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Mechanics Corner: Greening up diesel with biodiesel

Allen Schaeffer Published on 30 September 2013

Diversifying our transportation fuels beyond just petroleum to use homegrown energy sources gets a lot of attention about this time in Washington, and this year is no different.

Natural gas from domestic shale reserves is most in the news now, but there’s also a healthy discussion about the use of more ethanol and biodiesel.

Using something other than petroleum gasoline or diesel to power our tractors or cars isn’t something new at all. August was the 120th anniversary of the invention of the diesel engine – which first ran on peanut oil, not diesel fuel.

Mineral fuel oil (the precursor to today’s petroleum diesel) was the chief competitor to peanut oil at the time, and its prices and supply ultimately waylaid bio-based fuels from taking off to become the primary fuel.

Rudolf Diesel was quoted as saying, “The diesel engine would help considerably in the development of agriculture of the countries which use it.” We’re finally getting around to listening more to that sage advice.

Using more bio-based fuels is in our future for several reasons. Farmers certainly have a stake in the feedstock crops like soybeans, and using biodiesel in your tractors and machines “supports the cause,” and that’s as good a reason as any.

Government is also requiring that more renewable fuels be blended into the fuel supply (aka the renewable fuels mandate: RFS2). A number of states also require biodiesel use: Minnesota (B2), Oregon (B5) and Pennsylvania (B2).

California is near adopting a low-carbon fuel standard later in 2013 that will also require the use of some percentage of renewable diesel fuels in the next few years.

Aside from these state mandates, using biodiesel could cut your fuel costs if the price of diesel and the price of biodiesel are competitive, though this has not typically been the case.

And, if you buy a new farm tractor, some manufacturers pre-fill the tank with a blend of biodiesel fuel as well. So biodiesel is definitely here today and will be tomorrow.

Production of biodiesel increased from about 25 million gallons in the early 2000s to almost 1.1 billion gallons in 2012.

This sounds like a big number until you consider that annual U.S. on-road diesel market is 35 billion to 40 billion gallons. Consistent with projected feedstock availability, the industry has established a goal of producing about 10 percent of the diesel transportation market by 2022.

Just about everyone has a different definition of biodiesel. Biodiesel is produced using a broad variety of feedstocks – soybeans primarily but also canola, safflower, and animal fats and waste vegetable oil from processing plants and restaurants.

This diversity has grown significantly in recent years, and the industry demand for less expensive, reliable sources of fats and oils is stimulating research on next-generation feedstocks such as algae and camelina.

Today’s biodiesel fuels are what are known as a “first-generation” biodiesel – with basic processing at local facilities and simple splash blending with petroleum diesel.

The first-generation biodiesel fuels are typically processed at one of the over 150 local biodiesel plants and then trucked to petroleum diesel marketers or distributors where it is blended into the petroleum diesel supply to the desired blend ratio.

Most biodiesel produced today is sold at blends of 5 percent or less (5 percent biodiesel and 95 percent ultra-low sulfur petroleum diesel), though in the Midwest you can routinely find B20 blends.

This model has served us well but has limitations for the future; the end product can’t be shipped by pipeline, there are long-term storage and stability issues, and batch quantities are prone to quality control problems.

The second-generation biodiesel fuels (typically called renewable diesel fuels) will be produced with diverse feedstocks in larger quantities using different refining processes that mix it right in the petroleum diesel production line at the refinery, with the finished blended product shipped by pipeline to local distributors, more like a “drop in” replacement for petroleum diesel.

While it’s true that any diesel engine can run on biodiesel, there’s more to the story. First and foremost, fuel quality and type determines performance because there is work to be done, so knowing what your equipment and engine manufacturers’ warranties and guidelines are for using biodiesel fuels is an essential first step.

Assuring that you’re attentive to the special storage and handling requirements of biodiesel fuels is very important. This involves checking for water in the storage tanks, initial fuel filter changes on the pump and tractors followed by close monitoring.

Most important is to assure a good-quality consistent biodiesel fuel supplier that adheres to the industry quality spec BQ 9000.

Aside from energy security, biofuels are good for the environment. According to the EPA, biodiesel reduces greenhouse gas emissions by at least 57 percent and up to 86 percent when compared to petroleum diesel – making it one of the most practical and cost-effective ways to immediately address climate change.

In addition, biodiesel sharply reduces major tailpipe pollutants from petroleum diesel, particularly from older diesel vehicles, including highway vehicles and farm tractors and equipment.

Talking future fuels and energy always drums up chatter about “new technology” – things that are “in the lab” or “right around the corner” to solving all our climate and energy problems. Right.

We’ve got the solution today. I’d put a clean-diesel tractor running on biodiesel up against any technology out there any day of the week.  FG


Allen Schaeffer
Executive Director
Diesel Technology Forum