"Solar-powered cargo ship" is pure greenwashing

[sketerpot]

There's been some buzz lately about a solar-powered hybrid cargo ship that is supposedly a huge step forward for green technology. Except that it only manages to generate 0.01% of its power from the sun. Here are some calculations.

Isn't that great? We had wind-powered ships, now they are solar-powered. Err, progress!

Except there is a small hangup, as the Los Angeles Times mentions:

But unlike any of the diesel-spewing, power-draining vessels that travel here, the Auriga Leader sports 328 solar panels on its top deck -- a small array that provides 10% of the energy used by the giant ship...

Oh, well it's only 10%. But hey, that's great, right? 10% of a full-sized, sixty thousand cargo ship? That's awesome! Eco-yeah!

...while she is docked.

Oh.

Okay, I'll cut the shtick. First off, it's not even 10% when it's docked: the LA Times article reports the ship's power consumption as 400 kW, whereas the 40 kW figure for the solar array is a nameplate capacity. LA Times screwed that up. Throw in a typical 10% capacity factor, and you only average 4 kW of power, or 1% of the cargo ships' needs. When it is not moving.

So really, what fraction of this cargo ships' power does the $1.7 million solar array generate? (Oh, you heard right: $1.7 million.)

I'll start with the capacity factor. The range for PVs is about 10-20%; since the cargo ship passes through the North Pacific (the geodesic between Japan and California, I believe), it spends its time in northerly latitudes and so will be on the lower end of the scale.

Now, for the engine. The engine size of the Auriga Leader is not mentioned anywhere I looked. So here's a similar-sized container ship I chose randomly: NYK Vega. It weighs 94,000 metric tons, and has an 87,000 horsepower engine. Auriga Leader weighs 60,000 tons, so I'll adjust that to 56,000 hp, keeping the power::weight ratio constant. (Okay so far?) This is about 40 megawatts of mechnical power.

I tacitly assume that this full power is used continuously. I believe this is correct: the power of the engine is used to push against fluid drag at cruising speed, so pretty much all the time. And it would be used at full speed/full power, for simple economics (why would they travel at half speed?). So, there's the assumption.

Given that: we have a solar array that averages maybe 4 kWe in the north pacific, and a diesel engine running at 40 MW mechanical power. So then, assuming a perfectly efficient electric motor, the PVs could contribute 1/10,000th of the ship's propulsion.

1/10,000

Just thought I'd clear that up.

Impressive! And the solar panels only cost about $1.7 million to install!

Really, the brazenness of this propaganda move is kind of surprising. I need to be more cynical.

[Starglider]

Really, the brazenness of this propaganda move is kind of surprising. I need to be more cynical.

I have a burst of perverse glee whenever I see something like this. Greenpeace and most similar organisations are pathological liars, constantly cherry-picking statistics and being as misleading as possible when they aren't just outright making up falsehoods. They are also nearly as superficial as PETA. So when companies throw their 'own medicine' right back at them like this I have the urge to cackle maniacally.

[OmegaChief]

Out of interest, would there be any way to provide the power needed for large cargo ships by environmentally friendly means?

Aside from waiting until we (hopefully) have something like a fusion powered boat.

[Surlethe]

Out of interest, would there be any way to provide the power needed for large cargo ships by environmentally friendly means?

Yes. If nuclear power is good enough for the navy, it's good enough for commercial ships.

[Eris]

Out of interest, would there be any way to provide the power needed for large cargo ships by environmentally friendly means?

Aside from waiting until we (hopefully) have something like a fusion powered boat.

Assuming we get practical fusion, it will take a bit till it's practical to scale down that far, if we ever manage it. Not to mention the costs of having the people and equipment to run such a device. Nuclear fission nuclear fusion is not. Big ships are probably never going to be as green as other kinds of vehicles can be. You could have them go nuclear, but then you have all the proliferation problems. (I personally wouldn't mind those compared to global warming, but I'm never going to be put in charge of much, either.) Cleaner burning engines - more efficient diesel, LNG, or what have you - are the best practical advance we could incorporate them at the moment, really. Not that that should be downplayed - cleaner burning engines in all our big ships would improve things enormously, and in the long run save money besides, even ignoring the climate and environmental impacts.

[Samuel]

Ship kites?

[Commander 598]

Ship kites?

Well, they're not really "power", like an engine or solar power... They do however provide a 20-30%* boost in efficiency with good winds and is an infinitely cheaper, more practical, and less complex option than inefficient solar panels and hope.

*Wiki figure for the MS Beluga Skysails.

[Sea Skimmer]

The kite idea is interesting, but they present a very serious handling problem for the very small crews of modern container ships. Some kind of sail and mast setup that can automatically fold down when not needed would be more practical, if more expensive to install upfront. But I don’t expect anyone is going to invest in technology like that anytime soon, shipping isn’t hurt nearly as much as other oil users by high prices. That is because much of the fuel they burn is utter crap that can’t be used for anything else. Most shipping firms are very tight on cash too, because they bought so many new ships in the early 2000s which now have nothing to carry.

[Sea Skimmer]

Also I meant to add, ships also just waste fuckloads of fuel because they never ever turn the main engines off during the operating season. They run 24/7 even while the ship is tied up to a pier for days unloading and loading. This is done for reliability reasons, since any engine failure is a disaster and it sure isn’t quick or cheap to for example replace the piston rings on a 100,000hp diesel. Since the engine never turns off until the ship goes into a dockyard for a refit, the potential for saving energy from alternative sources is minimal.

[tim31]

This is done for reliability reasons, since any engine failure is a disaster and it sure isn’t quick or cheap to for example replace the piston rings on a 100,000hp diesel.

Of course, it isn't particularly cheap or easy to do that in a modern engine found in the car you get into and start with the key. But yeah, it's still a major engineering job with a heavy marine diesel. It's also worth pointing out that marine diesels are some of the most efficient internal combustion engines in the world in terms of consumption over distance factor in power to weight ratio.

[Batman]

I'd assume them keeping the engines running on 'idle' when docked, while definitely wasting fuel, would do so at a far lesser rate than them operating at capacity. Okay, technically, when actually DRIVING the ship the engines AREN'T wasting fuel (beyond the inherent waste in any modern day fossile-fuel engine). Are you talking about the waste of them keeping the engines going PERIOD or the fuel useage of those engines being bad compared to those vessels drawing power from portside facilities?

[Commander 598]

The kite idea is interesting, but they present a very serious handling problem for the very small crews of modern container ships. Some kind of sail and mast setup that can automatically fold down when not needed would be more practical, if more expensive to install upfront. But I don’t expect anyone is going to invest in technology like that anytime soon, shipping isn’t hurt nearly as much as other oil users by high prices. That is because much of the fuel they burn is utter crap that can’t be used for anything else. Most shipping firms are very tight on cash too, because they bought so many new ships in the early 2000s which now have nothing to carry.

As I understand the Beluga Skysail's kite is computer controlled, but I don't know any specifics beyond wiki articles like:

The SkySails propulsion system consists of a large foil kite, an electronic control system for the kite and an automatic system to retract the kite. The system bears similarities to kitesurfing. After tests on the Baltic Sea, the first commercial installation is planned for January 2008. The kites, which have an area of around 320 square metres (3,400 sq ft), can be flown at altitudes of 100–300 metres (330–980 ft). Because of the stronger winds at these heights, they receive a substantially higher thrust per unit area than conventional mast-mounted sails. A ship equipped with the current SkySails could consume from 10 to 35% less fuel.[citation needed] The SkySail-system is implementable on many large vessels.[citation needed] A conventional ship with a SkySail-system has two propulsion methods, making it a type of hybrid vehicle.
MS Beluga Skysails in Newport, Wales.

MS Beluga Skysails is the world's first commercial container cargo ship which is partially powered by a 160-square-metre (1,700 sq ft), computer-controlled kite. The kite could reduce fuel consumption by 20%.[citation needed] It was launched 17 December 2007 and departed the northern German port of Bremerhaven to Guanta, Venezuela in January 2008. Stephan Wrage, managing director of SkySails GmbH announced: "During the next few months we will finally be able to prove that our technology works in practice and significantly reduces fuel consumption and emissions."[citation needed]

The ship completed its journey on 13 March 2008 after sailing from Germany to Venezuela, then to the United States, and ultimately arriving in Norway.[1] While the kite was in use, the ship saved an estimated 10-15% fuel, $1,000 to $1,500 per day.[2]

[PhilosopherOfSorts]

The kite idea is interesting, but they present a very serious handling problem for the very small crews of modern container ships.

I'm no expert, but this sounds like a fairly easy problem to solve, its not like there is any shortage of people. I know training them will take time and money, and you have to pay them, but if the end result is, say, a twenty-five percent savings in yearly fuel costs, I can see the idea chatching on. The deciding factor would be weather or not the fuel savings offset the intallation and extra crew costs. Right?

[Sky Captain]

And consider the fact that Auriga is a car carrier with a huge unused top deck where you can put a lot of solar panels. On an ordinary container or bulk carrier ship there would no nowhere near that much space because of a need for unobstructed access to load and unload the cargo. Solar power might be practical for small lightweight recreational boat to cruise around the lake on a sunny day but not for heavy cargo ships

[madd0ct0r]

I feel obligied to point out that container ships are still far more effecient then cars; lorries or planes.

A decent rail system beats them though, even more so if you can link it up to a green grid.

[Surlethe]

I feel obligied to point out that container ships are still far more effecient then cars; lorries or planes.

A decent rail system beats them though, even more so if you can link it up to a green grid.

You have any analysis supporting this opinion?

[Batman]

Well container ships ARE more efficient than cars, lorries, or planes. They're also utterly USELESS for virtually all the transportation needs those vehicles serve of course.
And what's this 'green grid' supposed to be? Railbound transportation is either going to be fossil-fueled directly or being powered off a grid that is bound to be virtually exclusively fossil-fueled.

[K. A. Pital]

Railbound transportation is either going to be fossil-fueled directly or being powered off a grid that is bound to be virtually exclusively fossil-fueled

Nuclear power is exempt from the equation? Or geothermal and hydro? A railway network can be electrified by a "green grid" if you struggle to make it so; it might not be financially effective but sure as hell it could, at least in theory, be green and consume no fossil fuels.

As for the efficiency, ships are only so effective for their bulk traffic lanes which require water channels to operate; land traffic has railways as the most efficient transport and both are not in a very direct competition, because their delivery routes are so different. Bulk ship traffic will always be required for long overseas hauls, even if it loses some of it's coastal traffic due to competition from the railway.

I'm with Surlethe here. Operating nuclear-powered ships is a good idea. The USSR operated some nuclear bulkers in the north due to climatic conditions with positive results, such bulkers are rather expensive to build of course, but once again it's a choice between "clean" and "cheap".

[madd0ct0r]

I do apologise, ships can be better then rail sometimes.

the other points stand.

[Batman]

Railbound transportation is either going to be fossil-fueled directly or being powered off a grid that is bound to be virtually exclusively fossil-fueled

Nuclear power is exempt from the equation? Or geothermal and hydro? A railway network can be electrified by a "green grid" if you struggle to make it so; it might not be financially effective but sure as hell it could, at least in theory, be green and consume no fossil fuels.

'Bound to'. Not 'inevitably will'. For the very reasons you mention, any grid the rail draws power from WILL VERY likely primarily if not almost exclusively fossil fuel driven. Nuclear is equally unlikely because atoms are evil!!!

[Sea Skimmer]

Electrical trains can use regenerative breaking and pump a lot of the energy they use back into the grid, all without the big weight penalty of making the locomotive a hybrid with batteries In fact even modern diesel-electric locomotives use regenerative breaking already, because it cuts down on replacement costs for break pads. But the energy is simply turned into heat by a huge block of resistors for a lack of any place to put it.