See excerpt from Yahoo! Green:
The project was created by billionaire Richard Branson to empower exporters, importers, and even cruise-vacation-goers to choose the most efficient ships to do business with. The database lists engine size, type of ship, energy-efficient features, emissions, and other information about each ship along with overall ratings based on those facts.
The builders of the database have great expectations for the project. They expect it to reduce shipping CO2 emissions by as much as 25 percent.
The shipping industry has a very large carbon footprint and has been hard to regulate because shipping is a global business and national or regional restrictions are hard to enforce. The database is aiming to solve the problem by putting the power in the hands of businesses and consumers to affect change, instead of governments.
Shipping link: http://www.shippingefficiency.org
Yahoo column link: http://green.yahoo.com/blog/ecogeek/1390/new-database-rates-energy-efficiency-of-ships.html;_ylt=At0BvfEG1kiP3puTA5MKNfmAV8cX