Sustainability of Biofuels: Future Generations

By Tera Buckley
A generation its traditionally defined as the average length of time between the birth of parents and the birth of their offspring. Considering today's birth rate, a generation is about 30 years.

Biofuels have also been lumped into first-, second- and third-generational categories. We use first-generation biofuels in our fuel tanks today, so do we need to wait another 30 years until we fill up with second-generation biofuels and another 30 years for the third? Luckily, human and technology generations don't exactly correlate. Let's consider where we are with each of these generations.

First-generation biofuels are created largely from feedstocks that have traditionally been used as food. Today's first-generation biofuels (ethanol from corn and biodiesel from vegetable oil and animal fats) have taken a lot of heat in the media as being the culprit behind rising food prices. Although they may contribute to higher food prices, it is a very small effect, and the debate doesn't consider the environmental and energy security benefits of biofuels. Because there are limited quantities of low-cost options for feedstocks, first-generation biofuels have nearly reached their maximum market share in the fuels market.

Second-generation biofuels are made from nonfood feedstocks using advanced technical processes. Cellulosic ethanol is the most developed second-generation biofuel and is produced from the cellulose or cell wall of plant cells. Examples of potential feedstocks for the next generation of biofuels include forest residues (sawdust), industry residues (black liquor from the paper industry), agricultural residues (corn stover), municipal waste and sustainable biomass (jatropha, camelina and switchgrass). Feedstock costs remain high which is often due to processing (shredding, densifying, pulverizing and handling) and transportation, and not necessarily due to growing them. Also, market accessibility and acceptance are hurdles that need to be addressed. Despite these challenges, second-generation biofuels can widen the feedstock options and produce a much greater amount of fuel for the market, with the potential for greater greenhouse gas emission savings compared to first-generation biofuels.

Third-generation biofuels, like second-generation biofuels, are made from nonfood feedstocks, but the resulting fuel is indistinguishable from its petroleum counterparts. These fuels are also known as advanced biofuels or green hydrocarbons. In the future, algae will be a likely feedstock for these fuels. Several technological and economic challenges exist to bring third-generation biofuels to market.

Paving the pathway to third-generation fuels, the Energy & Environmental Research Center at the University of North Dakota developed a process that produces combinations of biofuels, such as propane, gasoline, jet fuel and diesel, that are equivalent to petroleum-derived fuels, enabling direct substitution with existing fuels and providing renewable options across the spectrum of fuel needs. Direct substitution means the biofuels could be used in cars, airplanes and military vehicles without modifications or additional logistical needs. The feedstock-flexible process can use various crop oils, waste greases and algae.

The key challenge for developing the next generations of biofuels is acquiring economical feedstock. Feedstock cost contributes 80 percent to 90 percent of the final fuel price for most processes and is critical to the economic viability of future generations of biofuels. There is likely room in the marketplace for all biofuel generations, with each broadening the feedstock and technology options and improving fuel performance. This article is the second in a series dedicated to helping readers develop informed opinions about biofuels. BIO

Tera Buckley is a marketing research specialist at the EERC in Grand Forks, N.D. Reach her at or (701) 777-5296.