Wood Waste to Energy—An Old Technology with New Benefits for Federal Facilities
November 11, 2003
Wood, the oldest and most common source of fuel for energy production, is receiving renewed interest because of its advantages in reducing costs and environmental impacts as well as its benefits with respect to energy security. This interest is reflected in recent data on energy usage. Biomass recently surpassed hydroelectric as the leading source of renewable energy in the country accounting for more than 50 percent of the nation's renewable energy use (that translates to more than 7,700 megawatts of electricity at thousands of large and small biomass-to-energy plants). The leading contributors to this impressive total are wood waste-to-energy plants. Now, federal facilities can implement their own biomass projects using FEMP's streamlined contract vehicle, the Biomass and Alternative Methane Fuels (BAMF) Super Energy Savings Performance Contract (ESPC).
The benefits of wood-to-energy projects are numerous. Compared to fossil fuels, utilizing wood waste as a fuel produces less nitrogen oxides, less ash, virtually no sulfur emissions, and no net increase in carbon dioxide (because trees remove carbon dioxide from the atmosphere). It also reduces the volume of waste to landfills.
There are huge quantities of wood waste generated each year in the United States and the vast majority of it is unutilized or significantly underutilized. Because of its abundant supply, wood waste offers substantial benefits in energy security. A�domestic alternate fuel source affords protection against interruptions in the supply of other fuels and the large number of wood waste sources also provides protection against fuel price volatility.
Given the age of the industry, it is not surprising that converting wood to energy is a mature and well-established technology. Whether the application is for space heat, process heat, or the production of electricity, no other type of fuel has been used successfully in more types of projects or system designs. There are, in addition, many attractive new developments that could have a large impact on the energy industry. Included among these are small modular gasification systems and the larger biomass gasification combined cycle systems that provide dramatic increases in efficiency.
More typically, the wood is used to produce steam in a boiler using standard stoker technology or newer fluidized bed combustion technology. Energy is currently produced this way in thousands of settings throughout the world using conventional, "off the shelf" equipment. The systems can be designed to produce heat, electricity, or both in combined heat and power systems. Wood biomass systems produce electricity in units ranging in size from 5 kilowatts to 75 megawatts.
Another viable application for wood waste as a fuel is in the co-firing of conventional coal-fired boilers. Here, co-firing refers to the introduction of biomass as a supplementary energy source in high efficiency boilers. In most instances, this practice requires relatively minor modifications to existing systems and can significantly decrease emissions of sulfur dioxide and nitrogen oxide.
Economics of Wood-to-Energy
The heat content of wood waste typically ranges from 8 to 18 million Btu per ton depending primarily on the moisture content. For grid-connected, utility-size energy plants the energy cost per Btu of wood is similar to that of coal. However, for smaller projects (1 to 5 megawatts) it is possible in many locations to secure a supply of wood waste for only the cost of transportation, presenting the supplier with a better option than landfilling. The economics of biomass projects are highly dependent on transportation costs with 50 miles being the furthest that the fuel is typically transported. To avoid price hikes associated with a limited supply, it is better to design biomass systems that do not outsize the local supply and also have several different sources of supply available.
Potential Sources of Wood Waste
Waste wood is generated in tens of thousands of businesses and industries throughout the country. Although many of the sources generate quantities too small to be collected economically, there are estimated to be more than 5,000 facilities that generate significant quantities of wood waste. Today, in the United States, wood waste used in energy systems comes mainly from manufacturing residues, construction/demolition debris, and dedicated energy crops. Manufacturers of wood products generate an enormous amount of residue in the process of making lumber, furniture, pallets, paper, etc. In general, less than 50 percent of the tree ends up in a final product with the balance being waste in some form. Although some of this waste (e.g., the black liquor remainings from making paper) is used exclusively for internal plant energy requirements, in most cases it is either not used or under utilized. This represents a vast untapped resource. Approximately 144 million tons of wood residuals result from the milling process (including logging) each year; 37 million tons come from construction/demolition; and 32 million tons originate from waste wood/yard trimmings. The portion of wood waste that is sent to landfills could otherwise serve as a cost-effective fuel for a biomass energy project.
A resource assessment developed for FEMP by DOE's National Energy Technology Laboratory has identified more than 1,200 large (over 100,000 square feet) federal facilities that are within 50 miles of at least 10 sources of wood waste that could serve as a fuel supply for a biomass project. There are more than 4,700 wood waste sources within 50 miles of these facilities. (The national map below displays the wood waste sources that are within 50 miles of a large federal facility.) Either federal agencies as consumers, or suppliers of wood waste as sellers, can locate potential matches by contacting the staff at the BAMF Program.
Benefits of a Biomass Project Through BAMF Super ESPC
Under the BAMF Super ESPC, agencies can partner with prequalified, competitively selected energy services companies (ESCOs) and use an expedited contracting process to implement their projects quickly, avoiding the uncertainty and delay of depending on appropriated funding. The ESCO arranges financing for project development, equipment, and installation, and the debt is paid back over time from the guaranteed cost savings generated by the project. FEMP's experienced project facilitators can guide the agency through the entire process, providing expert consultation and assistance with technical, contractual, and financial aspects of the project. Benefits that can be expected with implementation of a biomass project through the BAMF contract are:
- Energy cost savings;
- Energy security—Protection against interruptions in the gas and electric grids by having an alternate fuel source;
- Utility cost stabilization—Protection against price volatility;
- Environmental benefits—Wood waste as a fuel compared to fossil fuels produces less nitrogen oxides, less ash and virtually no sulfur emissions. It reduces the volume to landfills. Also in terms of greenhouse gases, there is no net increase in carbon dioxide, because trees remove carbon dioxide from the atmosphere (as opposed to fossil fuels); and
- Meets Federal goals for use of renewable energy and an alternative financing vehicle.
To find out more about the process for using the BAMF Super ESPC to implement a biomass energy project at your facility, contact one of the following: Christopher Abbuehl, BAMF National Program Representative, at 215-656-6995 or Christopher.Abbuehl@ee.doe.gov; Steve Cooke, BAMF Technical Lead, at 304-285-5437 or firstname.lastname@example.org; or Danette Delmastro, FEMP BAMF Team Lead, at 202-586-7632 or email@example.com.