Renewable Energy Contractor to Build 189-Megawatt Wind Project in Sunburst, Montana

MINNEAPOLIS, MN (January 9, 2012) - Mortenson Construction was recently

selected by San Francisco-based developer, NaturEner, for the construction
of the Rim Rock Wind Project. Located on nearly 21,000 acres approximately
20 miles north of NaturEner's Glacier I and 2 Wind projects, previously
constructed by Mortenson, Rim Rock will generate189-megawatts of wind power
-- enough energy to power approximately 66,000 homes.

Mortenson is responsible for the design and construction of access roads,
foundations, erection of 126 Acciona 1.5-megawatt turbines, overhead and
underground electrical collection system, (2) 230kV substations, the
generator tie line, and an O&M facility. Construction began late October,
proceeding through the winter months and is expected to be complete in
October, 2012.

Montana's wind attributes are unique to the industry. According to AWEA,
the state is ranked third in the US for potential wind generating capacity,
with more than 944,000 megawatts available for production. This much wind
energy could produce more than 210 times the state's current electricity
needs. Along with Montana's vast wind resources, the siting for this project
was selected because of the ease of access to the property and the
business-friendly development atmosphere in this part of Montana.

"Mortenson is excited and pleased to have been selected by NaturEner to
construct their third project in the area. We are also very excited to
return to the communities where our team members and community members had
such a positive experience constructing the Glacier I and 2 Wind projects,"
said Kevin Deters, a general manager for Mortenson's Renewable Energy
Groups.

Since entering the renewable energy market in 1995, Mortenson Construction
has become a leading builder of wind power facilities in North America,
constructing more than 100 wind projects generating more than 11,000
megawatts of renewable power across the United States and Canada. With 100
percent of Mortenson's business in the power sector coming from renewable
energy, Engineering News-Record ranked Mortenson the 11th largest power
contractor in the U.S. for 2010. In addition to wind power, Mortenson's
Renewable Energy Groups, also construct facilities that generate solar
power, biofuels and hydro-electric power.

About Mortenson Construction
Founded in 1954, Mortenson Construction is a U.S.-based, family-owned
construction company. Ranked as the 19th largest contractor in America,
according to Engineering News-Record, Mortenson provides a complete range of
services, including planning, program management, preconstruction, general
contracting, construction management, design-build, and turn-key
development. Mortenson has offices in Chicago, Denver, Milwaukee,
Minneapolis, Phoenix, and Seattle with international operations in Canada
and China. For more information, please visit
www.mortenson.com/wind.