MALCOLM BRABANT: A stiff breeze in the southern Atlantic provides optimum conditions for this pioneering ship carrying 200,000 tons of iron ore from Brazil to China.

It's fitted with so-called WindWings, which enable it to maintain speed, while reducing dependency on engine power.

CAPT.

NOLI PARAUNDA, Master, Berge Olympus: In my 15 years as a ship captain, I have never been more excited.

MALCOLM BRABANT: Noli Paraunda from the Philippines skippers the Berge Olympus.

Just as aircraft wings create lift, these devices generate thrust when installed vertically and automatically adjust to wind speed and direction.

CAPT.

NOLI PARAUNDA: I firmly believe that our collective efforts can significantly reduce carbon emissions from ships and eventually realize our goal of zero carbon shipping.

JAMES MARSHALL, CEO, Berge Bulk: I think this is an all-hands-on-deck moment.

It's a critical point, and we all need to really pursue the war against climate change.

MALCOLM BRABANT: Ship owner James Marshall is so impressed, he intends to re-equip much of his 85-strong fleet.

JAMES MARSHALL: We're looking at, in good conditions, around seven tons of fuel that we save every day.

That's around 20 tons of carbon dioxide.

So we're hoping to remove nearly 5,000 tons of CO2 per annum using these wings on board one of our large ships.

MALCOLM BRABANT: So what sort of percentage of saving is that in terms of carbon for the voyages of that ship?

JAMES MARSHALL: It's around about 15 to 20 percent we hope to save.

MAN: Downwind for one final leg for Sir Ben Ainslie and Land Rover BAR.

MALCOLM BRABANT: And this was the inspiration for what may be a wind revolution, Britain's boat in the 2017 America's cup captained by Sir Ben Ainslie.

SIR BEN AINSLIE, Four-Time Olympic Gold Medalist: So, I have been a sailor all my life.

I love being on the water.

It's a great sense of freedom, really, to be powered by the wind.

And it's really amazing that this wing technology can now use the power of Mother Nature, the power of the wind to drive commercial shipping into the future.

MALCOLM BRABANT: We met Sir Ben at the secretive workshop building this year's America's Cup boat.

Are they wings or are they sails?

SIR BEN AINSLIE: They're definitely wings.

So they're not -- if you think of the old clipper ships from centuries ago, soft sails that powered them.

These are solid wings going on these modern-day ships that are really generating a huge amount of thrust.

And they're impressive bits of technology.

MALCOLM BRABANT: Shipping accounts for 3 percent of all the world's CO2 emissions.

Older vessels can sometimes be five times dirtier than newer ones.

There's been a warning from the International Maritime Organization that, unless stringent measures are taken, shipping emissions could rise by 50 percent over the next 25 years.

This ferry to the Isle of Wight off the South Coast of England is part of the necessary change.

KEITH GREENFIELD, CEO, Wightlink: Victoria of Wight's carbon footprint is about 20 percent less than a conventionally powered vessel.

MALCOLM BRABANT: Keith Greenfield's company operates Britain's first hybrid ferry as part of his green commitment.

Not all vessels are suitable for wind power.

KEITH GREENFIELD: She has electric motors, driving propellers, batteries, and then diesel generators that generate the electricity.

MALCOLM BRABANT: But what's the advantage of that?

KEITH GREENFIELD: Firstly, the diesel generators can operate very, very efficiently because they just hum away at the optimum revs, minimum emissions.

They pump up the batteries gradually, and the batteries do all the hard work.

MALCOLM BRABANT: Some of these climate change innovators are based in Portsmouth, home to HMS Warrior that combined wind and steam power nearly two centuries ago.

JOHN COOPER, CEO, BAR Technologies: If we're presenting the wing to a potential customer.... MALCOLM BRABANT: In a building overlooking the harbor, chief executive John Cooper leads a team working to convince owners of conventional cargo vessels like these that they should be sprouting wings.

He says they should pay for themselves in six years.

JOHN COOPER: We want to actually employ WindWings on as many of those fleet out there, because the biggest saving in carbon is not actually building new ships.

MALCOLM BRABANT: At present, only two vessels are using this system.

The other is the Pyxis Ocean, a Singapore-based bulk carrier.

A third, a long-range tanker, has just been ordered.

JOHN COOPER: Two years' time, up to 50 percent of tankers and bulk carriers will be ordered with some sort of wind proportion.

And BAR Tech, we aim to dominate that market.

MALCOLM BRABANT: How can you be so confident that it's going to be that big?

JOHN COOPER: The results.

They can't be ignored.

MALCOLM BRABANT: Yacht designer Simon Rogers is developing a rival system, which it's claimed will be even greener when it's ready in two years' time.

Besides clusters of three wings, solar panels power an electric generator, whose clean exhaust gases drive propellers.

SIMON ROGERS, Technical Director, Windship Technology: With our carbon capture system and heat recovery, we actually achieve true zero, so basically no CO2 and no black soot, basically.

The exhaust fumes that are coming out of the back of the vessel are actually breathable.

MALCOLM BRABANT: After leaving the European Union, the British government pledged to turn the country into an economic powerhouse.

But these British climate change trailblazers are struggling to unlock government support.

And as a result, WindWings are being built in Spain and China.

JOHN COOPER: I would love to build them in the U.K.

There is some hurdles.

The big thing that the U.K. government really needs to think about is import duties on some of these materials.

Here's another chance to actually bring a wind-powered technology to the U.K., and I hope we don't squander it.

MALCOLM BRABANT: The ferry company would like to upgrade to all electric vessels, but that's proving impossible.

KEITH GREENFIELD: The U.K. grid just wasn't really designed for what it now needs to do, which is to deliver power to us and to other businesses around the country in the way that we now need.

Like many businesses, we're clamoring for connections, but we're not being given any clarity as to when that will be.

MALCOLM BRABANT: On our return journey from the Isle of Wight, we had to make way for the Prince of Wales, a $4 billion aircraft carrier which has been an object of derision in Britain after being plagued by breakdowns, including a driveshaft problem.

So is it possible to fit warships with sails?

JOHN COOPER: Yes, of course, we could fit a WindWing to the aircraft carriers, but actually I don't think it's that practical.

The aircraft carriers do actually have a service speed of 30 knots.

And, therefore, actually that would be quite, quite fast for this wind-powered technology.

So we'd love to.

I think it would be more of a publicity stunt, rather than a reality, but, yes, we'd certainly pick up the phone to the Navy, that's for sure.

MALCOLM BRABANT: Warships aside, the future is looking bright, as shipping turns back to the future.

For the "PBS NewsHour," I'm Malcolm Brabant in Portsmouth.