Clean Ships

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Oceangoing ships move tons of raw materials and finished products between continents, and intercontinental shipping has become more important as economies have become more globalized. Despite their role in a healthy economy, large cargo ships and oil tankers also cause air pollution and water pollution. Pollution from oceangoing ships comes from four sources: (1) exhaust; (2) ballast water, which is water that ships draw into empty tanks to provide stability and then dump out as the ship enters port; (3) fuel leaks and oil spills; and (4) dumped wastes. Laws dating back to the 1970s address air and water pollution but have ignored the wastes discharged from large ships. Residents of port cities, however, have known for some time that their air has been fouled mainly by ships. “These ships are essentially floating smokestacks,” Vickie Patton, an attorney at the Environmental Defense Fund, told USA Today in 2004. Another concern is that ships produce more sulfur oxide and nitrogen oxide gases than CO2, and the sulfur and nitrogen compounds contribute more to global warming than CO2 does.

Shipping causes two additional hazards to the environment: (1) the introduction of invasive species and (2) water pollution. Many invasive species that have infiltrated ecosystems around the world arrived in ballast water. Hundreds, perhaps thousands, of invasive species from microbes to fish and plants have traveled via ballast water. Cargo ships, tankers, cruise
ships, tugs, and smaller boats also foul waters with small but constant fuel leaks, large oil spill accidents, and accidental or intentional waste-dumping. The shipping industry therefore has two critical issues to address: (1) the need to build new clean-running ships to replace older, dirtier vessels, and (2) stricter adherence to laws against emissions, fuel spills, and illegal dumping. Unfortunately, very few laws exist to regulate ballast dumping. Governments can help by passing laws to require the shipping industry to clean up its current operations and seek new technologies to circumvent the ballast problem.

Washington’s Port of Seattle has taken the initiative with a plan to require that all ships that regularly enter the port convert from dieselpowered engines to clean ships. This of course will be an enormous undertaking for two reasons: (1) many thousands of ships currently cruise the world’s oceans, and (2) the majority of ships are registered with countries that may not make the environment a priority. Despite the challenges, the Port of Seattle has been specific in what it expects from clean ships. First, vessels in port will be allowed to plug into onshore electric power sources rather than burn fossil fuels. Second, ships may be required to burn lowsulfur fuel while at berth and perhaps while at sea. Third, the shipping
industry should continue its recent push to convert to diesel blends that reduce fossil fuel combustion. Fourth, current ships can be retrofitted into more energy-efficient designs. Fifth, the efficiency of operations at terminals should be improved to speed loading and unloading and so reduce the time ships wait offshore.

As the old generation of ships disappears and a new generation takes its place, shipbuilders will pursue the following objectives, listed in order of their feasibility:

1. better shapes to reduce drag
2. low-drag paints and finishes
3. new propeller designs
4. clean-burning fuels
5. onboard emissions scrubbers
6. hull air-blasters to reduce hull-water resistance
7. hybrid vessels

In 2008 the Christian Science Monitor writer Gregory Lamb discussed an even more innovative approach than the previous options: “When the cargo ship Beluga SkySails left the port of Bremen, Germany, in January, it carried with it a high-tech version of an ancient means of propulsion. During its 11,952-nautical-mile [22,135-km] voyage to Venezuela and
back, the ship launched a giant kite from its bow, sending it hundreds of feet into the air to capture the stronger and more consistent winds found above. The 1,720-square-foot [160-m2] kite, controlled by onboard electronics, exerted enough pull on the ship to provide about 20 percent of the engine power required for the journey.” This approach was certainly innovative, but hardly practical for today’s global shipping industry. Nevertheless,
transportation always has room for people with inventive ideas to help the environment.

The Austrian engineer Michael Frauscher may have hit upon a more practical solution than huge sails. Frauscher builds hybrid recreational boats that run on electricity when starting or idling or when underway at slow speed. These boats then transition to regular fuel combustion when they reach higher speeds outside the harbor. “Everybody knows about

More than 80 percent of transportation greenhouse gas emissions in the United States
comes from on-road vehicles. Light trucks, or light-duty trucks, are sport utility vehicles,
pickup trucks, and vans. Heavy-duty vehicles are commercial trucks, trucks with more
than two axles, and buses.

hybrid cars,” Frauscher said in the San Francisco Chronicle in 2008, “but hybrid boats are different.” Since most of the pollution from boats comes when they are in harbor, the hybrid boat has been designed to first solve this problem. San Francisco has added new ferries to its existing fleet that burn a blend of biodiesel (fuel made from biological sources) and low-sulfur fuel to reduce dangerous emissions by 85 percent lower than federal emissions requirements. Hybrid technology as well as low-emissions fuels may signal the next wave in cleaner ships.