CARACAS, United States — The MS Beluga Skysails, a cargo vessel that uses a towing kite system to achieve better shipping fuel economy, completed its first shipment this week.

Global DHL Forwarding used the vessel to deliver 71 containers from Germany to Venezuela as part of a larger effort of creating a less-carbon intensive transport and logistics network. The ship's wind propulsion feature allows it to either travel faster or use up to 20 percent less fuel.

The maiden voyage was completed at a time when ship-related greenhouse gas emissions are under fire from several fronts. Earlier this week, a report commissioned by the U.N. International Maritime Organization surfaced, finding that ship-related emissions, at 3.5 percent of global carbon emissions, were grossly underestimated and nearly double than previous estimates of 1.4 percent.

Carbon emissions could rise another 30 percent by 2030 because of predicted increases in world seaborne trade, an industry responsible for shipping more than 90 percent of traded goods by volume, according to Reuters.

At the same time, the Bush Administration and the U.S. Environmental Protection Agency are facing pressure from lawmakers and environmentalists to tighten pollution laws at U.S. ports, the Associated Press reported.

The EPA plans to enact regulations next year after the the U.N. International Maritime Organization sets up global standards, which will likely happen next year. But many argue that waiting would offset gains made by curbing road transportation-related emissions.

Cargo ships can produce smog-forming emissions equal to 350,000 new cars, according to environmental group Friends of the Earth. The maritime group recommended restricting nitrogen oxide standards for new ship emissions in 2011 and with an 80 percent reduction by 2016. With current turnover rates, however, the reduction may not be achieved for nearly 30 years.

In late 2007, ports in Los Angeles and Long Beach, Calif., enacted a program that will require ships to turn off all on-board power systems while docked. The policy includes the prohibition of big rigs at the ports that are built before 1989.

A recent study from Energy Futures found that U.S. container ports are among the biggest sources of pollution and greenhouse gas emissions in the country.

The study's findings stem from three factors: ports are traditionally located near densely populated coastal settings, containers and big rigs trucks using the ports use diesel and a main fuel source and prevailing winds sweep fumes and pollutants onshore.