Energy is perhaps the most significant driving force of our economy, our environment and our quality of life, which makes it a significant issue in land development. One of the major consumers of energy is space conditioning, which includes cooling, heating, and/or humidity control of buildings.

At the Head of the Table
As is consistent with its mission, SLDI is helping to position the land development industry at the forefront of sustainable energy solutions. On July 17th, 2008, SLDI sponsored its first conference on sustainable energy at the Grand River Conference Center in the SLDI headquarters hometown of Dubuque, Iowa.

Dubuque Mayor Roy Buol welcomed participants and opened the conference with a talk about regional sustainability. A full day of informative presentations followed, centered on the following subjects:

• The Biomass Debate - Where does biomass fit in the renewable energy equation, and what other initiatives are taking place and/or should be taking place regionally?
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• Regional Biomass Resources - focusing on urban ­discarded wood resources and biomass from sustainable forests
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• Environmental Considerations
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• Energy System Opportunities
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• Technologies and Business Opportunities
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• Project Development Initiatives and Assistance

Biomass Potential in Practice
The Midwest Combined Heat and Power (CHP) Application Center from the University of Illinois at Chicago presented a study on the potential use of wood biomass as a distributed energy source in Iowa. The study was modeled on the energy demand of a 100-million gallon-per-year ethanol production facility (or an industrial facility with similar energy needs).

The study can be found at: www.erc.uic.edu/PDF/mueller/IowaWasteWoodStudy.pdf. The types of wood waste that were analyzed in the study were:

• Forest Residues – includes logging residues and land clearing for future developments
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• Primary Mill Residues - In the process of converting trees into wood products, waste residues are generated consisting of bark and other fine wood residues
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• Clean Urban Wood Wastes - This category includes the wood components of municipal solid waste such as pallets, yard trimmings, construction wastes, and others

CHP Benefits
CHP systems in commercial, institutional and industrial facilities are beneficial to the facility owners as well as society in general. Benefits to facility owners for deploying CHP systems include reduced energy costs, reduced lifecycle costs, attractive ROI’s, improved reliability, and improved economics for enhancing indoor air quality. These systems help society in many ways, including improved environmental quality, reduced energy consumption and improved homeland security. The CHP systems can be economically attractive for many types of buildings, including, but not limited to the following:

• Office Buildings
• Data Centers
• Educational Facilities
• Hospitals
• Hotels
• Ice Arenas
• Nursing Homes
• Refrigerated Warehouses
• Retail Stores
• Restaurants
• Supermarkets
• Theatres
• Wastewater Treatment Facilities
• Ethanol Plants
• Food Processing Plants
• Livestock Farms

Energy Efficiency
Two-thirds of all the fuel used to make electricity in the U.S. is generally wasted by venting unused thermal energy, from power generation equipment, into the air or discharging into water streams. While there have been impressive energy efficiency gains in other sectors of the economy since the oil price shocks of the 1970’s, the average efficiency of power generation within the U.S. has remained around 33% since 1960. The average overall efficiency of generating electricity and heat by conventional systems is around 51 percent.
Integrated systems for combined heat and power (CHP) significantly increase efficiency of energy utilization, up to 85%, by using thermal energy from power generation equipment for cooling, heating and humidity control systems. These systems are located at or near the facility using power and space conditioning, and can save about 40% of the input energy required by conventional systems. In other words, conventional systems require 65% more energy than the integrated systems, as shown in the above diagram.

The study concluded that wood waste can be an attractive fuel source. While Iowa is not known for an abundance of wood waste, there is potential in Dubuque and other Iowa cities along the Mississippi River. Further, generating capacity would increase – perhaps double – if bordering states’ wood waste is accounted for. SLDI