BIOMASS ENERGY


Biomass -- an umbrella term for plant matter that was recently alive -- can be used to make all kinds of energy including heat, electricity and fuel. Research on the environmental and economic effects of biomass energy is ongoing, but the United States currently has more installed biomass power capacity than any other country in the world. In fact, biomass accounts for roughly half of all the renewable energy produced in the United States. Although ethanol from corn kernels has received the lion's share of attention paid to biomass lately, the dominant commercial use of biomass is wood waste, which is burned for heat and power in the lumber, pulp and paper industries.

The U.S. ethanol fuel industry has boomed over the last few years. Initially it took 10 years for the industry to produce a billion gallons per year, and 10 more years to double production to 2 billion gallons per year. In 2007, production increased again to 6.5 billion gallons. This growth is a testament to the will and dedication of responsive growers and foresters, who have sparked capital investment, economic development and job creation in their communities. But it also raises critical questions of sustainability -- to date, the majority of biofuels produced have had unintended effects on the environment, and as a result, it is time to stop making more food-based biofuels.

Wood is a particularly promising source of biomass if it is derived from sustainably managed operations or reclaimed waste products.

The challenge is to ensure that all biofuels, whether traditional or "next-generation," are produced in ways that conserve our natural resources instead of subsuming natural areas, adding to water pollution and contributing to global warming. Fortunately, American farmers now have tremendous opportunities to grow sustainable energy crops, power their own operations with renewable energy and eventually manufacture fuel on a larger commercial basis.

Wood is a particularly promising source of biomass if it is derived from sustainably managed operations or reclaimed waste products. Sustainable forest management requires, for example, the protection of old growth forests and critical wildlife habitats, rather than wholesale conversion to intensively managed, monocultural tree plantations. Tree plantations may look like forests, but they provide only a fraction of the habitat and ecosystem benefits of a diverse natural forest. The waste products best suited for use as biomass are those that would otherwise end up in a landfill, such as construction debris.

Wood can be burned to generate electricity and heat far more cleanly than its fossil fuel counterparts. Lumber and paper companies have burned wood waste for decades, but this chart shows that the practice is now spreading -- and illustrates the massive scale of wood biomass compared with that of ethanol. Communities and businesses can burn wood biomass for electricity, heat and steam.

Ethanol Production from Wood, in Billions of BTUs



Source: Energy Information Administration (DOE 2008) Annual Energy Review -- Renewable Energy. Online: http://www.eia.doe.gov/emeu/aer/renew.html

How Biomass Works

Today's biomass energy comes from annual row crops, such as corn and soybeans, and organic leftovers from forestry and agriculture, such as corn stovers, rice husks, wood waste and pressed sugar cane. Researchers are now developing ways to produce energy from special, fast-growing "energy crops" such as willow and switchgrass. Collectively called biomass , these crops can be treated in different ways to produce electricity or vehicle fuel. Biomass can be:

• Burned in power plants to produce heat or electricity, with fewer harmful emissions than coal.

• Fermented to produce fuels, like ethanol, for cars and trucks.

• Digested by bacteria to create methane gas for powering turbines.

• Heated under special conditions, or "gasified," to break down into a mix of gases that can be burned for electricity or used to make a range of products, from diesel to gasoline to chemicals.

Where It's Used

Most biomass in use today is burned for heat or used to make ethanol, but bioenergy can be generated in many ways. Biomass power plants across the country burn wood and agricultural waste to generate electricity for industries and residents, and more than 100 plants in 31 states burn methane gas collected from landfills. Together these facilities contribute 7,000 megawatts to the national power grid. In the Southeast and Pacific Northwest, the lumber, pulp and paper industries generate 60 percent of the energy they need to run their factories by burning wood waste.

A small but growing number of conventional power plants substitute biomass for a percentage of the coal they normally burn -- a process known as cofiring, which reduces emissions of sulfur dioxide and carbon dioxide. When one medium-sized power plant adds sustainably sourced biomass to its mix, the reduction in its global warming emissions is equivalent to taking 17,000 cars off the road.(1) The process works best when the coal plant is physically close to the source of biomass.

The Importance of Getting Biofuels Right

Amid the growing consensus that we must act now to stop global warming, invest in our economy and secure our energy future, biofuels have been alternately hailed as the solution to all our woes and condemned as a bad idea that might even contribute to global hunger. The reality is that we can cultivate biomass and convert it into fuels in ways that are deeply destructive, or in ways that reap environmental benefits.

When using food crops or any biomass grown on prime arable land, we need to be careful about our impact on the global land and food markets. While prices for these commodities are driven by many factors, including a growing population, changing diets and high energy costs, corn ethanol and soy-based biodiesel do add to the competition for resources, and thus play a role in driving up food prices and speeding the conversion of natural ecosystems such as rainforests. While more research is needed to determine the scale of this role, it is imperative that we invest in practices that reduce these environmental and social impacts so we can transition to alternative biomass sources and biofuel technologies that better address these risks.

At this point, we cannot afford more food-based ethanol and need to move on to the next chapter in the biofuels story.

At a minimum, we need to ensure that biofuels reduce global warming pollution compared to gasoline and diesel over their full life cycles, accounting for emissions impacts from land use changes. Land-impact considerations must include soil erosion and water runoff, soil and water quality, and wildlife habitat. One action that a small but growing number of ethanol refineries have taken to reduce atmospheric impacts is biomass gasification, whereby both heat and electricity generated by a single biomass fuel source drive the fermentation process. Combined with better agricultural practices, this could significantly reduce global warming pollution.

At this point, we cannot afford more food-based ethanol and need to move on to the next chapter in the biofuels story. Spurred by high oil prices, federal and state incentives, and the ethanol boom, researchers are now developing biofuels from the cellulosic (non-edible) parts of various plants. Once commercialized, these technologies will allow us to adopt biofuels far more widely, including fuels that do not compete with food for land. For instance, crop residues and winter cover crops, if managed carefully, could provide hundreds of millions of tons of dry biomass each year. While these technologies are promising, and help to address concerns surrounding food prices and displaced food production, they are not immune to the same land use issues raised by grain-based ethanol. Even cellulosic crops must be managed in a way that protects soil fertility, water quality and wildlife habitat.

These changes have been greatly enabled by the federal renewable fuel standard outlined in the Energy Security and Independence Act of 2007. Calling for 21 billion gallons of "advanced biofuels" -- based on materials other than corn -- by 2022, the act spells out lifecycle greenhouse gas performance standards for biofuels,(2) as well as biomass sourcing safeguards designed to protect our sensitive wildlife habitats, federal forests and most threatened ecosystems, such as native prairies and natural forests.

As both fuel and food prices demonstrate greater volatility, we are entering a new world in both energy and agriculture.

Federal safeguards are a critical first step toward securing sustainable biomass over the long run. If biofuels are going to deliver on their promise to be an environmentally preferable alternative to petroleum-based fuels, they must be produced sustainably. Rigorous international standards for the sustainable management of biofuels will help ensure that a consistent standard is applied throughout the global market, preventing the "export" of unsustainable production methods -- such as tropical deforestation to plant biofuel crops -- to other countries. Multi-stakeholder efforts to develop international standards are well under way (e.g., the Roundtable on Sustainable Biofuels) and hold the best promise for ensuring that biofuels lead us to more secure and sustainable fuel systems.

As both fuel and food prices painfully demonstrate, we are entering a new world in both energy and agriculture. As the focus of biofuel research moves from corn and other food-based crops to better, more diversified options such as agricultural residues and cover crops, farmers are still at the heart of the solution. American farmers will have to embrace new crops, new practices, and new policies that reward performance rather than production.

How Much It Costs

The cost of energy produced from biomass depends on the type of biomass being burned, the type of energy being produced (heat, electricity or fuel), the technology used and the size of the plant. Power plants that burn biomass directly can generate electricity at a cost of 7 to 9 cents per kilowatt-hour.

Direct-Fired Biomass Combustion Technology Characteristics

Performance

Typical Duty Cycle Baseload

Net Plant Capacity (MW) 35

Net Plant Heat Rate (HHV, Btu/kWh) 14,500

Capacity Factor (%) 80

Economics

Total Project Cost ($/kW) $3,000-5,000

Fixed O&M ($/kW-year) $83

Variable O&M ($/kWh) $.011

Fuel Cost ($/MBtu) $0-3

Levelized Cost of Energy (¢/kWh) 6.7-1.5 cents

Applicable Incentives

Open loop $10/MWh PTC, seven-year MACRS*

Closed loop $20/MWh PTC, seven-year MACRS*

Technology Status

Commercial Status Commercial

Installed US Capacity (MW) 7,000

* The Modified Accelerated Cost Recovery System (MACRS) is the current method of accelerated asset depreciation required by the U.S. income tax code.



Source: Black and Veatch, Renewable Energy Transmission Initiative, Phase 1A, table 5-1.

Over time, if the growth of biomass is sustainably managed, burning biomass can result in zero net carbon dioxide emissions, meaning that the carbon dioxide released in the burning can be absorbed right back from the atmosphere by growing more biomass.

Advantages

• Farmers and foresters already produce a great deal of residue. While much of it is needed to protect habitat, soil and nutrient cycles, tens of millions of tons could be safely collected, and even more could be collected in the future with the right management practices. Every year in the United States, roughly 39 million tons of crop residues go unused.(3) Properly harnessed, this waste could produce about 7,500 megawatts of power -- enough for every home in New England.

• Unlike coal, biomass produces no harmful sulfur or mercury emissions and has significantly less nitrogen -- which means less acid rain, smog and other toxic air pollutants.

• Over time, if the deliberate growth of biomass is sustainably managed, burning biomass can result in zero net carbon dioxide emissions, meaning that the carbon dioxide released in the burning can be absorbed right back from the atmosphere by growing more biomass.

• Using biofuels in our cars can potentially produce less global warming pollution than gasoline, and allows us to invest our energy dollars at home rather than in foreign oil.

• Switchgrass, a promising source of biofuel if planted in such a way that it does not replace native habitat, is a native, perennial prairie grass that is easier to grow responsibly than most row crops. It can help reduce erosion and nitrogen runoff, and it increases soil carbon faster when mowed than when standing.

• Many ethanol production plants are owned by farmer-cooperatives, which help preserve the economic vitality of rural communities.

What's around the Corner

• Aggressive action to develop advanced biofuels by 2015 could allow America to produce the equivalent of the same amount of oil by 2050 that we currently import from the Persian Gulf. If at the same time we make our vehicles more efficient and make plug-in hybrids widely available, biofuels could help virtually eliminate our demand for gasoline.

• Flexible-fuel vehicle requirements are being considered at the national level that will prompt manufacturers to equip all new cars and trucks for both gasoline and biofuels within about a decade.

• Improved high-tech "gasification" systems could bring down the cost of biomass energy to 5 cents per kilowatt-hour.

• Farmers will find innovative ways to produce more food and more biomass utilizing sustainable management practices that increase yields, generate useful by-products and improve degraded and marginal soils, while simultaneously protecting critical ecosystems. Researchers are testing the ability of fast-growing, cost-efficient trees such as poplar and eucalyptus, and grasses such as switchgrass and alfalfa, to be harvested as biofuels.

• More power plants will soon burn biomass along with coal to reduce their polluting emissions. Facilities can recover the cost of adopting the new technology within a few years.

Renewable Energy Meets Wildland and Wildlife Conservation

Certain sensitive lands -- such as parks, monuments and wildlife conservation areas -- and ecologically sensitive marine areas are not appropriate for energy development. In some of these places, energy development is prohibited or limited by law or policy, and in others it would be highly controversial. NRDC does not endorse locating energy facilities or transmission lines in such areas. Siting decisions must always be made extremely carefully, with impacts mitigated and operations conducted in an environmentally responsible manner.

For more information on the intersection between clean energy development and wildland and wildlife conservation in the American West, including locations of parks, wildlife refuges and other conservation areas, see this Google Earth-based feature.