The rules for the competition have been recently posted, and the goal is to get better fuel economy. Entries can run on biodiesel, ethanol, or, in the zero-emissions category, on electricity. The snowmobiles will be rated in categories like emissions, noise, and acceleration.The idea is to make internal combustion snowmobiles suitable for use in fragile natural areas, like in national parks. The quieter and cleaner a machine is, the less it will disturb both plant and animal life.

The goal for the zero-emissions category is even more specific: make a snowmobile that won’t skew the research being done at Summit Station in Greenland. Scientists there are working to understand the absorption of atmospheric gases by the ice cap, and any emissions from fossil fuels burned at the site can mess up the results of their measurements.

Can we expect to see any of these in the local Sno-Cat dealership? Probably. The SAE seems to expect that the biodiesel and ethanol versions would be pretty cheap to build for retail sale, and that they’d do pretty well on the showroom floor. Hybrids aren’t allowed in this competition for just that reason — the system is too expensive to be worth it for manufacturers or buyers at this point.

Remember when I said diesel prices were lower than gasoline for the first time in years? Remember when I wondered if that would change American diesel buying habits? Well, it has, apparently. Volkswagen and Mercedes-Benz are both reporting increases in sales of their clean-diesel vehicles.

If you’re in the market for a clean diesel car, here are the 50-state diesels available right now, with their starting MSRP:

• Audi Q7, SUV, $50,900
• Mercedes R320 BlueTec, crossover, $49,100
• Mercedes ML320 BlueTec, SUV, $48,600
• Mercedes GL320 BlueTec, SUV, $58,200
• Volkswagen Jetta TDI, sedan, $22,700
• Volkswagen Jetta SportWagen TDI, wagon, $23,870
• Volkwsagen Touareg 2 TDI, SUV, $42,800

Each of these is available from the manufacturer as of today, and are eligible of a federal tax credit of about $1000. Check FuelEconomy.gov for details.

Image of a BMW diesel at the 2009 Detroit Auto Show by Kristen Hall-Geisler.

In the wake of crazy high gas prices last summer and the collapse of the U.S. auto industry over the past nine months or so, all three Detroit car makers shelved plans for new diesel engines slated for pickup trucks. Mercedes-Benz and Volkswagen forged ahead with their clean diesel plans, but sales haven’t been as peppy as they had hoped.

Now, with cheaper diesel and tougher CAFE standards in the future, will U.S. car buyers flock to clean diesels? Or will the stinky stigma remain while we save our pennies for the Tesla S electric sedan or the Chevy Volt, which GM has promised not to abondon despite bankruptcy?

I’ve driven a couple of the clean diesels on sale in the U.S. and had pleasant experiences. You can revisit the Mercedes Blue-Tec and VW Jetta TDI posts for the scoop.

The Formula 3-class car is based on a Lola chassis, but as much of the project as possible was converted to sustainable parts, such as a front spoiler made from potato starch and flax fiber, and a steering wheel derived from carrots.

Here’s how it all breaks down:

• The average fuel economy of the manufacturers’ car and light truck fleets will increase by 5% every year beginning in 2012 and ending in 2016
• Cars must average 39 mpg; light trucks and SUVs must average 30 mpg by 2016
• Overall average will be 35.5; current overall average is 25 mpg
• Will go hand-in-hand with EPA initiative to reduce tailpipe CO2 emissions by 40%

What’s not known is how extended-range electric vehicles like the Chevy Volt or hydrogen cars like the Honda Clarity will figure into the calculations. The feds say they’re working on it.

If you’d like this information in a live, five-minute video starring yours truly, check out Portland’s KGW NewsChannel 8.

Bentley, maker of high-end British cars, announced that all of its Continental models will be 85% recycleable (or 95% recoverable). This in addition to its promise to make its entire lineup FlexFuel compatible by 2012.

The company pointed out that it has also reduced gas, water, and electricity consumption by 25% over the past nine years while the number of cars that roll of the assembly line has grown by ten times in the same period.

It may be a moot point, though, this recyclability, as the company also pointed out that 70% of all Bentleys ever built are still on the road. Longevity and the low miles these cars usually rack up may be the greenest things about any large luxury car. That and the green it takes to buy one in the first place.

Photo by theignitionpoint.co.uk.

Well, anyone can visit the site to learn about Volkswagen’s TDI clean-diesel engines, but it’s aimed at U.S. car buyers, who are still a bit leery of the technology.

The first hurdle in America is cost. In Europe, gasoline carries a heavy tax, making diesel vehicles the cheaper choice in the long run, despite higher initial cost. VW wants to convince us here in the U.S. of the value of fewer fill-ups and great gas mileage — like the nearly 40 mpg I got in the Jetta TDI Sportwagen.

Second is the lingering perception that diesel is stinky and gross. Thanks to strict emissions standards in the U.S. — and stricter standards on the way — diesel is no longer the sooty, smelly mess of a fuel that it used to be. Clean diesel pretty much lives up to its name, and VW rival Mercedes has a tail-pipe treatment in the BlueTec system that cleans the emissions further.

Don’t forget the benefits of biodiesel, especially when it can be made from post-consumer oils. VW has long been on the biodiesel wagon, even allowing customers to use it without violating the warranties on their new diesels.

I was at a meeting with Stefan Jacoby, CEO of VW North America, last week. He said VW is leaning heavily on its clean-diesel and improved gasoline technologies to improve fuel efficiency by as much as 50% in the next few years rather than investing heavily in hybrids and EVs. We’ll find out in the next decade how that strategy plays out for VW, versus the likes of GM’s Chevy Volt extended-range EV or Mitsubishi’s i MiEV.

Image by Kristen Hall-Geisler.

Halvorsen has no intention of busting down garage doors in the middle of the night to take away gasoline cars. The new rules, if enacted, would apply only to new cars sold in 2015 or after. Her idea is to push car companies to make cleaner-running cars, not to wreck the Norwegian economy–even though Norway is the sixth largest oil exporter in the world, according to Reuters. On the other hand, Norway is home to electric-car upstart Think.

A sampling of the veggie-based goodness found in the car:

• Front spoiler and side mirrors made from a potato starch core and flax-fiber shell
• Steering wheel that uses a polymer derived from carrots and other root vegetables
• Seat with a soybean oil foam and recycled polyester fabric
• Plant-based lubricants
• 2-liter turbo engine running on biodiesel
• “Smog-eating” radiators coated with a catalyst that turns ozone into oxygen
• Non-carbon disc brakes and — coming soon — cashew shell brake pads

The American Le Mans Series will revive its Green X Challenge Award with Michelin tires as the sponsor for 2009. The prototype and GT cars that acheives the best performance and fuel efficiency with the fewest emissions will win the award.

Lest you doubters think Michelin is jumping on the green bandwagon, they’ve been rewarding eco-friendly innovations for a while now. Eleven years ago, they created the Challenge Bibendum for clean vehicles, then in 2006 sponsored the Michelin Energy Endurance Challenge at the 24 Hours of Le Mans in France. In 2008, it extended the Energy Endurance Challenge to all European Le Mans-series races.

For its part, ALMS has been making the most inroads into green racing, with hybrid, biofuel, and clean diesels at the starting line. ALMS President and CEO Scott Atherton has applauded President Barack Obama’s green auto initiatives, and sees the track as a proving ground for new consumer technologies.

Racing will probably never be as clean a sport as, say, competitive tree planting, but initiatives like the Michelin’s Green X Challenge can help sate our need for speed and our preference for breathing cleaner air.

Photo of the E85-powered Corvette at the last ALMS race of 2008 courtesy of American Le Mans.