We've been on a mad dash since we left California, let me be blunt. So today, we did some good ol' fashioned upkeep. Some folks built out the back of the bus, some folks got us food, and the rest of us were at an internet cafe down the street making plans, making phone calls, answering emails and getting it done. Chores is good.

Right now it's evening-- night has just hit the street with black, and there's a general feeling of satisfaction of a day well done. Done got connections, done email, done sawed and nailed a new coupla bunk beds. Done went and scheduled us fuel.

That last one is my job. I spent half of my day today calling biodiesel retailers all around the Twin Cities area. No, they don't have biodiesel, yes, they only have five percent. No, they've stopped buying B99 this season, yes, oh lordy, they have B20.

I've written before of the trickery of feedstock. To be truly sustainable biodiesel it has to be made from a sustainable vegetable oil source. This includes waste vegetable oil. It does not include GMO soy or Indonesian Palm Oil. Many folks sell a blend of biodiesel/diesel. The feedstock is usually soy, not neccessarily GMO. Growing a domestic fuel that reduces emissions by seventy percent is a huge leap forward from foreign oil. It can also support unsustainable agricultural practices. Some fuel crops can be grown in rotation with other crops and thereby reduce pesticide use. Some are monocrop monsters. Not simple stuff, not ever.

Wherever we land, I start looking for B99 WVO. It can usually be found in cooperatives. The profit margin on biodiesel is practically nonexistent, so folks who make the extra effort to source WVO biodiesel aren't usually in it for the money. The problem is that when you're rolling through town late at night nothing's open but the big truck stops, and if those have biodiesel, it's usually a blend, and the kid of the counter might just be surprised to learn he's selling biodiesel at all (let alone be able to tell you what the feedstock is).

There are folks who make it themselves, but let me be blunt: making a single batch of fuel is at least three days work, not including the time it takes to source the oil and other ingredients. When I toured in an SVO bus in 2004 the homebrewers we met were making just enough fuel for themselves and had no more to spare.

We've had several major fill-ups of amazing, sustainable fuel, starting with a top-off from People's Fuel Co-op in Denver, then tallow feestsock B99 from Cardwell in Salt Lake City, plus WVO B99 from the Denver Biodiesel Coop. We've got some great fuel lined up, from the Prairie Fire Biodiesel Cooperative and from other producers in New Orelans, Austin and beyond. Our friend Matt from Bid For Green is putting us in touch with vendors of high-quality fuel along the way. But in some areas of the country, finding biodiesel could be a competitive sport.

It's 8pm. You're about to enter Wyoming. You've got several hours of driving ahead of you. You must stick to a southerly route. Now: find biodiesel!

Every day is challenege day.