MOUNTAIN VIEW, CA — In an effort to both reduce costs and “green up” computing, Google is considering launching a fleet of “water-based datacenters” to house the company’s massive search-engine servers.By anchoring a group of supercomputer-outfitted barges up to seven miles offshore, Google hopes to be able to employ wave energy to power and cool the equipment, thereby not only reducing the cost of their operation, but also utilizing renewable energy resources. In addition, locating the datacenters offshore would relieve the search giant of the burden of property taxes in the several countries, including Britain and the U.S., that now house the datacenters.

Off-shoring for tax reasons is nothing new. Large companies, including some in the adult industry, for years have sought to diminish taxes by banking and locating their operations in tax-friendly countries. The use of renewable energy to power computers is new, though. Now Google just has to figure out how to make the system work.

In a patent application, Google described the system: “Computing centers are located on a ship or ships, anchored in a water body from which energy from natural motion of the water may be captured, and turned into electricity and/or pumping power for cooling pumps to carry heat away.”

For Google and other large computing entities, the proposed system could be a godsend. Google’s current datacenters are the size of soccer fields, and they grow every time the Web does. They require massive cooling systems — powered by massive amounts of electricity — to ensure the machines don’t overheat.

According to research firm McKinsey and think tank Uptime Institute, datacenters consumed 1 percent of the world’s electricity in 2005. By 2010, datacenters are predicted to leave a larger carbon footprint than the air-travel industry.

Other companies also are investigating energy conserving cooling alternatives. Microsoft is considering building a datacenter in Siberia, and Sun plans to house a datacenter in an abandoned coal mine, using ground water to cool the equipment. Sun said the move could save $9 million annually and use half the energy a gound-level center consumes.