The International Energy Agency (IEA) projects that by 2030 global electricity demand will almost double, according to a recent report, The Business of Innovating: Bringing Low-Carbon Solutions to Market.

With the environmental stigma associated with generating power with fossil fuels, whether at large power generation plants or on-site industrial plants, a number of resourceful manufacturers are looking to turn their solid waste streams into clean, renewable biofuel power sources.

Biofuel can be used to generate electricity, heat, or steam needed to operate a manufacturing plant. Increasingly, modern biofuel technology incorporates cogeneration capabilities, also called combined heat and power (CHP), to produce both electricity and heat or steam from one fuel source. Cogeneration is considered especially efficient because it maximizes the energy captured and minimizes the energy released into the environment as hot air or hot water and wasted.

For one particularly energy-intensive industry—pulp and paper manufacturing—biofuel has long been a fuel of choice. Paper manufacturers have used wood lignin (black/spent liquor recovered from the pulping process) as a fuel in recovery boilers since the 1930s, and solid wood residue since the 1960s. The technologies used in such systems are direct-firing, co-firing, gasification, pyrolysis,
and anaerobic digestion.

Many paper manufacturers are thriving producers of bioenergy that they sell to their local utilities. In regions where power costs have been too low, historically, to justify investments in cogeneration, green energy credits have prompted some mills to do so recently. In some cases, the credits render it more profitable for the mills to sell the power they generate on the open market than to
use it themselves.

Lessons Learned from Paper Mills

The efforts that pulp and paper companies have devoted to sourcing biomass at their facilities warrant a closer look to evaluate their level of success. Other industries may glean lessons from their initiatives as well.

Paper manufacturers sourcing biofuel include Verso, Simpson Tacoma Kraft, and MeadWestvaco.

Verso Paper Corp. Verso is a North American producer of coated papers, used primarily in magazines, catalogs, and advertising literature.

On Jan. 9, 2012, the Memphis, Tenn.-based manufacturer announced the completion of a $45 million renewable-energy project at its pulp and paper mill in Quinnesec, Mich.

Design upgrades to the mill’s existing combination boiler, which already has been burning biomass from waste wood sources, will enable it to deliver an additional 28 MW of green energy for mill consumption, bringing to 95 percent the share of electricity it generates from renewable, carbon-neutral, wood-based biofuel. The mill anticipates that the upgrade will reduce carbon emissions by 147,000 metric tons per year.

System upgrades also include a new, energy-efficient turbine generator and a biomass handling system to expand the mill’s capabilities so that it can process residual wood, such as tree tops, limbs, and bark, in keeping with Forest Stewardship Council (FSC) forest sustainability standards.

Verso Vice President of Energy and Technology Mark Daniel said, “In addition to reducing our carbon footprint, [this] will improve boiler combustion and efficiency and will markedly reduce the mill’s reliance on electricity produced from fossil fuels.”

The combined heat and power (CHP) boiler at Simpson Tacoma Kraft generates an average thermal load of 760,000 lbs. per hour of steam. The large pipe shown delivers 875-PSI steam to the turbine, which converts it to 40 MW of electricity. Photo courtesy of Simpson Tacoma Kraft, Tacoma, Wash.

Verso President and CEO Mike Jackson said, “The completion of the Quinnesec renewable energy project is a milestone in the implementation of Verso’s long-term energy strategy. Besides delivering annual energy savings, the project helps Verso deliver on our commitment to increase our use of renewable biofuel.”

Verso’s new CHP boiler system apparently is part of the company’s strategy to create new revenue sources from green energy.

In “New Energy-Related Revenue Streams for the Paper Industry,” an article published in the Summer 2011 issue of Gravure, Daniel was quoted as saying, “We believe the capability to produce and sell wood-based bioenergy to the grid and ultimately to produce and market advanced biofuels and biochemicals will be a critical element in Verso’s future success—and in the success of the
entire U.S. paper industry.”

Bill Cohen, a Verso company spokesperson at the company’s Bucksport, Me., mill, said that the upgrade fits into the company’s business strategy, as outlined in its annual report, not only to reduce energy consumption and its carbon footprint, but also to increase production of green energy from biomass.

A second unit is now under construction at the Bucksport mill, Cohen said.

Simpson Tacoma Kraft Co. The Simpson Tacoma Kraft mill, Tacoma, Wash., which manufactures bleached and unbleached kraft pulp and linerboard, recycles 500 tons of waste paper and boxes every day as part of its fiber mix, turning it into packaging paper.

The company invested approximately $85 million to modify both of its biomass boilers and to install a steam turbine and other equipment needed to cogenerate both steam and electricity. The project went operational in July, 2009.

“The P&P industry has been the largest producer of cogenerated electric power for many years,” said Greg Narum, environmental manager at Simpson Tacoma Kraft. “I believe that most pulp mills in the U.S. cogenerate power.”

The combined heat and power (CHP) boiler at Simpson Tacoma Kraft generates an average thermal load of 825,000 lbs. per hour. The large pipe shown delivers 875 PSI steam to the turbine, generating 40 MW of electricity. Photo courtesy of Simpson Tacoma Kraft, Tacoma, Wash.

The biomass CHP plant generates 55 MW from a combination of wood-based biomass and wood lignin recovered from the wood pulping process. The biomass-based fuels burned generate steam, which spins a turbine and a power generator, making electricity while also providing process steam for the mill operations.

In accordance with a 12-year power purchase agreement (PPA), the Tacoma mill sells the electricity it produces to Portland, Ore.-based Iberdrola Renewables. “The PPA provides an assured, reasonable return on the capital investment by adding renewable power to the company’s portfolio of pulp and paper products,” Narum said. The mill sells more than 25,000 MWh per month, he added.

Jan Johnson, communications director for Iberdrola Renewables, the offtaker for the power, said the company not only purchases the electricity, but also handles the logistics of transmitting roughly 40 MW (enough to power 430,000 homes) to the Sacramento Municipal Utility District (SMUD) via Tacoma Power’s and interstate transmission lines.

Tacoma Power partnered with Simpson to define the infrastructure and power needs to support the cogeneration facility. The utility provides power to Simpson’s operations in Tacoma, and provides transmission service to Iberdrola Renewables for the renewable power it purchases from Simpson.

This is consistent with the trend for utilities that get their power from fossil fuels to look to “green up” their energy portfolios by increasing the number of renewable-energy sources in their mix. The utility companies in 27 states and Washington D.C. have renewable portfolio standards (RPS) requiring them to
source a minimum percentage of their electricity from renewable-energy sources.

MeadWestvaco Corp. MeadWestvaco, Richmond, Va. is serious—$285-million-serious—about providing its Covington, Va., paper mill with a cogeneration boiler that will convert the waste of the logging and papermaking processes into electricity and steam to power the mill.

The new boiler will replace two older,coal-fired units. MeadWestvaco expects to have permits for the project later this year, allowing for a boiler start-up in 2013.

The boiler will use tree bark and other logging byproducts, as well as wastewater residuals from the papermaking process, to produce power.

Scott Openshaw, spokesman for MeadWestvaco, noted that MeadWestvaco’s initiative is driven mainly by a desire to make the plant capable of being self-sufficient, and also to provide savings in plant operations and maintenance.

An additional financial incentive is a $1 million performance-based grant from the Virginia Investment Partnership program, for which the company qualifies.

The installation announcement generated community and labor good will as well.

In a June 28, 2011 Roanoke Times article, Covington City Manager John Doane called the investment “major money,” and added, “The beneficial impact to this community is that it will provide the mill sustainability to its more than 1,000 jobs. It has a positive environmental impact, too.”

Roy Hall, former president of Covington Paperworks Union Local 675, said, “I feel sure that today’s announcement is a welcome sign of MeadWestvaco’s renewed confidence in the men and women who work at the Covington mill.” Hall continued, “The boiler should have an overall positive effect on the environment as well as to position Covington to be more efficient and competitive in the
marketplace.”

Applications for Other Manufacturers

While bioenergy is especially suitable for paper mills, it is likely to have applicability for other manufacturers as well, especially for those that can take advantage of its CHP capabilities.

For the oil industry, alternative energy sources are keenly on their radar screens. Some oil companies continue to research ways to bring renewables on par with conventional fuels. For example, ExxonMobil, the world’s largest oil company, is evaluating algae as an alternative biofuel source.

As testimony to the merits of biofuels as an energy source for industry, Marvin Odum, president of Shell Oil Co., spoke out in favor of biofuel incentives at the U.S. Energy Department 2011 Energy Information Administration (EIA) Energy Conference.

“The international market for biofuels is growing [and] with the right policies in place, it could grow even faster,” Odum said. In his address, he emphasized that government incentives need to be changed to include biofuels and that the U.S. government should provide regulatory certainty to encourage long-term investment.

International energy and transportation company Alstom is keen on developing the next generation of supercritical and ultrasupercritical steam power plants that will increase both fuel and thermodynamic efficiency. The previously mentioned, “Bringing Low-Carbon Solutions to Market” report includes a case study featuring Alstom. The article makes the case for the next generation of steam power plants by comparing the 500-MW power produced by conventional coal-fired steam plants–and emitting 2.72 million metric tons of CO2 per year—with a supercritical plant operating at 44 percent efficiency that would emit 1 million fewer metric tons of CO2 per year.

This metric makes a convincing argument for looking at the big picture of energy generation and concentrating on ways to squeeze out greater efficiencies in boiler plants.

What is biofuel?

Biofuel is derived from the conversion of biomass directly into liquid fuel, as well as from solid biomass. Biomass is any organic material made from plants or animals. According to the U.S. Department of Energy, Energy Efficiency and Renewable Energy, domestic biomass resources include agricultural and forestry residues, and terrestrial and aquatic crops grown solely for energy purposes. The department also considers municipal solid wastes and industrial wastes to be biofuel sources, although paper mills are prohibited from using it in their boilers by federal and state regulations, according to industry insider Greg Narum of Simpson Tacoma Kraft.

Biomass gets its energy from the sun, which is stored in plant leaves, stems, and roots.

Environmental benefits of biomass are that the energy is renewable, and plant matter is relatively abundant in most parts of the world. Although CO2 is released back into the environment when the biomass fuel is burned, among the selling points for using biomass as a fuel versus fossil fuels is that the CO2 released is equal to the amount that the plant adsorbed while it was growing—thus
creating a carbon-neutral effect.

Some estimates are that biomass fuels currently generate about 11,000 MW, or 4 percent of the energy used in the U.S., where the most common form of biomass is wood and wood waste.

American Forestry and Paper Association, www.afandpa.org

Biomass Power Association, 100 Middle St., P.O. Box 9729, Portland, ME 04104, www.usabiomass.org

Forest Stewardship Council U.S., 212 Third Ave. N., Ste. 504, Minneapolis, MN 55401, 612-353-4511, fscus.org

Iberdrola Renewables Inc., 1125 NW Couch St., Ste. 700, Portland, OR 97209, 503-796-7000, www.iberdrolarenewables.us.

MeadWestvaco Corp., 501 S. 5th Street, Richmond, VA 23219, 804-444-1000, www.meadwestvaco.com

Simpson Tacoma Kraft Co. LL, a subsidiary of Simpson Lumber Co. LLC, 801 Portland Ave., Tacoma, WA 98421, 253-572-2150, www.simpson.com

Verso Paper Corp., 6775 Lenox Center Court, Ste. 400, Memphis, TN 38115, 877-837-7606, www.versopaper.com