Is diesel-electric or all-electric the future?

[Corvidae]

Originally Posted by waterman46

For small boats with displacement hulls, which need to travel long distances for several days at low speed without access to any outside sources of fuel or electricity, and with limited area for solar panels, the only reasonable and most overall efficient solution other than wind power is the direct drive diesel engine, with modern design of pollution reduction and high efficiency.

https://www.youtube.com/watch?v=_n-8dYlqV0s

There are also commercial solutions using direct solar to motor power. Maybe not reasonable, but they do work.

[Adelie]

Originally Posted by waterman46

When they make an all-electric SUV with 500 mile range for less than $50K, I'll be interested. Looks like we're a long way from that. I'm told there are newer hybrids which can be recharged from a fixed power source and will use that mainly until battery is low, then switch to fuel. Seems like a better compromise.

The don’t even make gas powered SUVs with that range for less the $50k so you are setting up impossible requirements, especially as inflation drives up the cost of all vehicles as time goes on.

[moseriw]

compare diesel and e-motor cars. It is said that the climate footprint equals at about 240.000 km but be sure that the batteries are done at 120.000. An one can noit recycle them - this is a dream. The seldom earth parts are so small that the recycling is far too expensive. So the are dumped!

Conclusion: e propulsion needs 50% more climate ressources than any common diesel.

But it can not be true what may not be true.

[Simon.Sails]

Originally Posted by moseriw

compare diesel and e-motor cars. It is said that the climate footprint equals at about 240.000 km but be sure that the batteries are done at 120.000. An one can noit recycle them - this is a dream. The seldom earth parts are so small that the recycling is far too expensive. So the are dumped!

Conclusion: e propulsion needs 50% more climate ressources than any common diesel.

But it can not be true what may not be true.

Complete nonsense, ... even the most performant/long range Teslas has much lower co2 equivalent emissions for its entire lifecyle (a very conservative estimate of 200k km) than any gas-powered car.



https://www.psi.ch/en/media/our-rese...-electric-cars

You can deny reality all you want, just search for 5-8 year old Tesla model S with more than 150k km... you still pay a good price for them.

Today's cars are even better. Let's stop this disinformation and focus on actual applications.

[GordMay]

Originally Posted by moseriw

... Conclusion: e propulsion needs 50% more climate ressources than any common diesel ...

Source?

Originally Posted by Simon.Sails

Complete nonsense, ... even the most performant/long range Teslas has much lower co2 equivalent emissions for its entire lifecyle (a very conservative estimate of 200k km) than any gas-powered car...

Indeed.

[Na Mara]

Originally Posted by waterman46

As road vehicles have vastly different propulsion requirements, there is no point in comparing them to boats. And there is no point in comparing small boats to any very large vehicle, such as a railroad engine or ship either.

For small boats with displacement hulls, which need to travel long distances for several days at low speed without access to any outside sources of fuel or electricity, and with limited area for solar panels, the only reasonable and most overall efficient solution other than wind power is the direct drive diesel engine, with modern design of pollution reduction and high efficiency.

The topic has been discussed ad-infinitum in previous Forum posts.

I'm sorry but I don't agree with this assessment. The full electric sailboat with regen using hydro generation and solar is absolutely possible today and more efficient in use than the alternatives. My back of an envelope calculation earlier showed this. With 20kW of engines and an induction stove you would need on average to generate maybe 30kWh a week. Hydro generation will get you 5-10 of those, so you need enough solar to supply 20-25kWh a week. Make it 21kWh to make the math easy, then you need enough solar to generate 3kWh a day. In the Caribbean average daily insolation is 5kWh/m^2. The efficiency of todays solar panels in charging batteries is about 20%, so you will need about 3m^2 of panels. That is easily doable on a catamaran and not impossible on a monohull.

The fossil free cruising sailboat is possible with today's tech and in use it will be massively greener than the fossil fuelled alternative. Its just that the embodied emissions of such a boat and its enormous initial cost (and how that money could accomplish way more carbon abatement elsewhere) entail that while it is possible it is not advisable if your goal is saving the planet.

The full electric displacement motorboat is a totally different kettle of fish. Let's imagine a 45ft cat with very skinny easily driven hulls powered by two 10kw motors. You will want that boat to be able to motor continuously 24/7 and to be able to do that even in inclement weather when full power is needed. Here we can ignore ships systems as the drives totally dominate the calculation. 2x10x24 is as near as makes no difference 500kWh a day including drive inefficiencies. Even with the multilayered solar panels of the future (45% efficient) capable of netting you on average 2kWh/m2 a day you are going to need 250m2 of panels. At most the footprint of a 45ft cat is 14x8=112m2. Basically you would need twice that real estate to have a hope of making this work, but then you would have greater windage and more mass and so you would need bigger drives and thus would need even bigger panel area. It just does not work. The full electric long-range motor cruiser is just not possible with today's tech or even with tech available in the near future, period. Also for reasons outlined earlier series hybrids aren't clever either (max75% efficiency of straight diesel).

Basically, until we have commercially available hydrogen and a means of storing onboard at really high pressures SAFELY (at least 10000psi, see footnote) then the motor cruiser is stuck with diesel.


Footnote, 33kWh of hydrogen at STP is 11000 litres give or take and has the same energy content at the drivetrain as roughly 6 litres of diesel. To compress H2 to the same energy density requires storage at 1750 atm, which is 26000psi. Let's allow 250% greater volume for storage of the H2 than we do today for diesel. Then we need to store the H2 at 10000psi. 10000psi storage of gases is feasible with today's tech, but such containers are heavy, expensive, and not something you want to be standing next to incase of an accident.

[Na Mara]

On the electric cars, I second GordMay and Simon.Sails with the caveat that the article that prompted this thread indicates that while all electric cars are greener than most of the alternatives on a lifecycle analysis the exception is plugin hybrids using HVO or other renewable fuels. These appear to be greener still.

[Na Mara]

The problems of storing H2 aboard is why commercial shipping is betting on ammonia as an H carrier. You can store ammonia as a liquid, with comparable energy density to diesel, at 300psi safely at standard temperatures. If I were a betting man, and thinking about how motorised shipping and boating will be powered in the future and I was prepared to wait 10 years for ROI I would be buying shares in ammonia production, distribution and ammonia based fuel cell tech. Its a good bet that this is what will replace bunker fuel and diesel in shipping and boating.

As an additional plus you could even ditch the propane and use the ammonia or even the hydrogen freed from it to cook with.

[moseriw]

Originally Posted by GordMay

Source?



Indeed.

Easy: Tesla says the batteries will last 8 years. My mileage is 10 000 km.
So assuming the will last 12 years... my mileage will be 120.000 km

https://www.ifo.de/DocDL/sd-2019-08-...2019-04-25.pdf

[moseriw]

skip..

[moseriw]

The problems of storing H2 aboard

Yes and the trick is NOT to store it but to use it immediadly and without compressing it to 700 bars but to work on only 0,75 bars.

Electrolysis with saltwater and the splitted HHO directly into a small buffer to constantly feed the gas or diesel engine.

[Nidnoi_V]

Hi OP
I have done some research even do you are partly right there are many factors you need to put in to play i have gotten multiple people Power usage and also done some Calculation where you can compare your usage etc. if we are here in the Nordic Region and are sailing not motoring " from people i have asked and talked with " they save roughly 50-70% of diesel usage plus don’t have the lovely Noise of either a Generator or engines running to charge batteries if you are interested in getting the Excel sheet let me know
The sheet is based on a 60” Catamaran.
Send me a Pm with your mail.

If people here could share the following

Boat size
Weight Sailing not Dry weight.
Engine’s size
Cruising speed
Fuel usage per hour
This will help making my Excel sheet much more complete presently I have for Yanmar hj50 and hj80.

[Simon.Sails]

Originally Posted by Na Mara

On the electric cars, I second GordMay and Simon.Sails with the caveat that the article that prompted this thread indicates that while all electric cars are greener than most of the alternatives on a lifecycle analysis the exception is plugin hybrids using HVO or other renewable fuels. These appear to be greener still.

Interestingly in Germany and Switzerland the opposite has been found to be the case; most hybrid cars were bought by companies for tax purposes (green vehicle tax exemption etc.), but used for long distance drives almost daily. With that usage hybrid cars were actually the least environmentally friendly of all cars. That's because the ee was only used for the first 20km or so, after that a slightly more inefficient petrol engine was used.

But yes, in the cited study with the usage pattern of the average urban commuter hybrid make a lot of sense. In a way a fully electric boat with a small backup gas generator approximates that solution the closest.

[Simon.Sails]

Originally Posted by moseriw

Easy: Tesla says the batteries will last 8 years. My mileage is 10 000 km.
So assuming the will last 12 years... my mileage will be 120.000 km

https://www.ifo.de/DocDL/sd-2019-08-...2019-04-25.pdf

I'm not sure whether you're serious or trolling to be honest. The study by H.W. Sinn has been thoroughly debunked by other scientists and disagrees with any other international study on the subject. I'd recommend reading the Paul Scherrer Institute study or Fraunhofer Institute studies cited above.

https://www.wiwo.de/technologie/mobi.../24237236.html

Tesla does NOT say its batteries will only last 8 years or 100k-150k miles, (160-240k km), that's the vehicle battery warranty. I'm sure I don't have you explain the difference to you.
https://www.tesla.com/support/vehicle-warranty

There are plenty of Tesla's driving around with 250k+ km on the clock. 100k km would only be 500 full discharge cycles, a laughably low estimate given how modern Lithium battery can last in excess of 3'000 discharge cycles, the same has been found with older Tesla batteries even when they reverse-engineered them.

[Na Mara]

Originally Posted by Nidnoi_V

Hi OP

If people here could share the following

Boat size
Weight Sailing not Dry weight.
Engine’s size
Cruising speed
Fuel usage per hour
This will help making my Excel sheet much more complete presently I have for Yanmar hj50 and hj80.

1. 43ft monohull
2. 14 ton with full tanks and stores
3. 90hp
4. 6 kn on average under sail, 6.5kn on engine
5. 0.7l per nm so 4.5l an hour.

Just had a crazy thought.

What about installing two indepedent 6kW oceanvolt saildrives sharing one of their 7.6kW batteries. That should give me 10nm of electric motoring, and sufficient power for all but the windiest of days for close quarters stuff (on those days I have the big one in reserve) for the cost of about 25000 euros fitted and vat paid.

Advantages,

1. 400W of hydro generation plus 500W of solar would be enough to get me into and out of most marinas and anchorages without ever firing up the main engine reducing fuel use.
2. Induction cooker would be easily supported on this size of bank.
3. Using the electric drives when they are most efficient in close quarters, stop go scenarios, saves the main engine for long haul duty lowering wear and increasing service intervals.
4. As the pods also work as engines they can be kept clean of the seaweed that bungs up watt sea pods mounted in exposed locations.
5. Better manoeuvrability in tight spots with two off axis drives.

Disadvantages,

1. Pods would be in unavoidably exposed locations but this seems to be the modern way if you look at arcona and salona.
2. Two more holes in the bottom of the boat.
3. Greater drag on the boat when sailing.
4. About 25000 euros to install.

Basically this is neither a parallel nor series hybrid. Its a boat with two (well actually 3) entirely independent motors. One of these is reserved for long haul motoring while the other two are for getting into and out of places.

Is it just me or does that not deliver all of the benefits of a series hybrid, and most of the benefits of an all electric sailboat, for a fraction of the embodied emissions and cost? I'd still need to find a way of fitting a kW of solar to cover the recharging away from marinas but that should be doable.

Or am I missing something?