B9 Shipping's Diane Gilpin has been working on plans for a sail-powered cargo
ship since 1994.She was inspired by The Atlantic Clipper, a sail-assisted cargo ship that sailed between the UK and the Caribbean in the 1980s.
"What I think we need to be looking at is the significant impact on global greenhouse gas emissions. A recent study showed that if [the global shipping fleet] was a country, it would be the sixth-largest emitter in the world," she says.
The world needs to develop a technology that is capable of moving commodities in significant quantities in order to address this challenge, she says.
The answer that B9 is proposing is a coastal cargo ship that combines massive carbon-fibre DynaRig sails - such as those used on the superyacht, the Maltese Falcon - with an engine that runs on bio-gas made from food waste using a process called anaerobic digestion.
The liquid bio-methane produced by this process can be used in an existing LNG engine.
"Effectively, we are combining technology that already exists in a way that will enable us to build a 100%-renewably-powered cargo vessel immediately," she says.
The company hopes the vessel will sail 60% of the time.
Using bio-gas means they can more accurately predict operational costs, says Diane Gilpin. This has also meant working closely with the British Met Office on sophisticated weather routing products.
A scale model of the vessel was tested over the summer at Southampton University. The results are being used to predict performance and to optimise routes.
Richard Pemberton, a research engineer at the university who took part in the testing, says he feels the project has potential.
"[With] the right cargo on the right route, then sail power becomes viable, particularly if fuel costs just get higher and higher," he says.
Mr Pemberton doesn't see hybrid sailing ships taking over quite yet however.
"Some of the cargo will still be shipped with normal fossil fuels," he says.
Let's sail away As well as numerous small-scale projects, commercial attempts to harness wind power are on the increase.
A German company called
SkySails is already marketing a system that uses a giant kite to help tow
commercial shipping, cutting fuel consumption.In Japan the Wind Challenger project, backed by the University of Tokyo, is also looking at fitting sails to cargo ships.
Nick Brown, of shipping experts Lloyd's Register, says the society is seeing a lot of interest in wind technology.
"I think it comes down to a commercial decision, on a combination of investment cost and the implications for probably longer sailing times," he says.
According to Mr Brown, when it comes to "cleaner" forms of propulsion, choice is limited.
"If there are no ships, there is no world trade. Half the world freezes, the other half starves.
"The big risk is the view on carbon emissions, because LNG is hugely beneficial - much, much cleaner than alternative fossil fuel options available at the moment - but [it is still] a fossil fuel," he says.
"And obviously nuclear power has been used successfully in applications by navies for more than 40 years, but there's a big political and societal block to it being adopted more widely. So, the focus is much more on renewables. And wind is potentially really exciting."
For now, using sail technology in commercial shipping remains something of a niche. But rising oil prices, and the resulting slower speeds at which international freight moves, could all push its economic viability.
"The shipping industry isn't an emotional industry whatsoever, it is purely commercial," says Southampton University's Richard Pemberton.
"If someone could make money out of [sail technology] and get a good return, then they'll back it. It is that simple. And the big shipping companies are very interested in it, so they must see some potential in it making money."
