u.s. colleges powered by biomass by junsong zhang ...u.s. colleges powered by biomass by junsong...

U.S. Colleges Powered by Biomass Energy

Biomass for energy initiatives are fast-becoming part of

carbon-neutral solutions at many institutions of higher

education in the United States, and provide real-world

examples for student learning and research.

A Summary of Th

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U.S. Colleges Powered by Biomass by Junsong Zhang, Mingming Lu, Sumana Keener, and Joseph Harrell

em • The Magazine for Environmental Managers • A&WMA • April 2016



Many colleges in the United States have been actively implementing various initiatives to reduce their carbon footprint and free themselves from coal. Biomass, such aswoodchips, wood pellets, and cellulosic byproducts, offers institutions of higher learning an alternative to coal, since energy from biomass is considered both renewable and carbon neutral.

The University of Cincinnati (UC), like many other U.S. colleges,has tested biomass use, such as woodchips and paper pellets,and is now considering wood pellets. UC has obtained a permit for burning clean cellulosic fuels after stack tests approximately three years ago demonstrated such fuel usecould meet appropriate standards. UC also collected relevantinformation from other U.S. colleges to learn from peers.

Table 1 provides a summary of biomass power plants amongU.S. universities. Among the 18 power plants we could find,seven are located in the New England Region, six in theWest North Central Region, two in the Mountain Region,one in the Middle Atlantic Region, one in the East NorthCentral Region, and one is located in the South Atlantic Region. Of these, a few cases are presented in detail.

University Biomass Power PlantsUniversity of IowaPre-2003, the University of Iowa consumed approximately25,000–35,000 tons of coal annually for heating and electricity.To help meet an objective of using 40-percent renewable energy by 2020, two solid fuel boilers (one stoker and onecirculating fluid-bed) on the main campus were converted

for biomass co-firing, with projected savings of $670,000 peryear.1 The stoker boiler uses woody biomass and the circulatingfluid-bed boiler utilizes oat hulls and woodchips. From 2003to 2006, 74,527 tons of biomass were consumed, which accounted for approximately 10 percent of the energy generated.

Results from stack tests2 indicated that co-firing 50-percentoat hulls could significantly reduce emissions of fine particulatematter by 90 percent, polycyclic aromatic hydrocarbon (PAH)by 40 percent, and fossil carbon dioxide by 40 percent, ascompared to coal. Furthermore, the University of Iowa plansto include miscanthus, an energy crop readily available in the area.

The University of Iowa’s Oakdale Campus installed a newbiomass boiler to replace a natural gas boiler in 2011. Thenew boiler for woodchips can be used to supply steam andhot water for Oakdale Campus.3 The university also offerseducation and research opportunities for faculty and students

who are interested in working with the biomass boiler. Asmaller gasifier has been planned for research purposes.

University of Minnesota The University of Minnesota uses 9,000 tons of corn stoverannually (i.e., the leaf, husk, and cob remaining in the fieldfollowing the harvest of cereal grain) for gasification to producesyngas. The cost-effective reactor can meet up to 80 percentof campus heating and electricity demands by producing approximately 15,000 lb/hr of 150-psi steam. The wet scrubber downstream removes 95 percent of fine particulatesfrom the flue gas. Since 2010, approximately 677,000 tonsof agricultural residue have been identified within 100 milesof the campus.4

Middlebury CollegeMiddlebury College in Vermont built a new biomass gasificationsystem in 2009 in order to achieve a 40-percent reduction innet carbon emissions. The new gasifier can process 75 tonsof hard woodchips every day to generate 22,000 lb/hr of

The University of Missouri’s boiler usesover 100,000 tons of biomass annually andcan accommodate a variety of biomassfeedstocks, such as clean wood byproducts,corn stover, and biomass crops.



250-psi steam.5 It generates enough energy to replace 50 percent of the previous no.6 fuel oil consumption (2 milliongallons per year) and cut 40 percent of Middlebury’s totalcarbon dioxide output.6

University of MissouriThe University of Missouri started to apply biomass combus-tion in 2013. Projects included the removal of an older coal-fired boiler and the installation of a bubbling fluidized-bedboiler for biomass. The boiler uses over 100,000 tons of biomass annually and can accommodate a variety of biomassfeedstocks, such as clean wood byproducts, corn stover, andbiomass crops. Since 2014, the University of Missouri hasachieved their sustainability goals: 19-percent reduction inenergy use and 52-percent reduction in greenhouse gas emissions.7

Technologies UsedAs shown in Table 1, a variety of technologies and feedstocksare in use: eight university power plants use gasification; ninechoose direct biomass combustion; and one co-fires biomasswith coal.

Gasification Technology Biomass gasification is a two-stage process. The first stage,pyrolysis, is the thermal decomposition of biomass in the ab-sence of oxygen. It produces 75–90 percent volatile gaseoushydrocarbons and non-volatile materials such as biochar.21

The second stage is an oxidation process, where hydrocar-bons and chars react with oxygen to produce syngas, carbondioxide, and methane. Gasifier configurations of fix-bed, flu-idized-bed, or entrained-flow-bed have been reported.22

College Name Biomass Sources Technology Student Attendance A O E

University of Iowa Main Campus1,2 (IA) Oat hulls, Woodchips, Miscanthus Biomass co-firing 32,150 B 2 4

University of Iowa Oakdale Campus3 (IA) Woodchips, Landfill gas Biomass combustion 32,150 B 2 4

University of Minnesota4 (MN) Corn stover, Woodchips Biomass gasification 51,147 W 2 S

Middlebury College5,6 (VT) Woodchips Biomass gasification 2,526 C 2 4 5

University of Missouri7 (MO) Woodchips, Corn stover, Biomass combustion 35,441 B 2 1 Switchgrass, Miscanthus i

Green Mountain College8 (VT) Woodchips Biomass gasification 710 C 2 S

Eastern Illinois University9 (IL) Any biological Material Biomass gasification 8,913 C 2 8

University of Montana10 (MT) Woodchips Biomass gasification 12,922 E 2 1

Mount Wachusett Community College11 (MA) Woodchips Biomass gasification 4,170 B 2 6

Chadron State College12 (NE) Woodchips Biomass gasification 3,000 C 1 5

Northwest Missouri State University13 (MO) Woodchips, Pelletized paper, Biomass combustion 6,485 N W 8 A

Bennington College14 (VT) Woodchips Biomass combustion 755 M 2 8

Colby College15 (ME) Woodchips Biomass gasification 1,825 C 2 9

Colgate University16 (NY) Woodchips Biomass combustion 2,800 N E 7

Longwood University17 (VA) Woodchips Biomass combustion 5,096 N 2 7

Dartmouth College18 (NH) Wood pellets Biomass combustion 6,342 M 2 N

University of Idaho19 (ID) Woodchips Biomass combustion 10,474 M 1 N

Norwich University20 (VT) Woodchips Biomass combustion 3,400 N 2 S

Notes: NA = not available

Table 1: Details of Selective University Biomass Power Plants in the United States.



Biomass CombustionBiomass combustion refers to 100-percent biomass use with-out coal. The reported power cycle efficiency is only 23–25percent, lower than that of coal, but an old coal-fired boilercan be retrofitted for 100-percent biomass burning withoutmajor modifications on the boiler itself.21

Co-firing with Coal According to the International Energy Agency’s Energy Tech-nology Essentials report, although the power cycle efficiencyof biomass combustion is up to 10 percent lower than forcoal at the same capacity, co-firing efficiency (35–45 percent)is higher than that of biomass combustion.23 Meanwhile, co-firing technology can also reduce upgrading costs comparedto gasification, as it requires only minor changes in fuel stor-age and handling.

Combined Heat and Power (CHP)Combined heat and power, also known as cogeneration,refers to electricity generation followed by heat recovery. This process is more efficient than generating heat or poweralone.24 All the institutions using biomass have employed theCHP process to reduce waste heat and lower carbon emissions.

Biomass FeedstockTwo types of biomass have been reported, energy crops andwoody materials from agriculture or industrial byproducts. Amajority of the U.S. institutions have focused on local bio-mass supplies, typically within 100 miles, to reduce trans-portation costs. Energy crops such as switch grass andmiscanthus have a stable feedstock supply, but are still in re-search and development. A larger amount of biomass is

B T S Air Pollution Control Device Operation Began Environmental Benefits

O B 3 Baghouse, Flue-gas desulfurization 2003 40% renewable energy consumption by 2020

W B 3 Baghouse 2011 40% renewable energy consumption by 2020

C B 5 Wet scrubber 2009 Substitute for 80% of fossil fuel usage

W B 2 Cyclone separator, Baghouse 2009 40% reduction in net carbon emissions; 50% biomass consumption

W B 3 Baghouse, Selective catalytic reduction 2013 19% reduction in energy use; 52% reduction S in greenhouse gas emissions

W B 7 Cyclone separator, Baghouse 2010 Substitute for 85% of fossil fuel usage

A B 8 Cyclone separator, Electrostatic precipitator 2011 80% reduction in net emission of greenhouse gas

W B 1 Electrostatic precipitator 2007 10% reduction in greenhouse gas emissions

W B 4 Baghouse, Cyclone separator 2002 682.65 tons of carbon dioxide reduction per year

W B 3 Cyclone separator 1991 50% reduction in energy cost

W B 6 NA Wood: 1982, Paper: 1993, 80–85% renewable energy consumption Animal Waste: 2001

B W B 7 Multi-cyclone separator 2008 85% renewable energy consumption

W B 1 Cyclone separator, Electrostatic precipitator 2012 9,500 tons of carbon reduction; Carbon neutrality by 2015

W B 2 NA Early 1980s 76% renewable energy consumption

W B 5 NA 2011 76% renewable energy consumption

W B 6 Multi-cyclone separator 2008 NA

W B 1 Multi-cyclone separator 1986 NA

W B 3 NA 2013 Substitute for 650,000 gallons of fuel oil

Table 1: Details of Selective University Biomass Power Plants in the United States (continued).



needed than coal due to its lower heating value and, there-fore, space for biomass storage is also an important consider-ation. Additionally, appropriate design modifications on thefeeding system may be required. Proper staff training to operate biomass boilers is essential.

ConclusionBiomass energy use at U.S. colleges not only can provideclean energy, but can also serve as a real-world laboratory for faculty, staff, and students on alternative fuels and theirassociated environmental benefits. em

References1. The University of Iowa Biomass Fuel Project Supporting Materials. See http://www.facilities.uiowa.edu/uem/renewable-energy/biomassfuelproject.pdf (ac-

cessed Jan 8, 2016).2. Al-Naiema, I.; Estillore, A.D.; Mudunkotuwa, I.A.; Grassian, V.H.; Stone, E.A. Impacts of co-firing biomass on emissions of particulate matter to the atmosphere;

Fuel. 2015, 162, 111-120.3. The University of Iowa Biomass Facilities Management. See http://www.facilities.uiowa.edu/uem/renewable-energy/orep.html (accessed Jan 8, 2016).4. University of Minnesota Renewable Energy Initiatives. See http://renewables.morris.umn.edu/biomass/ (accessed Jan 8, 2016).5. Biomass at Middlebury. See http://sites.middlebury.edu/biomass/ (accessed Jan 8, 2016).6. Smith, B. Biomass District Energy Update: Current Trends and Issues in the U.S.; District Energy, Third Quarter, 2011; available online at http://fdcenterprises.com/

BiomassDistrictEnergyUpdateCurrentTrendsandIssuesintheUS_August2011.pdf.7. University of Missouri Energy Management. See http://www.cf.missouri.edu/energy/em_renewable/index.html (accessed Jan 8, 2016).8. Green Mountain College. See http://www.greenmtn.edu/sustainability/sustainability-on-campus/ (accessed Jan 8, 2016).9. Eastern Illinois University Renewable Energy Center. See http://www.eiu.edu/sustainability/ (accessed Jan 8, 2016).10. University of Montana Biomass. See http://www.umt.edu/biomassplant/ (accessed Jan 8, 2016).11. Mount Wachusett Community College. See http://mwcc.edu/sustain/biomass/biomass-conversion-project/ (accessed Jan 8, 2016).12. EREC Biomass Energy Resource Center, Chadron College. See http://www.biomasscenter.org/resource-library/case-studies/campuses/chadron-state-college

(accessed Jan 8, 2016).13. Northwest Missouri State University. See http://www.nwmissouri.edu/aboutus/fuels/about.htm (accessed Jan 8, 2016).14. Biomass Energy and Bennington College. See http://webfac.bennington.edu/vimbruce/files/2012/01/Biomass-report-draft_complete.pdf (accessed Jan 8, 2016).15. Colby College. See http://www.colby.edu/magazine/biomass-plant-models-clean-energy-4/ (accessed Jan 8, 2016).16. Colgate University. See http://colgate.edu/distinctly-colgate/sustainability/ (accessed Jan 8, 2016).17. Longwood University. See http://www.longwood.edu/sustainability/29712.htm (accessed Jan 8, 2016).18. EREC Biomass Energy Resource Center, Dartmouth College. See http://www.biomasscenter.org/resource-library/ case-studies/housing/dartmouth-college’s-

sachem-village (accessed Jan 8, 2016).19. EREC Biomass Energy Resource Center, University of Idaho. See http://www.biomasscenter.org/resource-library/ case-studies/campuses/university-of-idaho

(accessed Jan 8, 2016).20. Norwich University. See http://lifeat.norwich.edu/renovations/biomass/ (accessed Jan 8, 2016).21. International Renewable Energy Agency. Biomass for Power Generation; Volume 1: Power Sector, June 2012; available online at https://www.irena.org/

DocumentDownloads/Publications/RE_Technologies_Cost_Analysis-BIOMASS.pdf (accessed Jan 8, 2016).22. Puig-Arnavat, M.; Bruno, J.C.; Coronas, A. Review and analysis of biomass gasification models; Renewable and Sustainable Energy Reviews 2010, 14 (9),

2841-2851.23. Energy Technology Essentials: Biomass for Power Generation and CHP; International Energy Agency, January 2007; available online at

https://www.iea.org/publications/freepublications/publication/essentials3.pdf (accessed Jan 8, 2016).24. Salomon, M.; Savola, T.; Martin, A.; Fogelholm, C.J.; Fransson, T. Small-scale biomass CHP plants in Sweden and Finland; Renewable and Sustainable Energy

Reviews 2011, 15 (9), 4451-4465.

Junsong Zhang and Mingming Lu are with the Department of Biomedical, Chemical, and Environmental Engineering at the University of Cincinnati, OH. Sumana Keener is with Progress in Energy & the Environment LLC, Cincinnati, OH. Joseph Harrell iswith UC Utilities and Technology Support, Cincinnati, OH. E-mail: [email protected].

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