How Can Technology Reduce Global Shipping's Fuel Consumption?


Car transport ship, photo: Rennett Stowe via flickr.

If we're going to start this great transition off of oil we really need to start thinking hard about how we're going to move ourselves and our goods around the globe. Part of that is thinking conceptually about it--how to change our habits and usage patterns for long-distance travel. The other part is how technology can change this. Let's deal with shipping and aviation separately. Shipping is up first. Though it doesn't get as much coverage as other issues under the broad banner of transportation, TreeHugger has covered many ways to make shipping more environmentally friendly and reduce its fuel consumption a number of times. Here are some of those highlights:


photo: lotsemann via flickr
Slowing Down Saves Tons of Fuel
As I suggested in a previous post, simply slowing down can have a great impact on the amount of fuel consumed. Known as 'super-slow-steaming' container ships traveling at speeds of 12 knots (14 mph) are going half of the top speed modern ships of this size can attain. This is in fact slower than the speeds which merchant ships sailing by wind power alone achieved over 100 years ago during the height of the golden age of sail.

The advantage is great fuel, and therefore cost and environmental, savings. A spokesperson for Maersk says that reducing speeds by 20% below the previous norm results in reducing fuel consumption by 40% per nautical mile (a nautical mile is equal to 1.15 regular miles).

When you consider that the fuel used by container ships and other modern ships is quite a bit more polluting than the fuel you use in your car--the bunker fuel that powers ships has 2,000 times the sulphur content of diesel fuel--this savings is doubly significant.

Since about 70% of global shipping's pollution occurs with 250 miles of land, global regulations to specify cleaner fuel be used could have serious implications for improving air quality and human health, in addition to reducing fuel usage and lowering global greenhouse gas emissions. In total, shipping is responsible for about 4% of total climate change emissions.


photo: SkySails
Kite Sails Reduce Fuel Usage Too
Another method to reduce fuel consumption which seems to capture the imagination, as it uses very old technology to augment modern methods, is deploying kites sails on cargo ships.

For a number of years now, tests have been underway--showing great promise--demonstrating how even on cargo ships powered by fossil fuels, if you deploy a kite sail significant savings in fuel consumption can be achieved. Even the smaller-scale kite sails used to prove the concept can substitute for 20% of the ships engines' power.

Part of that is because these kite sails are deployed far higher than even the tallest mast could go. In fact diagrams from German manufacturer SkySails show them deployed up to 200 meters above the ocean surface.


photo: Low-tech Magazine
What About More Sail-Powered Ships?
Which brings us to the question of whether there might be other quasi-revival uses for sail-powered vessels in modern shipping, even if it's only in niche applications--and ignoring the possibility that constrained oil supplies force the situation.

Before you scoff, keep in mind that while it's not exactly long-distance shipping and is on a small scale, sail power is still currently being used to ship grain in British Columbia and used to move wine in France.

Also keep in mind that while the sail-powered merchant ships of the 19th century did require far more people per unit shipped than container ships do today, the image of square-rigged ships crammed to the gunnels with crew applied more to a man-of-war than to the merchant fleet. The fastest clipper ships only had a crew numbering in the thirties.

Computerized, Automated Sails Reduce Crew Numbers
Also, modern computerized sail handling could reduce those crew numbers further. The largest sailing ship in service today, the five-masted Royal Clipper can be sailed with a crew of just twenty. And, as Low-tech Magazine has detailed, as far back as 1902, the five-masted Preussen (pictured above) had automated sail handling, requiring a crew of 48 people and having an 8,000 ton capacity. For the Preussen's trip between Germany and Chile, it took between 58 and 79 days, cruising at a best average speed of 13.7 knots.

That may be only about 5% of the capacity of a modern container ship, with nearly four times the crew, but it's also nearly 100% lower emissions and fuel consumption (the Preussen used stream-power for automated sail handling and supplemental power is still required today if you're going to reduce crew sizes). You even have similar speed once under way, assuming super-slow-steaming.

Perhaps that's never going to happen. But the point in bringing it up, more than anything else, is to highlight the fact that in our efforts to get off oil, it's not just high-tech solutions that should be considered, but re-considering older solutions with modern adaptation as well. After all, humanity has a far longer history on this planet without oil than with it.


photo: Ingrid Taylar via flickr
Can Ships of Today's Size Be Powered Without Fossil Fuels?
If we're really to eliminate oil use from modern shipping it's replacing that fossil fuel energy with something else--everything discussed so far, assuming any modern incarnation of sail-powered vessels also has engine backup, is about reducing fuel usage, not replacing it.

Considering that the current largest container ships each consumed 380 tons of bunker fuel per day--essentially a slight step up from throwing asphalt into the engine--that's a tall order. Despite efforts to deploy solar-power aboard some ships, don't expect renewable energy to replace fossil fuels, not at least at the current size of ships.

In fact, though the US Navy is currently researching biofuels to power its fighter jets, when it comes to launching its so-called Green Strike Force in 2016, the ships themselves will be nuclear-powered.

While this allows ships to operate for literally decades without refueling, the effects of a nuclear accident (even if remote), really don't sit well with my green conscience and it doesn't seem right to advocate this as a way to eliminate oil usage in long-distance shipping

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More on Minus Oil:
Minus Oil: Energized Ideas for Surpassing Petroleum
Minus Oil: Forget Hybrids and Solar Panels, We Need Active, Exciting and Vibrant Cities
How Can We Detox Our Cars From Their Oil Addiction?
How Can We Reduce Oil Consumption & Still Ship Goods and Ourselves Around the Globe?

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