Emissions to air - new challenges for the power generation industry

Stationary Source Emissions
On 2nd December the British Standards Institution finally published BS EN 14181 - Stationary Source Emissions. EN14181 Stationary Source Emissions - Quality Assurance of Automated Measuring Systems is the new European standard intended to improve air pollution standards by tighter monitoring of emissions. The standard describes the quality assurance procedures required to ensure that Automated Measurement Systems (AMS), known in the UK as Continuous Emission Monitoring Systems (CEMS), installed to measure emissions to air, are capable of meeting legislative requirements arising out of EU Directives.

While a range of standards relating to monitoring emissions to air are either under development or have already been published, EN14181 is one of the most significant and demanding standards ever to be developed by the European Committee for Standardization (CEN). Approved in October 2003 by CEN, with its adoption by BSI the standard is now live and will have far-reaching consequences for regulators, equipment manufacturers, test houses and process operators.

It is however true to say that many of those who are impacted by EN14181 are still unsure about the extent and nature of its impact on their operations.

BSI's definition for the standard covers the following:-air, quality, air pollution, industrial facilities, gas analysis, determination of content, measurement, concentration, combustion products, pollutant gases, dust, quality assurance, routine verification, computation, uncertainty, standard deviation, calibration, measuring instruments and automatic equipment.

No mean feat for any organisation to get to grips with its implementation quickly and effectively!

Implemented through a permit system, the standard describes the quality assurance procedures needed to ensure that Automated Measurement Systems installed to measures emissions to air are capable of meeting the uncertainty requirements on measured values specified in legislation - for example EU Directives or national legislation.

EU Directive 2000/76/EC on the Incineration of Waste, for instance, specifies measurements every three years. This includes daily emission limit levels, which specify 95% confidence intervals for single measurements should not exceed fixed percentages e.g. 10% for carbon monoxide and 20% for sulphur dioxide and nitrogen dioxide respectively.

The standard incorporates three different levels of Quality Assurance:-

  • QAL 1 which covers the suitability of an AMS for its measuring task e.g. either before or during the purchasing process of the system
  • QAL 2 consists of a procedure to calibrate the AMS and determine the variability of the measured values obtained by the system which is suitable for validation following its installation.
  • QAL 3 sets out the procedure to both maintain and demonstrate the required quality of measurement results during the normal operation of the system. This is achieved by checking that the WHOLE RANGE 9 (INCLUDING zero and span characteristics) are consistent with those determined at QAL 1 stage of the process.

    Clearly, getting QAL 1 right is fundamental to the success of the process - for any operator, the investment in an AMS can be significant and developing a closer working relationship with the supplier of the AMS plays a critical role which is not simply confined to the purchasing point - purchasers will also be looking to AMS suppliers for a significant level of support and after-sales service on an on-going basis.

    At this early stage however -it is probably fair comment to say that EN14181 is currently impenetrable to even knowledgeable end-users and still appears very much open to interpretation.

    Applications specialist Martyn Stonestreet at Servomex, the specialist gas analysis solutions provider, believes that end-users need to ask some key questions right at the start of the decision-making process before deciding what system to buy.

    "End-users need to ensure complete transparency of information in order to select the system that will really meet the needs of EN14181. In particular, they need clear data about cost of ownership, performance, cost of ownership, performance, reliability of equipment and required maintenance level and support availability. Selecting an AMS manufacturer who can really deliver is critically important to the successful implementation of the Standard on an ongoing basis. Buying the cheapest or discovering that your supplier cannot in reality provide the level of support and skills you need will cause serious problems if these issues are not properly addressed at the outset."

    The Environment Agency is currently developing a Method Implementation Document (MID) and Technical Guidance on the application of EN14181, which will be available by the middle of this year. All end-users will be expected to start fully implementing the standard by early 2006.

    Compliance with QAL 1 requirements will be assessed by the Environment Agency under the MCERTS scheme for Continuous Emissions Monitoring Systems and will cover suitable ranges of certification - typically 1.5x ELV for incineration and 2.5x-3.0x for large combustion plant, although there may be some exceptions to this.

    For the power generation industry in particular this is a key document - especially in the light of the recently issued Draft Reference Document on Best Available Techniques for Large Combustion Plants1 by the European Integrated Pollution Prevention Control Bureau - the pan-European body charged with drawing up comprehensive guidance on pollution prevention and control across all major EU industry sectors.

    The BREF covers in general combustion installations with a rated thermal output exceeding 50 MW. This includes the power generation industry and those industries where 'conventional' fuels are used where the combustion units are not covered within another sector BREF.

    It covers not just the combustion unit but also upstream and downstream activities that are directly related to the combustion process.

    Currently in draft format, the BREF sets out specific emission levels to air for specific gases for both new and existing plants, individual combustion techniques, plant types, and types of fuel.

    As Martyn Stonestreet from Servomex concludes "Both the introduction of EN14181 and the BREF guidance will undoubtedly present the power generation with significant and potentially costly challenges of implementation. Ensuring that they have the right equipment, services and support in place to obtain maximum environmental and process efficiency will be key to future success and profitability." By Elaine Coles, IMS.

    IMS
    0117 929 3041


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    | air quality | gas | incineration

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