BioDiesel Benefits

Biodiesel Displaces Imported Petroleum

The fossil fuel energy required to produce biodiesel from soybean oil is only a fraction (31%) of the energy contained in one gallon of the fuel. You get 3.2 units of fuel energy from biodiesel for every unit of fossil energy used to produce the fuel. That estimate includes the energy used in diesel farm equipment and transportation equipment (trucks, locomotives), fossil fuels used to produce fertilizers and pesticides, fossil fuels used to produce steam and electricity, and methanol used in the manufacturing process. Because biodiesel is an energy-efficient fuel, it can extend petroleum supplies and makes for sound state or federal energy policy.

Biodiesel Reduces Emissions
When biodiesel displaces petroleum, it reduces global warming gas emissions such as carbon dioxide (CO2). When plants like soybeans grow they take CO2 from the air to make the stems, roots, leaves, and seeds (soybeans). After the oil is extracted from the soybeans, it is converted into biodiesel and when burned produces CO2 and other emissions, which return to the atmosphere. This cycle does not add to the net CO2 concentration in the air because the next soybean crop will reuse the CO2 in order to grow.

When fossil fuels are burned, however, 100% of the CO2 released adds to the CO2 concentration levels in the air. Because fossil fuels are used to produce biodiesel, the recycling of CO2 with biodiesel is not 100%, but substituting biodiesel for petroleum diesel reduces life-cycle CO2 emissions by 78%. B20 reduces CO2 by 15.66%.3

Biodiesel reduces tailpipe particulate matter (PM), hydrocarbon (HC), and carbon monoxide (CO) emissions from most modern four-stroke CI engines. These benefits occur because the fuel (B100) contains 11% oxygen by weight. The presence of fuel oxygen allows the fuel to burn more completely, so fewer unburned fuel emissions result.

This same phenomenon reduces air toxics, because the air toxics are associated with the unburned or partially burned HC and PM emissions. Testing has shown that PM, HC, and CO reductions are independent of the feedstock used to make biodiesel. The EPA (USA) reviewed 80 biodiesel emission tests on CI engines and has concluded that the benefits are real and predictable over a wide range of biodiesel blends (Figure 1).

In older two-stroke engines, B20 can reduce CO, HC, and PM if the engines do not consume excessive amounts of lube oil. If lube oil consumption is high, PM benefits from B20 use may be less than shown in Figure 1.
In addition, one of the first benefits that people notice when using biodiesel or biodiesel blends is the smell. Using biodiesel can make diesel exhaust smell better; more like cooking odors.

Biodiesel can be used in its pure form (B100) or blended with petroleum diesel. Common blends include B2 (2% biodiesel), B5, and B20. B2 and B5 can be used safely in most diesel engines. However, most vehicle manufacturers do not recommend using blends greater than 5%—using higher blends will void some engine warranties. Check with your owner’s manual or vehicle manufacturer to determine the right blend for your vehicle.

Note: You should never fuel your vehicle with clean or used grease or vegetable oil that has not been converted to biodiesel. It will damage your engine.

BioDiesel Advantages	BioDiesel Disadvantages
Domestically produced from non-petroluem, renewable resources Can be used in most diesel engines, especially newer ones Less air pollutants (other than nitrogen oxides) and greenhouse gases Biodegradable Non-toxic Safer to handle	Use of blends above B5 not yet warrantied by auto makers Lower fuel economy and power (10% lower for B100, 2% for B20) Currently more expensive More nitrogen oxide emissions B100 generally not suitable for use in low temperatures Concerns about B100’s impact on engine durability

.