Lesson: Evaluating Woody Biomass Options for North Carolina’s Electricity Future

As coal-burning power plants seek ways to reduce their carbon dioxide emissions in response to the North Carolina Renewable Energy Portfolio Standard (REPS), some are evaluating the use of woody biomass for the generation of steam, heat, and/or electricity by co-firing with coal.  In this lesson, students will learn about and assess the potential for various types of woody biomass to replace coal with emphasis on North Carolina’s biomass resources and their region specifically. Students assume the role of various stakeholders and participate in a discussion with classmates who represent officials from a local power plant that is seeking to substitute 20% of its coal with woody biomass.  The class will evaluate each available woody biomass option and come to a group consensus about which option, if any, is best from an economic, environmental and public health perspective.

Woody Biomass options to be evaluated in this lesson include:  wood waste/forest residues (chips made from bark, sawdust and other byproducts of milling timber and making paper; logging waste); torrefied wood; and pellets from higher value wood, including roundwood and short-rotation woody crops.

2011 NC Clean Energy Data Book Released!

The NC Sustainable Energy Association (NCSEA), a membership organization representing individuals, businesses, government and non-profits that promote renewable energy and energy efficiency, has compiled the “first-ever” 2011 NC Clean Energy Data Book (pdf).   For each region of the state you can get information about Existing Commercial and Government Energy Efficiency, Potential for Residential Energy Efficiency, Registered Renewable Energy Facilities, Training, Support, and Community College Assets, and Strengths, Weaknesses, Opportunities, and Threats pertaining to renewable energy and energy efficiency.

Links to high resolution maps and images from the book will also be available on the companion website soon.

Renewable Energy Technology Resource Maps for the United States

These Renewable Energy Technology Resource Maps for the United States are available form the National Renewable Energy Laboratory (NREL) as PowerPoint slides: slides are available that show the theoretical potential for renewable energy resources in the US including solar, wind, biomass, and hydropower.

In addition, maps showing the county-level distribution of various biomass resources (crop residues, urban wood waste etc.) are also available.

Debate Topic: Should forests and tree farms count as a renewable energy source?

This question was just considered by the NC Utilities Commission which concluded that yes, whole trees count as a renewable energy resource. The argument from those who oppose such a ruling is that counting whole trees as a renewable fuel would risk the state’s forests to over-harvesting.  The N & O article, State: Whole trees count as renewable fuel, from October 11th, 2010 further discusses this ruling and its potential implications.

Pose this question to your students, divide them into two groups, one group in favor of  whole trees counting as a renewable energy resource and the other group in favor of only wood waste like sawdust and other scraps counting as a renewable energy resource.  Next, ask them to conduct research on the social, economic, and environmental consequences of their  preferred biomass source (whole trees or wood waste) and come prepared to present their side and debate the issue.

The Bioenergy Cycle

This figure from the Oak Ridge National     Laboratory comes with a descriptive text that is useful as one “walks” through the cycle.  Perhaps such a figure could be used to guide your students into creating their own diagram for a local example of bioenergy use?

NC Biomass Roadmap

The North Carolina Biomass Roadmap: Recommendations for Fossil Fuel Displacement through Biomass Utilization is a 2007 report that  contains recommendations that should be carried out by 2017 to increase biomass utilization in North Carolina.  The stated goal is that by 2017, North Carolina should displace 10% of its gasoline and diesel needs and 7% of its power needs using North Carolina bio-based fuels and power.

FOR TEACHERS this report and its appendices represent a resource for NC-specific biomass data and graphics, such as a list of Key Biomass Resources in North Carolina as well as a list of biomass/ biofuel plants in NC and a glossary of key terms.

A four page abridged summary of this report is also available.

A printer friendly Biomass and Bioenergy Glossary is also available from the North Carolina Cooperative Extension.

Southern Alliance for Clean Energy

According to the Southern Alliance for Clean Energy, “the Southeast is the region with greatest growth potential for biopower.”  Check out their webpage on biopower for an overview of this energy source, its benefits and its challenges.

Torrefied Wood Resources

Earlier this year, UNC-Chapel Hill’s co-generation plant announced that it would be coal-free by 2020.  As coal-burning power plants seek ways to reduce their environmental impact, some are turning to the use of biomass (plant material or animal waste) for the generation of steam, heat, and/or electricity.

Earlier this month, the co-generation plant, already one of the most efficient power plants in the nation, co-fired coal with biomass in the form of dried wood pellets and will continue to test wood pellets in addition to torrefied wood – aka biochar – a product that is similar to charcoal.

Here are some useful links to learn more about torrefied wood:

NPR Story: Roasted wood: An alternative to coal energy?

PPT Presentation: Using Torrefied Wood for Electricity, Briquette & Pellet Production

Pdf of a PPT: What is Woody Biomass Energy and What Will it Mean to Forestry in North Carolina?

Suggested Student Reading: Net Benefits of Biomass Power Under Scrutiny

In this June 2010 New York Times article, the advantages and disadvantages of using biomass to generate electricity are discussed in light of the increased scrutiny and opposition this renewable energy source is receiving.  This article should give your students something to think about and to investigate further, especially if your community has a biopower facility or is considering one in the future.

Biomass and Bipower: Fact Sheets

Created for students by the US Department of Energy, The ABC’s of Biopower provides an overview of biopower and describes the four primary classes of BioPower systems: direct-fired, cofired, gasification, and modular.

Also be sure to check out the NC Sustainable Energy Association’s newly designed website and you will find a set of fact sheets with NC specific information on a variety of energy sources, including biomass.