The test involving 30 machines in the Washington, D.C., area has just begun. Pepsi hopes to begin rolling them out worldwide over the next several years, said Robert Lewis, vice president of packaging and equipment development.
The new machines use 5.08 kilowatt-hours of energy per day, down about 15 percent from a nationwide average of 6 kilowatt-hours used by current machines. Current machines already use 44 percent less energy on average than the machines used six years ago.
"That was the equivalent of burning five 100-watt bulbs constantly," Lewis said, referring to the 2003-era machines. "We're currently down to about two 100-watt bulbs. They're not using a lot of energy as it is."
The new machines also emit about 12 percent less greenhouse gas, in part by keeping the drinks cool with carbon dioxide instead of the usual hydrofluorocarbons (HFCs), which scientists say contribute to global warming.
The green machines, which have won the praise of Greenpeace, are the latest step PepsiCo is taking to promote its more environmentally friendly ways. Both PepsiCo and Coca-Cola Co have come under fire for issues such as using too much plastic, and have made changes such as making lighter bottles and conserving more water.
The new machines are more expensive than current equipment, Lewis said, but declined to say by how much.
PepsiCo, whose brands include Pepsi, Mountain Dew, Sierra Mist and Aquafina, currently has about 4 million to 5 million vending machines and coolers around the world.
Vending machines are typically owned and serviced by the company's bottlers, which share their revenue with the offices, schools and stores that house them. Therefore, those customers will not incur any charges for the new machines, yet will benefit from lower energy bills, Lewis said.
PepsiCo worked with Greenpeace Solutions, an arm of the large environmental organization, to develop the program.
Greenpeace Solutions Director Amy Larkin said PepsiCo was leading the way to improve a technology that people use every day but rarely think about.
"They're transforming the industry in a way that is going to be more climate-friendly to a great degree, so what can I do but applaud that," Larkin said.
While Pepsi's greener vending machines are the first in the United States, Unilever Plc's Ben & Jerry's ice-cream brand introduced coolers that use carbon dioxide, she noted.
Coca-Cola has introduced HFC-free vending machines in Britain, and used them at official venues at last year's Beijing Olympics.