Adam Gardner has come a long way since nicknaming his band's tour bus "the Earth Eater." Last October, the Guster guitarist/vocalist, who also co-founded environmental nonprofit Reverb, traveled from his home in Portland, Maine, to Capitol Hill to testify in front of Congress about the benefits of biofuel to the music industry. "I've never been more nervous in my life," Gardner recalls. But after wiping the sweat from his brow, he successfully relayed his Earth-friendly message to curious politicians in Washington, D.C. "I basically said, 'We'd love for Reverb to be out of business, as far as coordinating biodiesel for tours,' " he says. "[Artists] should be able to pull up to any ol' truck stop and get it. It shouldn't be something we have to find for tours."

Since co-founding Reverb in 2004, Gardner, who runs the nonprofit with his wife, environmentalist Lauren Sullivan, has helped green more than 50 tours, reduce 30,000 tons of carbon dioxide, distribute approximately 250,000 gallons of biodiesel and spread the Earth-conscious message to 4.5 million music fans. And his efforts won't stop there.

"The environment is on the forefront of everybody's mind right now," Gardner says. "Our job is to keep it there until it's no longer a problem." Having already greened tours for such acts as the Dave Matthews Band, Jack Johnson, Linkin Park, Maroon 5, Barenaked Ladies and John Mayer, among many others, Gardner says interest continues to rise among artists and fans who are interested in helping Mother Earth.

With a baby on the way and a new Guster album in the works, Gardner found time to speak with Billboard about the benefits of biodiesel, educating concertgoers and affordable ways to green a tour.

How did your invitation come about to speak in front of Congress about the benefits of biofuel?
They wanted to hear my perspective as somebody who uses biodiesel and also travels around talking about the challenges in finding it. They were very interested in what Generation Y thinks about biodiesel. So I was able to show all of the stats in how many fans participate on these tours. Originally, I think they were like, "Oh, my God. Here comes some other pseudo-celebrity who wants to show their support." But they learned that my head is really in this and I'm not just here to raise a flag.

One of Reverb's main focuses is outreach to fans via eco-villages at concerts. What progress has been made on that front?
Fans have a huge impact on a tour. Eighty-five percent of a carbon footprint [at a concert] is from fans driving to and from it. We have volunteers going out there and they let fans know to check out all of the stuff that's happening in the eco-village and to talk to the local nonprofit groups. We also encourage them to carpool and offset their drive to and from the show. We receive donations for carbon offsets from fans at the shows. On the Dave Matthews Band's tour last summer, over 1.2 million miles of driving were neutralized by the fans.

What was the genesis of Reverb?
[My wife Lauren and I] were living in New York City at the time. We met in college at Tufts University. That was shortly after I met my bandmates in Guster. While Guster was touring and gathering momentum and steam, my wife was doing environmental stuff. We were, like, "How do we bring our two worlds together? We never see each other." Through Lauren's work with the Rainforest Action Network, she saw how valuable it was to have artists backing a campaign.

We tucked that away in the back of our head, and when we were in New York together and she was ready to try something new, she thought of Reverb. We decided to help out bands that wanted to go green, and not only add their voices to existing campaigns, but make their tours become campaigns.

The whole model of having an eco-village and having the tour being green itself is based on Bonnie Raitt's 2002 Green Highway, which was an environmental campaign she did on her tour that summer. Bonnie Raitt and her manager, Kathy Kane, were huge mentors in helping us start Reverb. Reverb was part of Kathy Kane's foundation until we got our own nonprofit status.

You've been playing in Guster for 16 years. When was the turning point to consciously reduce the negative environmental impact of your touring?
Before I started thinking about environmental stuff, I remember hearing about Neil Young traveling around the country on biodiesel. That was the first time I heard about biodiesel. Of course, I assumed that biodiesel was only for superstars, because it would be too expensive and too hard to figure out. But after Reverb formed, and we sent out bands like Guster, who are not superstars, we showed that if you have a bus, you can do this.

Have you ever met a band that has cut down on touring to help the environment?
I'm not saying artists shouldn't tour. Music wouldn't live very long if there wasn't live music. There's no replacing the live experience. But what does it mean to have a "green tour"? The answer is a lot of things. There are many ways to reduce the impact of a tour. The goal is to do as much as you can to reduce your impact. It's not all or nothing. Any time my band goes out on tour we add a new element. A lot of people who are environmentally minded become a deer in the headlights, thinking, "There's so much that needs to be done to make a change." And you end up getting stunned into doing nothing. For Reverb, our message is not "all or nothing," but starting somewhere. You go out you chip away and get deeper into the greening each time.

Some say biodiesel isn't as great as everyone may think. What are your thoughts?
There are some recent question marks about biodiesel, but the biodiesel we seek out isn't being imported from the rainforest of Latin America. It's made here in the States. It's domestically produced fuel that not only decreases our dependence on foreign oil, which obviously has political implications, but also is a more environmentally friendly fuel that has way less emissions than petroleum.

There are a number of feedstocks for biodiesel. A lot of it in this country is made from soybeans. But some places-like a biodiesel plant that's about to go into business here in Portland, Maine-collect wasted vegetable oil from restaurants that would otherwise be thrown away. So that's really eco-friendly. Even when you consider soybeans, a recent study from the Department of Energy shows that there's a 74% reduction in carbon dioxide emissions from using biodiesel. That takes into account the growing of the soybeans. It's pretty significant.

Biodiesel can also be used in a blend as well. Most artists don't own their own vehicles; they lease them. More and more leasing companies are comfortable with using biodiesel. Many of them who aren't comfortable using biodiesel hold the line at B20, which is a blend of biodiesel and regular petroleum. There are others using B100 - a pure blend of biodiesel fuel. Jack Johnson, for example, will be coordinating biodiesel, among other things, for his tour. He has been using and will continue to use B100.

Using biodiesel can sometimes cost more than petroleum-based diesel. How are artists paying for it?
We lay it all out for them. There are a lot of ways it can be paid for. Bonnie Raitt, for example, auctions off 10 seats in the fourth row [of concerts] to go toward green expenses. Sometimes it goes toward the charity of her choice. Serj Tankian is doing ticket auctions. He also added something called an eco-fund, where 50 cents of every ticket will be put toward the greening of his tour. The Fray also donated 50 cents of their ticket [sales]. And if you sell enough tickets, you can end up doing more than just covering your green costs.

There's a band called Stars, which is a cool band from Montreal with members of Broken Social Scene. Somebody from Stars called, saying, "We'd love to have a tour, but we don't know how to pay for it." So we have a program called the Green Grants Mentoring Program, where if there's overage from another band's tour, we can then put that toward bands that want to tour green on a smaller level. It's musicians helping each other, which is really cool.

What efforts has Reverb made to help concert venues go green?
It's important to take a work-with approach, and not any sort of adversarial approach. It's like, "Hey, we're trying to be as green as possible, this is what we'd like to see on your end." In the (tour) rider, we'll actually give venues links and resources. What's cool about having Reverb staff travel with the tour is that we're dealing directly with the venue operators. They'll see firsthand all of the (biodegradable) utensils we're using. A lot of them are finding out that it doesn't cost any more to get this stuff, and in some cases it's a better deal. So it's starting to make sense to a lot of these venues. I'm seeing a lot of progress. A lot has happened since we entered the game in 2004. There has been a huge tide of momentum in the past couple of years. Reverb is getting inundated with phone calls from venues and bands.

What role are the artists playing in making venues more environmentally aware?
On Jack Johnson's tour this summer - some of which we'll be coordinating green stuff for - they're requesting recycling to happen at all their venues. It's not even a request at this point. It's a deal-breaker for them. Another example is Guster playing a radio festival in Boston for WBOS (92.9-FM). We made the event carbon neutral, and then they wanted to learn more about what we were doing. The event was Earthfest, so they already had a bunch of greening elements happening, but we helped them go deeper on it. We also had them look at their own station. So they became the first commercial radio station to become carbon neutral. And that happened because they had an environmentally minded band headline their festival.

How far along are large-scale music festivals in going green?
I think the reason Reverb hasn't done too much on the festival side is because there are a lot of festivals out there already doing a good job out there. I think festivals are a great place to showcase greening efforts and elements, because people are there for multiple days, and you can take greening a lot further because you're in a stationary place. I don't claim to know exactly what every festival is doing. But having played Bonnaroo (Manchester, Tenn.), I was impressed with their outreach at Planet Roo. Guster has also played Austin City Limits (Austin, Texas).

Have you worked with bands that have taken a DIY approach to greening a tour?
Hot Buttered Rum converted the diesel engine of their van to run on straight vegetable oil, so they go around getting a bunch of grease from restaurants that would normally be thrown away. They basically go dumpster-diving in various Chinese restaurants around the country and fill up their van. The gas mileage is the same as diesel. For smaller bands, that's a really good way. Another band, Oakhurst, bought an old Greyhound bus and converted it to run on grease. There's a bit of an upfront investment to do the conversion but once it's done you have free fuel. But for bigger bands, they don't own their buses or trucks, so they can't make the modifications to them.

Where is the music business lacking in greening efforts?
The things lacking most are knowledge and help. And that's the void Reverb is trying to fill. A lot of people think it's too hard or too expensive. For example, we've done some work with Warner Music Group. We have them looking at energy efficiency in their headquarters in New York City. They're going to save money by taking a closer at their energy and water usage. It's just a matter of getting the information out there and having people facilitate it.

Are greening efforts in the music business a trend, or do you expect environmental awareness to continue?
It's not a trend. It's something that has been building momentum for a long time. And now that we're seeing the actual effects, more and more people are becoming aware and want to take action. So we're just trying to help people, whether they're in a band or a fan of the band. It starts with the artist and reverberates out to their fan base.

Aside from what you're doing with Reverb, what are Guster's future plans?
We're actually making a record this summer. So we'll be writing and recording - and making babies. Our drummer just had a baby, and my wife is due in May. Our lead singer is due in June. We have a lot of material that we're excited about but we haven't recorded any of it.