Converting Large Vessels To Na-S Battery Electric

Large ships make their money by moving goods as quickly and cheaply as possible. Turnaround time in port is often less than 48 hours, sometimes less than 24. That means to partially recharge the batteries they will need around a 1GW supplied every hour (based on your 57.6 GW-hrs figure). You're going to need quite a few power stations to be able to supply that amount of energy on top of normal consumption (plus that for all the proposed electric cars which will be around?).

Not to mention the cooling problem. At 95% efficiency, that's almost 3 GW.

Cheers

Phil Hobbs

to:

n similar calculation have been done before:

I would like to see a 80MW electric motor...

Bye Jack

Many ships use diesel-electric power now.

The QE2 was converted from steam to D-E, during her refit.

I think in the future there will be even more electrically propelled ships. The diesel or gas turbine sits there fat dumb and happy turning at a constant RPM while the propellers are doing their thing rapidly changing pitch, speed and direction moving the ship along. Their efficiency is good and are more reliable when compared to mechanical transmission schemes.

Electricity is useful for electric-hydraulic bow thrusters which aid in turning or docking ships, and the newer electric propulsion pods work like inboard-outboard motors with a 360 degree steering radius and can make the ship go sideways if necessary. Nice to have if you're visiting a port with limited or no tugboat services like some cruise ships in the Caribbean.

If it weren't for transit speed requirements we might see a return to sail - or kite aided propulsion systems. Using a kite seems pretty far out until you consider the kites are steered similar to multi-line kite-boarding kites, but with servo motors up in the kite - they take up little deck space, are controlled by computers linked into the weather forecasts, and plan courses accordingly. Also winds aloft are greater and more predictable than surface wind.

You could use water cooling, if you could find enough water somewhere.

Steam was reasonably efficient, but the plants were so complex that it was hard to find crew to keep them running. Direct-drive diesel is way simpler, and I guess that diesel-electric is pretty simple too, especially with multiple/redundant generators and motors.

I rode the QE2 to Europe once. I couldn't get the engine room tour because they had just had a fire and it was a mess. It took us a couple more days than normal, because of the plant damage.

In the 1920s ferries were used to cross the San Francisco Bay. Years later some of these freeies were bought by the Washington State Ferries. During the 80s I got to take a tour of the engine room on one of these old ferries while traveling on one when visiting the San Juan Islands. Besides having the original engines they also had the original generators and motors. So I think diesel-electric must be pretty good. Those old electrics were really cool. And in great shape too. All the engine, generator and motor controls were updated somewhere along the way but the basic machines were all original. It was obvious from the look of the windings that they were original. Sure couldn't get that kind of tour today. I just had to ask the Purser and it was up to him if I could get a tour. Things were quiet so he said sure. All the guys in the engine room were obviously proud of their work. I was really impressed. Eric

If you ever get the chance to sail on the PS Waverley, then the engine room is a sight to behold.

The same is true of any old beam-engine in steam.

ain similar calculation have been done before:

most or all of the double bottom tank volume.

A lot of short routes are dedicated with cargoes that require a lot of hand ling on the loading and discharge, i.e., banana boats from Columbia to Flor ida.

Owners don't like it but it's very common for the crew slow the loading, i. e., throttle back at the manifold on tankers, to spend more time at the mal l. The dock rats are complicit for the easy overtime pay so the port capta in is always pissed off at a lot of strangers.

They'll need another big Na-S battery at the dock.

Bret Cahill

"They aren't making any money sitting on Rio de la Plata."

-- Port Captain

I don't brake for large stuff unless, of course, it's in the road.