A Unique Renewable Energy System...
Nebraska Innovation Campus Using Unique Financial Tool to Build Heating/Cooling System
Using a unique renewable energy system, University of Nebraska-Lincoln students and Lincoln residents help provide energy to heat and cool Nebraska Innovation Campus when they shower and flush. The Centralized Renewable Energy System on the Innovation Campus warms and cools buildings by exchanging heat from treated wastewater discharged from a city facility next to the research park.
Innovation Campus is adjacent to the Theresa Street Wastewater Facility, which serves 70 percent of Lincoln, including nearly all of University. The facility releases treated effluent into Salt Creek, which runs along the north side of the campus. The designers of Innovation Campus worked with city officials and state environmental officials to safely utilize the wastewater stream without harming Salt Creek.
Unique Financing Used
The $12 million Centralized Renewable Energy System is being financed with Qualified Energy Conservation Bonds from both the city of Lincoln and the Nebraska Energy Office. The bonds were authorized by Congress in the 2008 Energy Improvement and Extension Act. The original legislation authorized just $800 million of QECBs nationwide. In 2009, Congress increased to $3.2 billion the funding for states, territories, large local governments, and tribal governments to issue QECBs to finance renewable energy and energy efficiency projects. The total allocation was divided among the state and territorial issuers according to population. Nebraska was allocated $18.502 million.
Qualified Energy Conservation Bonds may only be issued for qualified purposes as defined in the U.S. Internal Revenue Code such as reduce energy consumption in publicly owned buildings by at least 20%, implement green community programs, rural development, certain renewable energy facilities and mass commuting projects.
As of February 2014, all but about $300,000 of Nebraska's allocation had been committed to projects. More information about Qualified Energy Conservation Bonds is at the Energy Office's website.
Unique Renewable Energy System
The idea to use wastewater for heating and cooling originated in early stages of campus planning. Alvine Engineering, an Omaha firm involved with developing the campus master plan, had worked on a similar concept for a Chicago office building that uses Chicago River water for its air conditioning cooling towers.
Tetrad Property Group, the company developing phase I of the campus, worked with Olsson Associates to design the system. Designers said there are less than a dozen similar projects in the United States, with none quite like Innovation Campus' system.
The system serves as a geothermal ground loop that uses wastewater, instead of the ground, as its heat sink. The plant discharges effluent at up to 15,000 gallons per minute during daytime peaks. Water temperatures range from 57 to 75 degrees Fahrenheit, depending on the time of day and year. The effluent water is pumped from the plant's discharge point to a heat exchanger building on campus. There, it is used to heat or cool a second stream of water that circulates through a 6,000-foot loop of pipe through campus. On a typical summer day, it might cool the system water from 88 degrees to 78 degrees, creating 10 degrees of cooling for campus buildings. Initial infrastructure can serve up to about 1.1 million square feet of laboratory and office space, with additional expansion available later.
The two streams circulate in self-contained loops so that the effluent is returned for discharge into Salt Creek without mixing with water that circulates through campus. An existing environmental permit prohibits water being discharged into the creek at more than 90 degrees. The system has been engineered so that the water will not exceed 85 degrees.
It is expected to reduce heating costs by about 30 percent and cooling costs by about 25 percent compared to traditional systems in the long term.