As the name implies, the sewer heat recovery system will extract heat from local sewers, which will then be used to heat buildings and domestic hot water. This innovative method is said to have significant advantages over conventional gas or electric heat. Sewer heat will generate half the greenhouse gas emissions of natural gas, with substantially lower levels of air-shed pollutants.
The city investigated two sustainable heat source options: biomass and sewer heat.
Biomass energy is created by burning wood residue to produce heat. The proposal was to burn wood pellets derived from sawdust, which is normally a waste product at sawmills.
The city had originally investigated biomass technology as an option due to its very low greenhouse gas emissions, and the fact there were fewer technical complications than that of the more novel sewer heat system. However, it was determined that there is insufficient time available in the project schedule to conduct the necessary public process, which would be required to obtain an air quality permit. Also, further research into sewer heat recovery satisfied the city that it could resolve some of the technical issues associated with this option.
There are only three similar sewer heat recovery facilities presently operating worldwide. When completed in 2009, Vancouver’s sewer heat recovery system will be the first use of this technology for district heating in North America.