The future of batteries, solar, and electric motors....

[alexanick]

Is it not possible to incorporate some kind of generator into an electric motor to keep it running after you have started it from a solar panel storage battery?

[StuM]

Originally Posted by alexanick

Is it not possible to incorporate some kind of generator into an electric motor to keep it running after you have started it from a solar panel storage battery?

Yes. It is not possible.

What you describe is a "perpetual motion machine of the first kind".

[ramblinrod]

F|€£*, if we get thru the next year without nuclear holocaust it will be a miracle. As for boat powering, if the world
isn't a glowing desert, perhaps we'll have Mr. Fusion by then.

Plutonium may be readily available at the corner store.

[Salty Joe]

Crazy post....

It's hard enough even if IT literate to work out what's working well now not to mention 20 years from now purely useless intellectual exercise.

If it is a sailing boat right now if you saw America's cup they can do 4x wind speed using foils and wings. This is why your question is even more irrelevant. Regardless sails and boats are going through huge development last round the world foiling mono hulls singlehanded blasting around the world using water generators generating enough energy to keep everything working.

These are known realities today . The only reason most of us are not using this stuff today is cost.

Batteries, there are already five or so technologies better ( lighter more dense etc) that lithium. It's just cost but per Ah delivered, over life time it's not cost it's just up front cost that is the reason people are not using today. Batteries are just storage mechamisms the generative technologies are moving so fast it hard not to see 5x improvement in just what's known today.

Thousands of today's cruisers are living off basic hybrid systems today cruising the world in relative comfort so with well informed decisions today,it's already a reality, off grid energy combined with sails for propulsion. By hybrid I mean combos of solar ,wind, alternator, generator etc.

I was interested if your post was talking about what's hot today not sure of value of 20 years from now.

[hafa]

I posted the following points in another thread, but feel it appropriate to repeat them here.

Note that my comments address widespread commercial availability of the technologies under discussion. Micro scale, limited small scale and extravagantly funded projects are exceptions:

First, please note that I own and run a company that does residential solar power design and installation, and our home, business and yacht are all off-grid.

That said, I think that there's a bit too much enthusiasm in general for the potential development and near-term capabilities of solar and battery technology.

Points:

1. There is a tremendous amount of vaporware in this industry, particularly from research institutions;
2. The efficiency of commercially available solar panels has improved a whopping 8% in 47 years;
3. The dominant commercially available battery technology is 160 years old;
4. The "newest" battery technology (Lithium ion) is 40 years old, and is still not commercially available in the majority of the market;
5. lifepo4 has seen a boost from the enthusiast sector, but this technology also has limitations and it's unlikely that affordable fully automated charging systems will be widely available in the near-term, thus relegating lifepo4 to niche status for the immediate future.

Although we have seen a tremendous reduction in cost and concurrent increase of availability of panels in the last 8 years due to flooding of the market with inexpensive Chinese units, there is no indication that significant improvements in production or storage technologies for the commercial market are forthcoming.

The upshot?

1. Energy production and storage density (as observed previously Li-ion is ~1/100th that of diesel by weight) is a tiny fraction of what is required in order to continuously drive a boat using alternative energy alone.
2. The laws of thermodynamics rule out "perpetual motion" ideas that seem to propagate in these kind of discussions.

Economics is the primary driver for R&D in this area, and the current climate is not conducive to the significant investment required to fully develop breakthrough technologies.

[Jdege]

Personally, the only possible game changer I see as a possible future are super capacitors, and the main gain there is charging time. That could help electric cars significantly, but I don't think it'd make much difference to a cruising boat.

[waterman46]

Solar panels in Sails? Only if you lay them out horizontally on deck.

The all electric boat for long distance cruising without shore power will work just fine with today's or future technology if you only use the motor less than 1 hour every 3rd day. As others say, do the math .

[GTom]

Wind - turbines are quite well researched, I don't think there is much growing potential here. Besides: your best wind-power devices are your sails!
Adding WATER here: hydro generators are already available, they have some room for improvement (efficiency, mounting options, price). Advantage of the hydro is if you are sailing near hull speed, you practically don't loose speed.
Solar: I hope for a massive improvement in efficiency AND pricing. Still, you need sun for solar, thus on cloudy, dark days even top efficient panels are as good as useless.
Batteries: Here I also hope to get a boost. Actually a more reasonable pricing on Li-batteries would be a nice immediate help.

In 20 years without major breakthrough in battery tech I foresee this for your Lagoon:
- 1kW solar capacity (today ~7 m2, then 3 m2)
- 2x600W or more Hydro generators (one for each hull)
- a 80kWh battery (like Tesla model S, today ~1/2ton, costs ~12k$, then: 1/4ton, 5k$)
- Electric engines just as today

In a fair sailing day you sail and charge the batteries (mainly with the 24h producing hydro), when wind conditions are less favorable you turn on the engine. I don't foresee fully renewable engine-driven bikini-shows in the near future, unless you keep 1-2 tons of lithium on board (if you do so, please anchor far enough from any marinas ...) and get a direct connection to a nearby power station to charge.

[Paul Elliott]

Originally Posted by GTom

Solar: I hope for a massive improvement in efficiency AND pricing.

Solar panels are around 20% efficient now. Even if they somehow could become 100% efficient, that 5x improvement still doesn't come close generating the power needed for all-electric long-distance cruising (assuming a reasonably-sized array on a "normal" boat).

Electric motor efficiency is already close to 100%.

I can see no breakthrough ahead for hull shape or propeller design. The massive experimental all-electric catamaran design probably has the least practical water drag, but I would think that the huge windage of the superstructure and solar array would make anything but a downwind run fairly impractical. Forcing such a boat upwind for extended periods would require more power than it could generate.

We either need to carry lots of fuel, or harness the wind. Sailboats already harness the wind. Hydrogenerators work well, but not for all-electric propulsion! (That would be perpetual motion.)

Or we need "Mr. Fusion".

[Paul Elliott]

Here's the solar circumnavigator I am referring to:

[GTom]

I am highly sceptical about all-electric too, but efficient power generation might help a lot trough no wind/bad wind situations.

That "circumnavigating solar cat" couldn't do much good in Northern Europe - not to mention Arctic/Antarctic waters.

Originally Posted by Paul Elliott

Solar panels are around 20% efficient now. Even if they somehow could become 100% efficient, that 5x improvement still doesn't come close generating the power needed for all-electric long-distance cruising (assuming a reasonably-sized array on a "normal" boat).

Electric motor efficiency is already close to 100%.

I can see no breakthrough ahead for hull shape or propeller design. The massive experimental all-electric catamaran design probably has the least practical water drag, but I would think that the huge windage of the superstructure and solar array would make anything but a downwind run fairly impractical. Forcing such a boat upwind for extended periods would require more power than it could generate.

We either need to carry lots of fuel, or harness the wind. Sailboats already harness the wind. Hydrogenerators work well, but not for all-electric propulsion! (That would be perpetual motion.)

Or we need "Mr. Fusion".

[john61ct]

Need sails that **are** solar panels, also all other surfaces, never ming angles, so cheap doesn't matter

[Paul Elliott]

Here are some more calculations. For the baseline power requirements, I am using my 44 ft cruising sailboat. If I am really trying to conserve fuel I can drop the RPM way down and motor at perhaps 4 kts (just over half hull-speed). At this speed my diesel engine burns about 0.5 GPH. Given the energy capacity of diesel fuel is about 38 kW/gallon, that means my power requirement at this speed is 19kW.

Assume an electric engine is twice as efficient as a diesel. With an electric engine I would need 9.5 kW at this speed. Motoring for 24 hours at this speed would consume 228 kWh.

Solar panels typically put out about 13W per square foot.

A 40-ft power catamaran might have 800 sq ft of deck area. Completely covered with solar panels that gives 10,400W.

This would be enough to power the cat at (say) 5 kts while the sun is shining brightly, with a little left over. But given that the panels will probably be pointing straight up, the actual daily power production will be close to 52 kWh. If you have 100% efficient batteries, that gives you only 5.5 hours of motoring time per day. (In this example, the batteries really do nothing for you.) Assume a doubling of solar panel efficiency. That still only gives you ten hours per day of motoring. The rest of the time you are drifting.

Instead of a power cat, how about my sailboat, with solar-cell sails?
My sail area (main + jib) is roughly 1000 sq ft. Let's assume that because of the angles, and adding a little back for reflection off the water, that my solar-sails will give 5W per sq ft. That's 5 kW, or about 25 kWh per day.

Now cover my 264 sq ft of deck with solar panels. Half of that will be in the shade, so the power output in full sun will be 264 * 13 * 0.5 = 1.716 kWh, or about 8.6 kWh per day. Add in the solar sail power and that totals 10.3 kWh per day.

My solar sailboat can only run the electric motor for a bit over one hour per day. I would need to store that energy in a battery while the sun was shining, and then use it up in one hour. Double the solar efficiency and it's still a ridiculously bad situation.

I can sail 2100 miles from San Francisco to Hawaii with my meager 300W panels and only burn about ten gallons of diesel to keep the batteries charged. If I turned off the refrigerator and some nonessential electronics I would never need to run the engine. I already have LED lights. I just don't see the benefit of going to electric propulsion.

And let's not forget clouds. On a couple of my Hawaii treks we had heavy cloud cover for more than half the trip.

I've got a good friend who is burning with desire to convert his 50-ft cabin cruiser over to electric, with diesel generator backup. I've shown him the math and he doesn't care. He's an extremely smart guy, and he just wants to do it. I look forward to helping him with the project. As long as he doesn't want to actually go anywhere it should work well enough.

[GoingWalkabout]

Originally Posted by Kinnigit

First of all, this question is more about the industry 15 years from now. So keep that in mind.

I've been looking into getting into sailing, another conversation, and in the 1,000's of hours of research (ADHD) into systems, I came up with a solid curiosity as to what systems will look like down the road when we buy our world cruising catamaran and retire.

-Lithium batteries are all the rage but the price reflects their infancy in the market.
-Solar has been around for years but is taking leaps and bounds now due to interest in alternative power. Size and qauntity of panles vs power output will get better.
-Electric motors are swinging deep into mainstream with companies like Tesla, and the like, having a new mass demand to pilot cars. That will translate into marine sooner or later.

So, as a person who is in his 30's, and a IT engineer, I am wondering if 15-20 years down the road if we could be sitting at a full electric line of Lagoon 450's, for instance, in theory.

Theory?

-Solar power advanced enough to power any realistic power needs between day cycles?
-Advanced wind and motion generators?
-Boat windows that have solar power elements built in and remain transparent.
-Electric motors replace diesel engines? I can think of a mountain of pros there when it comes to maintenance and supporting systems, lines, holes in the boat.
-Lithium batteries will be smaller or X times as powerful and lasting than current sized units. (Due to the demand even now for them to become better everyday)

Just thinking out loud.

In 20 years could we realistically see a full electric line of boats as standard market options?

You certainly are thinking in the right direction. I liked your comment about windows having solar capture capability. You should know that experimental sails have been constructed with solar panels built in. Not the panels we see today but the next generation of in fabric solar collection.

[NCGunDude]

Paul, thanks for the write up. It looks like diesel is here to stay. As the power cruisers like to say, the wind doesn't always blow, neither does the sun always shine.