Americans are hearing the term "renewable energy" more and more as we face escalating fossil fuel prices and fuel supply shortages. On the national level, President Bush outlined an Advanced Energy Initiative in his State of the Union Address, with the goal of replacing more than 75 percent of U.S. oil imports from the Middle East by 2025. On the state level, Governor Tim Pawlenty and his administration are strong proponents of reliable, low-cost and environmentally superior energy services. At the city level, St. Paul Mayor Chris Coleman has signed the U.S. Mayors’ Climate Protection Agreement that will require the city to reduce pollution and increase the use of clean, alternative energy.

It is at this level that District Energy St. Paul is leading the way in the use of renewable energy.

District Energy operates the largest hot water district heating system in North America. We currently provide heating service to more than 175 buildings in and around downtown St. Paul (30.5 million square feet) and cooling service to more than 85 buildings (17.7 million square feet). Our primary fuel source is clean, renewable wood waste collected from the Twin Cities metropolitan area. The "green energy" supplied to our customers is produced at an adjacent combined heat and power (CHP) plant.

The CHP plant’s location demonstrates the viability of siting a renewable-energy combined heat and power facility in an urban environment. Managed by a District Energy affiliate, the biomass plant (St. Paul Cogeneration) is the largest wood-fired CHP plant serving a district energy system in the United States. All Minnesotans can be proud that their State Capitol Complex is the first in the nation to be heated and cooled primarily with green energy.

CHP is a proven technology that significantly increases the efficiency of power plants. The CHP process captures more than 50 percent of the waste heat generated by traditional power plants and converts it to steam. Thus, this process can operate at more than twice the efficiency of conventional electricity-only power facilities, resulting in twice the useful end energy for the same raw energy input. Every new unit of electricity produced at a CHP plant using a renewable fuel reduces the amount of power that would be supplied by the burning of fossil fuels at other facilities, significantly reducing air pollution and helping to improve local economic development.

More than 600,000 tons of wood waste – including tree trimmings, industrial residue, and construction and demolition materials – are generated annually in the Twin Cities metro area, resulting in huge storage and disposal problems. The CHP plant turns up to half of this renewable resource into green energy annually, replacing about 60 percent of District Energy’s use of coal. Wood waste that was previously sent to landfills or burned openly is now put to good use, helping the community solve a waste disposal problem and keeping energy dollars in the local economy.

Our use of a renewable energy source to produce heat and electricity has had a positive effect on the environment: carbon dioxide (CO2), sulfur dioxide (SO2) and particulate emissions have been reduced by more than 60 percent. Our goal is to derive approximately 80 percent of our annual energy needs from the CHP plant. This goal, plus offset power production from coal, will reduce CO2 emissions by 280,000 tons per year.

District Energy believes that economic growth and environmental stewardship go hand in hand. For 22 years, our actions have supported our values in the sustainable use of natural resources, reduction of waste, energy conservation and public education. We are proud of our accomplishments, but will continue to search for better, more efficient ways to supply energy to our customers while protecting the environment.

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Anders Rydaker was named president of District Energy St. Paul in 1993. He has more than 30 years of experience in the district energy field. Between 1983 and 1990, Rydaker provided on-site consulting service during construction of St. Paul's hot water district heating distribution system and conversion of a steam heating plant. He also initiated several energy-saving projects for District Energy, including combined heat and power and development of the initial district cooling feasibility studies. A native of Sweden, he introduced district cooling to the Swedish market and successfully developed the innovative cooling system for Stockholm using deep lake water cooling. In 2003, Rydaker was awarded the Prestigious Energy Prize for pioneering district cooling technology in Sweden. Rydaker can be reached at (651) 297-8955 or anders.rydaker@districtenergy.com. Copyright © 2006 Anders J. Rydaker. All rights reserved

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