Editor’s note: This is the second part of a five-part series exploring the topic of sustainability. The next part will be about sustainability and its relationship to agriculture and food.

One important concern related to sustainability is where energy should come from.

As there is a limited supply of carbon-emitting fossil fuels, scientists are constantly looking into different areas of research to find new sources of fuel, such as biofuels.

Because of the predominance of biofuels studies at Iowa State, it is important to understand the pros and the cons of alternative fuel sources.

Biofuels are often hailed as an important part of the solution to the energy problem and an eco-friendly way to reduce dependence on foreign oil. More recently, however, biofuels have come under criticism for their effects on the environment. Still, some contend that the possibilities for a bioeconomy are many – and promising.

Dermot Hayes, professor of economics in the college of agriculture and life sciences, was involved in a study, published earlier this year, that focused on the concerns of increased ethanol production. While the federal government’s Energy Act called for the increase, the amount of land cleared for ethanol production could have adverse affects on the environment.

While biorenewable fuels made from plants are the result of a mostly closed carbon cycle – the plants absorb carbon from the atmosphere before they creating carbon-emitting fuel – they do not reduce carbon emissions “in the medium term,” Hayes said.

That means that when farmers across the world convert forest or grasslands to cropland, carbon emissions result. Eventually, because ethanol provides more energy than is needed to produce it, the product and cost analysis show the investment will net a savings in carbon emissions. Unfortunately, it will take years for that to occur.

In the meantime, carbon emissions would actually increase before decreasing.

The land use issue is even more complex when the issue of hunger is taken into account. When land is cleared in one part of the world to make a fuel crop, more land has to be cleared in order to grow food crops, Hayes said.

“When you take a piece of land the size of Iowa cropland, you need to replace it, and other countries will replace it,” Hayes said.

Also related to the issue of hunger is the fact that some foreign countries that are more dependent on corn than Americans are paying more for the crop than they have in the past. Overall, corn prices have risen to approximately $6 a bushel, up from $2.30 a bushel in 2006.

On the other hand, one of the major advantages of ethanol Hayes mentioned is that it has had a positive effect on the economy. Iowa’s economy in particular has been boosted because of the rise in biofuel production.

“If these carbon and hunger issues become more controversial, we might reduce the subsidies on corn ethanol and replace [corn ethanol] with cellulosic ethanol,” Hayes said.

Cellulosic ethanol can be made from the stover, or stalks and leaves, left in the field after the grain is gone.

Oil companies that currently use ethanol are favored by the federal government. If corporations use ethanol, their tax burden is reduced by 51 cents for every gallon that they blend. Hayes said the savings is presumably passed along to the ethanol producers themselves. Hayes said this is technically referred to as a tax credit, but many refer to it as a subsidy.

The cellulosic ethanol Hayes mentioned is of interest to many, but he said some versions have a more environmentally positive effect than others. If cellulosic ethanol comes from grasses, it places constraints on the land.

“Biofuels from corn stover would be as close to a sustainable system as we’re going to get,” Hayes said.

Robert Anex, associate professor of agricultural and biosystems engineering and associate director of Iowa State’s Bioeconomy Institute, said there are many processes and feedstocks that could be tapped into for creating biorenewables. Even animal fat and waste can be used to create diesel fuel, he said.

Anex said the feedstocks of corn and soybeans that are being used to create most biorenewables were an obvious choice since people already grow those commodities. However, he said, corn stover and switchgrass could also be used because he believes the future of biorenewables can be full of other possibilities.

“The future can be very, very different,” Anex said.

He said the current agricultural system has been designed to produce food and feed, and accrue subsidy.

Adding fuel to that system means designing a different agricultural system.

“There are lots of different ways to design agriculture,” Anex said.

Anex said strictly growing corn grain to make biofuels on a large scale is probably not a good idea, because it is hard on the soil and, since it requires a lot of nitrogen, leaves a lot of nitrogen in the water system.

One possibility is using corn stover, as Hayes mentioned, which would not create too great of a change for farmers, nor would it cost very much.

Anex also said the environmental impact that corn leaves can be lessened.

For example, a winter grain could be grown after the corn is harvested which can absorb the leftover nitrogen, allowing significantly less of the chemical to come off the fields.

Anex said if people can eventually buy that crop from the farmers who grow it between seasons, farmers may choose to grow it, which could offset the negative environmental effects of growing corn. A possible grain that could work for this is called triticale, a hybrid between wheat and rye.

“I want to create a biofuel industry that is sustainable,” Anex said.

He said he wants the industry to create significant environmental, social and economic benefits, rather than merely providing another source of fuel.