Burning desire: with high energy costs as a backdrop, entrepreneurs eye biomass as a market worth cultivating.

Downed tree limbs, branches and trunks, whether from storms or from land clearing efforts, can make up a significant portion of the unsorted loads heading into mixed C&D recycling plants.

Whether the practice of burning or distilling this debris and harnessing the energy can be considered recycling or simply an alternative disposal option is often debated.

Advocates and defenders of the practice may not be able to convince anyone that waste-to-energy or biomass efforts are a form of recycling, but, considering current energy markets, they might get a better hearing on biomass' resource conservation merits.

A kilowatt hour of energy derived from solid waste or green waste can certainly preserve a certain amount of coal, fuel oil or natural gas. Determining to what extent the practice can be done affordably and cleanly seems to be the next frontier.

GLOBAL CONCERN

Chopping down forests to provide heat, energy and shelter was a critical part of the evolution of the economies of Europe and North America. Not until after forests were cleared did concentrated efforts to mine coal and drill for petroleum begin to occur.

For the most part, the nations of Europe and North America have urged leaders in other parts of the world to avoid the temptation to similarly de-forest their lands for the purpose of development. But with coal difficult to transport and oil trading at $50 per barrel, this has at times been a tough sell.

The United Nations Food and Agricultural Organization (FAO) has been attempting to offer a way for such nations to take advantage of their forest resources in a sustainable manner.

In a statement released earlier this year, the FAO offered bio-energy derived from agriculture and forestry as "a key element in achieving two of the U.N. Millennium Development Goals: eradicating extreme poverty and hunger and ensuring environmental sustainability."

Establishing such processes could offer an opportunity for advisors, equipment suppliers and plant operators who understand how to process what in North America might be termed "green waste," preparing it as an energy source.

By the FAO's definition, bio-energy is produced from biofuels (solid fuels, biogas, liquid fuels such as bio-ethanol and bio-diesel) and can come from a variety of sources, including crops such as sugar cane and beet, corn and energy grass or from fuel wood, charcoal, agricultural wastes and by-products, forestry residues, livestock manure and other sources.

CLOSER TO HOME

North Americans, for the most part, are able to pay the going global rate for energy, but that does not mean biomass is being ignored on the home front.

Even the FAO, though focused on developing nations, has determined that, "Scenarios developed for the U.S.A. and the EU indicate that short-term targets of up to a 13 percent displacement of petroleum-based fuels with liquid bio-fuels (bio-ethanol and bio-diesel) appear feasible on available cropland."

In the developed nations, growing crops to produce biomass fuel is not the only option. Nations like the United States also produce a bounty of solid waste, a healthy percentage of which could be suitable for processing as biomass fuel.

In several parts of the country, green waste and even clean C&D scrap wood is being used as boiler fuel.

Emissions remain a concern for many, especially when the biomass stream starts to include demolition debris.

A system being championed by Taylor Recycling of Montgomery, N.Y., does not involve burning and, according to its advocates, can address emissions concerns.

The company is a long-time recycler of construction and demolition debris, producing scrap metals, recycled aggregates, clean wood and recyclable gypsum.

In the process that Taylor Recycling has developed, after recovering traditionally recyclable materials, another sorting process can separate out potentially hazardous items, leaving a set of clean materials appropriate for the innovative energy process it hopes to introduce throughout the country.

Instead of burning it, the biomass gasification process that Taylor is going to be deploying literally pours hot sand over ground-up materials that are no bigger than the size of a softball. The sand pours over that surface area, rapidly heats that biomass and converts it to a gas that is substitutable for natural gas.

Another firm looking to establish itself in the biomass markets is Green Energy Resources, Huntington, N.Y. Green Energy hopes to increase the number of "co-firing" plants in the United States. These plants burn wood along with coal, with the wood used to provide additional energy and to neutralize the amount of mercury released from the coal.

Green Energy claims to have more than one-half million tons of biomass inventory at the ready in North America, "accrued from a diverse number of national and local suppliers."

Academics are also interested in the possibilities of biomass. At the University of Minnesota, researchers are using dried corn stalks as experimental biomass fuel for a gasification process that partially combusts the material but does not cause it to fully burn--cutting down on emissions.

KEEPING IT CLEAN

While finding alternative energy sources appeals to most people, proving that biomass plants can operate cleanly may ultimately be the harder sell.

Near Bangor, Maine, a new boiler plant proposed by Georgia Pacific has generated "mixed reviews," according to a local media report.

A public hearing on the biomass boiler drew generally favorable comments from city officials, but some residents felt pollution would be an inevitable by-product of the plant.

An Alton, Maine, resident opposed to the plant fears not only of impure emissions caused by the burning of wood purchased from C&D materials recyclers, but also sought to ensure that the resulting ash was handled and disposed of properly.

C&D materials will be provided by Casella Waste Systems, Rutland, Vt., and a sub-contractor.

As with many forms of recycling, the market will play the starring role in determining whether such ventures are worthwhile. If the money can be spent to adhere to the license and there is still a profit margin for those in the supply chain, then such biomass efforts may indeed pick up a greater share of the nation's energy market, as advocates are hoping.

The author is editor of Construction & Demolition Recycling and can be contacted at [e-mail].