Not all biodiesel is created equal – a critical assessment of biodiesel feedstocks

There is an ongoing debate in the media about biodiesel and sustainability, which in this context equates its long-term effect on the environment. While biodiesel is being touted as part of the solution to US energy independence and a way to slow global climate change by curbing green house gas emissions, a scientific debate has arisen concerning the true sustainability of biodiesel as compared to conventional petroleum fuel in regards to climate change. Factors such as land use and net carbon emissions are being analyzed by these studies, yet important details have often been left out of recent sensationalist media reports. The media is currently oversimplifying complicated issues surrounding very different types of biodiesel.

It has come to light that not all biodiesel is created equal and some types are more sustainable than others. While there are many factors that affect biodiesel’s sustainability, it is the choice of feedstock that is the most crucial. Each feedstock has its own unique ecological footprint and there are many factors that contribute to its sustainability. These include the crop itself, how it’s grown – including fertilizer choices and soil conservation methods, its proximity to the extractor and producer, how the oil is extracted, how it’s transported, how the oil extraction facility is powered, and so on.

The current debate is centered on the virgin feedstocks that currently dominate the biofuels industry. Biodiesel from virgin feedstocks such as soy and palm oil are being seriously reviewed for their long-term environmental impact. Yet not all virgin feedstocks are equal in their sustainability. As for biodiesel made from virgin oils, which is mostly soy in the US, it is important to realize that soybean oil is a by-product of the soy meal and feed industry and was shipped to other markets overseas until recently due to excess supplies. While oil produced as a by-product from an existing industry makes environmental and economic sense, simply growing a crop for biofuels alone often does not.

Early research indicated that biodiesel significantly reduced carbon emissions compared to its petroleum counterpart. Two recent studies indicate that a real danger exists concerning biofuels and global climate change when forest ecosystems are destroyed in order to grow crops for oil production. This is especially detrimental in tropical regions where forests act as enormous carbon sinks, let alone the irreplaceable loss of biodiversity deforestation incurs. Estimates show that it could take 30 to 90 years of biodiesel production before the amount of carbon that would have been absorbed in a tropical forest equals the carbon saved by growing biodiesel crops on the same land. Ninety, or even thirty, years to reach the carbon break-even point means that we are increasing net carbon emissions for the short term by pursuing tropically-grown palm oil biodiesel. However, evidence indicates that biodiesel coming from existing agricultural fields should help alleviate global warming immediately since the biomass on those fields was removed long ago. Also, the plant that grew the oil removed an equivalent or greater amount of carbon dioxide from the atmosphere than burning the fuel releases. Tropical deforestation and palm oil may be the extreme case, but there will be consequences from the use of any energy source and choices must be made wisely based on good science.

However, there is not a debate about biodiesel produced from recycled and waste resources. It is unanimously agreed upon that biodiesel made from recycled resources, such as waste cooking oil, is extremely sustainable and far better for the planet than petroleum and even some other types of biofuels. Biodiesel produced from recycled and waste resources has a clear ecological and sustainability advantage based on today’s technology and feedstock availability.

Blue Ridge Biofuels in Asheville, NC is a sustainable biodiesel company that is committed to making the most sustainable choices available in our biodiesel production. The most important of these choices is the feedstock. Blue Ridge Biofuels was founded on the “waste fryer oil to biodiesel” production model. Our goal has been to produce fuel from sustainable, local sources and to buy recycled oils as long they are obtainable when we need to supplement our own supply.

Blue Ridge Biofuels is a unique entity in that it is vertically integrated in all of the aspects of biodiesel feedstock collection, production, and distribution. We have long believed that having control over the other aspects of the fuel business is integral to a financially viable and sustainable business model. As part of the waste-oil-to-fuel production method, Blue Ridge Biofuels provides a rendering service wherein the company collects waste oil from restaurants and cafeterias in Western North Carolina and processes this into biodiesel fuel at the production facility. Blue Ridge Biofuels collects waste vegetable oil from approximately 175 restaurants and has collected over 120,000 gallons of WVO since 2005 that have been processed into biodiesel.

Feedstocks are not the only aspect to consider when looking at biofuels and sustainability. Energy inputs for processing are often fossil energy sources and thus impact a facilities’ sustainability index. The source of the alcohol (ethanol or methanol) used for biodiesel production generally makes up 10 to 20 percent of the total volume of energy inputs into the process. Most biodiesel producers currently use methanol derived from natural gas, which is a fossil fuel source that contributes to net carbon dioxide emissions and global warming. Blue Ridge Biofuels has installed a special boiler that allows us to cleanly burn our glycerin co-product or waste oils to generate heat for our biodiesel production.

Critical examination of all these processes must occur if we are to truly produce and use fuels that are renewable, sustainable, and green.

Although waste cooking oil is part of the solution to meet US energy needs, it is not produced in enough quantity to displace more than a fraction of our nation’s oil consumption. Therefore, developing feedstocks that have synergistic relationships with other agricultural products and industries ultimately makes the most since for both economic and environmental reasons. One example of a biodiesel crop’s synergistic relationship is growing canola as a winter cover crop and harvesting the oil seed before tilling the stocks into the soil for spring planting of food crops.

Soybeans and other common feedstocks are “gateway” feedstocks that are currently available and will ultimately open the door for new markets, research, development, and the commercialization of smarter and more sustainable feedstocks. Soy may be an easy fit for the current national level of biodiesel production, but better options must be pursued if the biodiesel industry is to grow and become truly sustainable. But the truth is there simply isn’t enough crop land available to displace the current level of petroleum diesel consumption in the US with biodiesel based on agriculturally-grown feedstocks. In the case of biodiesel, it appears that algae could be the leading contender for large-scale production and sustainability.

Early research indicates that algae could grow up to 500 times more oil feedstock annually for biodiesel production than oil derived from soybeans on a per acre basis. Constructed algae systems can also be used to treat domestic and industrial waste water streams found in every city across the US. These waste water treatment facilities currently rely on a bacteria process but they could be converted to algae systems as upgrades are necessary for aging treatment facilities. Additionally, technology has been developed to grow algae in the smoke stacks of coal-fired power plants for the purpose of sequestering carbon and reducing emissions. This type of algae production for biodiesel seems like a perfect fit to reduce the impact of burning coal for grid electrical energy.Just as future energy will have to come from diverse sources in the future, so should biodiesel feedstocks, and a diverse portfolio of agricultural products for both fuel and other resources is a plausible approach. It is likely that all feedstocks will find their niche in the biofuels industry as long as they are balanced in that they provide value in the form of other products. As is becomes evident that sustainability is a diverse framework of solutions that includes conservation, energy efficiency, public transportation, changes in lifestyle and energy consumption, biodiesel producers will realize that sustainability is an incredible profit margin for future generations.

Written by Brian Winslett, founding partner at Blue Ridge Biofuels

Melita Kyriakou, CFO and partner at Blue Ridge Biofuels, contributed to this article

Abbreviated version published in Biodiesel Magazine June 2008