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"But since even the most efficient internal combustion ship engines are no more than 50% efficient, a [...]" But how efficient are the coal, nuclear, or natura

"But since even the most efficient internal combustion ship engines are no more than 50% efficient, a [...]" But how efficient are the coal, nuclear, or natural gas needed to charge the batteries? At best 60%? Was it mid 20s or mid 30s for PWR nukes? 50% thermal efficiency is insanely good. And the battery ship? To the 90% battery efficiency, knock a few trips through a transformer (95%) and power converter. So 0.6 * 0.95 * 0.95 * 0.9 - = 0.48% thermal efficiency By contrast shipping fuel is a waste product that is going to get made whether or not the ships sail (i.e. largely free to produce energetically). Talk to me about cleaning ships S emissions and Ill get excited. In the meantime put all those Li ion batteries into hybrid versions of Ford F350 and heavy trucks used by contractors. That will make a much larger dent in CO2 emissions.

jamal-kumar 4y ago
I think what is making these companies move towards other options is their bottom line - if they don't have to spend on fuel, why should they? (By the way a lot of what I've seen for the generation so far is in stuff like power-generating "sails" which are really interesting, so maybe not even relying on land sources)
- sbaiddn 4y ago
  This isn't good for their bottom line. The efficiency of batteries is comparable to shipping oil at best, and electricity is rather expensive while shipping oil is almost free. Shipping oil is filthy, dirty, hard to use. To a good approximation one wants it. To a better approximation no one on land can use it because if its high S content precludes it from being used on land (illegal and you need something that can deal with high Sulphuric acid) Its a byproduct of the refinery that only shipping can use (they can and do burn straight diesel too). It is really very cheap. [1] Ban it, if you must. But without market shenanigans itll never be cheaper to use a massive battery. [1] without looking at the price, I wouldn't be surprised if its currently gone up in price. In Europe right now anyone who can burn it on shore is eyeing it and the EU has suspended many environment regulation. But thats a blip; once Germany's economy collapses the EU's energy needs will be much smaller
defrost 4y ago
To expand on heavy container ship engine design, which is worth a look for its own sake: > Fuel consumption at maximum power is 0.278 lbs per hp per hour (Brake Specific Fuel Consumption). Fuel consumption at maximum economy is 0.260 lbs/hp/hour. At maximum economy the engine exceeds 50% thermal efficiency. That is, more than 50% of the energy in the fuel in converted to motion. [2] [1] https://en.wikipedia.org/wiki/W%C3%A4rtsil%C3%A4-Sulzer_RTA96-C https://en.wikipedia.org/wiki/W%C3%A4rtsil%C3%A4-Sulzer_RTA9... [2] http://www.emma-maersk.com/engine/Wartsila_Sulzer_RTA96-C.htm http://www.emma-maersk.com/engine/Wartsila_Sulzer_RTA96-C.ht... [3] https://www.mhi.co.jp/technology/review/pdf/e501/e501055.pdf https://www.mhi.co.jp/technology/review/pdf/e501/e501055.pdf
sbaiddn 4y ago
Just to clarify: Shipping fuel is a filthy byproduct no one really wants. Some of it can be cracked to other products but, in the end, if it ain't burned on ships it will be just burned onshore, probably a third world country, in whatever burner can deal with its acidity or in a big blowtorch to heaven

jamal-kumar 4y ago

I think what is making these companies move towards other options is their bottom line - if they don't have to spend on fuel, why should they? (By the way a lot of what I've seen for the generation so far is in stuff like power-generating "sails" which are really interesting, so maybe not even relying on land sources)

sbaiddn 4y ago
This isn't good for their bottom line. The efficiency of batteries is comparable to shipping oil at best, and electricity is rather expensive while shipping oil is almost free. Shipping oil is filthy, dirty, hard to use. To a good approximation one wants it. To a better approximation no one on land can use it because if its high S content precludes it from being used on land (illegal and you need something that can deal with high Sulphuric acid) Its a byproduct of the refinery that only shipping can use (they can and do burn straight diesel too). It is really very cheap. [1] Ban it, if you must. But without market shenanigans itll never be cheaper to use a massive battery. [1] without looking at the price, I wouldn't be surprised if its currently gone up in price. In Europe right now anyone who can burn it on shore is eyeing it and the EU has suspended many environment regulation. But thats a blip; once Germany's economy collapses the EU's energy needs will be much smaller

defrost 4y ago

To expand on heavy container ship engine design, which is worth a look for its own sake: > Fuel consumption at maximum power is 0.278 lbs per hp per hour (Brake Specific Fuel Consumption). Fuel consumption at maximum economy is 0.260 lbs/hp/hour. At maximum economy the engine exceeds 50% thermal efficiency. That is, more than 50% of the energy in the fuel in converted to motion. [2] [1] https://en.wikipedia.org/wiki/W%C3%A4rtsil%C3%A4-Sulzer_RTA96-C https://en.wikipedia.org/wiki/W%C3%A4rtsil%C3%A4-Sulzer_RTA9... [2] http://www.emma-maersk.com/engine/Wartsila_Sulzer_RTA96-C.htm http://www.emma-maersk.com/engine/Wartsila_Sulzer_RTA96-C.ht... [3] https://www.mhi.co.jp/technology/review/pdf/e501/e501055.pdf https://www.mhi.co.jp/technology/review/pdf/e501/e501055.pdf

sbaiddn 4y ago

Just to clarify: Shipping fuel is a filthy byproduct no one really wants. Some of it can be cracked to other products but, in the end, if it ain't burned on ships it will be just burned onshore, probably a third world country, in whatever burner can deal with its acidity or in a big blowtorch to heaven