Biodiesel facts

Biodiesel is made from vegetable oil or animal fat (triglycerides) reacted with methanol or ethanol and a catalyst (lye), yielding biodiesel (fatty acid methyl or ethyl esters) and glycerin as a by-product.

It can be used in any diesel engine without modifications — diesel engines run better and last longer with biodiesel. And it can easily be made from a common waste product: used cooking oil.

Biodiesel is a much cleaner fuel than conventional fossil-fuel petroleum diesel (“dinodiesel”).

• Biodiesel burns up to 75% cleaner than petroleum diesel fuel.
• Biodiesel reduces unburned hydrocarbons (93% less), carbon monoxide (50% less) and particulate matter (30% less) in exhaust fumes, as well as cancer-causing PAH (80% less) and nitrited PAH compounds (90% less). (US Environmental Protection Agency)
• Sulphur dioxide emissions are eliminated (biodiesel contains no sulphur).
• Biodiesel is plant-based and using it adds no extra CO2 greenhouse gas to the atmosphere.
• The ozone-forming (smog) potential of biodiesel emissions is nearly 50% less than petro-diesel emissions.
• Nitrogen oxide (NOx) emissions may increase or decrease with biodiesel but can be reduced to well below petro-diesel fuel levels.
• Biodiesel exhaust is not offensive and doesn’t cause eye irritation (it smells like French fries!).
• Biodiesel is environmentally friendly: it is renewable, and “more biodegradable than sugar and less toxic than table salt” (US National Biodiesel Board, based on US Environmental Protection Agency studies).
• Biodiesel is a much better lubricant than petro-diesel and extends engine life — even a small amount of biodiesel means cleaner emissions and better engine lubrication: 1% biodiesel added to petro-diesel will increase lubricity by 65%.
• Biodiesel can be mixed with petro-diesel in any proportion, with no need for a mixing additive.
• Biodiesel has a higher cetane number than petroleum diesel because of its oxygen content. The higher the cetane number, the more efficient the fuel — the engine starts more easily, runs better and burns cleaner.
• With slight variations depending on the vehicle, performance and fuel economy with biodiesel is the same as with petro-diesel.
• Biodiesel can be used in any diesel engine without modification.

Diesel emissions and cancer

A U.S. Department of Energy study at the University of California at Davis found that using pure biodiesel instead of petro-diesel reduced cancer risks from exhaust emissions by 93.6%.

The study, Chemical and Bioassay Analyses of Diesel and Biodiesel Particulate Matter, 1996, used a 1995 Dodge 3/4 ton pickup truck with a 5.9-litre Cummins B Turbo diesel and tested 100% biodiesel (ethyl ester of rapeseed oil — REE), 100% diesel 2-D low-sulfur fuel and blends of 20% REE and 50% REE with the 2-D diesel fuel. In test after test the study found the highest risk came from 100% diesel fuel, followed by the 20% REE blend, the 50% REE blend and, lowest risk, the pure biodiesel.

“Use of the 100% REE fuel produced the lowest genotoxic (DNA-damaging) activity in the tests. Blended fuels in the non-catalyst-equipped engine produced less emissions than the 100% diesel fuel… The use of the 100% REE fuel resulted in the lowest emissions compared to the REE blends and 100% diesel fuels.

“The highest relative specific mass mutagenic activity collected during either the hot or cold test cycles was the particulate matter collected from the 100% diesel fuel emissions… The lowest relative specific mass mutagenic activity was from the particulate matter collected from emissions of l00% REE fuel.”

NOTE: There’s nothing special about ethyl ester of rapeseed oil biodiesel, other types of biodiesel have similar characteristics.

A U.S. Department of Energy study at the University of California at Davis found that using pure biodiesel instead of petro-diesel reduced cancer risks from exhaust emissions by 93.6%.

The study, Chemical and Bioassay Analyses of Diesel and Biodiesel Particulate Matter, 1996, used a 1995 Dodge 3/4 ton pickup truck with a 5.9-litre Cummins B Turbo diesel and tested 100% biodiesel (ethyl ester of rapeseed oil — REE), 100% diesel 2-D low-sulfur fuel and blends of 20% REE and 50% REE with the 2-D diesel fuel. In test after test the study found the highest risk came from 100% diesel fuel, followed by the 20% REE blend, the 50% REE blend and, lowest risk, the pure biodiesel.

“Use of the 100% REE fuel produced the lowest genotoxic (DNA-damaging) activity in the tests. Blended fuels in the non-catalyst-equipped engine produced less emissions than the 100% diesel fuel… The use of the 100% REE fuel resulted in the lowest emissions compared to the REE blends and 100% diesel fuels.

“The highest relative specific mass mutagenic activity collected during either the hot or cold test cycles was the particulate matter collected from the 100% diesel fuel emissions… The lowest relative specific mass mutagenic activity was from the particulate matter collected from emissions of l00% REE fuel.”

NOTE: There’s nothing special about ethyl ester of rapeseed oil biodiesel, other types of biodiesel have similar characteristics.

Greenhouse gases and global warming

Human-caused global warming is one of the greatest and most urgent challenges facing humanity and life on earth today.

The main culprit is the enormous amount of the potent greenhouse gas carbon dioxide (CO2) released into the atmosphere by the burning of fossil fuels (petroleum, coal, natural gas).

Burning fossil fuels releases more than 6 billion tons of CO2 per year, twice as much as the biosphere can absorb. The excess CO2 is clogging the atmosphere, with the result that less solar heat is reflected away, more heat reaches the earth’s surface, and global temperatures rise.

Using vegetable oils or animal fats as fuel for motor vehicles is in effect running them on solar energy.

All biofuels (including fuel ethanol) depend on the conversion of sunlight to energy (carbohydrates) that takes place in the green leaves of plants.

Plants use water and CO2 from the atmosphere as the raw materials for making carbohydrates. Burning plant (or animal) products in an engine releases the CO2 back into the atmosphere, to be taken up again by other plants. The CO2 is recycled.

Natural mechanisms work to hold the amount of CO2 in the atmosphere at a stable level, maintaining a balance between the CO2 removed from the atmosphere to be “fixed” into growing organic matter and the CO2 released back into the atmosphere when the organic matter burns or dies and decays. The net amount of CO2 in the atmosphere stays the same.

Activities that don’t disrupt this balance are described as carbon-neutral.

In fact, there’s no actual reduction in the amount of CO2 produced when biodiesel is burned instead of petro-diesel — the same amount of CO2 will come out of the exhaust pipe with either fuel.

But the CO2 released by burning biodiesel is part of the current natural cycle, it does not raise the level of CO2 in the atmosphere and does not act as a greenhouse gas. Biodiesel is carbon-neutral and does not increase global warming.

Petro-diesel is not carbon-neutral. Burning petro-diesel unleashes CO2 that has been trapped deep in the earth for millions of years, upsetting the natural balance and raising the level of CO2 in the atmosphere, causing global temperatures to rise. Fossil-fuel CO2 is an active greenhouse gas.

In practice however, not all biodiesel is carbon-neutral. It depends how it’s produced. “Life-cycle” studies of the whole production process from sowing the seed to filling the fuel tank can show a different picture.

Industrialised agricultural production of oil crops like soy or rapeseed depends heavily on fossil-fuel inputs which must be included in the equation, and biodiesel made from these crops is not carbon-neutral. But petro-diesel is a lot worse.

Organic farms don’t use fossil-fuel-based chemical fertilizers and their fossil-fuel inputs are much lower, shrinking to zero when they produce their own fuel and energy on-farm, as a growing number of organic farmers are doing. Biodiesel produced this way is carbon-neutral or very close to it.

Biodiesel made from used cooking oil (WVO — waste vegetable oil) should also qualify. Most WVO ends up in the sewers and landfills where it does no good and doesn’t offset any fossil-fuel use. Converting it to biodiesel is a much better option, a social service. Reduce, reuse, recycle.

The US produces at least 1.1 billion gallons a year of used cooking oil, and most of it goes to waste.

By comparison, US commercial production of biodiesel in 2006 was only 250 million gallons, most of it made from new soy oil, very little from used oil.

Biodiesel homebrewers, small-scale local projects and local coops nearly always use WVO, seldom new oil. This is truly “green” fuel.