Biodiesel Resource

Biodiesel provides up to a 90% reduction in most vehicle emissions, including those that cause cancer and contribute to global warming. Biodiesel contains essentially no sulfur or aromatics, and allows for the use of catalytic converters and other emissions-reducing technologies. Biodiesel production yields 96% less hazardous solid wastes, uses 79% less water, and consumes 70-90% less energy than fossil diesel production does. Blends as low as B20 have reduced soot exhaust by 83%. Biodiesel removes deposits in tanks and fuel systems left by petrodiesel. And biodiesel has a nice smell compared to petrodiesel when burned!

Biodiesel Is Healthier For Both the Environment and Your Health

The transportation sector accounts for nearly a third of our nation’s greenhouse gas (GHG) emissions, with projections rising to 36 percent by 2020. While changing behavior has the potential to reduce transportation fuel use and GHG emissions, large and sustainable reductions have never been achieved in this manner in the United States. The increase in wealth and vehicle ownership, combined with a decrease in household size and population density, has resulted in lower vehicle occupancy rates. Devoting our efforts to developing cleaner and more sustainable alternatives for our large transportation infrastructure is necessary if any noticeable progress is to be made.

Biodiesel became the first renewable fuel to complete the Tier I and Tier II health effects testing requirements as authorized by the Clean Air Act Amendments (CAA) of 1990. These tests are the most stringent emissions testing protocols ever required by U.S. EPA for certification of fuels or fuel additives. As a result, the data compiled provides a comprehensive inventory of the environmental and human health affects of biodiesel.

Major findings of the study showed that B100 (100% biodiesel) is 10 times less toxic than table salt, as biodegradable as sugar, and reduces the majority of harmful emissions experienced by petroleum diesel. Summarized below are the results from the emissions comparison portion of the study.

• The overall ozone (smog) forming potential of the speciated hydrocarbon exhaust emissions from biodiesel is 50% lower.
• The exhaust emissions of carbon monoxide (a poisonous gas and a contributing factor in the localized formation of smog and ozone) from biodiesel are 50% lower.
• The exhaust emissions of particulate matter (recognized as a contributing factor in respiratory disease) from biodiesel are 30% lower.
• The exhaust emissions of sulfur oxides and sulfates (major components of acid rain) from biodiesel are completely eliminated.
• The exhaust emissions of hydrocarbons (a contributing factor in the localized formation of smog and ozone) are 95% lower.
• The exhaust emissions of aromatic compounds known as PAH and NPAH compounds (suspected of causing cancer) are substantially reduced for biodiesel compared to diesel. Most PAH compounds were reduced by 75% to 85%. All NPAH compounds were reduced by at least 90%.

Other studies have been completed comparing biodiesel’s environmental and human health effects to petroleum diesel. One of the more comprehensive was a joint study sponsored by the U.S. Departments of Agriculture (USDA) and Energy (DOE). This 3.5-year lifecycle study was released in May of 1998 and compared the total lifecycle costs and benefits of both petroleum diesel and biodiesel. This study revealed:

• Overall life-cycle emissions of carbon dioxide, a major greenhouse gas, from biodiesel are 78% lower than the overall carbon dioxide emissions from fossil diesel.
• Emissions of particulate matter, recognized as a contributing factor in respiratory disease and a human health hazard, were 32% lower than emissions from fossil diesel.
• Overall lifecycle emissions of carbon monoxide from biodiesel are 35% lower than overall carbon monoxide emissions from fossil diesel. In addition, the usage of biodiesel reduces bus tailpipe emissions of carbon monoxide by 46%.
• The amount of particulate matter soot in bus tailpipe exhaust was reduced by 83.6% by using a B20 biodiesel blend.
• The use of B20 results in the elimination of life-cycle emissions of sulfur oxides (a major component of acid rain) from bus tailpipes. The DOE study noted, “Biodiesel can eliminate SOx emissions because it is sulfur free.”
• Methane, one of the most potent greenhouse gases, is reduced by 3% when compared to the overall life-cycle methane emissions from fossil diesel. Though these reductions may appear to be small, they can be significant when estimated on the basis of CO2-equivalent warming potential.
• The overall bus tailpipe emissions of hydrocarbons, which contribute to the localized formation of smog and ozone, are 37% lower for biodiesel than fossil diesel. This property of biodiesel allows for a beneficial effect on urban air pollution.
• The production of biodiesel also results in 79% less wastewater than does the production of fossil diesel.
• Hazardous solid wastes resulting during biodiesel’s lifecycle are 96% less than hazardous solid wastes resulting during fossil diesel’s lifecycle.

You can see from the data above that biodiesel is an overwhelmingly cleaner alternative to petroleum diesel. However, biodiesel has shown small emissions increases of oxides of nitrogen (NOx) when compared to those of petroleum diesel. The study noted “the use of B100 in urban buses increases life cycle emissions of NOx by 13.35%. Blending biodiesel with petroleum proportionately lowers NOx emission. B20 exhibits a 2.67% increase in life cycle emissions of NOx. Most of this increase is directly attributable to increases in tailpipe emissions of NOx. However, some of the prominent researchers in the field have claimed that NOx emissions do NOT increase. Furthermore, various research projects investigating remedies to the NOx problem are showing promising results.

Two techniques that have proven successful at reducing NOx emissions while maintaining the other emissions reductions are retarded fuel injection timing and using current NOx control technologies. The lack of sulfur present in pure (100%) biodiesel allows for the use of existing NOx control technologies that cannot be used with conventional diesel. These two options require modifications that do not allow the engine to be fueled interchangeably with petroleum diesel. However, the new EPA mandate that will take effect in January of 2007 will reduce current sulfur levels in diesel fuel from 500 ppm to 15 ppm, allowing for catalytic converter use with all biodiesel blends. A third option is to add something to the fuel itself. Preliminary data has shown that cetane enhancers and antioxidants could reduce NOx from biodiesel. It’s also worth noting that the addition of hybrid-electric technologies substantially reduces NOx emissions.

NREL released a report in 2003 that modeled fleet emission scenarios for a heavy-duty diesel fleet using a 20% biodiesel blend. Twelve episode days were modeled, five of which were analyzed in detail to evaluate the effects of biodiesel fuel use on urban and regional ozone air quality. Since ozone is regulated by the Environmental Protection Agency, daily maximum 1-hour and 8-hour ozone concentration limits are set. Measured ozone is typically reported to EPA to the nearest 1 part per billion (ppb). It was found that the maximum ozone increase was .26 ppb, which is well below 1 ppb. NREL then concluded that the use of biodiesel is estimated to have no measurable adverse impact on 1-hour or 8-hour ozone attainment (in the area tested). So, an argument can be made that the increase in NOx should not discourage biodiesel use because on a regional level, any adverse impacts would be unnoticeable. Biodiesel pollutes much less than petroleum diesel when you look at the big picture (see graphic below), and it is more than likely that the NOx issue will be resolved in the very near future.

Air pollutants as the percentage of biodiesel blended in diesel fuel increases.