A luxury tax on energy. (Conservation).

Aspen, Colorado, already known for its ski slopes, is trying to become known as well for its efforts to conserve energy and decrease power plant carbon dioxide emissions. Under the joint city/county Renewable Energy Mitigation Program (REMP), people who build large new homes in Aspen are given a budget for how much energy they can use to run their households. Exceed that budget, homeowners are told, and they must pay a fee.

Fees are based on a house's size. For houses between 5,000 and 10,000 square feet, the fee is $5,000. A house over 10,000 square feet costs twice that amount. Outdoor amenities such as a pool or a heated driveway incur further fees. Homeowners also have the choice of offsetting part of their fossil fuel consumption by installing renewable energy systems in their new digs.

Since its inception in January 2000, REMP has collected about $1.5 million. The money, administered by Aspen's nonprofit Community Office for Resource Efficiency (CORE), is used to fund select energy efficiency projects and purchase energy from alternative sources.

The idea grew out of discussions by local officials on ways to improve energy efficient> explains CORE director Randy Udall. Initially, he says, there was concern that such a plan would merely "give rich people a license to pollute" (U.S. Census figures peg the median Aspen home at $750,000, compared with $166,600 for the rest of the state). But in the end Udall and local officials decided that the idea was justified if the fees could be used to do environmental good by offsetting the impact of large homes and their amenities.

According to CORE's 2001 annual report, the program has doled out $666,600 for projects including solar hot water panels for an affordable housing complex and an energy-efficient lighting plan for a local sports complex. Udall says REMP now spends $50,000 per year on wind power, which he estimates will keep 40 million pounds of carbon dioxide out of the air over the next 10 years.

The program also has earmarked funds for $100 rebates to residents who buy water-and energy-efficient clothes washers, but this program has so far had only 17 takers. The annual report notes that more marketing is needed to increase residents' awareness of the washer program.

"We are beginning to see more people install renewable energy systems in lieu of paying the REMP fees," says Udall. But he can't say for certain whether this reflects an interest in energy consciousness or in expediency. "[W]hether the owners--millionaires or better--give a damn about energy usage is anyone's guess," he says. "In general, I would hazard to say no."

"REMP is a perfect example of how to make economic principles work to save the environment," says Thomas Drennen, an assistant professor of economics at Hobart and William Smith Colleges in Geneva, New York. "It gives housing consumers a choice--if they're going to exceed a certain `fair' level of energy consumption, then they'll have to pay to offset it elsewhere. So if they want heated driveways, then they'll have to help fund home conservation efforts for others, such as through weatherization programs or efficient lighting programs."

Kenneth Richards, a lawyer and economist at the Indiana University School of Public and Environmental Affairs, says the program has the virtue of being easy to administer--the money is simply used to fund projects, and there is little bureaucracy or red tape involved. But Richard Shaten, a faculty associate with the Institute for Environmental Studies at the University of Wisconsin-Madison, is concerned that programs such as REMP send the message that "if rich people want to do something about [pollution], they can, but for the rest of us it's obviously too expensive."

Still, Shaten also says REMP shows that people can make a difference by living sustainably. Udall says he's considering expanding the program to Vail, another well-heeled community, where half the homes cost $369,100 or more.