Input Stories

Americans pour the equivalent of 350 billion kilowatt hours of energy from hot water down their drains every year. Now, however, more and more localities are interested in reclaiming it (The Wall Street Journal, subscription). 
 
What’s going on: At Colorado State University’s new Spur campus at the National Western Center in Denver, the heating and cooling system is fueled by wastewater—and other such projects are popping up all over “North America as the technology becomes more accessible and cost-effective.”  

• In addition to the CSU campus, sites in British Columbia, New York state and Washington state are also either starting new thermal wastewater endeavors or expanding existing ones.  

Why they’re doing it: Heat-pump systems—which recover wastewater energy and use it to heat and cool buildings and heat water—save large amounts of water and reduce emissions. 

• On the Spur campus, cooled wastewater goes into the city sewer system, cutting down on the amount of water, energy and time sewage treatment plants need to cool it.  
• “The system saves … five Olympic pools worth of water a year,” Brad Buchanan, head of the National Western Center Authority, told the Journal.  

Proven successes: In Vancouver, British Columbia, an energy utility started the first sewage heat-recovery system in North America in 2010. Fifteen years later, the utility “delivers 70% of its energy to customers using renewable energy, with wastewater heat recovery being the ‘primary’ piece of it.”  
 
Infrastructure differences: In Europe, using wastewater for heating is a common practice, but it’s made far easier by the fact that countries there “developed extensive district heating networks decades ago. … These centralized systems already have the pipes in place to circulate recovered heat throughout neighborhoods.”  

• In the U.S., most buildings use individual heating systems, which can recover heat but require new infrastructure for each building.  

Gaining traction: But more American sites are now using wastewater for heating and cooling.  

• “In New York state, construction of a wastewater heat-recovery system has begun at Whitney Young Manor, a multifamily housing development in Westchester County, and a system is being designed for the Amalgamated Housing Cooperative in the Bronx, both with support from … the New York State Energy Research and Development Authority.”