On its way to the Statue of Liberty, the Miss Freedom backs away from the pier with white smoke spewing from its twin smokestacks. Then, as the captain turns out to the harbor, yet more soot streams out of the stacks.
But by the end of next year, the 3.5 million people who board the ferries annually to visit Lady Liberty may have another sight: a trimaran that can use the wind, turning on solar-charged electric motors when it's at the dock. "What someone will see when the boat is at the pier is nothing – no soot, no white smoke, nothing," says Robert Dane, CEO of Solar Sailor, the designer in Sydney, Australia.
Cutting pollution on the waterfront is an important part of the effort to cut smog and greenhouse-gas emissions. According to New York City's estimate, waterborne transportation represents 8 percent of its overall emissions. It's far higher in California, where commercial oceangoing vessels are responsible for about 80 percent of emissions of sulfur oxides and almost 13 percent of the nitrogen oxides emitted by mobile sources in the state, according to estimates by the Air Resources Board.
That's one reason that ferry services around the nation are looking for new ways to operate. The changes are important because ferries are a high-profile form of transportation, carting both tourists and commuters. In essence, they can become "floating billboards" for what can be done.
"What better way to reduce emission than using cleaner, renewable energy out on the water?" says Teri Shore of Friends of the Earth in San Francisco. "Clearly, diesel ferries need to be cleaned up."
In fact, starting last Friday, the US Environmental Protection Agency is requiring refiners to provide ultralow sulfur diesel for harbor vessels, such as tugs and ferries. This is expected to cut emissions from about 3,000 parts per million to a maximum of 500 parts per million. By 2012, the EPA will require that marine engines be designed so that total emissions are 15 parts per million or less.
"When you pair the clean diesel with a clean engine, you get an even more dramatic pollution reduction," says John Millett, a spokesman for the EPA.
For some, the EPA standards are only a starting point. For example, the San Francisco Bay Area Water Transit Authority has contracted for two ferries that are required to be 85 percent better than the EPA requirement. On Wednesday, it asked boat builders to bid on yet two more of the vessels.
The authority is leaving it up to boat builders to find the best way to reduce emissions. "If they don't meet the standards, we reject them," says Mary Culnane, manager of marine engineering for the authority.
Washington State, which operates the largest ferry system in the US, will switch over to ultralow sulfur diesel fuel by the end of this year. In the past, it tried using biodiesel but found its fuel filters were getting clogged very quickly, says Jonathan Olds, environmental program manager for Washington State Ferries.
"We're beginning a study to find out what went wrong and hope by the beginning of next year to have the biodiesel back on the ferries," says Mr. Olds. "One of the things we hope to come out of this is maritime biodiesel standards."
In Fort Lauderdale, Fla., Water Taxi Inc., which builds such vessels, is producing the maritime equivalent of an automobile hybrid. "Initially, we wanted a pure hybrid situation using high-tech batteries," says Bob Bekoff, the president. But after almost all those scenarios failed, he's shifted over to a combination of diesel and battery power. The fuel savings are about 50 percent, estimates Mr. Bekoff.
In March, Seattle-based Foss Maritime Co. said it would build the first hybrid tugboat. The vessel will work in southern California as part of a plan to clean up air quality at Los Angeles-area ports.
But the most unusual-looking vessels are probably the hybrids for the Statue of Liberty, which are designed to use solar and wind energy as well as diesel.
Other harbors may be following suit. Two years ago, the National Park Service gave "points" to companies that used green technology in bids to take passengers to Alcatraz Island in San Francisco Bay. The winning company, Alcatraz Cruises, a division of Hornblower Marine, expects to begin service at the end of 2008.
Terry MacRae, Hornblower's CEO, thinks the Solar Sailor concept is of use for only certain kinds of routes. "The technology is very expensive," he adds.
Yet however clean the ferries get, federal legislation may still be needed to clean up pollution from foreign-flagged ships. According to the US Senate Committee on the Environment and Public Works, many large oceangoing vessels burn fuel with a sulfur content of 27,000 parts per million.
On May 24, Sens. Barbara Boxer (D) and Dianne Feinstein (D), both of California, introduced legislation that would require vessels entering US waters to burn fuel with a sulfur content of 1,000 parts per million, unless the EPA says the technology for that is not available. Then, vessels would be allowed to burn oil with 2,000 parts per million.
The World Shipping Council, which represents many international ocean carriers, says it would prefer to see a global solution instead of unilateral rules. It says it is not opposed to tightening the standards. "There is currently in London a major effort to upgrade current standards, and the US has an aggressive proposal – similar to the Boxer legislation – in that process," says Don O'Hare, vice president of the council in Washington.