A new draft consultant report commissioned by the city recommends hot water biomass—burning wood waste from sawmills to heat water— as a heat source for Nelson’s buildings. There are still some details to be worked out with the consultant, says Nelson Hydro manager Alex Love, before the report is presented to Nelson City Council in the spring.
An earlier version of a district energy system plan for Nelson in 2010 envisioned using the water in Kootenay Lake as a heat source. The new study by Associated Engineering in Vancouver shows that method to be technically feasible but too expensive, and recommends hot water biomass instead.
If it works out, the system would offer local energy independence, lower greenhouse gas emissions, lower building energy costs, and utilization of local renewable energy sources.
How it works
“It would use a boiler that burns sawdust and wood chips, and produce hot water that would be piped to various client buildings,” Love told The Nelson Daily in a recent interview. “Instead of having their own boiler or forced air furnace system, building owners would have a heat exchanger that would take heat out of the hot water loop and put it into their building heating loop. The heat exchanger is quite small— for a fairly large building it could be half the size of a filing cabinet.”
Enough local wood waste?
Asked if there is enough local wood waste, Love said, “Surprisingly, at first I thought maybe not, but we did a biomass study to determine how much is available, from what sources and quality, and what would it cost to get it here. It turns out that within 100 kilometers there is ten times what we could possibly use.”
No belching smokestack
Love said the facility would be a building that would house boilers and stored woodchips, with a loading ramp for trucks. He said it would not need to look “industrial,” citing one such facility elsewhere that is a timber frame building with glass walls.
He said there would be no exhaust other than water vapour.
“It is not like you would have an industrial facility belching smoke. The ones we have gone and looked at, you have to strain your eyes to actually see anything coming out of them.”
Love said there are several possible locations being considered but no decision has been made. Proximity to the downtown core would reduce piping costs, he said.
District energy systems
District energy systems are becoming more common for whole towns or for individual buildings or institutions, although fuel and methods differ.
For example, Revelstoke has been generating energy from burning wood chips from the Downie sawmill as a heat source for downtown buildings and for the mill’s own operation since 2005.
A self-funding utility
Love estimates the project would cost about $20-million, with development done in several phases.
“We would need to set it up as a self-funding utility which is why we are taking a really good look at the financial numbers to determine if we can make a go of it," he said.