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Introduction to Biodiesel
With today's skyrocketing cost of fuel and growing concern for our environment, today's diesel driver should start taking a long, hard look at biodiesel and its benefits.
What is Biodiesel?
Biodiesel is a biodegradable, clean-burning, non-toxic diesel fuel manufactured from renewable resources (eg: plan or animal oils). Biodiesel can be mixed with petroleum diesel to create biodiesel blends which is the most commonly available method of buying of biodiesel fuel for your car. The blend ratio is designed as Bx where x representations the percentage of biodiesel in the fuel. B5 means 5% biodiesel, B30 means 30% biodiesel. Pure biodiesel, B100, meets the ASTM (American Society for Testing and Materials) D6751 specification.
Benefits
Biodiesel provides numerous benefits, both for your engine and the environment:
- Renewable. Can be made from many oil sources, including vegetable oil, seed oil, yellow grease, tallow, and even used cooking oil.
- Reduces lifecycle greenhouse gas emissions.
- Biodegradable. Biodiesel spills degrade four times faster than petroleum spills.
- Safety: ten times less toxic than table salt and biodegrades as fast as sugar.
- Reduces diesel exhaust emissions. (Makes it easier to pass emissions testing.)
- Can be used in existing diesel engines (manufacturers may recommend specific blend restrictions).
- Can be used with the existing diesel fuel distribution infrastructure.
- Blends completely with petroleum diesel.
- Enhances diesel oxidation catalyst performance.
- Increases fuel lubricity and reduces wear.
- Increased cetane (ignition quality).
- Higher flashpoint than petroleum diesel (eg: less flammable).
Performance and Warranties
One obstacle to wide spread adoption of biodiesel is the fear that biodiesel will reduce the performance of a diesel motor or void its warranty. But biodiesel produced to standards should alleviate these fears:
- High Cetane number (>50 vs. 42 for petroleum diesel) means improved combustion.
- Improved lubricity: B1 (1% biodiesel blend) improves lubricity by up to 65%.
- BTU content: B100 has 5-9% less BTU than petroleum diesel. In a B20 blend, this works out to a 1-2% decrease. Biodiesel blends will contain less BTU but it's a very small difference compared to petroleum diesel.
- Additional filter changes may be required for B20 or higher blends. No additional filter changes are required for a B2 blend.
- Warranties: some auto manufacturers are now releases biodiesel specifications, stating which blends are acceptable under their vehicle warranties.
- The Canadian standard for biodiesel blends states that B1-5 blends are suitable for general public use.
- There have been no biodiesel-related problems with B20 in the U.S.A. over the past 3-4 years when biodiesel met ASTM B100 specifications and with proper fuel management.
Fuel Economy
As mentioned earlier, biodiesel contains less BTU than petroleum diesel. A B20 blend will contain about 1% less energy than petroleum diesel and under real world conditions, you may not even notice the difference. My own experience is that I have noticed a slight drop in power and fuel economy when running B40. With B5, I have noticed no difference at all. In contrast, the energy content of petroleum diesel varies by around 6% between winter and summer fuel and I definitely notice this difference, too.
Diesel engines and fuel systems are very expensive so I can understand people's caution in switching to biodiesel. At the very least, I'd recommend switching to B5. That alone would make a huge difference in spurring the growth of the biodiesel industry. Remember, petroleum is only going to get more expensive in the future. The sooner we embrace the alternative fuels, the sooner we'll have wide spread access to an affordable and environmentally responsible option.
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