Is biodiesel sustainable? To American soybean farmers, it obviously is. When asked this question, Johnny Dodson, president of the American Soybean Association and farmer from Halls, Tenn., says, "We continue to develop new varieties, we're increasing our yields with new technology. Soy biodiesel is a renewable, green, environmentally friendly fuel." His colleague on the ASA board, John Hoffman, a farmer from Waterloo, Iowa, says, "I think soybean farmers are a long ways down the road to sustainability." He points to the increase in yields and no-till practices that result in soybeans using less energy for each bushel produced. New varieties are becoming more water efficient and soybeans are a legume that fix nitrogen from the air into the soil, benefitting the crops that follow.

Growing more soybeans from less land using fewer resources is one answer to the question of sustainability, but the concept of sustainability has much broader implications. The renewable fuels standard (RFS2) as revised in the Energy Independence and Security Act of 2007 was passed to create demand to help build the biofuels industries, while incorporating three areas of sustainability. One is that eligible biofuels must come from existing cropland. Second, biofuels must meet targeted greenhouse gas (GHG) reduction goals. For biodiesel, this means a target of 50 percent fewer GHG emissions compared to fossil fuels. Lastly, there is a provision for the U.S. EPA to document water impact, although those findings were not to be incorporated into the rules.

There is a global context as well, with the European Union's movement towards using sustainability criteria for biofuels, and international roundtables that involve multiple stakeholders writing sustainability criteria for palm oil, soy and biofuels. Those voluntary movements are developing certification systems where third parties verify the sustainability principles are being followed. The U.S. soybean and biodiesel exporters may face sustainability criteria down the road.

The biodiesel industry is faced with learning what the new sustainability concept means in practical terms, in order to answer its critics and find ways to improve. The National Biodiesel Board's sustainability director Don Scott has been giving much thought to this as he works on the NBB response to the EPA's proposed rule. He also represents NBB in the Roundtable for Sustainable Biofuels and facilitates the NBB's task force on sustainability. Scott says the biodiesel industry had sustainability in mind when it established a goal of meeting 5 percent of the country's diesel demand with biodiesel by 2015, although sustainability is not explicitly mentioned. "We can produce that much biodiesel with currently available oil supplies, and without upsetting markets and creating indirect effects," he says. This would displace petroleum diesel derived from imported crude, and help reduce GHG emissions. The targeted biomass-based diesel volumes in the RFS are lower than the NBB's 5 percent goal, but would still provide some economic sustainability with a mandated level of use to help keep biodiesel producers going in poor markets until a rebound. "It (biomass-based diesel mandate) was an insurance policy to keep us on track to energy independence," Scott says. "That was the intent of the act, it wasn't sustainability."

The web of interrelated factors make sustainability discussions complex. Scott gives an example of the early discussion for the Roundtable for Sustainable Biofuels when waste-based biofuels were given strong preference over vegetable oils that also are used for food. "On its face, it's good," he admits. "But it neglects the benefits of using low value and under-utilized coproducts, which is essentially the situation we're at with soybean oil." The soybean market is driven by demand for the high protein soybean meal used for feed and food, historically creating large surpluses of soy oil that drag down the market. "By being able to use that coproduct and develop a market, it helps the overall economic stability of everyone," he says. Soybean oil has lost market share in the food sector, which has been picked up by soy biodiesel, helping maintain market stability. Greater market stability helps farmers and crushers working on low margins stay in business, providing protein and oil for food and energy.

Scott offered another example of relationships in agricultural systems when considering sustainability. In its report on water impact of biofuels, the EPA focused on the widespread concern that an increase in corn production to meet ethanol demand would have a negative impact on water quality. "They failed to look at the biodiesel side," he says. "They missed that when farming soybeans in rotation with corn, soy fixes nitrogen in the soil and therefore reduces the nitrogen that needs to be added to the following corn crop. Rotations also reduce weed and insect pressures, reducing the need for pesticides." The GHG and water quality benefits from the soy/corn rotation are not included in the EPA analysis. Scott says, "Any impacts of the EPA regulations that may limit soybeans will affect water quality."

When sustainability begins to be discussed globally, it gets even more complicated. "Anytime you try to look at agriculture at global scale, it gets difficult to mandate what the best practices are," Scott says. "Water use is one example that varies so much from region to region." In some regions where water supplies are tight, irrigation obviously becomes unsustainable for biofuel feedstocks, although the rotational benefits of certain crops may still apply. In other areas though, water supply is not a problem and irrigation is used sparingly at critical times to protect yields. "You add a little bit of water and you improve the yield, and by increasing the yield, this means there is another acre you don't have to farm," Scott says.

There are other dimensions of sustainability. Our economy has been built on energy derived from fossil fuels concentrated in large, underground pools, which are relatively cheap to mine and process. "We're not as good at harnessing solar energy," Scott says. "The better we get at harnessing solar energy, the more sustainable we become. Biodiesel is a good means of harvesting solar power, providing dense energy storage." The biodiesel industry's efficiency in energy conversion continues to improve, he says, from 3.2 units of energy produced for every unit used in production, to as high as 4.5 units in recent analyses. Producing biodiesel takes little water too, he adds, requiring on average only about a half gallon per gallon of fuel produced. "Last year, when we produced the biggest volume of biodiesel ever, using that average, the entire biodiesel industry used as much water as it took to irrigate a couple of golf courses in south Texas," Scott says.

The impacts on land use from rising biofuels production are getting the most attention in today's discussion on sustainability, particularly the inclusion of indirect international land use change projections. Scott says the NBB was comfortable with the RFS2 measure dealing with direct land use change that limits eligible biofuel feedstocks to those produced on existing cropland. The U.S. has not seen a net increase in crop acres since 1959, Scott says. Long term sustainability of the nation's land resource is not threatened by crop production, but by urban sprawl, with an estimated two acres of farmland lost to development every minute. Farm commodities aren't generating enough revenue to compete with other uses, he points out, and when land gets converted to subdivisions or shopping malls, there are much higher GHG emissions, lost habitat and impervious surfaces that upset water cycles.

Sustainability concerns have actually been addressed by U.S. policymakers for a long time, in a network of regulations to protect the quality of natural resources such as water and air. The national farm policy has dealt with land conversion through measures to stop sodbusting and swampbusting for years. The possibility of having to certify biofuel feedstocks as not coming from converted lands for the EPA's RFS2 rule struck many as being unnecessary. Dodson points out that every year when he goes into the Farm Service Agency, USDA's county-level office that administers farm programs, he has to certify his crops. The FSA provides aerial photographs of a farmer's fields to use for measuring acres, photos that also serve to document that no new land conversion has occurred.

Scott adds the industry may want to adopt an approach used by renewable electricity. Since it's impossible to separate the individual electrons produced by wind from those produced by fossil fuels, credits are assigned for renewable production based on the percentage of the total. Possibly a biofuel producer could claim a percentage of sustainable feedstocks based on farmer compliance in a given supply region. USDA offices already track all farmers and their participation in farm programs now. "EPA and USDA need to work together on this," Dodson suggests.

Future Implications
While work done by the NBB has focused on the near-term implications for the industry, discussions of sustainability also involve consideration for the future. Marty Matlock, a professor of ecological engineering and area director of the Center for Agricultural and Rural Sustainability at the University of Arkansas, has focused his attention on the long-term. "Over the next 150 years, we will have to increasingly move towards a biofuel footing in the energy sector," he says. Today's biofuel industry is starting where it can find traction to put in the infrastructure, but its future must incorporate the need to provide food, feed, fiber and fuel for an increasing world population "without one hectare more of land, and without one more drop of water," Matlock tells Biodiesel Magazine. As part of the Keystone Alliance for Sustainable Agriculture, Matlock has evaluated national-scale metrics for land use, water use, energy use, soil loss and climate impact for U.S. corn, soy, cotton and wheat crops over the past two decades." We're getting better," he says. "Ecological services are increasing. Over the past 10 years, we have dramatically increased biodiversity because we have dramatically increased adoption of conservation tillage. Pesticide applications have decreased dramatically across the landscape. Soil health and soil carbon are going up."

Biofuels have the potential to improve agriculture's sustainability by introducing new crops and cropping systems. "The biofuel production landscape in 20 years will be much more complex, integrated and diverse," he says. Opportunities for grass-based biofuels or reforestation efforts with woody biomass converted to biofuels could change the landscape and offer potential for more diverse cropping. U.S. agriculture has seen major changes in each generation, Matlock points out. He can remember as a kid on the farm in Oklahoma when soybeans were a new crop. "They called them Chinese beans then," he says. "Now, it's one of our standard export crops," he says. Canola is another relatively new crop, introduced in northern regions just in the 1980s.

Offsetting that positive potential though are concerns about the loss of what Matlock calls ecosystem services. "More than 60 percent of global ecosystem services upon which we depend for the things we get from nature is in decline-and 30 percent is in dramatic decline," Matlock says. The most familiar of those are water and soil quality issues. "We're also losing disease control-the ability of the biosphere to buffer the landscape from disease," he adds, with diseases expanding at a disturbing rate. One example is the colony collapse disorder seen in honey production. "Those bees are signals of what's happening to the biosphere," he says.

With the prospect that biofuels and farmers raising feedstocks will be facing sustainability litmus tests, Scott encourages people involved in the biodiesel industry to get involved in discussions about sustainability. The complex puzzle of interrelated economic, environmental and social factors that seek to minimize unintended negative impacts requires input from multiple stakeholders. Those who understand biodiesel and agriculture need to explain how things work so their concerns can be balanced with environmental and social concerns.

Matlock advises that any sustainability criteria should ensure short- and long-term prospects for success. "We're not going to be able to put all the pieces of the puzzle together all at once," he says. Policies need to be periodically revisited to look at local, national and global effects. Reiteration needs to be built into the system to avoid allowing policies to get entrenched, he says, "and we need to allow the opportunity to experiment."

Susanne Retka Schill is the assistant editor of Biodiesel Magazine. Reach her at (701) 738-4922 or sretkaschill@bbiinternational.com.