CO2 Emission Monitoring and Measurement Quality Control
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This thesis was carried out as part of the Measurement, Monitoring and Environmental Assessment (MMEA) program, which is one of the research programs managed by the CLEEN Ltd. The Program concentrates on developing environmental monitoring technologies and tools for measurement quality control. The project was primarily financed by the Finnish Funding Agency for Technology and Innovation (Tekes). Work was developed in co-operation with Helsingin Energia and IndMeas Oy. European Commission set new regulations for third Emission Trading System period (2013-2020), that increase requirements for risk assessment, uncertainty estimation and continuous accuracy surveillance for CO2 monitoring system. The main objectives of this thesis were to research methods and requirements of CO2 emission monitoring and quality control. To meet these objectives three independent methods are described and discussed to determine CO2 emissions in power plants that fulfil the set requirements. The presented methods were standard method, direct measurement method and energy balance method, which was developed during the research work. The results of the thesis indicate that all methods have their own strengths and weaknesses and applicability of these three CO2 monitoring methods are case specific. The standard method almost always provides the best accuracy, but its weakness is not to provide good real-time information in typical installations. Instead, the direct measurement provides good real-time information with reasonable accuracy. The greatest interest focused on the energy balance method, which was developed to enhance quality monitoring and provide redundant information for both the standard method and direct measurement. The energy balance calculation method can be used as emissions trading observation method or in combination with approved methods within certain limits. If more than one fuel is used in the boiler, it is also good to use other monitoring method as addition assurance. In order to meet the accuracy requirements of emissions trading system when using energy balance method, the most important energy flow measurements must be calibrated. Primary monitoring method and the authentication method should be selected so that they are not based on the same measurements. In this way dependence on individual measurements can be avoided. Also possible problems are detected quickly and they can be addressed with determination. The thesis includes the principles of energy balance calculations of CO2 emissions. To facilitate the deployment of the energy balance method the calculation has been conducted thoroughly in the thesis. All the presented methods are then applied in Salmisaari coal-fired power plant.