Almost as soon as human beings first came up with the idea of nailing a large sheet to a pole and
bolting it to the deck of a boat civilizations started sailing across seas and oceans to
discover new frontiers. The earliest record of a sailing ship is an image on an Egyptian vast
from about 3500 BC. About a thousand years ago the Vikings sailed all the way to North America.
Eventually sail power enabled Europeans to colonize a great deal of the planet from the
Americas down to Australia and New Zealand. And by the 18th century wind-powered trading ships were
criss-crossing the oceans constantly. Nowadays of course the internal combustion engine has
more or less confined sailing to a niche sport and a slightly expensive leisure past time.
I'm a bit of a landlubber myself to be honest, but I can certainly see the attraction of an
invigorating sea breeze and the freedom of wide open spaces that sail boat owners hanker after.
And if it wasn't for that pesky climate change that's probably the way wind powered sailing would
have remained. But according to the International Energy Agency commercial shipping accounts for
about two percent of global CO2 emissions and that number is set to rise dramatically as global
zero emissions by 2050. That means a blank sheet of paper and some blue sky thinking
with no suggestion too radical to at least be considered. One of those ideas is wind-powered or
wind-assisted freight ships. These are sailing ships, Jim, but not as we know them. In fact
they're a completely new generation of vessels using cutting-edge materials and technologies.
So could wind power once again provide a practical and economically viable solution
for the global shipping industry to genuinely reduce its carbon footprint?
Hello and welcome to Just Have a Think. When it comes to the art of
shoving a boat forward using wind power it appears that modern technology has moved
on from the large billowing sails that we all recognize from the romantic era of the tall ships.
There are three main alternative wind power technologies currently hoping to catch the eye
of freight shipping companies as a solution to reducing emissions and overhead costs for each
voyage. The first of the three is aerofoils - not dissimilar in principle to the wing of a plane
with a contoured top surface and a flat underside. On a plane that shape forces air to move more
quickly across the top of the wing and that reduces air pressure above the wing which causes
the air below it to push upwards and 'hey presto' - we have lift off. If you built a vertical
version of a plane wing and nailed it to a boat you could in theory produce forward thrust instead
of upward lift and pull your boat along that way. That's essentially what Swedish ship designers
Wallenius Marine have been developing in a joint venture with industrial technologists Alpha Laval.
Their first ship design is this one. It's called the Oceanbird and it'll be enormous,
at 200 meters long and 40 meters wide. The wing sails will tower 80 meters above deck and well
over a hundred meters above the waterline making the Oceanbird the tallest ship in the world.
But the sails are also telescopic which means they can be lowered right down to deck to allow
the Oceanbird unrestricted access to harbours and other areas. And they can also be rotated about
their axis to keep them in the perfect position to optimize available wind from any direction. The
optimal direction is not from behind the vessel as you might think but from the side. Keeping
the wing sails at the correct angle to the side wind maximizes the available surface area exposed
which results in the strongest forward thrust for the vessel. Wallenius Marine claim the wind alone
will provide enough power to get the Oceanbird across the Atlantic in 12 days at an average speed
of 10 knots and with an internal freight carrying capacity equivalent to 7 000 cars. You might be
thinking 12 days is a lot longer than it takes the fastest modern diesel engine ship to do the same
journey. And of course you would be absolutely correct. It's about twice the time in fact,
which is obviously a very considerable concern for a freight company. But Wallenius Marine also claim
that their aerofoil technology would reduce the carbon footprint of each journey by 90 percent,
not to mention achieving a massive saving on fuel costs. Now before you go hurtling down to
the comments section to crucify the messenger, I will point out that those performance figures
have apparently been gleaned from tests on a 23-foot scale model and there doesn't yet appear
to be any specific technical data available to back up the emissions reduction number,
so I think we'll have to take it with a slight pinch of salt until an actual sea going vessel
is launched. But the company are planning for a production ready design to be complete in 2021,
with deliveries by the end of 2024, so watch this space. The second of the three competing wind
propulsion systems appears to be the product of some serious blue sky thinking. Believe it or not
it's these rotating cylinders. Looks a bit like a complete no hoper to a layman's eye like mine, but
give it a chance because apparently it's not quite as hair-brained as you might think.
The system makes use of something the physics bods call the Magnus Effect. You and I observe
the effect all the time when we're watching sports like baseball, cricket or football.
When a player puts a bit of spin on the ball they can bend its trajectory through the air,
usually with the desired effect of being most discombobulating for the opposition.
It works because the spin causes air to move faster across one side of the ball and slower
across the other. That sets up a similar pressure differential to the aerofoils we just looked
at and that differential causes the ball to move in the direction of the lower pressure
airflow. It's also used in slightly more serious circumstances on things like guided missiles,
so it's a pretty well known and well researched phenomenon. And in the context of freight shipping
this is not a drawing board development concept either. It's already in use on real vessels.
It's known as a Flettner Rota, named after the German inventor and architect
who first came up with the idea in the 1920s along with the Finnish engineer Sigurd Savonius,
whose name you might recognize from Savonius wind turbines. Finnish company Norsepower
was founded in 2012 and has been developing these rotor sails for freight vessels ever since.
They're not designed to provide all of the motive power for the ships though. Their job is really to
increase the efficiency of each voyage so as to minimize fuel consumption and reduce emissions
as much as possible. One of their big advantages though is they can be very easily retrofitted to
the deck of pretty much any ship, and often within a day, which means they're a relatively quick win
for freight operators. A typical freight ship fitted with these rotors could expect to reduce
fuel use by 400 tons a year saving nearly $200 000 at today's prices and reducing its CO2 emissions
by 1200 tons. So far North Power's rotors have achieved 140,000 hours of operational service,
saved more than 3,000tons of fuel and reduced CO2 emissions by almost 10,000 tons.
And the rotors are tiltable too so access is not hampered either. The biggest obvious
drawback is that they reduce the amount of deck space available which on a large container ship
would mean lost revenue for the freight operator. That's not an issue that would be encountered by
our third wind power technology though. This one is probably the wackiest looking of all three.
Rather than mounting your cells straight to the deck, how about extending them up into the air
on the end of a winch. Effectively what you've got here is a kite assisted propulsion system.
It looks bonkers I know but again there's some definite method in the madness here. It's a
concept that was first tried way back in 2007 on a heavy cargo vessel called the MS Beluga Skysails.
Again not as a full replacement for the diesel engine but as a complementary technology
to maximize efficiency and minimize fuel consumption and emissions.
The ship was fitted with a 160 square metre kite sale for its maiden voyage across the Atlantic
from Bremerhaven in Germany to Guanta in Venezuela. On route the efficiency of the sky
sails system was tested for eight hours a day in winds of up to force five and it was considered a
great success with calculated savings of up to two and a half tons of fuel per day saving a thousand
dollars for every day of the voyage. The designers reckoned that with really large kite sales of
up to 600 square meters of surface area fuel savings of between 10% and 35% would be possible
depending on the route. But why should a sail that's tethered to the boat on a very long rope
be any better than a sail that's tied to a mast on deck? Well there's two fairly significant
advantages over traditional cells, and for that matter over the other two technologies we've
just looked at in this video. The first is wind speed. The closer the air movement is to the water
the more friction it encounters and therefore the slower it travels. But way up at 300 meters above
the sea the wind encounters no such impediment so it's much stronger. The second big advantage of a
kite sail system is that you don't lose any deck space, so a full container ship could easily have
this technology retrofitted on deck with immediate benefits in cost and emissions reductions.
It's probably unlikely that wind power will ever completely replace mechanical propulsion systems
of one description or another in ocean going vessels, and it's quite likely that a greater
reduction in emissions will be achieved through the development of batteries for short distances
and biofuels , hydrogen and possibly even ammonia as low or zero carbon fuels for longer voyages,
but as a complementary source of power these wind assistance technologies may well prove to
be a very attractive option. As our global population grows, shipping of goods around
the world is likely to increase as well. The International Maritime Organization projects
that emissions from shipping will increase by 50 percent up to 2050 if no changes are made,
so developments like this could be crucial in our efforts to mitigate climate change.
If you've crewed one of these boats or if you've been involved in developing these technologies
or even if you've got views on how you think wind power could and should be deployed in the
coming years, then jump down to the comments section below and leave your thoughts there.
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