The emission is measured by using a continuous CO2-concentration measurement in the stack and a stack gas flow measurement.
The good traceable accuracy is reached by accredited on-site calibrations of these components.
Through the coal balance of the boiler a traceable reference value for CO2-concentration is obtained. An accurate balance is possible when the boiler is fired by using a homogenous (secondary) fuel only.
The stack method has been taken into use at a coal power plant in Finland.
For the plant’s yearly CO2-emission the uncertainty of 1,8% was reached, well under the uncertainty level of 2,5% set by the EU regulations.
By measuring the CO2-emissions directly from the stack the plant avoided costly sampling and analysis of the ingoing coal flow - the traditional way of determining the emission.
“Compared to coal sampling the stack method has been a smart investment for us”, says Samuli Björkbacka from the coal power plant.
The method is applicable to all power plants using natural gas or fuel oil as their secondary fuel.
The method will be presented at the CEM 2014 Emission Conference in Istanbul 14-16 of May 2014.