Sunday, September 23, 2007

Inital Thoughts on the Carbon Balance of SVO

The phrase "emissions reductions" seems to be wholly misconstrued by a disturbingly large portion of biofuel advocates, critics, and average folks with limited information on the issue. Last month, during a forum on plant-based fuels at Burning Man, a representative from one unnamed biodiesel manufacturer stated plainly that "biodiesel is emissions free". When pressed, the speaker admitted uncertainty about the definition of "emissions free", and whether or not biodiesel fits that bill.

I can clear that up right now: anything the burns produces emissions. What the spokesperson was trying to say is that biodiesel may offer emissions reductions over regular diesel fuel. And this is true: biodiesel reduces the emissions of most pollutants by about 50% (see my biodiesel mythbuster for more detail).

That being said, it's always important to qualify statements about emissions reductions with the source of the fuel under discussion. Why? Because NET emissions are different for all of them. Just last Friday, researchers released a new study showing that ethanol made from most feedstocks, and biodiesel made from rapeseed (canola), actually increase net greenhouse gas emissions (via increases in Nitrous oxide - N2O).

That's quite a buildup to the purpose of my post: How does Straight-Vegetable-Oil fare in the battle to obtain the most significant GHG emissions reductions (I'll deal with other pollutants later)? Here are some initial thoughts on the issue.

SVO reduces net greenhouse gas (GHG) emissions (when compared to biodiesel) for the following reasons:

  • SVO is typically a recycled waste product collected from restaurant fryers. GHGs produced in cultivating, harvesting, and processing the feedstock shouldn't be counted since they would occur anyway.
  • SVO requires almost no processing or transport when compared to biodiesel. Oil, even used vegetable oil, must be transported to a biodiesel manufacturing facility, processed, shipped to a distributor, and then shipped to local retailers.
  • Here's an interesting tidbit that warrants further research: According to the Greasecar exhibit at this year's Burning Man, waste oil is typically picked up by chemical companies that ship it to China for processing. There, it's turned into pet food or cosmetic bases and shipped back to the United States. If this is true, using SVO domestically actually circumvents significant CO2 emissions and therefore is carbon negative. You could even call it a carbon sink.

While I can't substantiate this yet, I also don't have any reason to believe it's not true.

The moral of the story is this: any discussion about biodiesel/SVO pros and cons must take into account the specific oil source. The best answer is almost always 'it depends..."

Friday, September 14, 2007

Vegtruck goes to Burning Man

Last week concluded this years Burning Man, which you can read more about [here].
It wasn't difficult to tell which vehicles had been on the playa for 8-days. After a brief rain and several dust storms, everything was plastered white, and I leap-frogged burners all the way back to Oregon.

This year's theme, the Green Man, warranted additional consideration for reducing personal impact. Before leaving Corvallis I was able to fill myauxiliary 36-gallon tank with vegetable oil from a local restaurant (thanks to Enviofuel for topping it off with filtered oil), and also picked up a spare fuel filter for the SVO system (Davco 234). My stock tank was filled with b100, as per usual in the summertime. I figured that at 26 mpg (which is possible when the truck is fully loaded with 388 lbs. of fuel and steel tank - 30 mpg is standard) I would need exactly 36 gallons to make it to Burning Man and back - about 850 miles or so.

My calculations were right on, and I'm happy to report that I used a grand total of less than one gallon of biodiesel on the trip, relying solely on 100% vegetable oil. It went something like this: as I was getting onto the highway in Corvallis, I switched over to the SVO system. I drove through Oregon and into Northern California, stopping for less than 30 minutes per stop (I don't like to let it sit on SVO for too long), and thenswitched back to b100 to camp. I did the same thing on day 2, and the whole way back. My stock tank fuel gauge was pegged slightly below 'F' when I pulled into the driveway in Corvallis.

Total fuel cost for the trip: < $3.30 + $8.64 (Road Tax) = < $11.94


Upon arrival I hurried over to a scheduled biofuel demonstration which turned out to be a friend from Corvallis representing Enviofuel (it's a small world we live in). They were making french fries and talking about SVO systems - always a good time.