electric ships do not generally use regenerative braking. At least I have not heard of any that use regen.
Anyway, the bottom line is ships that travel with variable speeds and service loads (drive kinda like a car) are much better suited to hybrid or full electric propulsion. Also, hybrid ships save fuel in a somewhat different way than hybrid cars. Ships have multiple power sources, and the trick is to keep as few power sources online as possible while still getting the job done.
Ah, I see now. Thanks for explaining that to me!