The Biodiesel/Ethanol Debate: What's Better for the Environment?

February 22, 2012

No alternative fuel is fully free of resource and environmental impacts, as the biodiesel/ethanol debate highlights. Compare the fuels' pros and cons.

The need for a cleaner burning fuel can lead to a biodiesel/ethanol debate. By comparing the qualities of the two fuels, you can decide which one is best to use from the point of view of the benefit to the environment.

Raw Materials
The materials used to make both biodiesel and bioethanol need to be taken into consideration to determine the effect they have on the environment. While the main ingredient of bioethanol is crops such as corn, biodiesel makes use of vegetable oil. The former requires the use of large amounts of land on which to plant the crops, which are then chopped down to be used. Making use of cellulosic waste can help to redress this balance. For the latter, it is necessary to consider the process involved in making the oil, however, this will be less of a concern where the oil has already been used, as the process will recycle it. Biodiesel requires the use of sodium hydroxide, which can cause damage to the environment if it is not disposed of properly.

Production Process
The process for manufacturing biodiesel is less labor intensive than that for bioethanol, resulting in less energy needing to be used. While biodiesel is produced simply by combining all the necessary components, the pulp that comes from the crops used to make ethanol must be heated. This can result in biodiesel being better for the environment due to the reduced level of energy use needed to produce it. However, it can be argued that the carbon dioxide created by the ethanol production process is negated by the crops used while they are growing, which help to remove carbon dioxide from the environment.

Waste Products
Both biodiesel and bioethanol create waste products as part of their manufacturing process. The glycerine that comes from making biodiesel can be used to make soap or added to a compost heap to be used in planting. This benefits the environment by recycling the waste rather than dumping it. The solid waste from the original meal in ethanol fuel needs to be disposed of, which will often mean it going to landfill, as there is no other use for it.

Although the use of both biodiesel and bioethanol reduce the level of CO2 emissions, they make use of chemicals that result in emissions. Combining biodiesel ingredients with dangerous chemicals such as sodium hydroxide produces gases that disperse into the environment. The process of cooking the pulp during the ethanol production process creates excess heat, which also effects the environment.

The biodegradable nature of biodiesel means that it is easier on the environment in its normal state than ethanol. This is due to the fact that the latter is alcohol, which can prove harmful to the environment if it is not disposed of properly.

The Truth about Biodiesel Emissions

The general consensus is that greenhouse gas emissions are lower with biodiesel than they are with conventional gasoline or diesel. Other research has claimed that some biodiesel, especially biodiesel made with rapeseed oil, actually increases CO2 emissions. What is the reality?

The Environmental Protection Agency has conducted extensive research into biodiesel emissions. In every case, they discovered that biodiesel emits fewer greenhouse gases than petroleum diesel.

The EPA noted that the exact reduction depends on the type of oil used in making the biodiesel. With waste grease, for instance, the reduction over fossil fuel is 86 percent and with soy oil it is 57 percent. These are startling reductions. In all instances, the elements used to make biodiesel are renewable.

Clean Air Act
Biodiesel stands alone among alternative fuels by having satisfied the Clean Air Act's health testing requirements. One of its biggest pluses is that it greatly reduces the amount of unburned hydrocarbons. Along with nitrogen oxide, unburned hydrocarbons are the main causes of smog. Under testing, the amount of unburned hydrocarbons was 50 percent less with biodiesel than with regular diesel.

Biodiesel virtually removes all sulfates and sulfur oxides (the major ingredients of acid rain), making biodiesel emissions much cleaner.

Global Warming
The closed carbon cycle of biodiesel results in vastly reduced emissions. It offers less harm to humans than regular diesel and the small amounts of CO2 that are released into the air can be captured by plants. In time, those plants can be used to make more biodiesel. This has the effect of reducing global warming.

Biodiesel is fully approved as a fuel, including 100 percent biodiesel, which has been classed as an alternative fuel by the Department of Energy and several other agencies. The volume of biodiesel production rose by 1400 percent between 1999 and 2008. This means it's much more widely used now and is often found in commercial vehicles, which can often be the worst polluters.

It also means that the fuel is more widely available as a commercial product. Biodiesel can run in any diesel engine without modifications. The only possible problem is that biodiesel can release existing deposits on fuel tanks walls and in pipes, and these can cause clogs in the engine.

Land Used
The huge increase in the production of biodiesel means that more land has been used for the production of plants that can be pressed for oil. In turn, this means less land used for the cultivation of food. It's something of a trade off, with farmers going for the money offered by biodiesel. It's a balancing act that needs to be worked out in the future. Biodiesel emissions offer a great way of reducing our carbon footprint in the short term, and a good move to alternative fuels.

The truth about biodiesel emissions is that, in spite of one study to the contrary, they're much lower than gasoline and diesel emissions and offer a good way forward.