Business challengesEnergy providers need to balance plant finely to maximise output

while minimising emissions of sulphur dioxide (SO2), nitrous oxides

(NOx) and particulates. In January 2008, compliance with the European

Large Combustion Plant Directive (LCPD) came into force. The directive,

2001/80/EC of October 23rd 2001, defines regulatory limits on these

pollutants.

These regulations provide three options for generators to use:

> Emissions Limit Values (ELV)

> National Emissions Reduction Plan (NERP)

> Opt-Out (only for plants with short remaining working life)

ELV requirements set limits for the pollutant concentration per cubic

metre of gas through the station chimneys. This was the option

selected by EDF Energy.

In most cases, control automation and emission measurement systems

were already in place to help balance commercial performance with

regulatory compliance requirements, but overall information about

environmental compliance from the existing system was only available

on a monthly basis as offline reports. In order to keep emissions firmly

in the forefront of operators’ minds, continuous real-time information

was needed. However, to ensure that staff were responding

appropriately to the emissions limits, these needed to be calculated

in strict accordance with the regulators’ constraints. With continuous

on-line information available, which stays in step with the regulatory

reports, EDF Energy wanted to secure a definitive record of emissions

from its power stations in Nottinghamshire.

A key objective was to provide more immediate and continuous

real-time information about emissions, the aim being to change

operational behaviours in order to optimise the plant environmental

performance.

How we helpedCapula used OSIsoft solutions both to capture emissions data in real-

time, and to analyse and present this to operators and their managers

on a continuous basis. These mission critical solutions combine

automation control, real-time data historians and business applications

to provide integrated solutions that bridge the historic divide between

engineering, commercial and regulatory activities.

EDF EnergyPower Stations Emissions Monitoring

Business benefits delivered

> Compliance with Large Combustion Plant Directive (LCPD)

> Conformance to Emissions Limit Values (ELV) regulations

> Modern, reliable, real-time emissions data influencing operator behaviour

> Ability to see pollutant trends

> Better understanding of plant operation

> Opportunity to modify plant parameters to optimise performance

> Enables efficient delivery of regulatory compliance

> Improved profitability

Using the OSI PI Advanced Computing Engine (ACE), calculations are made on the data acquired

from plant, and are presented to operators by PI Process Book graphics and trends showing current

performance against the regulated hourly, 48-hourly and monthly targets.

Calculations are configured on a ‘per-chimney’ basis, the chimney being the output of a ‘Large

Combustion Plant’. Emissions are also calculated on a ‘per unit’ basis. The information is presented

on a moving average basis, so that operators can determine how emissions are changing with time.

Emissions data is calculated for hourly, 48 hour and monthly averages, and rules are applied to

ensure its validity, including looking at input signal health and the application of stack weightings.

For instance, these rules account for whether an instrument is in calibration and/or fault mode or

whether the unit is in start-up or shut-down mode.

Why CapulaAs a long-term partner of OSIsoft in Europe and with a wealth of PI application developments in

the power generation industry, Capula was very well-placed to successfully execute this project.

Capula installed and continue to support EDF Energy’s PI systems, and consequently

understand the architecture.

EDF Energy

EDF Energy is the UK’s largest

producer of electricity, employing

nearly 20,000 people and the

largest generator of low carbon

electricity in Britain. It produces

around one-fifth of the nation’s

electricity.

Part of their portfolio are two

2000MW coal fired power stations

which are subject to the European

Large Combustion Plant Directive

and for which specific emissions

reduction targets apply.

Capula Limited Orion House, Stone, Staffordshire ST15 OLT

t: +44 (0)1785 827000 e: sales@capula.co.uk

www.capula.co.uk