A team of adventurers planning to drive a pair of hybrid Hummers to the South Pole later this year will soon test the specially modified vehicles on a 400-mile run across the frozen Arctic Ocean off the Alaska coast.

The "micro-expedition" leaving the Prudhoe Bay oil fields next week will give organizers a chance to drive the vehicles in subzero temperatures under the eyes of an Alaska off-road guide trained to handle polar bear encounters, according to the group's application for a state land-use permit. While polar bears won't be an issue in Antarctica, cold and ice will.

The effort has been organized by Drive Around the World, a California-based nonprofit whose members have conducted previous long-distance treks to raise money or highlight social issues.

The Antarctica trip, a 22-day, 1,200-mile journey planned for the relative warmth of December -- summer in the Southern Hemisphere -- is designed to showcase renewable energy in one of the harshest climates imaginable, according to the groups' website.

The group hopes to highlight the need for sustainable practices, said Jonathan Knowles, a member of the expedition who works for Autodesk, an international software company that provided the program to design the rigs.

"It's about starting conversations around the challenges we face," such as limited fossil-fuel resources, said Knowles.

The vehicles have been modified with electric motors and can be powered with batteries and synthetic paraffin kerosene, an aviation biofuel made partly from used cooking oil, the organization said.

But for the Alaska trial, the group plans to use a nonrenewable fossil fuel -- No. 1 diesel -- to power the Hummers.

The donor-funded group couldn't afford the more expensive biofuel for the practice run. Completing the first "biofuel hybrid transit" of Antarctica requires staying within budget, Knowles said.

In Alaska, the team will test the Hummers' snow-friendly paddle tracks that will replace wheels and special insulation designed to keep subzero temperatures outside the rigs.

On sleds, they'll pull an Airstream trailer -- sleeping quarters for many of the 10 travelers -- and a double-walled bladder carrying up to 600 gallons of fuel, according to the application for the Alaska permit.

Much bigger fuel loads have been hauled across the tundra and sea ice, said Sean Willison, a specialist at the Department of Natural Resources handling the permit.

He said on Wednesday the permit application had received no negative comments.

Team members arrived in Anchorage this week from the Lower 48. Their application says they plan to leave an oil field road at Oliktok Point in western Prudhoe Bay on Sunday, heading west to Barrow, the northernmost town in the U.S.

"I am beyond excited. Take every little kid you knew on Christmas Eve and that's me," said Doug Pape, a former Marine from California going on the excursion.

If the sea ice is rough or soft, the group can also travel inland on snow roads created by rollagons, giant rigs with roller-pin wheels that pack down snow for fuel deliveries to Barrow and other North Slope towns.

The seasonal roads are crisscrossed by local travelers and companies such as Arnie's Northern Outfit and Cargo. The Barrow-based company imports cars and other supplies to North Slope villages after they've been purchased in the big cities of Anchorage and Fairbanks, where they're cheaper.

Owner Arnie Arey will serve as a guide and polar bear guard for the expedition, bringing along his own truck with tracks for wheels.

"I'm happy to be helping," he said.

The trip will provide a dress rehearsal that wouldn't be possible in California, allowing cold-weather tests on modifications like the heating system that circulates propylene glycol -- a radiator fluid and antifreeze -- to warm up the battery pack, engine and fuel tanks before driving.

Temperatures on the North Slope have been hovering around zero, higher than the minus-20 temperatures common at the South Pole in December. The Hummers will have satellite phones and an emergency locator beacon that can be activated to notify responders such as the North Slope Borough search and rescue squad.

The adventure has already faced one big hurdle getting its equipment to Anchorage. The cargo company hired to ship the Hummers and other gear to Alaska was hobbled when one of its ships, the North Star, developed mechanical issues.

The Hummers arrived in Anchorage — but the trailer and spare parts hadn't yet made it.

Pape said he and others were scrambling on Tuesday looking for replacement gear, including fender wells for the Hummers to keep snow, ice and other debris from damaging hoses and wires.

There's a lot of "critical stuff" still sitting on the dock in Tacoma, Pape said.

Drive Around the World, created by former Silicon Valley software engineer Nick Baggarly, made a trip to Prudhoe Bay in 2005 as part of a 16-month journey across much of the globe. That time, it was a mission to raise funds to find a cure for Parkinson's disease, according to the zerosouth.com website.

Rod Roddenberry, a TV producer going on the journey, said the shipping challenges are a good reminder of the need to be resilient on a remote, self-supported expedition.