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<br /> TOP PLANTS
<br /> A/S—a Denmark-based company that designs
<br /> 1. Green energy. Four Cummins Power Generation engine gensets utilize the biogas to and builds biogas plants—delivered the an
<br /> generate electricity for the local distribution system. Courtesy:Avant Energy Inc.
<br /> s 1l.. aerobic digestion technology,and Barr Engi-
<br /> . �.�I neering Co.provided engineering support for
<br /> '� -�'
<br /> the project.Biomass loading began in October
<br /> 2013 and operations commenced on schedule
<br /> ' iii ; two months later.
<br /> .� :, 4�i "As is the case with all power plants in a
<br /> -- i °�•. 4► northern climate, especially an extreme cli-
<br /> 7 ' _ °i, ; +' mate like Minnesota,freeze protection is al-
<br /> 1 ••111.... , ,k 1.
<br /> i ( 'y ,,, ways a key priority.We started operation last
<br /> r } ' 1�" # I 1h"' ""1 winter during one of the coldest on record,
<br /> a /' t ' Y but worked to successfully solve what can be
<br /> 114 I it m ' .f fir very pesky freeze problems,"said Benjamin
<br /> r 2 -- ! Simmons,asset manager for HTBE.
<br /> ' ' , 1'�.�
<br /> ,., il— It l
<br /> Enthusiasm for Renewables
<br /> �
<br /> ry - . /�, �� }
<br /> 1; � Minnesota was a logical location for design-
<br /> - ; e; 1 ing and.building HTBE. The state has one
<br /> - of the nation's most aggressive renewable
<br /> energy standards, requiring all utilities to
<br /> • 1 I g enerate at least 25%of their electricity from
<br /> renewable energy sources by 2025.
<br /> cleaners as the product leaves the anaerobic with challenges. For HTBE, the technology Wind is the clear leader in the state's
<br /> digesters. is not particularly familiar to most people in renewable portfolio. It produced 15.7%
<br /> Three large,white,dome-shaped gashold- the U.S.,so its first challenge was educating of the in-state generation in 2013, plac-
<br /> ers—each with a 9,000-cubic-meter capac- the community about the project. ing Minnesota fifth nationally based on
<br /> ity—store the biogas for future use in one Avant wanted local residents to understand production percentages. Given the state's
<br /> of four 2-MW Cummins Power Generation that a facility of this kind is a long-term asset. latitude, many people may be surprised to
<br /> C2000 N6C engine gensets (Figure 1). The HTBE provides important benefits to the lo- learn that Minnesota has annual solar radi-
<br /> onsite gas storage allows dispatch flexibility cal community by collecting and processing ation similar to parts of Florida and Texas,
<br /> to provide on-peak electricity, maximizing local wastes,and creating a renewable source but that potential remains largely untapped.
<br /> 1 revenue potential. The electricity produced of electricity that flows directly into the host In 2013, however, the Minnesota Legisla-
<br /> i is supplied directly to the local distribution community's power system. The company ture passed an omnibus energy bill requir-
<br /> system serving the City of Le Sueur. shared project information with the public ing public utilities to generate 1.5%of their
<br /> I Heat recovery is another important part of early on in the development phase.It hosted energy from the sun, so solar is likely to
<br /> the process. Cooling water from the engine meetings with community leaders,held open gain some ground in the future.
<br /> i water jackets is the main source of reclaimed houses for local residents,and offered regular But agriculture remains one of the state's
<br /> 1 energy.The heated water is fed into an insu- construction updates. largest industries,so a plant that utilizes farm
<br /> lated storage tank and then used in the gas In addition,Avant placed an emphasis on waste is a natural fit.HTBE filled that niche,
<br /> cleaner,feeding module,electric generation, hiring locally. Although the plant only has and its success could lead to development of
<br /> I and in-floor heating systems. seven permanent employees,local contractors, similar plants elsewhere. For utilities man-
<br /> HTBE also recovers energy from the businesses, farmers, and other area residents dated to meet renewable energy standards,
<br /> engine exhaust, which is used by the post- all contributed to construction and startup in biogas's dispatch flexibility offers clear ad-
<br /> digestion system.By utilizing the heat recov- various ways,and continue to support opera- vantages over wind and solar resources.
<br /> ery system,HTBE believes it extracts every tional activities.The plant also uses some sea- "We see strong potential for more BioPower
<br /> ounce of value possible from its process. sonal employees. plants and are pursuing project opportunities
<br /> The heat is supplied to the plant's belt dryer, throughout the country.BioPower is an espe-
<br /> thereby reducing the moisture content of the A Rapid Timeline cially attractive renewable option due to its re-
<br /> solid by-product. This makes it more valu- Minnesota winters offer a multitude of liable and dispatchable nature,but BioPower
<br /> able as a renewable solid fuel for combustion challenges, especially for construction is also more complex than wind or solar and
<br /> , offsite in biomass and coal-fired burners. It companies. Nonetheless, the project broke requires more logistical coordination during
<br /> , is also safe to reuse the separated solids as ground in December 2012 with a one-year development and operations.Areas with large
<br /> ,! a bedding material for livestock in place of goal for completion. amounts of food or agricultural waste and a
<br /> more expensive sawdust and wood shavings. "The aggressive construction schedule for local utility with a renewable appetite make
<br /> Although the plant's 8-MW capacity may the plant was a significant challenge,but we good candidates for BioPower,"said Dillon.
<br /> seem small compared to the average utility worked weekends and long hours. We also As a unique waste solution for rural areas
<br /> power plant,it is one of the largest facilities had good management and strategies in place and a reliable renewable energy resource,
<br /> of its kind.The plant is permitted to process to complete the project in the one year time- HTBE is the worthy recipient of a POWER
<br /> Iup to 45,000 dry tons of waste per year. frame,"Dillon said. Top Plant award.•
<br /> Avant managed the construction, hiring a —Aaron Larson is a POWER associate
<br /> A Community Asset variety of firms to perform mechanical,elec- editor(UPOWERmagazine,
<br /> Developing a power plant of any type comes trical, structural, and building work. Xergi @AaronL_Power).
<br /> December 2014 I POWER www.powermag.com 29
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