As a result of the decision to build a new Co-Gen Facility at the Port Angeles Site there has been a lot of public discussion on the environmental aspects of the project. With this has come a lot of speculation, opinion and in some cases, misinformation. Here are some critical facts to help sort out the facts from opinions.
As a result of the cogeneration project there will be a resulting net decrease in overall emissions by approximately 66%. That the boiler is larger than our previous biomass boiler and still can reduce emissions is due to progress in technology. Advancements have been made in boiler combustion technology as well as in pollution control methods. The previous boiler relied primarily on wet scrubber technology called a venture scrubber. Since then new advances in particulate removal have enabled the widespread commercial use of electrostatic precipitation (ESP). The NPI USA Project has an ESP to remove particulates coupled with a hybrid direct contract condensing economizer to reduce emissions substantially. Since 1972, the year No. 8 Boiler was installed, the EPA has passed many new regulations that protect air quality. All these requirements must be met in order for the new boiler to operate. This table shows the emission reductions that occured when the new biomass boiler came on line in 2014.
Fine particulate is the subject of much research and more emphasis than it was in the past. PM2.5 (particulate matter less than 2.5 micro-meters, or microns) is the current measurement for fine particulate. Estimates of PM2.5 in Clallam County are made by the Department of Ecology and Olympic Region Clean Air Agency. The chart displays the source apportionment for PM2.5 and comes from Ecology data. While industrial and commercial operations have some emissions the majority of PM2.5 is from wood stoves and fireplaces, wildfire and slash burns, and marine vessel traffic.
When NPI USA’s boiler started up, it drew upon local sources of forest slash for boiler fuel. The most important sources of fuel are those closest to the mill. Use of the forest slash as fuel for the boiler means that instead of burning these waste residual slash in controlled burns in the forest, the materials will be used as fuel for a modern boiler that has the latest pollution control equipment. There is the potential to reduce the 38% of PM2.5 emissions in Clallam County from slash burning down to much lower levels as a result of using these forest residuals in the CHP plant. This type of emission reduction in particulate was not taken into account during the permitting of the boiler but is a real factor in local particulate reductions.
We can all agree that energy efficiency is important. For NPI USA’s CHP project the efficiency will set new records in the mill for overall efficiency. Traditional power plants operate with efficiencies in the 32 to 34% range while new power plants can do a little better. At NPI USA the steam used to spin the turbine and produce electrical energy is then used in paper making process to dry the paper or used in other process areas. This is why the combined heat and power (CHP) process makes sense. Produce the energy and then use the left over heat in our manufacturing process. Regular power plants don’t typically do this. They have no use for the left over heat after it leaves the turbine electrical generator.
Coal plants calculate their energy efficiency based on the high heating value (HHV) method. NPI USA calculates efficiency using the lower heating value (LHV) method because biomass fuel normally contains significant moisture. If NPI USA used the HHV method our efficiency would pencil out to be in the 70 to 80% range.