Renewable Energy: Frequently Asked Questions

For the benefit of our readers, we have prepared a series of frequently asked questions about renewable energy - specifically, the types of technologies that are most likely to figure into Alabama's renewable energy future.

Corn-derived ethanol often is described as a nonviable energy source over the long run. Why?

As National Geographic observed in a recent issue, “It’s easy to lose faith in biofuels if corn ethanol is all you know.”

Corn is a clean-burning fuel source that renewable energy specialists readily acknowledge has played — and will continue to play — an important role in advancing America down the path toward energy security. Currently, virtually all of the nation’s ethanol is produced from yellow feed corn. Even so, some experts stress that this role will be only a limited one at best.

In the view of some critics, corn requires vast amounts of fossil fuels in the form of nitrogen fertilizer to grow. They contend that processing corn into ethanol exacts an even greater environmental toll, both in terms of the fossil fuels required for its cultivation and of the carbon dioxide — the principal culprit behind global warming — emitted in the course of its conversion. Indeed, by some estimates, corn production consumes roughly as much fossil fuel in the course of its cultivation and conversion that it yields in ethanol.

Aside from that, Americans consume more than 320 million gallons of gasoline a day, and there currently is not a biofuel crop on the planet that can provide for this volume of fuel consumption. Even under the most ideal conditions, it would take an additional 400 million acres of corn to produce the ethanol required to replace the amount of gasoline consumed annually — basically all of the open land currently available in the United States, including pastureland.

Why is corn-derived ethanol criticized for contributing to world hunger?

Critics of corn-derived ethanol maintain that the growing demand for corn-derived ethanol has played a role in driving up food prices. Consequently, the United States, the world’s largest food donor, has drastically reduced its levels of food purchases for developing nations within the last few years.

The higher food prices not only have reduced American food aid for the world’s poor but also are making it harder for the poorest people to buy food for themselves.

Why not pursue biodiesel instead of corn as a renewable energy source?

Biodiesel, much like corn, has its place within the big picture of renewable energy. In fact, the distillation process required to convert oil into biodiesel actually requires less energy than what is needed to convert corn into ethanol.
Many farmers and entrepreneurs across Alabama and the rest of the nation have begun refining oil derived from soybeans, canola and similar crops to power farm equipment and other types of machinery as an energy saving measure.

Other nations are deriving even more success from biodiesel production. For example, Germany already has emerged as a major biodiesel producer, generating about half a billion gallons of biodiesel a year with oil pressed from canola seeds.

Nevertheless, there are limits to biodiesel, particularly high production costs. Growing demand for biodiesel already has pushed up the costs of feed stocks used in the production of this renewable fuel, rendering it less profitable.

Corn-derived ethanol and biodiesel have been described as “bridge technologies.” What does this mean?

Many energy experts, including Mark Hall, an Alabama Cooperative Extension System renewable energy specialist, believes that the current handful of biofuels may comprise only the first step in what undoubtedly will amount to a much longer and broader path toward energy security. Hall has described these current alternative energy sources as bridge technologies — approaches “that will help us gain a measure of self-sufficiency until more lucrative technologies can be developed.”

Some energy experts stress that there is no magic solution to energy security. What do they mean?

Energy experts foresee a diverse path to energy security involving many different types of renewable energy technologies. There is no single magic bullet.

They stress that even domestic petroleum production will play a role in the U.S. energy future. In addition to corn-derived ethanol and biodiesel, other likely players in this future will include biomass-derived ethanol, geothermal energy and even algae.

What is biomass and why is it often touted as a vast improvement over corn-derived ethanol?

Biomass — derived from wood, switchgrass and agricultural residue, to name only a few sources — offers great potential, particularly to Alabama, as a renewable energy source.

Unlike corn-derived ethanol production, in which only the kernels are extracted to make ethanol, every bit of biomass can be used in energy output. Equally appealing is its smaller carbon footprint. Compared with corn-derived ethanol, growing biomass requires far fewer inputs from fossil-fuel derived products, such as nitrogen fertilizer. Likewise, their conversion into ethanol results in considerably fewer carbon dioxide emissions.

Why is Alabama so well suited to biomass production?

Alabama abounds in many types of biomass sources, particularly forestry biomass and agricultural by-products. Because of its warm climate, it also is especially well suited for growing switchgrass, considered an especially promising biomass source. Because of Alabama’s vast potential, it, along with other southern states, often is described as the Middle East of biomass energy.

If biomass is so promising, why don’t we see more biomass-derived ethanol?

Despite the immense potential of biomass, researchers are still searching for a cost-effective method for breaking down the cellulose in these plants — the tough chains of sugar molecules that comprise the cell walls of these plants.

Despite substantial progress within the last few years, this remains a major challenge. For now, biomass production is limited only to a few pilot plants.

Why is pond scum — algae — often promoted as a potentially lucrative energy source?

Algae are full of lipids — oil — which means that they, potentially, at least, could provide a direct and highly cost-effective source for producing biodiesel.
Because of its moderate climate and plentiful water supplies, Alabama and other southern states are especially well suited to grow algae commercially. Also, in renewable energy terms, the more appealing strains of algae are found in saltwater. Some of these saltwater strains conceivably could be grown in saltwater aquifers in western Alabama.

Source: Mark Hall, Alabama Cooperative Extension System Renewable Energy Specialist

Posted by Jim Langcuster at October 11, 2007 03:57 PM