The energetic afterlife of Christmas trees

January 15, 2010 12:34:13 PM PST
Have you ever wondered what really happens to your Christmas tree after it's picked up for recycling?

From the curbside to the back of a waste recycling truck, the life cycle of a Christmas tree can go far beyond its use to celebrate the holidays.

"This pile that you see behind me is what's been delivered in just the last couple days from the curbside collection," said Waste Management Recycling Program Manager Rebecca Jewell.

Most people figure their trees end up at the dump, or perhaps a compost pile, but actually they go many steps further, turning into an alternative energy resource for biomass-fueled power plants.

"The Christmas trees are really ideal for this kind of a biomass application. The resin makes them burn really hot, which makes the biomass facilities run even more efficiently than typically they might," said Jewell.

Jewell said that last year the Waste Management San Leandro station recycled 368 tons of Christmas trees collected from its Alameda County customers, and the potential statewide is staggering. According to the National Christmas Tree Association, approximately 2.8 million Christmas trees are sold each year in California. If each of those trees is recycled, together their biomass could produce about 21,000 tons of fuel. With that amount of fuel, a biomass-fired power plant can generate enough energy to power 8,500 homes for one month.

"We really want to respond to the residents' interests and to the state's interests for alternative fuels," said Jewell.

Here's how that's happening with Christmas tree recycling -- they go from the curb to a processing pile at the waste station, loads of them are plucked and put into a mulching machine and the cascading result of wood chips is then ready to be trucked, in this case to Rio Bravo Rocklin a biomass-fueled power plant in Central California -- it's one of about 50 such plants in the state. Rio Bravo burns urban wood and forest wood waste to produce electricity and sells all its output to PG&E.

As a result, your recycled Christmas tree is contributing to the state's clean energy commitment to produce 33 percent of electricity with renewable fuel sources by 2020.