Feature
Story
Campus Steams Ahead:
Biomass to fuel increased
steam production
Doug Maust, P.E., Principal; Joe Witchger, P.E., Senior Mechanical Engineer; Leigh Harrison, P.E., Principal
Engineer; and Eric Stadsvold, P.E., Industrial Engineering; HGA Architecture Engineering Planning
The University of Minnesota is a ‘Big
Ten’ powerhouse school with 50,000
students on its Minneapolis-St. Paul
campus. Surprising to many, the institution also operates several small campuses in rural parts of the state with just a
few thousand students in each location.
The campus in Morris, Minn., is just
such a place. There, about 2,000 students attend a liberal arts school that is
recognized nationally as among the top
three public liberal arts institutions. Its
setting is western Minnesota, where it is
surrounded by cornfields and farmland
defined by fence rows and narrow
bands of trees and brush filling shallow
gullies that edge the fields.
In 2002 the University accepted a
challenge from the Board of Regents to
develop fuel diversity for its heating
plant while meeting an overarching goal
of developing ‘green’ energy solutions.
After first considering the addition of
wood-chip-fired cogeneration to meet
winter heating loads, the University discovered that a dual-pressure boiler using
local biomass would be a better fit with
its existing plant – and provide better
overall economics than producing electricity in its market. It is currently moving ahead with plans to expand steam
production. This project is funded
through the design phase and is in the
University of Minnesota’s capital request
to the state legislature for 2005 funding.
Predesign efforts by HGA Architecture
Engineering Planning were supported by
Barr Engineering and FVB Energy.
Seeking Green Solutions
The University has taken a role in
the development of green energy by
exploring options that can meet its
technical and operating requirements
and demonstrating energy solutions
that may be useful to others in either
the short or the long term. Toward this
goal, the Morris campus is seeking to
diversify its fuel mix. Volatile natural
gas prices have had a significant impact
on its operating cash reserves as gas
prices have spiked over the last five
years. For Lowell Rasmussen, Associate
Vice Chancellor of the University of
Minnesota-Morris, the challenge was to
identify the best technical solution to
meet campus energy needs.
Using biomass as fuel seemed an
obvious choice because the University
and its West Central Research Station fill
a leadership role in supporting state economic development. Biomass fuel is plentiful in the area and has the potential to
be a source of revenue for the local community. It also provides an opportunity to
reduce campus energy costs.
The effort then turned to finding the
right technologies to implement the plan.
Barr Engineering supported HGA’s effort
regarding material-handling strategies,
and FVB Energy identified boiler technologies, manufacturers and projected
the likely cost range of biomass fuels.
Morris is a small school with a big-school infrastructure. The campus is currently heated from a central steam plant
with three high-pressure boilers. Total
steam generation capacity is 90,000 lb,
distributed at 20 psig. Gas is the primary
boiler fuel, purchased on an interruptible
rate and supplemented with fuel oil
stored on site. Two 600-ton electric centrifugal chillers provide cooling to half of
the space on campus. All electricity is
purchased from the local utility. Campus
energy meters showed a 2003 peak
demand of 2. 5 MW of electricity in summer; 28,000 lb/hr of steam in winter; and
800 tons of cooling from the central
plant. Future remodeling projects and
other campus growth could double the
plant cooling load. Steam demand for
building heating and domestic hot water
is expected to grow very little.
When the University first began
considering how to meet future energy
demand, combined heat and power
(CHP) seemed like a potential solution
since it had received a lot of industry
attention. One of the most common
configurations is a CHP plant generating
electricity locally with a back-pressure
