Solar-powered voyage across Atlantic

October 14, 2006 11:06 AM

Catamaran "sun21" prepares for record-breaking voyage Next week, "sun21", which has been constructed specifically for this purpose, will begin its journey from Basel in Switzerland to New York. It will be the first solar boat ever to cross the Atlantic: entirely dependent on sunlight, not consuming one drop of gasoline.
posted by booksprite (28 comments total)

Here's a photo I took this morning of "sun21" while it was on public display in Basel.


posted by booksprite at 11:10 AM on October 14, 2006

Um, didn't boats do this for, uh, centuries?
posted by jmgorman at 11:19 AM on October 14, 2006

I'd be concerned about bad weather/big waves ripping that panel array right off the boat.
posted by dontoine at 11:19 AM on October 14, 2006

So which would be faster, wind or sun? His route starts the 16th of Oct and ends the 8th of May, but he seems to be taking a rather long way. Anyone want to crunch the numbers?
posted by furtive at 11:29 AM on October 14, 2006

Yeah, they were doing this ages ago, and considerably faster, too. About two months over and a month back was doable about 400 years ago. This might be less labor-intensive to operate than a sailing ship, but, other than that, I'm not seeing the advantage.
posted by MadDog Bob at 11:35 AM on October 14, 2006

dontoine, thats the first thing that ran through my mind. That and what happens after 3 stormy days, and you NEED to maneuver out of something, but you batteries are low...
posted by DesbaratsDays at 11:36 AM on October 14, 2006

that's the - your batteries -- argh
posted by DesbaratsDays at 11:38 AM on October 14, 2006

In 1905, a three masted schooner corssed the atlantic ocean in 12 days, four hours.

Mari-Cha IV holds the curent crossing record for a monohull, at 6 days, 17 hours.
posted by b1tr0t at 11:57 AM on October 14, 2006

Surely it'll be faster to use solar power than wind?

Otherwise we might as well just stick sails to our cars.
posted by reklaw at 11:58 AM on October 14, 2006

According to the organisers, "the boat is equipped with solar modules, batteries and motors allowing a constant speed of 5–6 knots (10–12 km/h) 24 hours a day, equivalent to the average speed of sailing yachts."
posted by booksprite at 12:03 PM on October 14, 2006

Something tells me he needs to stop from time to time to recharge the batteries, perhaps explaining an alterior motive for the 9 stops along the way.
posted by furtive at 12:07 PM on October 14, 2006

If nothing else, reklaw, It's hard to tack effectively in traffic.
posted by MadDog Bob at 12:08 PM on October 14, 2006

Hey, I just noticed that the Rotterdam to Gibraltar leg of the journey will be done by means of a freighter. Look at the enlarged version of the route. At least that gets around any potential problems in the notorious Bay of Biscay.
posted by booksprite at 12:13 PM on October 14, 2006

Phew. Who snarked?

The point here isn't faster and in fact the manufacturers have already proven solar can work for passenger boats, at least in light-duty applications.

Of course wind power is renewable, but has enormous maintenance requirements and severely limits navigational options. A number of manufacturers are looking at green ships like the Orcelle concept. I can foresee the irony of solar-powered oil tankers.

That and what happens after 3 stormy days, and you NEED to maneuver out of something, but you batteries are low...

All modern sailing vessels have back-up motors run on gasoline, you know.
posted by dhartung at 12:27 PM on October 14, 2006

Ummm, I hate to say it, but...

SWISS NAVY?
posted by orbis23 at 1:05 PM on October 14, 2006

If nothing else, reklaw, It's hard to tack effectively in traffic.

Remember, folks -- the leeward lane is the passing lane.
posted by Opposite George at 1:33 PM on October 14, 2006

It's often sunny when there's no wind, so it's not surprising that people will try to make something that can function both as a sail and a solar panel. Solar Sailor. Eco Ranger.

I'm not so sure about solar-powered oil tankers, though. Topside surface area would vary roughly with the square of vessel size, weight with the cube. If it can only do 5-6 kts on a small boat, I don't think it has much chance of powering a large tanker.
posted by sfenders at 1:41 PM on October 14, 2006

More importantly, oil is still dirt cheap and the diesel engines in oil tankers are extremely efficient.

It is nice to see research being done, but solar is as much of a pipe-dream as hydrogen, as a power source.
posted by b1tr0t at 1:46 PM on October 14, 2006

Don't tell me that there aren't immense upkeep requirements on solar cells. They have to be replaced. They have to be cleaned. And electronic components in sea air always have problems. Using solar power to sail is hardly even an intellectual exercize - it is public masturbation.
posted by jmgorman at 2:31 PM on October 14, 2006

Given that wind is created by thermal differences, you could make the argument that ships have been solar powered for the last millennium or so.

Of course you could take that argument to its extreme and say that pretty much any form of energy that we have on earth can be traced back to solar energy in some form, so maybe that's not all that useful of a statement.
posted by Rhomboid at 3:31 PM on October 14, 2006

Topside surface area would vary roughly with the square of vessel size, weight with the cube.

I guess so, but the required power depends more on the size of a cross-section of the underwater hull, not the total water displaced. By my calculations, covering the entire deck of a normal 30-foot sailboat with solar panels might get you 2 or 3 horsepower at peak, while a 10hp motor might be the minimum normally used to propel such a craft. Covering the whole top surface of a 1940 T2 tanker could get you about 550 horespower from solar power, compared to the 12000 its engines delivered. So, solar power is almost as awkward for propelling small boats as for large ones.

That just makes it all the more amazing that this thing can average 5 knots. I guess a light-weight catamaran with a roof is the way to go if you're going to run it on solar power.
posted by sfenders at 4:46 PM on October 14, 2006

It's also worth pointing out that the solar cells probably required more petroleum to make than would be consumed by quite a number of crossings at that speed.

From what I understand, they are very energy-intensive devices to manufacture, and it takes most of the useful lifespan of a cell to get back the energy it took to make it.

Essentially, it's just a different way to store power... it doesn't really generate it 'for free'. They're sort of like low-current, high-lifetime batteries.
posted by Malor at 5:51 PM on October 14, 2006 [1 favorite]

...solar is as much of a pipe-dream as hydrogen, as a power source.

Morbo: WINDMILLS DO NOT WORK LIKE THAT!
posted by spazzm at 5:54 PM on October 14, 2006

solar is as much of a pipe-dream as hydrogen, as a power source

Maybe this is the point you were making, but hydrogen is not an energy source any more than a battery is. Hydrogen, despite being the most abundant element in the universe, is incredibly rare on Earth. Hydrogen is produced normally as a byproduct of industrial processes involving coal, oil and other hydrocarbons, or by electrolysis of water. Obviously both of these methods require energy, and by conservation of energy, you don't get more energy out than you put in.
posted by matthewr at 6:14 PM on October 14, 2006

That was my point, but it is worth repeating in greater detail.

I love science and gadgets and stuff, but solar cells are really only useful where traditional energy delievry is difficult or impossible. Oil works for shipping now, and I suspect biodiesel would be a more efficient solution than solar cells. I don't know where nuclear and coal would rank. World coal reserves are extreme, and you can make a kind of gas fuel from it but you would probably need new engines. Nuclear has been tried but doens't seem practical.
posted by b1tr0t at 8:08 PM on October 14, 2006

From what I understand, they are very energy-intensive devices to manufacture, and it takes most of the useful lifespan of a cell to get back the energy it took to make it.

Malor, from my understanding, that is an oft repeated myth, and most solar cells have a conservative life expectancy of about 25 years and are carbon positive after about 6 years. So about 4:1 on carbon. (This is from memory and I'm not having much luck googling it).

Of course, if the above boat wants to keep crossing the Atlantic, I wish it luck in keeping its solar panels for even 6 years.
posted by wilful at 3:02 AM on October 15, 2006

willful, I'm talking more about energy, rather than carbon. It's possible my stats are outdated, but I gather that making solar cells takes a tremendous amount of energy input during the manufacture, to the point that solar cells are not self-sustaining. If you had a plant that made them, it couldn't make enough solar cells to make more solar cells. If it were powered only by its own output, it would steadily diminish over time and eventually fail.

Unless we figure out a better way to make them, they're just like hydrogen... a way to STORE energy, not GENERATE it.

The carbon positive part is great, but it's only a partial solution. And, even at that, cutting carbon output by 75% is still not enough... we need to get back to carbon-neutral. (Carbon-negative for a couple generations would be even better.)

What we really desperately need is fusion, and we should be putting huge resources into figuring it out. If we can get fusion energy working reliably, humanity will enter a golden age of such prosperity that we can't even imagine it.
posted by Malor at 7:03 PM on October 15, 2006

Carbon is a shorthand measure of energy, assuming (reasonably) that the solar cell manufacturing plant is powered by coal or oil. So what I had to say above is correct, solar cells produce more energy than their manufacture a long time before their expected lifetime use.


Oh and we don't have to get back to carbon negative.

As for fusion, tell me where we are in 20 years.
posted by wilful at 7:15 PM on October 15, 2006