Download - CO N T E N TS
CO N TAC TS
MANAGER’S WELCOME ANDOVERVIEW OF DAMHEADCREEK CCGT STATION
PAGE 2
THE PERFORMANCE OF THESTATION’S ENVIRONMENTALMANAGEMENT SYSTEM
Our EMS
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HOW WE ARE RESPONDING TO ONGOING CHALLENGESFACING DAMHEAD CREEK
Key Issues
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INPUTS AND OUTPUTS FOR2009 AND ENVIRONMENTALPERFORMANCE STATISTICS
Station Processes
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OUR OBJECTIVES AND OURP ROGRESS TO DATE INACHIEVING OUR TA RG E TS
Targets & Achievements
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HOW WE ARE WORKING INHARMONY WITH WILDLIFE THATTHRIVES ON OUR SITE
Conservation & Biodiversity
PAGE 11
DECLARATION FROM THE ECO-MANAGEMENT AND AUDITSCHEME VERIFIER
EMAS Validation
PAGE 15
CO N T E N TS
Introduction
Damhead Creek Power StationKingsnorth, Hoo, near Rochester,Kent ME3 9TXtelephone: 01634 257600
ScottishPower Energy Wholesale:www.spenergywholesale.com
community on the Isle of Grain – there wereno justified community complaints in thecurrent three-year EMAS period.
Damhead Creek is also the steward of a 32-hectare wildlife area established to mitigatethe environmental impacts of the station’sconstruction and operation. Habitatimprovements were carried out on themitigation land during 2012 and ongoingmonitoring has shown it is rich in biodiversity.
Our 2012 EMAS Statement has beenexternally verified, and it is hoped it will givestakeholders confidence in our people, plantand processes – and underline ourcommitment to being ‘Trusted with theEnvironment’.
Damhead Creek has an open policy oncommunication with our stakeholders. If youwould like further information, or to commenton how we could improve performancefurther, we would really like to hear from you.
LEE WARREN, Station Manager
Welcome to Damhead Creek EINTRODUCTION
Welcome to the fifth Damhead CreekPower Station EMAS Statement, whichdescribes how the station is improving itsenvironmental performance.
2012 was an eventful year for the powerstation as it started to get in shape to meetever-tightening environmental legislation.
The new Industrial Emissions Directive (IED)will introduce strict new targets for ouremissions to air when it comes into force atthe start of 2016. Station staff recognised itwas essential to get ready now – particularlyby improving our control of a key emission,called oxides of nitrogen (NOX).
NOX is formed from the nitrogen content ofair when it is burned with natural gas at ourcombined cycle gas turbine (CCGT) powerstation. This year the station embarked on amulti-million pound project to reduce theamount of NOX that the station produces byimproving our combustion hardware and fine-tuning its operation.
For more than half the year, the plant waseither shutdown or operating at reduced loadas we worked towards implementing asolution. At times, up to 200 contractors wereon site for the outage that also included thecomplete overhaul of our two gas turbinesand steam turbine.
It’s been a huge investment in the future ofDamhead Creek, aimed at helping ensure wecomply with future legislation and improvingour efficiency.
The successful delivery of the outage –without a Lost Time Accident – was just one ofthe highlights of a busy year. Station staff aimto achieve continuous improvement of ourenvironmental performance and site-ledprojects have continued to reduce our use ofkey resources, such as water and energy, andimprove our control of waste.
As Station Manager, it is particularlygratifying that all these activities have been
delivered without anenvironmental breach
or notifiableenvironmentalincident– that’s sixyears now with anunblemished record.
The station alsocontinues to enjoy agood relationship withstakeholders and the
local
Damhead Creek, near Rochester, Kent, is an800 megawatt (MW) combined cycle gasturbine (CCGT) power station that hassupplied electricity to businesses andhomes in southeast England since 2001.
The gas-fired station was built in 2000 onland that was used as a gasworks in WorldWar 1, producing hydrogen for airships. Thestation was commissioned in 2001 and, threeyears later, was acquired by ScottishPower,which is part of the IBERDROLA Group.
Damhead Creek’s main generating plantconsists of two gas turbines and a steamturbine, and it can generate enoughelectricity to meet the needs of 800,000homes. CCGT technology is one of the moreefficient forms of thermal electricitygeneration and creates fewer emissions perunit of electricity compared withconventionally-fired thermal power stations.
The station has an air-cooled condenser tocondense the exhaust steam, minimising theuse of process water and avoiding the needfor cooling water to be extracted from theMedway Estuary.
In January 2011, the UK Governmentapproved proposals submitted byScottishPower for a second CCGT atDamhead Creek.
Damhead Creek 2 will have 1000MWcapacity – enough to supply up to 1.5 millionhomes – and will be built on land east of thecurrent station. Construction work isexpected to begin in 2015.
k EMAS Statement
Damhead Creek’s Environmental Management System (EMS) provides the structureand systems for developing, implementing and delivering the station’s environmentalpolicy. The station’s EMS was recertified to the international standard ISO 14001 inNovember 2011 and is due for recertification in 2013.
In 2011, the auditor commented on employees’ “excellent” understanding of theenvironmental issues relating to the plant, process and operation. The auditconcluded: “Good internal communication continues to be a strong point, ensuringthat staff awareness of requirements is maintained.
“A positive approach is taken to quality, environmental and health and safety riskmanagement in all operations and maintenance activities.The EMS continues to be wellmanaged and suitable for the processes and activities carried out on site.”
Two minor non-conformities were found – both of a technical nature, with noimpact on the station’s environmental integrity. A Health, Safety and EnvironmentForum meets monthly to discuss relevant issues. While day-to-day implementation ofthe EMS is carried out by the site’s Environmental Team Leader with the help of keystation personnel.
Station supplieselectricity for800,00 homes
ENVIRONMENTAL MANAGEMENT SYSTEM
Gas turbine rotor blades are exposed during the 2012 outage that involved up to 200 contractors
KEY ISSUES
Damhead Creek operates within legislation and regulations thatcover a multitude of environmental factors, including emissions toair, our use of resources such as water, and waste produced by theplant. This section reports on how the power station monitors andcontinually improves its environmental performance.
Pollution Prevention & ControlDamhead Creek operates under strictconditions set out in a Pollution Prevention& Control (PPC) permit, issued andmonitored by the Environment Agency (EA)under the Pollution Prevention and ControlRegulations 2000.
The PPC Regulations are driven by the EU’sIntegrated Pollution Prevention and Control(IPPC) Directive and require the use of BestAvailable Techniques (BAT) to eliminate orminimise polluting emissions.
PPC permits cover emissions to air, landand water, as well as noise, vibration andheat loss. They also cover the use of energyand raw materials, waste reduction and themanagement of potential risks.
Damhead Creek is opted-in to the LargeCombustion Plant Directive (LCPD) via theNational Emission Reduction Plan (NERP) andmust measure its emissions to air using aContinuous Emissions Monitoring System(CEMS) and report the results annually.
The station’s CEMS equipment on both gasturbines meets the Monitoring CertificatedStandards (MCERTS) standard required by theEA. Quarterly Compliance AssessmentReports are submitted by the station to theEA which provide information on emissionsto air and water and other aspects coveredby the PPC permit.
Running RegimeDamhead Creek was closed down or runningon reduced load for more than half of 2012while outage work took place. As a result,our generated output has been reducedsignificantly compared with a normal yearof operations.
The power station generated a total outputof 3,361 GWh in 2012 – down 42% comparedwith the 2011 figure (5,745 GWh). See tablebelow for five years’ figures.
Since March 2011, the CCGT has beenproviding an ancillary service to National Gridto help ensure the integrity of powersupplies to the nation through a frequencycontrol contract.
Damhead Creek’s role during the contractperiod has been to operate in a way thatsmoothes out the peaks and troughs insupply and electricity demand, and byreacting to any potential shortfall by othergenerators. This has been particularly
important now that wind generation hasstarted to play a greater role in providing theUK’s energy, yet wind production is by itsnature less predictable than other forms ofgeneration.Under the frequency controlcontract, Damhead Creek has normallyoperated at around 75-80% of full capacity,with a reduction in efficiency as a result.
The plant adjusts its output automaticallyto prevent deviations in the 50Hz networkfrequency – increasing or decreasinggeneration as necessary to keep the systemstable.
Damhead Creek will be alert for furtheropportunities to provide such ancillaryservices to National Grid. Normally, thestation would operate a two-shifting runningregime – starting up and shutting downoperations to take advantage ofopportunities to generate in the electricitymarket.
Global Climate ChangeScottishPower is committed to reducingemissions of the greenhouse gas carbondioxide (CO2) across its energy portfolio insupport of the reduction targets set by theUK Government.
The primary mechanism for reducing CO2
across power generation and heavy industrythroughout Europe is the EU EmissionsTrading Scheme (EU ETS) that effectively putsa price on carbon.
An overall CO2 cap is set and carbonallowances are distributed through a NationalAllocation Plan (NAP). Participants in EU ETSmust ensure the amount of carbon theyproduce is within their allowances – or theymay have to buy extra allowances to coverincreased emissions.
EU ETS requires each eligible installation toproduce an annual greenhouse gas emissionsreport for the previous calendar year, whichmust be externally verified before beingsubmitted to the regulator by the end ofMarch. This enables the installation’s CO2
emissions to be balanced with carbonallowances set by the NAP.
In 2012, station staff prepared for Phase IIIof EU ETS, which will start from January2013. The new, more-rigorous third phasewill see changes in how allowances areallocated, including the removal of freeallowance allocation for sites purelygenerating electricity.
Following a site inspection, whichexamined the station’s procedures forcomplying with the new phase of EU ETS, theEA confirmed the station’s submission was inorder and a permit would be issued on 1stJanuary 2013.
Modern CCGT gas stations, like DamheadCreek, typically produce only 40% of the CO2
produced by a conventional coal-fired powerstation for the same amount of electricityoutput. Damhead Creek strives to ensure theoptimum efficiency and performance of ourgenerating plant to maximise electricityoutput – Damhead Creek typically operatesat just under 55% delivered thermalefficiency – resulting in less fuel used andlower carbon emissions per unit of gas.
Key Issues for Damhead Creek
A contractor removes insulation around thecombustion chamber of one of the turbines
E L E C T R I C I TY GENERAT E D
2012 2008
3,361 5,745 6,058 5,775 5,602GW h
2010 20092011
Gross Electricity Output
In 2012, the station produced 1,252,412tonnes of CO2 – just under half the totalamount in 2011 due to the reducedoperational hours during the year.
A more accurate comparison is the amountof emissions per GWh of electricity produced.
This shows that in 2012, Damhead Creekproduced 373 tonnes of CO2 per GWh,slightly up on 2011 (368t/GWh) but figureshave been relatively stable over the past fiveyears.
Combustion chambers, incorporating hotceramic liners, help ensure most of thecarbon in the fuel is converted into CO2
rather than carbon monoxide (CO), a gas thatis highly poisonous if inhaled by humans.
As part of the Section 36 submission forthe proposed new CCGT at Damhead II, a plotof land has been set aside for potentialdevelopment as a Carbon Capture facility.This would facilitate Carbon Capture andStorage for both CCGTs if required by futurelegislation.
Acidification and Air QualityNatural gas is the cleanest of all fossil fuelsused for electricity generation.
Compared with coal and oil-firedgeneration, combustion of natural gasreleases relatively small amounts of sulphurdioxide (SO2) and NOX, and virtually no ash ordust. SO2 and NOX emissions can affect airquality and disrupt ecosystems through acidrain damage to vegetation and watercourses.
Damhead Creek must control its emissionsto air of SO2 and NOX under the terms of theLCPD and IPPC, while concentration-basedemission limits for SO2 and NOX have been setby the EA as part of the station’s PPC.
At present, Damhead Creek comfortablymeets its emission limits for SO2 and NOX.
However, emission limits will be furtherconstrained from 1st January 2016 with thelaunch of the Industrial Emissions Directive(IED). Damhead Creek has opted-In to the IEDand is confident of meeting the new tighter
rules imposed by the legislation.
The IED will consolidate seven existingdirectives, including the LCPD, the IPPCDirective and the Waste Incineration Directive(WID) into one cohesive piece of legislation.
The directive focuses on limiting airpollutants such as SO2, NOX and dust and willsignificantly tighten emission limit values forlarge combustion plants and other industriesthroughout the EU. It also strengthens theconcept of Best Available Technology (BAT)in controlling emissions and introduces newrequirements for monitoring, plantinspections and compliance reporting.
Oxides of nitrogenA key consideration for Damhead Creek inrecent years has been how the station willrespond to tighter emission limits for NOX.
The station has historically experiencedhigh-release concentrations of NOX and, priorto 2007, has reported breaches of50mg/Nm3 concentration – its formeremissions limit for oxides of nitrogen.
As a result, the EA agreed to vary theplant’s PPC permit to allow an increase in thestation’s NOX emissions limit to 60mg/Nm3.
Meanwhile, ScottishPower began toinvestigate the cause of the issue andidentify a possible solution with themanufacturers of the gas turbines (GTs),Mistubishi Heavy Industries.
This has been brought into focus by theprovisions of the IED, which require thestation to comply with a future NOX emissionlimit of 50mg/Nm3.Damhead Creek producesthermal NOX. Thermal NOX forms whennitrogen in the air reacts with oxygen duringthe high temperature combustion processwith natural gas. More NOX is produced as theturbines work harder while the gradualdeterioration of the GTs may also haveplayed a part.
The gas turbine strip down is well underway and, right, GT compressor blades are exposed
In 2012, a major project began involvingstaff from the station and elsewhere inScottishPower, and experts from MitsubishiHeavy Industries, to improve the combustionperformance of the station’s two Mitsubishi701F gas turbines.
The improvement work, initially carried outon GT2, included fitting new hardware – suchas new designs of burners, nozzles andcombustion baskets – while the turbine’soperation was also fine tuned, includingadjustments to the temperatures involved inthe combustion process.
The work was carried out during the majoroutage – that ran from May to November in2012 – and which saw both GTs and steamturbine stripped down and refurbished. GT1underwent modifications to its burnerhardware that had previously been provenon its sister unit.
Both units had returned to service by thefinal month of 2012 and the station began aperiod of efficiency testing, monitoring andevaluation to assess the success of the GT2improvement work in reducing NOX
emissions towards the future 50mg/m3 limit.
Improvements have been seen in NOX
production on both gas turbines and acrossall loads since tuning and restart followingthe outage – although there is furtherprogress to be made. A decision will be madeat a future date on introducing the latestmodifications on GT2 to GT1.
There is no ‘off the shelf’ solution toreducing NOX on these machines but throughengineering innovation, working togetherwith Mitsubishi, the station believes it will bebe able to achieve the new ELV in 2016.
The total amount of NOX produced in 2012was 773 tonnes – less than half (42%) of the1862 tonnes produced in the previous yearas a result of the constrained operation dueto the major unit outages. However, NOX
figures per kg/GWh were also significantlyless – down from 324kg/GWh in 2011 to230kg/GWh in 2012.
Sulphur dioxide
In 2012, Damhead Creek agreed with the EAa significant change in the way its SO2
emissions are calculated to correct ahistorical error.
It was the station’s position that thechemical equation used by the station since2008 was erroneous – resulting in reportedemission figures being up to 27 times higherthan expected for a modern CCGT.
Station staff lobbied the EA through theJoint Environmental Programme (JEP) toagree a new, accurate calculation of theemissions to prevent future over-reporting –and this was successfully concluded in 2012.
JEP is a research programme, funded bythe UK’s leading generators – includingScottishPower – into the environmentalimpacts of electricity generation.
As a result of the change in calculation andreduced generation activity in 2012, totalannual SO2 figures for Damhead Creek havebeen substantially reduced – from 115.6tonnes in 2011 to just 1.66 tonnes in 2012(0.49kg/GWh) – and figures are now in linewith similar CCGT plants of the same age.
Volatile Organic CompoundsVolatile Organic Compounds (VOCs) areorganic chemical compounds that havesignificant vapor pressures and can affect theenvironment and human health.
At Damhead Creek, VOC emissions arisemainly as a result of fumes from hot oil usedby the station’s GTs and steam turbine.
External UKAS/MCERTS qualifiedcontractors have in the past monitored VOCsemissions four times a year at the stationstacks, while studies have been carried outinto the feasibility of fitting VOC abatement.
In 2012, the station gained acceptancefrom the EA that there was little more that
could be done to clean up the light oil fumes. A change in the monitoring schedule was
also agreed with the EA and Damhead Creekmoved during the year from a quarterly to anannual monitoring methodology. Thestation’s PPC will be amended to reflect thenew reporting arrangement.
In 2012, the station emitted a total of 22.5tonnes of VOCs compared with 37.9 tonnesin the previous year – a reflection of thereduced number of station running hours.
Gas Supply Management
The UK has moved from being a netexporter of natural gas to a net importer asNorth Sea gas reserves began to decline,resulting in a national debate on security ofsupply.
In 2005, ScottishPower signed a 10-yeargas supply agreement with Statoil of Norwayto receive 500 million cubic metres of naturalgas a year via a North Sea pipeline.
The agreement helps support the
continued stability and security of supply forour CCGTs and domestic gas customers. Thecompany is looking at other ways ofdiversifying its gas sources as UK suppliescontinue to decline.
From October 2010, ScottishPower has hadan annual LNG regasification capacity of up to2.75 bcm at the Isle of Grain importationterminal that supplies Damhead Creek.
Use of WaterDamhead Creek requires a secure supply ofclean water for use in steam generation andthe station’s offices and workshops.
In recent years, the station has movedtowards being mainly self-sufficient in waterthrough the extraction of borehole water andinstallation of a water recovery plant.
In 2009, a new borehole was drilled into afreshwater aquifer 200m below ground thatcan supply the station with around 306 litresof water per minute, offsetting an equivalentamount of townswater.
Borehole water is used for making processsteam along with recycled process waterfrom a blowdown blast cooler. This supply istreated in the station’s water recovery plant,which was commissioned in 2010.
The use of borehole water has achievedconsiderable further savings – most of thestation’s potable water needs are nowsupplied from the borehole, recycled waterand water recovery plant.
In 2012, borehole water made up 54% ofwater supplied to the station – a total of44,279m3. Again reflecting the reduction inthe station’s operation during the year, thisfigure was down on the amount extracted in2011 (55,230m3).
Meanwhile, 37,046m3 of townswater wassupplied to the site in 2012. As a result ofwater-saving initiatives, in the space of sixyears the station has reduced by a third thevolume of townswater it uses – from 31.25m3/GWh in 2006 to 11.02 m3/GWh in 2012.
In 2011, boreholewater abstraction wasconstrained by technical difficulties at thegroundwater abstraction plant.
This resulted in a greater proportion oftownswater being used – with a significantincrease in the quantities of Sulphuric Acidand Sodium Hydroxide used to process thiswater in the station’s water treatment plant(WTP).
This spike in WTP chemical use is shownclearly in the graphs shown above.
Damhead Creek’s air-cooled condenser(ACC) returns exhaust steam to water forreuse in the system, and avoids the need forcooling water to be abstracted from theenvironmentally-sensitive Medway Estuary.
The ACC tubes covers an area of more than105 hectares and consists of 36 large coolingfans that force air over a heat exchanger.
Only small quantities of water, such aswater treatment plant effluent, treatedsewage and surface water run-off, aredischarged from the site into the estuary.
This discharge is sampled and analysedmonthly by an external laboratory to ensurethe waste water meets PPC permit conditionsand the results form part of the station’s CARto the EA.
Use of EnergyStation staff are committed to ensuring itsprocesses and operational activities areenergy efficient.
In recent years, several projects have beencompleted to ensure continuousimprovement in performance and staff haveshown an innovative approach to reducingworks power use in particular.
Nevertheless, the amount of electricityimported for works use increased in 2012 asa result of the major outage and increasednumber of personnel on site.
In the current EMAS Statement period, anumber of energy-saving initiatives havebeen advanced:
■Jet washing the condensers on the ACChas improved their efficiency and reducedthe number of fans required to condense thesteam.
The ACC is prone to fouling from fibrousairborne material, such as pollen, blossom,dust and insects, which sticks to condenserfins and affects their performance.
As a result, more fans are required tomaintain the condensers at an optimumtemperature therefore clearning made theheat exchange process more efficient.
Jet washing has also improved the heatexchange rate of the closed circuit coolingwater (CCCW) system that is also susceptibleto fouling from airborne particles.
After cleaning, the number of fansrequired to operate over a 24-hour periodwas reduced from 10 to only four, withelectricity savings and improvements inefficiency. Going forward, a system softwareprogramme is being developed to give earlywarning of the need for condenser cleaning,based on feedback about plant conditions.
■ LED lighting was fitted during thestation’s 2011 outage at the heat recoverysteam generator (HRSG). Three LED high bayfittings replaced old sodium lights, withresulting savings in electricity costs andmaintenance bills. Station staff have alsonoticed improved colour rendition while theLEDs are more durable and environmentally-friendly, being free of mercury and lead.
■ Energy and water efficiency were
KEY ISSUES
6 . 0
5 . 0
4 . 0
3 . 0
2 . 0
1. 0
0
2 0 0 8 2 0 0 9 2 010 2 011 2 012
Sodium Hydroxide(kg/GWh)
7.0
6 . 0
5 . 0
4 . 0
3 . 0
2 . 0
1. 0
0
2 0 0 8 2 0 0 9 2 010 2 011 2 012
Sulphuric Acid(kg/GWh)
Production technician StephenHarwood in the control room at
Damhead Creek Power Station
EMISSIONS TO AIR AND WAT E R
2012 2009 2008
Carbon Dioxide, CO2
Carbon Monoxide, CO
Oxides of Nitrogen, NOX
Water Discharged
1,252,412 Te
13.69 Te
773 Te
92,923 m3
372.63
4.07
111.23
27.65
368.14
5.77
324
15.91
366.5
17.69
268
17.98
374.7
10.3
290
17.33
376.29
9.6
412
19.09
Te / GW h
k g / GW h
k g / GW h
m3/ GW h
2011 20102012
➀Natural gas is delivered to the station viaa three kilometre underground pipeline
that links in to Transco’s national transmissionsystem.
➁ The natural gas is burned in two gasturbines (GTs), which are similar to the
large jet engines found on aeroplanes, to heatcompressed air.
➂The hot gas expands through the turbineblades at 3,000 rpm, forcing a shaft to
rotate and drive a generator. In conventionalcoal-fired power stations, the hot exhaustgases are lost to the atmosphere, resulting inwasted heat energy.
➃At Damhead Creek, however, these hotexhaust gases, at a temperature of
548oC, are reused to heat water-filled tubesin two large boilers called Heat RecoverySteam Generators until it turns to steam.
➄Waste gases from this part of theprocess are released to the atmosphere
through the station’s twin 75-metre highchimneys.
➅Steam from the Heat Recovery SteamGenerators passes through a steam
turbine, expanding as it does so that its heatenergy drives the turbine rotor at 3,000 rpm.
➆ Exhaust steam flows to the station’s air-cooled condenser (ACC) that cools it
back into water to be recycled at the HeatRecovery Boilers. Damhead Creek’s ACCworks like a giant radiator, with 36 coolingfans, each 10-metres in diameter, forcing airover a heat exchanger with a surface area of105 hectares.
➇ In 2012, 54% of our process water wassourced from an underground aquifer
and mixed with recycled process water in aWater Recovery Plant. Mainswater is used fordomestic purposes. All water is treated at anon-site demineralisation plant.
➈Water discharges are released toDamhead Creek and are comprised of
water treatment plant effluent (waste water),boiler blowdown (water drainage), treatedsewage and surface run-off water.
Our process diagram (right) shows the inputs and outputsat Damhead Creek Power Station during 2012
Non-Hazardous Solids (tonnes)
Hazardous Solids (tonnes)
Non-Hazardous Liquids (litre)
Hazardous Liquids (litre)
40.22
0.004
0
10,040
WA ST E R E C YC L E D 2 012
Non-Hazardous Solids (tonnes)
Hazardous Solids (tonnes)
Non-Hazardous Liquids (litre)
Hazardous Liquids (litre)
78
12
62,103
22,840
WA ST E P RO D U C E D 2 012
15 , 0 0 0v o l t s
15 , 0 0 0v o l t s
GTg e n e r a t o r s
➂ t us
steamturbin
g e n e r a
waterecov
plan
domeswate
syste
watetreatm
plan
➅➀
➇
ambient air
Natural gas burned –237,105,897 therms
Electricity imported –– 3,430 MWh
Mainswater – 37,046 m3
Borehole water – 44,379 m3
Bulk Hydrogen –– 15,073 m3
Bulk chemicals
Sodium Hydroxide – 10.5 Te
Sulphuric Acid – 11.8 Te
>> INPUTS
R E S O U RCE USE
2012Net Gas Burned ( t h e r m s )
Townswater Use
Boreholewater Use
Electricity Imported
Sodium Hydroxide
Sulphuric Acid
2 3 7,10 5 , 8 9 7
3 7,046 m3
44,379 m3
3,430 MWh
10,500 kg
11,780 kg
therms/GWh
m3/GWh
m3/GWh
MWh/GWh
kg/GWh
kg/GWh
2009 20082011 20102012
DAMHEAD CREEK PROCESS DIAGRAM
7 3 0 0 0
7 2 0 0 0
710 0 0
7 0 0 0 0
6 9 0 0 0
6 8 0 0 0
2 0 0 8 2 0 0 9 2 010 2 011 2 012
Gas Burned (therms/GWh)1. 2
1. 0
0 . 8
0 . 6
0 . 4
0 . 2
0
2 0 0 8 2 0 0 9 2 010 2 011 2 012
Electricity Imported(MW/GWh)
3 0
2 5
2 0
15
10
5
0
2 0 0 8 2 0 0 9 2 010 2 011 2 012
Water Use (m3/GWh)TownswaterBoreholewater
70,546
11.02
13.2
1.021
3.12
3.5
69,398
12.47
9.61
0.147
5.88
5.90
68,901
9.31
12.55
0 . 217
0.73
0.49
70,710
15.33
–
0 .16 7
1.12
0.85
70,260
20.74
–
0 .19 6
1. 41
1.30
2 0
18
16
14
12
10
8
6
4
2
0
2 0 0 8 2 0 0 9 2 010 2 011 2 012
CO (kg/GWh)
3 9 0
3 8 5
3 8 0
3 7 5
3 7 0
3 6 5
3 6 0
2 0 0 8 2 0 0 9 2 010 2 011 2 012
CO2 (Te/GWh)
4 5 0
4 0 0
3 5 0
3 0 0
2 5 0
2 0 0
2 0 0 8 2 0 0 9 2 010 2 011 2 012
NOX (kg/GWh)
3 0
2 5
2 0
15
10
2 0 0 8 2 0 0 9 2 010 2 011 2 012
Water Discharge (M3/GWh)
7 0 0 0
6 0 0 0
5 5 0 0
5 0 0 0
4 5 0 0
4 0 0 0
3 5 0 0
3 0 0 0
2 0 0 8 2 0 0 9 2 010 2 011 2 012
22
04
040
12
8
2
103
840
12
t u r b i n es h a f t
gasturbines
➁heat
recoverysteam
generators
GTe x h a u s t
g a s e s
H R S Ge x h a u s t
g a s e s
➃➄
eamrbinee r a t o r
ateroverylant
mesticaterstem
wateratment
lant
➅
L Ps t e a m
H Ps t e a m
c o n d e n s a t er e t u r n
t u r b i n es h a f t
LP steamt u r b i n e
H P / I Ps t e a m
t u r b i n e
h o tr e h e a ts t e a m
cold reheat steam
m a k e - u p
storm water basin
domesticwastewater
surfacewater
run-off
plantdrainage
air cooledcondenser ➆
➈
water treatmentplant effluent
Waste recovered –
40.2t non-hazardous solids
0.004t hazardous solids
10,040 litres hazarous liquid
Total waste –
89.9 tonnes solid
84,943 litres liquid
Methane – 95.2 tonnes
Vo C s– 22.5 tonnes
Electricity exported – 3,361 GWh
Emissions to air
CO2 – 1,252,412 TeCO – 13.69 TeNOX – 773 TeSO2 – 1.66 Te
Total waterdischarged – 92,923 m3
>> OUTPUTS
Electricity Generated (GWh)
TOTA LS O L I D S
N O N - H A Z A R D O U SL I Q U I D S
TOTA LL I Q U I D S
H A Z A R D O U SL I Q U I D S
N O N - H A Z A R D O U SS O L I D S
H A Z A R D O U SS O L I D S
Non hazardous78 tonnes
Hazardous 12 tonnes
Disposed of38 tonnes
Recovered 40 tonnes
Disposed of12,800 litres
Recovered 10,040 litres
Disposed of12t tonnes
Disposed of62,103 litres
Non hazardous62,103 litres
Hazardous 22,840 litres
N B 0.004t of fluorescenttubes were recycled
covered in a Toolbox Talk in November 2011as part of a ‘Switch Off’ campaign. Thisincluded raising the awareness of turning offequipment when not in use, using timers onlights and using thermostats to reduceheating. Timers were installed on waterheaters in September 2011.
■ Meters have been installed on the ACC tomonitor electricity usage and help identifyany changes made to the DCS logic todetermine and improve energy efficiency.
■ A programme was completed in 2010 toinstall inverters on all of the HRSG roofexhauster fans to reduce their operationalspeed, with potential electricity savings of25% and a reduction in operational noise.
■ Damhead Creek updated its EnergyEfficiency Plan in June 2012 as part of its PPCpermit improvement conditions. Thistechnical document describes the meteringarrangements in place for gas and electricityusage, how the station uses energy,identifies areas where heat and energy arelost in the station’s process and suggestspossible areas for improvement.
The station continues to benefit fromsuccessful projects implemented in recentyears to secure significant energy savings,such as optimisation of the station’s heattransfer processes, especially in summerwhen ambient temperatures are higher.
Continuous Improvement
Staff at Damhead Creek aim to achieve acontinual improvement in the station’sefficiency, performance, reliability,compliance and controllable losses.
As a result of the major outage in 2012, itis anticipated there may be a slightimprovement in efficiency as a result ofbetter combustion performance.
For instance, redesigned blades were fittedas part of GT overhaul that will improve airflows, helping efficiency while reducing NOX
formation. Regular cleaning of the turbine aircoolers, which preheat gas for combustion,to minimise fouling by airborne particles hasalso improved the operation of the GTs andhelped them run better.
Meanwhile, work has been carried out toensure the continued excellentenvironmental compliance of the station.
■ During the 2012 outage, when work wascarried out 24 hours a day, a number of adhoc noise surveys were carried out with ahandheld noise meter both within the siteand externally. This helped ensure thatoutage work was within noise parametersstated by Medway Council.
■ The main gas feed to the station waspigged and inspected in 2012 to improvesafety and ensure compliance.
■Protection of the environment was, forthe first time, an integral part of the siteinduction process for contractors and new
staff. The induction covered issues such asnoise and waste – and the environmentalsafety message was reinforced by regularToolbox Talks.
■ In 2012, a survey was carried out using aremote camera to check the condition of theplant drains as part of the updated siteprotection monitoring plan to meet therequirements of the EA. This follows on fromwork done in 2009 to monitor the conditionof the station’s road drainage system.
■ The Storm Water Basin pH transmitterwas upgraded to MCERT certified equipmentto ensure the station meets currentlegislation.
■ During 2012 the station identified aproblem with the efficient throughput ofdemineralised water in its water treatmentplant, which depends on a mixed bedchemical regeneration with dilute sodiumhydroxide (NaOH) used to remove silica.
The station identified that the optimumNaOH concentration of 4% was not beingreached, which affected the completeremoval of silica during the mixed bedreaction. Work is now under way to replacethe NaOH dosing pumps and theconcentration analysers, which had beenfound to “drift” shortly after calibration, aswell as checking the function of the dosingpump discharge non return valves.
This should rectify the problem bydelivering the correct strength of NaOH andensuring the complete removal of silicathrough efficient mixed bed regeneration.
WasteScottishPower encourages the efficient useof resources including minimising wasteand promoting reuse and recycling.
The station recycles materials, wherepossible, although quantities are low in linewith the size of the site. Among the itemsuplifted for recycling are wood, scrap metal,electrical equipment, paper and card, wasteoil, plastic, batteries and fluorescent tubes.
A total of 89.9 tonnes of solid waste and84,943 litres of liquid waste were producedat Damhead Creek during the year – bothshow a sharp increase on the previous year.
The major outage in 2012 resulted in anincrease in septic tank sludge, waste solidsand liquid, although this presented greateropportunities for recycling.
Separate waste skips and containers andrecycling facilities were made available forcontractors involved in the turbine overhaul.This enabled the station’s environmentalteam to calculate, where possible, separatetotals for outage waste and that which had-arisen from normal plant activities.
The outage has generated of a largeamount of scrap metal – including two valvesthat weighed a total of three tonnes. About44% (40t) of our solid waste was recovered orrecycled in 2012 – including four tonnes ofpaper/card, six tonnes of waste wood and29.5 tonnes of iron/steel.
Damhead Creek is investigating thecategorisation of septic tank sludge which isremoved from site by tanker for drying andincineration before being sent to landfill. Atotal of 50,750 litres of sludge was removedin 2012 – 81% of our total liquid waste.
Station staff have argued that most of thesludge is comprised of water, which isseparated out and recycled – therefore thereshould be a corresponding reduction to theiroverall liquid waste figures.
In 2012, a new waste managementprocedure was compiled – essentially a one-stop shop for information relating to wastestreams, how they are handled and who isresponsible for implementing policy.
This has helped ensure clarity about wasteand recycling activity on site ahead ofchanges to The Waste (England and Wales)Regulations 2011, which will require thesegregation of certain wastes by 2015.
It will also enable station staff to betteridentify recycling activities and allowtargeted action to reduce waste to landfill.
Recycling and waste disposal bins in place for use by contractors during the station’s 2012 outage
Damhead Creek’s landholdings include amitigation area of 32 hectares that featuresa range of habitats that are rich in wildlife.
Planning conditions for the station’sconstruction required the operators to retainexisting habitats and create and manage newareas for biodiversity to help mitigate for theenvironmental impacts of the plant’sconstruction and operation.
As a result, the station developed amitigation strategy in liaison with Kent Trustfor Nature Conservation, the Royal Societyfor the Protection of Birds and NaturalEngland. The strategy will run for the lifetimeof the station and is reviewed every fiveyears by Medway Council, Kent CountyCouncil and Natural England.
The land on which Damhead Creek wasbuilt was reclaimed from the marshhundreds of years ago but retainscharacteristics of a wetland site.
The mitigation area includes rivers andstreams, standing open water and canals,intertidal mud and sand, reedbeds andcoastal saltmarsh – all of which are priorityhabitats in the UK Biodiversity Action Plan(UK BAP), the Government’s initiative toconserve vulnerable habitats and species.
The mitigation land habitats support avaried and important range of wildlife –
Damhead Creek adjacent toMedway Estuary and Marsheswhich are internationally important for wildlife. The 4,600-hectare estuary site has been recognised as a Site of SpecialScientific Interest (SSSI), a Special Protection Area (SPA) andRamsar site for its nesting and wintering bird populations.
Damhead Creek’s mitigation land and some of our special species, from top, Water Vole, Brown Hare and Great Crested Newt, and below, Barn Owl
BIODIVERSITY & CONSERVATION
including many UK BAP species and othersthat are rare or vulnerable in Kent. DamheadCreek habitat management plan (HMP) forthe mitigation area focuses on four key aims:
■ Providing wildlife corridors to link retainedfeatures and conserve habitats of highecological value
■ Creating wildlife habitats
■ Managing land to enhance its natureconservation value
■ Protecting existing access.
The HMP, which was reviewedand updated in 2012, aims tomaintain, protect or enhancehabitats such as wetlands,reedbeds, grasslands, nativewoodland, saltmarsh and scrub.
It also targets pro-active measures
to improve conditions for key speciesincluding Water Vole, Great Crested Newt andBarn Owl. The work also benefits largenumbers of common species and plants.
Careful hydrological monitoring is criticalto the area’s ecosystem. The mitigation landis drained by a network of channels, weirs,ditches and outfalls that must be maintainedon a regular basis.
Ecological studies are also carried out tohelp ensure the successful management of
the mitigation area. Our expertsconduct mammal, vegetation and
bird surveys, and ongoinghydrological monitoring,
which enable us to applythe best management
technique for habitatsand species.
Damhead Creek’s Habitat Management Planwas reviewed and updated in 2012 to reflectkey targets at the mitigation land.
Many objectives remain unchanged, suchas specific work to maintain open water,wetland and grassland communities in goodcondition for their wildlife communities.
But some new projects have been includedand others – concerning Sand Martins andEuropean Mink, which are not present on site– removed from the revised plan.
In 2012, bee hives were introduced to helppollinate flowers on the mitigation land andin recent years have expanded our nestboxprogramme for Barn Owls.
Up to three pairs of Barn Owls have nestedat Damhead Creek in the past – although noattempts were made in 2012, and thisfollowed on from a generally poor breedingseason for birds the previous summer.
Damhead Creek commissioned a breedingbirds survey in 2011 that found 50 speciespresent from May to July.
More than half (27) of the birds recordedwere species of conservation concern due totheir declining UK populations or reductionin range. Five UK BAP birds nested or mayhave nested in 2011: Cuckoo, Song Thrush,Linnet, Reed Bunting and Lapwing.
Other notable breeding species includedthe Amber-listed Stock Dove, Whitethoat,Green Woodpecker, Little Grebe, Dunnockand Mallard, while Pochard and Shelducklikely nested at the mitigation pools.
Nevertheless, the number of overall andbreeding species was reduced on totals inthe 2009 breeding survey – when 80 specieswere found and 29 nested.
The surveyors felt that work to the east of
BIODIVERSITY & CONSERVATION
The Berry Wiggins Drain after ditch and vegetation clearance work was carried out in 2012
the mitigation land to build a series of largestorage warehouses may have causedtemporary disturbance to the station’s birds.
A wintering bird survey carried out in2011/2012 also reported a slight reductionin species’ numbers – from 29 in 2011 to 27in the latest survey. The estuary area of thesite was most productive, holding goodnumbers of wildfowl and wading birds.
Construction work off site may also havecontributed to fewer Water Voles present insome areas of the mitigation land during avole survey in 2011– although surveyorsnoted that the vole population was stableand increasing elsewhere. The last survey in2009 had found the Water Vole population atDamhead Creek to be at a record high.
In response, habitat improvements forWater Voles has ben carried out during 2012and included ditch clearance at the BerryWiggins Drain – the main channel runningthrough the mitigation area.
This was the first time that dredging hasbeen carried out in three years and a widecorridor was cleared of vegetation along thedrain to improve foraging habitat.
Invasive scrub has also been removed andthe heights of the water channels that drainthe area adjusted, providing more flexibilityas staff strive to create ideal conditions forthe reedbed’s wildlife community.
Going forward, ecologists will start to carryout monitoring for Smooth Newts, fish anduncommon species of invertebrate.
The station will also consider putting inplace artificial ‘tennis ball’ nestboxes alongthe southern perimeter forthe UK BAPmammal Harvest Mouse, which was firstfound on the site in 2007.
Viviparous Lizard (above) and left, Grass Snake (top) and Slow Worm (below) were monitored
The station’s Dave Allsop with the goat herd
A summer survey for reptiles at Damhead Creek has highlighted the importance of themitigation land for three key species.
Healthy populations of Slow Worm, Grass Snake and Viviparous Lizard were recordedat the site during seven visits made by ecologists.
All three species are legally protected and are listed as priorities for conservationaction in the UK BAP due to the many threats the face, particularly loss of habitat.
Surveyors monitored all the likely sites on the mitigation land where reptiles couldoccur and put in place artificial cover – such as corrugated metal sheets – for the lizardsand snakes to hide beneath.
Slow Worm, a legless lizard, was the most common and widespread species – on 17thJuly, more than 100 were counted, including many juveniles.
The maximum count of Viviparous Lizard was 31 adults and 2 juveniles on 18th June.Both types of lizard preferred drier areas of the site, with the Wetland Creation Area, inthe southwest of the site, the hotspot for sightings.
Grass Snake was less abundant although it was recorded on most visits and it wasthough to associate closely with ditches and pond margins. The highest count was threeon 28th September.
Several scarce plant species occur on themitigation land and are subject to biannualmonitoring.
Over the years, the fortunes of somespecies have fluctuated as a result ofcompetition from more vigorous plants andother ground conditions.
In the most recent vegetation survey,carried out in 2011, it was noted that someof the target species were stabilising orshowing a slight increase.
Oak-leaved goosefoot, Annual beard-grass,Perennial glasswort and Brackish watercrowfoot were all thought to have benefittedfrom increased ground disturbance at thesite, such as on beside vehicle tracks.
However, the surveyors concluded threespecies – Divided sedge, Curved hard-grassand Sea barley – appear now to be absentfrom the site.
Keeping a watchon scarce plants
SPECIAL SURVEY HIGHLIGHTS SCALEOF STATION’S REPTILE POPULATION Damhead Creek purchased a herd of 47
goats to control vegetation on landearmarked for Damhead Creek 2.
The use of the goats – along with 120sheep and seven horses – did the jobefficiently, while minimising disruption tothe special wild animals on the 12ha site.
Station staff were concerned at thepotential impact of mechanical plant onprotected species such as Great CrestedNewt, reptiles and breeding birds.
The conservation grazing approachremoved grass and brambles gradually,giving wildlife time to move on or adapt.
A local farmer grazed his sheep on the landand looked after the welfare of all thelivestock during the project. Once the landwas cleared, one-way fencing was erected tostop wildlife from re-entering the site – andthe goats were presented to the farmer as athank you from the station.
Goat squad hiredto keep site clear
Damhead Creek has a rolling programme of environmentalobjectives aimed at continual improvement in performancein key areas such as emissions, waste, water and energy use.This section summarises recent major achievements andhighlights key targets for the year ahead.
Achievements 2010
Energy use Inverters were installed on the final fiveHRSG roof fans to reduce fan speed by 25% The closed cooling water setpoint wasincreased by 4OC in the logicThe logic was adjusted in HRSG 1+2preheater circuits so that the preheaterpumps run less when circuit temperature isabove 60OCFurther energy saving ideas wereimplemented as reported in the energyefficiency report prepared by the CarbonTrust.
Achievements 2011
Energy use A project is ongoing to change fluorescenttubes to new high frequency T5 lighting.Waste Waste removal was optimised to reducevisits to site by waste disposal company.Water Usage DCS modifications were ongoing at thewater recovery plant to maximise therecovery of water.Emissions to water A site drains inspection was carried out aspart of the site protection monitoringprogramme on oily water drains.
Achievements 2012
Emissions to air A major outage was delivered to improveNOX performance.Stakeholders An EMAS Statement was produced for thestation which was verified by an EMASassessor in 2013 Quarterly environmental bulletins weredelivered to staff.Outage delivery Environmental risk assessments werecarried out for key outage activities Weekly environmental spot checks wereconducted at key areas of plant An outage nuisance noise plan wasproduced to minimise the risk of nuisancenoise complaints from the community.Resource use We investigated ways to optimise use ofprocess chemicals.
BiodiversityDamhead Creek’s biodiversity action planwas reviewd and updated.Water Use A project improved our water treatmentplant’s mixed bed efficiencyA small drains survey was completed.WasteWaste segregation was improved toincrease recycling and reduce disposal costs.
Targets for 2013
ComplianceMaintain ISO 14001 accreditationMaintain compliance with PPC.Protecting the environmentManage land contamination at DamheadCreek 2WasteDeliver quantified reduction andreuse/recycling targets for five key wastestreamsEnergy UseIdentify projects to reduce energyconsumption in two areas of significantenergy useImplement two energy efficiency projects,install additional water metering as requiredand review 12 months’ metering dataWater UseImplement two water efficiency projects,install additional water metering as requiredand review 12 months’ metering data.
Damhead Creek works closely with thecommunity and other stakeholders tofulfil the station’s obligations as agood and trusted neighbour.
The station has an open policy oncommunications with stakeholdersand welcomes feedback on itsactivities and operations.
Staff at Damhead Creek work closelywith our regulator, the EnvironmentAgency, to ensure the station meetsits environmental responsibilities.
Damhead Creek has an excellenttrack record of environmentalcompliance – there have been nobreaches of consent or justifiedcommunity complaints in the threeyears since our last EMAS Statement.
The station reported a pollutionincident to the EA in September 2012,when a neighbouring landowner’ssewage treatment plant spilled overand waste solids contaminated a pondon the mitigation land. DamheadCreek facilitated efforts by the EA tore-oxiginate the water body.
The station liaises closely withconservation groups – includingNatural England, Medway Council, theRSPB and Kent Trust for NatureConservation – to develop andimplement the management strategyfor the mitigation area to promotebiodiversity.
Damhead Creek continues tosupport local schools and groups withdonations, where this is possible. In2012, the station donated a minisnowplow and gritter to AllhallowsPrimary School in Rochester topromote safety in cold weatherconditions (pictured above).
STAKEHOLDERS
TARGETS & ACHIEVEMENTS
The EU Eco-Management and AuditScheme (EMAS) is a management tool forcompanies to evaluate, report andimprove their environmental performance.
The core elements of EMAS areperformance, credibility and transparency.
Registered companies, such as DamheadCreek, are compelled to continuallyimprove their environmental performanceand provide evidence that they complywith relevant legislation.
Under EMAS, the station must produce aStatement of its performance againstenvironmental objectives which isapproved by a third-party EMAS verifier.
ABOUT EMAS
new certificateto be supplied
after EMASassessment
ScottishPower is part of the IBERDROLA Group, one of the four largestenergy companies in the world by market capitalisation. ScottishPowerGeneration Holdings Ltd operates ScottishPower’s diverse generationportfolio, which includes coal and hydro power stations, and CombinedCycle Gas Turbine stations like Damhead Creek.
For more information on our activities, visit ScottishPower’s website:www.scottishpower.com
Damhead Creek EMAS Statement 2012 is published by:Damhead Creek Power Station,Kingsnorth, Hoo, near Rochester,Kent ME3 9TX
Statement produced by Lauder Stewart Communications Ltd. Tel: 01475 540791
From M25 take junction 2 for the A2 (towards Canterbury or Dover). After approx. 10-15minutes’ drive, branch off on to the A289 (towards the Isle of Grain). At the roundabout, take
the A228 (towards Grain). At the next roundabout, Damhead Creek Power Station is signposted.
Damhead Creek EMAS Statement 2012