21 April 2005

Organic Material Largest U.S. Source of Renewable Energy

Biofuels, biorefineries promising technologies in development

 

Wood chips and other organic waste material are burned to generate electricity. (©AP Images)

By Cheryl Pellerin
Staff Writer

Energy issues are critical to earth's environment. This article is part of a series of articles on renewable energy, an increasingly promising element in future energy calculations.

Washington – Biomass, defined as any organic material, is one of the most familiar sources of renewable energy. Sawmill waste, forest thinnings, agricultural byproducts, animal and human waste, and the organic components of municipal and industrial waste all qualify as biomass.

Such materials can be burned to generate electricity and, unlike other renewable resources, can be converted directly into liquid fuels for transportation. Even methane fumes from landfills can be used as biomass.

This renewable resource can replace the burning of nonrenewable fuels such as coal, petroleum and natural gas.  Use of biomass energy reduces toxic air emissions, greenhouse gas buildup and dependence on imported oil.

In the United States, biomass has surpassed hydroelectric power (energy captured from flowing water and turned in to electricity) as the largest domestic source of renewable energy, according to the U.S. Department of Energy (DOE).

Biomass processing supplies more than 3 percent of total U.S. energy consumption -- mostly through industrial heat and steam production by the pulp and paper industry, and electrical generation with forest industry byproducts and municipal solid waste.

RESEARCH AND DEVELOPMENT

In 2000, to support the use and development of biomass in the United States, Congress passed the Biomass Research and Development Act.

The legislation created the National Biomass Initiative (NBI), co-chaired by officials from DOE and the U.S. Department of Agriculture, to coordinate technology development and issue joint solicitations for biomass research.

According to NBI Co-Director Don Richardson, other agencies with interests in biomass -- such as the Environmental Protection Agency and the National Science Foundation – also participate in the initiative.

A committee of representatives from industry, academia, nongovernmental organizations and environmental and conservation groups advises the NBI on technical and policy issues.

The NBI collaborates internationally through the International Energy Agency, and every four years sponsors an international biomass conference to compare technologies and approaches to biomass development.

In May 2004, Richardson said, delegates representing several hundred countries attended the Second World Conference and Technology Exhibition on Biomass for Energy and Industry in Rome, held jointly with the 13th European Conference on Biomass for Energy, Industry and Climate Protection.

BIOFUELS

At the DOE National Renewable Energy Laboratory (NREL) in Colorado, researchers are developing and advancing technology for biomass energy applications such as biofuels, biomass power for electricity and bioproducts that could replace petroleum-based fuels.

“The more interesting aspect of biomass is biofuels,” said NREL Director Dan Arvizu. “The fact is that 97 percent of our transportation needs are met by oil and 60 percent of oil is imported into this country. There are very few alternatives.”

 

Corn an other grains are used to make ethanol. (© AP Images)

Biofuels and hydrogen – another potential transportation alternative to fossil fuels -- are the two fastest-growing programs in the DOE mix of energy efficiency and renewable energy programs.

The most common biofuels are ethanol and biodiesel.

Biodiesel is made by combining alcohol (usually methanol, also called wood alcohol) with vegetable oil, animal fat or recycled cooking greases. It can be used as an additive to reduce vehicle emissions (typically by 20 percent) or in its pure form as a renewable fuel for diesel engines.

Ethanol is an alcohol, like that in beer and wine, made by fermenting any biomass that is high in carbohydrates such as starches, sugars or cellulose – the main part of the cell wall in most plants. Ethanol is mainly used as a fuel additive to cut down a vehicle’s emission of carbon monoxide and other pollutants.

Converting sugars in the corn kernels to ethanol “is pretty easy,” Arvizu said. “It’s much more difficult to convert what they call corn stover – the leftovers, stalks and other biomass material that’s not in the fruit of the plant.”

Converting corn stover and kernels to biofuel would produce 10 times the energy as that produced from kernels alone, Arvizu said.

Converting corn stover, he explained, “is not a simple task. You have to unlock the [molecular] structure and that typically takes a lot of energy. We’ve been working on a variety of enzymes that allow you to break down the cellulosic material and we’ve made great progress.”

Today the cost to convert a biofuel source to a U.S. gallon of ethanol is about $2.50, he said, “and we’re quickly moving toward the technology that will allow us to get down to $1.80 and ultimately to $1.07 in the year 2020.”

Unlike gasoline and conventional diesel, biofuels contain oxygen. Adding biofuels to petroleum products lets the fuel burn more completely and reduces air pollution.

When fossil fuels like petroleum burn, they release carbon dioxide that was captured by plants billions of years ago. This release contributes to the buildup of greenhouse gases, which some scientists believe contribute to climate change.

“Any time we can save by being more efficient or by not burning up a barrel of oil and instead burning a biofuel, those are net positives for our economy and for the notion of energy security,” Arvizu said.

BIOREFINERIES

On the DOE side of the NBI, he said, one of the most important approaches to biomass involves biorefineries – facilities that integrate biomass conversion processes and equipment to produce a range of fuels, power and chemicals from biomass.

By producing multiple products, a biorefinery can take advantage of the differences in biomass components and intermediates and maximize the value derived from the biomass resources, or feedstocks.

In Washington, July 20-21, the NBI, along with the European Commission Directorate General for Research and officials from Canada, is sponsoring the First International Biorefinery Workshop.

The invitation-only workshop will provide a forum for a technical review of biorefinery research, evaluate biorefinery markets, foster domestic and international partnerships, and share information on successful biorefinery research and demonstrations.

Richardson said the biorefinery concept is critical to biomass commercialization.

“We’re taking the model of the petrochemical industry,” Richardson said. “We would like to build a facility that doesn’t make a single product like ethanol. It may make ethanol as a low-value product and make a lot of it, but it may also make a lot of other products out of the same biomass stream. We may even produce the facility’s power from biomass.”

For additional information on renewable energy resources, see Washington File articles on solar energy, hydrogen fuel cells, wind power and green power marketing.