Why wood waste to energy is a no-brainer
Millar Western has a sawmill and a pulp mill in Whitecourt, two hours northwest of Edmonton. The modern sawmill is a marvel of modern technology, mostly devoid of humans and full of machinery to debark logs and cut them down to usable lumber.
Only about half of the log is turned into lumber. Most of the other half is chipped and fed to the pulp mill. The remaining 10% is considered waste. Millar Western produces about 250,000 tonnes of bark, sawdust, shavings and other assorted woody leftovers per year.
In the past these leftovers were burned in a beehive burner, but the Alberta government is slowly phasing them out, so Millar Western built a 25-megawatt biomass-fired power plant, Whitecourt Power, where burning waste can generate electricity. When the forest is managed properly, the resource is a lot closer to being carbon neutral than coal or natural gas.
This plant has EcoLogo status, which means they use only “clean” wood – no construction waste or painted or treated materials. That certification means they can sell renewable energy credits (RECs), giving them a small ancillary revenue stream.
“We get paid for electricity we sell, we get paid by farmers for our wood ash that we take to the farmers’ fields. We get paid for the RECs that we sell, and we also get paid a small amount from Millar Western for the waste wood.” says Brennan Anderson, operations manager for Whitecourt Power. The electricity they produce is the largest source of revenue.
The other big advantage to burning wood waste for power over using a beehive burner is the pollution controls.
“As for what comes out of our stack, it’s pretty much mostly water vapour. We remove 99.9% of particulates with the baghouse, and our CO and oxides of nitrogen emissions are well below our approval limits. So, in comparison to a beehive burner, we are far away the better way to go,” says Anderson.
Millar Western is now building a small five-megawatt $92-million project that will collect and burn biogas taken from their waste sludge. The project is small relative to the mills’ thirst for electricity — the sawmill and pulp mill together consume more than 85 megawatts of electricity.
If burning the wood waste from forestry companies for power is done on a wide scale, forestry companies could play a much more significant role producing renewable electricity.