On a cold winter’s day, the smoke – or steam, to be more precise – emitted from KoskiPower Oy’s power plant can be admired with a clean conscience. The boiler burns wood chips and bark, which are renewable natural products and thus represent excellent biofuels in terms of the environment.
The statistics on Koskisen's carbon dioxide emissions reflect positive development. In particular, a biofuel boiler investment carried out in 2005 has helped reduce emissions. The investment has reduced the need to use the heavy-fuel-oil boilers that nowadays serve as back-up boilers. This has resulted in a substantial decline in the volume of carbon dioxide generated by fossil fuels.
The flue-gas scrubber and electric precipitator in the bio-power plant clean nearly all of the fine particles from the flue gas.
“The particle limits for Koskisen Oy’s boiler plants are set in the environmental permit. Emissions from the main boilers are measured every two years, and emissions from the back-up boilers every five years or after every 4,000 operating hours,” explains environmental engineer Kimmo Järvinen.
“The measured emissions have generally met the permit limits.”
With the increase in the use of biofuels, the boiler plants’ sulphur dioxide (SO2) emissions have gone down considerably.
The thermal energy required by Koskisen Oy’s Järvelä mills is mainly generated by two biofuel-fired boilers. In 2013, the boilers combusted 283,000 loose cubic metres of biofuel, i.e. roughly 5 truck-and-trailer loads of wood chips and bark every day.
A major proportion of the thermal energy goes to drying veneer and pressing plywood at the plywood mill. Other major consumers of thermal energy are the chipboard mill, which uses it to press the boards, and the Sawn Timber division, which uses it to dry sawn timber.
There is also enough thermal energy to be sold as district heat, keeping some of the properties in Järvelä’s urban area warm on freezing winter days. In 2013, approximately 4,400 MWh of district heat was generated.
In previous decades, the thermal energy used by Koskisen’s mills was generated conventionally using heavy fuel oil, which is a fossil fuel and non-renewable natural resource with significant carbon dioxide emissions.
Following a power plant investment carried out in 2005, Koskisen switched to using mainly biofuels, and today nearly all of the thermal energy required by Koskisen’s mills is generated using biofuels.
That means we can continue to admire the puffs of smoke, or steam,
billowing out of the “mill’s smokestack” with a clear conscience. We
know that the mills are run and the products manufactured in a way that
helps protect the environment.