DENVER, Colorado (AFP) - The Democratic Party is using beer-based biofuel and a recycling brigade guarding trash cans to help ease the environmental impact of its convention in Denver this week.

The aim is to have the most environmentally-sustainable convention in modern US history. And the goals are ambitious.

"We've been committed to taking the practical steps to sustainability," said Damon Jones, a spokesman for the Democratic National Convention Committee.

"There are a number of things you can do that are not outrageous but are responsible and use good common sense."

The plan is to divert 85 percent of the waste produced by the 50,000 people coming to the convention into recycling or composting facilities.

Some 900 volunteers were enlisted to help delegates sort their garbage so it ends up at a recycling plant or composting facility.

Caterers and other vendors are also being instructed in waste diversion.

And the company hired to build the stage where Barack Obama will accept his party's nomination has been asked to use recycled materials and make sure they get reused when the stage is torn down.

Then there's transportation: General Motors will be providing a fleet of hybrid and flex-fuel vehicles, Coors is donating ethanol made with thousands of gallons of its beer waste and bus idling will be kept to a minimum.

Pollution is also being controlled through the use of wind and solar energy and efficient lighting, computers and appliances.

To top it all off, the party's "Director of Greening" hired an outside firm to calculate the convention's carbon footprint so it can be offset with carbon credits.

"We're really proud of the steps we've taken and if you compare another event that's taking place the next week we feel really good about our track record," Jones told AFP.

The Republican National Convention has also pledged to hold its "greenest" convention ever, but its plans are more modest.

"Having someone stand next to a trash can? I don't think so," said RNC spokeswoman Yohana de La Torre.

The Republicans are also using hybrid and ethanol-powered vehicles and have been cutting down on the use of paper products while asking vendors to use recycled materials for everything from the carpets to the signs filling the arena, de la Torre said.

Their offices were filled with reused furniture and recycling bins and the bulk of staffers found apartments within walking distance so they could avoid driving.

"We are trying to be stewards of the environment and are trying to encourage others to be," she said in a telephone interview.

"The Republican Party is home to Theodore Roosevelt who was the first American president to consider the long-term needs for efficient conservation of natural resources."

These greening efforts, while important, have become pretty standard for large events, said Kert Davies, research director of Greenpeace.

"This is all good manners at this point," he told AFP. "It's more important what they talk about inside the convention. ... The campaign platforms have to match the behavior."