How’s this for a college graduation present — a road trip across the United States with a dozen or so of your classmates on a tricked-out bus with computers, Internet access, comfortable couches, kitchen, bamboo flooring and LCD televisions with surround sound. Your responsibilities include talking about your trip, and occasionally, doing something equivalent to dumpster diving.

There’s a worthwhile purpose to the trip, too, said Lucas Schulz, one of 15 Dartmouth College students on a two-month, coast-to-coast tour in the Big Green Bus, during a stop in downtown Memphis in July. The bus design was conceived and conversion accomplished by the students, and is being driven across the United States to demonstrate how technology can work to conserve natural resources.

When the Big Green Bus roars down the road, it comes as close as any vehicle on earth to having a negligible environmental footprint. It runs on waste vegetable oil collected from restaurants, which virtually eliminates dependence on fossil fuels. It also uses solar energy to power its electronics and other accessories.

The concept of the bus was born five years ago, when several graduating Dartmouth seniors decided to go to an ultimate Frisbee tournament in Seattle. “After spending four years at an expensive school, they were all completely broke,” Schulz said. “They decided to buy an old school bus to run on veggie oil. They bought a real beater of a bus and drove it to Seattle and back, going on a roundabout route.

“They talked to a lot of people along the way and that was essentially the birth of the program. The second year, the old crew was gone, but they wanted to continue the program, so another crew was selected to carry on.”

The second year, another school bus was outfitted to run on vegetable oil and it was used to tour for the next three years. When that model was no longer useful, they converted a more highway-friendly 1989 MCI coach bus, which was completed in early April. This summer’s tour is its maiden voyage.

Dartmouth students planned, raised funds and made the modifications to the bus. Each student has a job to do on the tour, including repair and maintenance, talking to the media, cooking, photography and driving the chase car, a Volkswagen Jetta, which is also converted to run on vegetable oil.

According to a blog site for the trip, http://changents.com/change-agents/biggreenbus/story, “Mike Wood can fix anything so long as he has an impact driver and a hammer, and Marissa Knodel can make the best blueberry muffins you’ve ever tasted. Ben Gifford can multitask like no other and Kari Cholnoky is so small she can fit in one of the overhead storage bins, which is great for saving us tons of space!

“Our solar panels and persistent wifi connection means we are never out of touch. Tessa Murphy and Annabel Seymour, our video crew, and Kawa Amina, our photographer, will be uploading tons of content here throughout our road trip, so check back often.”

From Memphis, the students were headed to New Orleans, then through Texas to San Diego, San Francisco and then back up to Minnesota. They will loop around the Great Lakes and head back home to New Hampshire.

The group received several in-kind donations during bus construction, including the four Sunpower 315 solar panels on the roof which charge a huge tank of batteries. An inverter converts 24-volt DC current from the batteries to 120 volt AC current to run all the laptops, cell phones, lights and the air-conditioning when the engine is turned off. “We want the bus to have all the comforts of home, but do it in a way that we’re not pulling power off a grid or taking power from somewhere else,” Schulz said.

The bus runs on waste vegetable oil that can be found at any restaurant with a deep fryer. “We definitely hit the fast food joints, and every once in a while, we eat there, too,” Schulz said.

The blog site says, “We go dumpster diving behind restaurants and fast food joints to get our grease (always after asking politely first though).”

A visitor to the bus’ Memphis stop, Memphian Art Womble, was interested in the technology because he runs his pickup and car on waste oil, picked up at doughnut shops. The oil gives his exhaust a distinctive smell. “The only problem I have is that the cops follow me around,” he joked.

The bus is equipped with three tanks which hold roughly 150 gallons each. All the waste vegetable oil they acquire is filtered and dewatered on the fly, but it takes about a day before the oil is ready to be moved into one of the two primary fuel tanks. The other primary fuel tank contains refined biodiesel and is used to start the engine and clear the vegetable oil fuel from the engine prior to stopping.

“The big problem with the veggie oil conversion is that at ambient temperature, the oil is a little too cold, and a little too thick to spray into the injectors and go through the filters, so we have to heat it up,” Schulz said. “So we start the engine on diesel and use waste heat from the engine to heat everything up. When the temperature gets to a certain point, the light goes green and it shifts to veggie oil. At the end of the day, before you stop, you press a button which purges the injectors and replaces it with diesel.”

The bus gets about 7-8 miles per gallon.

The students haven’t tested the bus for emissions, “but the system in the Jetta was tested several years ago,” Schulz said. “Veggie oil was compared to regular diesel, commercially available biodiesel and homemade biodiesel and the veggie oil did best across the charts.”

The Jetta’s purpose is finding potential fill up opportunities and to run small errands when the bus is parked for the night.

The bus will take the students on a tour of over 30 states, and over 50 events — from science museums to statehouses.

“We don’t think of it just as a bus,” the blog site states. “It’s a green mobile classroom — a literal science fair project on wheels.”

The group received a big welcome in Memphis during stops at Agricenter International, Shelby Farms Park and dinner at the home of their hosts William Gillon and Adrienne Pakis-Gillon, followed by a visit with Shelby County Mayor A.C. Wharton and tours of the National Civil Rights Museum and Milagro Biofuel Refinery, a local biodiesel facility shuttered due to falling diesel prices.

The Big Green Bus program now includes underclassmen. The students’ majors include engineering, design, secondary education, environmental studies, film, biology, philosophy, government and international relations. Other students on the tour are Anna Wearn, Grayson Zulauf, Matt Smith, Sarah Rocio, Merritt Jenkins, Date Parizeau and Dylan Nelson.

Go to www.thebiggreenbus.org for more information.

The term “Big Green” is symbolic of the bus’s environmental focus and is also the moniker for Dartmouth’s varsity athletic programs.

e-mail: erobinson@farmpress.com