Life Cycle Assessment of Advanced Zero Emission Combined

Int. J. Environ. Res., 6(3):801-814, Summer 2012ISSN: 1735-6865

Received 23 Nov. 2011; Revised 4 May 2012; Accepted 14 May 2012

*Corresponding author E-mail: [email protected]

801

Life Cycle Assessment of Advanced Zero Emission CombinedCycle Power Plants

Ataei, A.*, Iranmanesh, A. and Rashidi, Z.

Department of Energy Engineering, Graduate School of the Environment andEnergy, Science and Research Branch, Islamic Azad University, Tehran, Iran

ABSTRACT:This study investigated different concepts for natural-gas-fired power plants with the CO2

capture, and compared them based on the net plant efficiency and emission of CO2. The cycles were based ona six oxy-fuel, one post-combustion and two pre-combustion capture concept. This paper presented theresults of an environmental evaluation performed by the application of the Life Cycle Analysis (LCA) methodusing SimaPro model to compare an Advanced Zero Emission Power Plant (AZEP) concept with a conventionalcombined cycle power plant from 50MW to 400MW. The LCA study was built upon the calculation and thecomparison of several impacts (emissions of CO2, CO, NOX, and SOX, consumption of water and primaryenergy) and several impact categories (climate change, acid rain, ozone depletion and Ecotoxicity). The workwas developed entirely using the Eco-indicator99 of the LCA method. The results showed that for all studiedimpacts, the AZEP power plants have fewer impacts. However, compared to the conventional combined cyclepower plants, the total primary energy consumption in the AZEP concept is bigger due to the lower electricefficiency.

Key words: CO2 capture, zero emissions, combined cycles, LCA, Simapro, Eco-indicator99

INTRODUCTIONThe target of the LCA study was the comparison of

the environmental burdens associated with differentelectric power production systems. Some differentcases of the same plant size (50 to 400 MW) wereconsidered: the conventional CCGT without CO2capture, a CCGT including the AZEP (85,100%) concept(Bolland and Undrum, 2003; Bolland and Saether, 1992;Sundkvist et al., 2001). The LCA study was built uponthe calculation and the comparison of several impacts(emissions of CO2, CO, NOX, and SOX, consumption ofwater and primary energy) and several impact categories(Greenhouse Effect, Acid Rain, Ozone Depletion, andPhotochemical Formation). Alternatively, combustionin O2 / CO2 atmospheres, whilst enabling almost totalCO2 and NOX recovery, require expensive and energy-consuming oxygen supplies.A less energy-intensiveproposition is based on Mixed Conducting Membranes(MCM), which produce pure oxygen from air. MixedConducting Membranes are made from non-porous,metallic oxides that operate at high temperatures of over700°C, and they have high oxygen flux and selectivity

(Möller et al., 2006). These materials consist of complexcrystalline structures, which incorporate oxygen ionvacancies. The transport principle for oxygen throughthe membranes is surface adsorption followed bydecomposition into ions, which travel through themembrane by sequentially occupying oxygen ionvacancies. The ion transport is counterbalanced by aflow of electrons in the opposite direction (see Fig. 1).Since this transport process is based on ion diffusion,the selectivity of the membranes is infinite as long asthe membrane surface is perfect. The driving force forthis oxygen transport is the positive difference in partialpressure between the retentive side and the permeateside of the membrane (Griffin et al.,2005). Thesescenarios can facilitate assessing the degree ofuncertainty of the developed LCA according to thechoices made. Outside the limits of this work falluncertainties due to imprecise knowledge of thedifferent parameters used in the Life Cycle Inventory(LCI), spatial and temporal variability in differentparameters of the LCI, and uncertainty due to theinaccuracy of the environmental models used.

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Ataei, A. et al.

Fig. 1. Mixed Conducting Membrane(Griffin et al., 2003)

MATERIALS & METHODSLife cycle assessment (LCA) is a method to evaluate

the environmental impacts of product systems ‘fromthe cradle to the grave’. The life cycle inventory (LVI)includes emissions and resources used from resourceextraction, production, and distribution, to the disposalphase. The impact assessment evaluates thecontribution of these emissions and resource uses tospecific environmental impacts such as global warming,human toxicity, and biotic resource extraction(Kanokporn and Iamaram, 2011; Veltman et al., 2010).LCA has been developed independently in a numberof applications and disciplines, including chemicalengineering and energy analysis. The assessment ofalternative energy technologies has been one of themost important application areas, and initialassessments have focused on the cumulative (fossil)energy demand, including embodied or “grey” energy.An important motivation in the 1970s was to comparefossil and renewable energy technologies consistentlyin terms of the energy services they delivered for agiven amount of fossil fuel. LCA has since beenextended to address a wide range of environmentalconcerns. It has been standardized by ISO.

In order to facilitate the understanding of the workpresented in this paper, the author presents a briefsummary of the LCA that serves as the basis for thestudy: a LCA model of a natural gas combined-cyclepower plant with or without CO2 capture with theobjective of identifying the main types ofenvironmental impact throughout the life cycle, in order

to deûne possible ways of achieving environmentalimprovements (Bolland and Undrum, 2003; Bolland andSaether, 1992; Saeedi and Amini, 2007; Salehi et al.,2010;Singh et al., 2011). The ûnal environmental effect aftera lifespan of 20 years, and the reduction in emissionsand pollution due to the use of a clean energy sourcewas also evaluated. It was analyzed during the differentstages of its life cycle, taking into consideration theproduction of each of its component parts, thetransport, the installation, the start-up, and theoperation (Clerici,2003). The software used in theenvironmental analysis was SimaPro7.0 by PréConsultants (Pre Consultants, 2011). The procedures,details, and results obtained were based on theapplication of the existing international standards ofLCA .In addition, environmental details and indicationsof materials and energy consumption provided by thevarious companies related to the production of thecomponent parts were certiûed by the application ofthe environmental management system ISO14001.According to the requirements of the standardISO14044, allocation was avoided, since only theproduction of electrical power was considered as thefunction of the system in the study. LCA methodologywas based on Eco-indicator99. A series of cut-offcriteria was established in order to develop the studyin practice by deûning the maximum level of detail inthe gathering of data for the different components.The main cut-off criterion chosen was the weight ofeach element in relation to the total weight. Thislimitation in data collection did not mean a signiûcantweakening of the ûnal results obtained; it simplyallowed the researchers to streamline, facilitate, andadjust the LCA study to make it more ûexible. Thecharacterization of each component was obtained fromthe most important basic data of its manufacture: theraw material required, the direct consumption of energyinvolved in the manufacturing processes, and theinformation regarding transport used. This informationfor speciûc substances included the primary energyconsumption use related to the production,transportation, and manufacture of 1 kg of material.Due to limitations of time and cost, the LCA wasperformed under the following conditions: The cut-offcriterion used was the weight of the components.Previous work has indicated that the most efficientand cost-effective utilization of the MCM reactor is itsintegration into a conventional gas turbine system toproduce an Advanced Zero Emissions Power Plant,the AZEP concept (Amini et al., 2008; Ataei et al., 2011;Ataei and Yoo, 2010; Yoo et al., 2010). The combustionchamber in an ordinary gas turbine is here replaced bythe MCM-reactor, which includes a combustionchamber, a ‘low’ temperature heat exchanger, an MCMmembrane, and a high temperature heat exchanger

Int. J. Environ. Res., 6(3):801-814, Summer 2012

803

(Bruun,2000). After compression in the ordinary gasturbine compressor, the compressed air at about 18 baris heated to about 800 - 900°C in the ‘low’ temperatureheat exchanger before it enters the MCM membrane(Ataei et al., 2011). The MCM section combines heattransfer and oxygen transport between the air streamand a sweep gas stream. Permeated oxygen is pickedup by means of the circulating sweep gas containingmainly CO2 and H2O. The concentration of oxygen inthe circulating gas is about 10% at the inlet of theburner. Hot combusted gas then enters the hightemperature heat exchanger co-current to the oxygendepleted air stream. This air stream is then heated to1200°C (up to 1400°C). The pressure difference overthe membrane should be kept low (below 0.5 bar) tominimize any leakage. About 10% of the combustedgas is bled off at about 18 bar and heat is recovered byheating a smaller part of the compressed air. The hotoxygen-depleted air is then expanded in the turbine togenerate electrical power. Waste heat in both theoxygen-depleted air stream and the CO2 containingbleed gas stream is recovered in HRSG’s by generatingsteam at various pressure levels and by pre-heatingthe fuel gas. The steam is utilized in a steam turbine forpower generation. The CO2 containing bleed gas isfurther cooled to condense water. CO2 is recovered,compressed from about sweep gas pressure, liquefied,and then pumped to its final pressure (100 bar). Theconcept allows 100% CO2 capture, and in this case,has less than 1 ppm v/v NOx in the oxygen-depletedoutlet air.

The first system design modeled is a referencesystem. As such, a traditional CCGT power plant waschosen (see Fig. 2). Data from such plants are inabundance, both in terms of thermo-dynamicalperformance used as a base in the modeling, and tosome extent, cost data. The AZEP 100% case is a“traditional” type of combined-cycle arrangement, butwith an MCM-reactor system replacing the traditionalcombustion chamber (Sundqvist et al., 2001). Air iscompressed in the gas turbine and is then heated inthe MCM-reactor. Due to MCM material and reactordesign limitations, the MCM-reactor outlet temperaturewas restricted to 1200°C, which is considerably lowerthan the reference CCGT. A percentage of the oxygencontained in the air, typically 50%, is transferredthrough the membrane, and is carried along by theCO2/H2O sweep gas. The oxygen containing sweepgas then reacts with natural gas to generate heat in acombustion chamber. A share of the sweep gas is bledoff to keep the sweep gas mass flow constant in theMCM- reactor. The heat contained in the bleed gas isrecovered in a separate CO2/H2O HRSG, providing extrasteam for the steam cycle and preheating the naturalgas fuel. The heat recovery has to be terminated at ahigher temperature than in the ordinary HRSG due to

the high water content in the bleed gas. After the HRSG,the water is condensed and the remaining CO2 iscompressed and liquefied from the MCM-reactorpressure at around 20 bar to delivery pressure at 100bar. A layout of the AZEP 100% cycle is shown in Fig.3. The third alternative, the AZEP 85% case, includesa sequential combustion chamber to increase theturbine inlet temperature. This is to improve the thermalperformance of the MCM-based power plant (Asen etal.,2003; Griffin et al., 2005; Möller; 2006). Fig. 4 showsa power plant including a sequential burner increasingthe turbine inlet temperature (TIT) to 1327ºC on theairside using natural gas as fuel. Table 1 lists the powerplant construction material requirements used in thisstudy. These values were based on a study thatexamined power generation via a number oftechnologies - for example, a 400 MW NGCC system.

Table 2 is a comparison between the AZEP power-plant concept (oxy-fuel) and the standard CCGTwithout CO2 capture from 50MW up to 400MW.Net plant efficiency is defined as:

(1)

The first term is related to thermodynamic work ofgas turbines, steam turbines, and gas turbinecompressors. This net thermodynamic work ismultiplied by a turbine to electricity grid efficiency, η t→e, which for most of the concepts is 0.97. The 2ndterm is the fuel cell electric work, while the 3rd termconcerns the losses related to DC to AC conversion.The last term is the sum of work related to consumersas auxiliaries, pumps, ejectors, CO2 compression, O2production and compression, amine absorption, andutilities. The base case of this LCA used the typicalnatural gas pipeline composition listed in the ChemicalEconomics Handbook (Lacson, 1999), which wasadjusted to include H2S (4 ppmv; based on thespecifications above). The composition of the naturalgas transported to the power plant is shown in Table3. To show the diversification of natural gascompositions found throughout the world, the rangeof wellhead component values is also listed in Table 3.

RESULTS & DISCUSSIONThe LCA study, built upon the calculation and the

comparison of several impacts (emissions of CO2, CH4,CO, NOX, and SOx, consumption of water and primaryenergy) and several impact categories (GreenhouseEffect or Global Warming Potential, Acid Rain, OzoneDepletion, and Photochemical Formation), shows a verygood environmental rank for the systems based on theAZEP concept, as seen in Table 4 and in Fig. 5. This is

804

Life Cycle Assessment

Fig. 2. The reference CCGT cycle (Möller et al., 2006)

Fig. 3. The AZEP 100% case (Möller et al., 2006)

Table 1. Power plant materials requirement for 400MW

Componen ts Amount

Constructional Alum inum (kg ) 440000 Conc rete ( m3) 6000 C opper (kg) 440000 Rock wool(kg) 660000 P olyethylene (kg) 1300000 C hr omium ste el (kg) 1800000 Reinforcing steel(kg) 8800000 Nicke l, 99.5%(kg) 6300 Chromium (kg) 976 C obalt (kg) 720 Cer amic tile s(kg) 4200

Operational Natur al gas(Mj) 154000000

805


Fig. 4. The AZEP 85% case. (Möller et al., 2006)

Table 2. Process Simulation Results of the 50 MW to 400 MW Power Plant Cases

Plant Data

Net power

output (MW)

Plant fired

heat (MJ/s)

Net p lant

ef fic iency

(LHV) (%)

CO2

compression

power (M W)

50 MW(15-50)

CCGT

63.9

120.6

53

-

AZEP 100% 46.2 95.4 48.5 0.49

AZEP 85% 53.9 107.1 50.3 0.47

100MW(51-100) CCGT 112 200.2 54.7 -

AZEP 100% 87 149.5 48.9 0.78

AZEP 85% 98 182 51.5 0.7

200MW(101-200) CCGT 208 339.1 56 -

AZEP 100% 143 290 49.2 1.67

AZEP 85% 178 314.7 52 1.51

400MW(201&uppe) CCGT 400 692.4 57.9 -

AZEP 100% 248.1 500.5 49.6 2.95

AZEP 85% 300.4 562.5 53.4 2.85

806

Ataei, A. et al.

Table 3. Natural Gas Composition

Component Pipeline composit ion Typical range of wellhead

Typical range of wellhead

Mol % (dry) Low value High va lue Carbon dioxide (CO2) 0.5 0 10 Nitrogen (N2) 1.1 0 15 Methane (CH4) 94.4 75 99 Ethane (C2H6) 3.1 1 15 Propane (C3H8) 0.5 1 10 Iso-butane (C4H10) 0.1 0 1 N-butane (C4H10) 0.1 0 2 Pentanes + (C5+) 0.2 0 1 Hydrogen sulfide (H2S) 0.0004 0 30 Helium (He) 0 0 5 Heat of combustion, LHV 48,252 J/g

(20,745Btu/lb) - -

Heat of combustion, HHV 53,463 J/g (22,985Btu/lb)

- -

particularly evident for two global effects, theGreenhouse Effect and the Acid Rain Potential, and fortwo impacts, the CO2, and NOX emissions. For all thestudied impacts and impact categories, the AZEP powerplants have less environmental impacts. However, dueto lower electric efficiencies, the total consumption ofprimary energy is larger for both the CO2-capturingconcepts compared to the conventional CCGT plants.The impact category Global Warming Potential(expressed in CO2 equivalents) is dominated byCombustion Emissions. Of the other emission sources(Gas Life Cycle, Auxiliary Systems, Liquid Waste), onlythe Gas Life Cycle emissions have a non-negligibleimpact on the Global Warming Potential. In the LCAstudy, the emissions of CO and CH4 (per kWe (LHV) offuel) for the AZEP plants were assumed to be on thesame level as in conventional CCGT plants. In the AZEPprocess, however, these components are mainly flashedoff after the CO2 liquefaction stage together with somenitrogen and oxygen. Probably more than 90% of thesecarbon components can be burnt in a catalytic converterand recycled to the CO2 compression train Appel at el,2002; Carroni et al., 2003; Carroni et al., 2002; Erikssonet al., 2006; Mantzaras et al., 2006; Mantzaras et al.,2000; Mark et al., 1996). Thus, the ‘Potential ofFormation of Oxidants Agents by Photochemical Effect’would be reduced accordingly. AZEP with nosequential burner will produce very little NOx sincethere is no combustion in the air stream. In the case ofsequential combustion in the air stream before theexpander, some NOx might be formed, dependent onthe combustion temperature. This has not yet beenstudied. However, the NOx formation will besignificantly lower than in a conventional CCGT.

Electricity generation from the NGCC power plantwithout CO2 capture implies an emission of 425 gCO2/kWh, with over 86% direct emission from fuelcombustion. In the case of the NGCC power plantcoupled with carbon capture and a storage system,this emission intensity decreases to 125 gCO2/kWh. Fig.5 illustrates the CO2 account and compares the emissionsources for both the cases, with and without CCS. Thecapture process at the power plant facility captures90% of the CO2 from the flue gas. However, additionalCO2 is generated from fuel combustion because of theenergy penalty, operational inputs, and theinfrastructure required for capture, operation,transport, and storage. The increased CO2 productionresults in a larger amount of ‘CO2 generated per unit ofproduct’ (508 gCO2/kWh).

Total CO2 captured in the production of electricitywith the CCS system is about 383gCO2/kWh, reducingthe CO2 capture efficiency over the complete life cycleto 75%. In addition to CO2 emissions, there are variousother direct and indirect emissions throughout all theprocesses, from raw material extraction for fuel,infrastructure, and other required materials to wastetreatment and disposal. Fig. 6 compares the absolutescores after characterization for ‘with CCS’ and ‘withoutCCS’ systems. The results show that there is an increasein all environmental impacts. These scores reveal themagnitude of the impact emanating from the whole lifecycle of electricity generation. The impacts areunevenly distributed over various processes (naturalgas combustion at the power plant, CO2 capture,infrastructure, solvent production) and locations(offshore natural gas production facilities, chemical

(a) Taken from Chemical Economics Handbook (Lacson, 1999)and adjusted to include H2S.(b) Taken from Ullmann’s Encyclopedia of Industrial Chemistry, 1986

807


Table 4. Comparing 1 p ‘Life cycle AZEP100%’, 1 p ‘Life cycle AZEP85%’ and 1 p ‘Life cycle NGCC’

Method: Greenhouse Gas Protocol V1.00 / C02 eq (kg) Indicator: Characterization (400MW)

Impact category Unit Life cyc le AZEP100%

Life cyc le AZEP85%

Life cyc le NGCC

Fossil CO2 eq kg CO2eq 30660571 32482622 41056289 Biogenic CO2 eq kg CO2eq 307221.75 307675.84 309914.55 CO2 eq from land transformation

kg CO2eq 454.98486 459.20713 479.14303

CO2 uptake kg CO2eq 370831.3 371274.13 373455.04

manufacturing sites, power plant facilities, iron and steelindustries, mining sites, etc.). The Damage assessmentfor LCI (AZEP 100%) is shown in Fig. 7. Directemissions at the power plant facility consist of varioussubstances, such as NOX, SOX, acetaldehyde,formaldehyde, and hazardous reclaimed wastes (Veltmanet al., 2010). The capture process, while capturing CO2,reduces NOx, SO2, and particulate emission. However,their net removal efficiency per kWh electricitygeneration is lower than the designed performanceparameter, due to the increased combustion of naturalgas to meet the energy requirements of the captureprocess. The results of single score LCI analyzing forNGCC and AZEPs are shown in Figs 8,9,10.

The energy penalty also results in increasedemissions of CH4, CO, and other pollutants that are notcaptured by the process. These compounds havepotential for causing various environmental impacts.Table 6 compares impacts due to direct emissions fromthe facility and their contributions to the total impact,quantifying the immediate hazards from capturetechnology. The contribution analysis in Table 6 shows

that the direct emissions at plant facilities are responsiblefor 45% and 57% of the total acidification and marineeutrophication, respectively for 85% of NGCC and 100%of AZEP concepts, respectively. The capture processreduces the score due to SO2 and NO2 removal; however,the reduction is insignificant to the impact from increasedemissions of NOx. Direct emissions from the plant facilityconstitute 45% of the total life cycle score. NOx emissionfrom fuel combustion is the main contributor to this impact(94% of the direct impact). The second major source (40%)of the impact is due to emissions of CH4 and SO2 in thenatural gas production chain and about 14% of the impact isfrom infrastructure demands. The results of LCI analysiswith weighting indicator for NGCC and AZEPs are shownin Tables 7,8,9.

Particulate matter formation potential (PMFP) resultsshow an increase of 33% in the total life cycle score.37% of the total PMFP impact is attributed to directemissions from the plant facility with NOx emissionsfrom fuel combustion being the largest contributor (93%).Natural gas production constitutes 32% of the impactand 31% is from infrastructure demands.

0

5

10

15

20

25

30

35

40

45

CO2 UptakeCO2 eq from landtransform

Biogenic CO2 eqFossil CO2 eq

kton

Life cycle NGCCLife cycle AZEP 85%life cycle AZEP 100%

Fig. 5. Comparing 1 p ‘Life cycle AZEP100%’, 1 p ‘Life cycle AZEP85%’, and 1 p ‘Life cycle NGCC’Method:Greenhouse Gas Protocol V1.00 / C02 eq (kg) Indicator: Weighting

808


Chart Title

05001000150020002500300035004000450050005500600065007000

Fossil fuel

Mineral

Land use

Acidificatio

n/Eutroph

Ozon layer

Radiation

Climate change

Resp. inorganics

Resp. organics

Carcinogns

Life cycle NGCC

Life cycle AZEP 85%

life cycle AZEP 100%

Fig. 6. comparing 1 p ‘Life cycle AZEP100%’, 1 p ‘Life cycle AZEP85%’ and 1 p ‘Life cycle NGCC’ Method:Eco-indicator 99 (H) V2.07 / Europe EI 99 H/A /Normalization

Fig. 8. Analysing 1 p ‘AZEP100 % (400MW) Method: Eco-indicator 99 (H) V2.07 / Europe EI 99 H/A /Single score

00.20.40.60.811.21.41.61.822.22.4

oxyg

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Cabit,

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ium, a

t reg

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Nickel,

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%, a

t reso

urce

s

Polye

thylen

e, LD

PE

rock

woo

l, pac

ked

Concre

te, no

rmal

Alumini

um, p

rodu

ction

Coppe

r at r

egion

a

Reinfor

cring

stee

l

Chorm

ium st

eel 1

8

MPtResources

ecosystem Qualityhuman health

0%20%40%60%80%100%

fossil fu

el

Mineral

Land Use

Acidific

atio

Ecotox

icity

Ozon l

ayer

Radiation

Climate

Change

Resp.in

or gan

ics

Resp.organi

cs

Carcinog

e

Chromium Steel 18/8, at plant/RER U reinforcing Steel, at plant/RER UCopper,at regional Storge/RER U Alminium, Production mix, at plant/RER UChromium, at regional storage/RER U Concret, normal, ar plant/CH UOxygen, burned in industrial furnace >100KW/RER U Rock wool, Packed, at Plant/CH UPolyethylene, LDPE, granulate, at plant/RER U Cobalt, at plant/GLO UNichel, 99.5%, at plant/GLO U

Fig.7. Analysing 1 p ‘AZEP100 % (400MW) Method: Eco-indicator 99 (H) V2.07 / Europe EI 99 H/A /Damageassessment

809


00.20.40.60.811.21.41.61.822.22.4

Natural

gas, burn

ed

oxygen

burne

d

Cabit, at p

lant

Chorm

ium, a

t regio

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99.55%

, at re

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rock woo

l, pack

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teel

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00.20.40.60.811.21.41.61.822.2

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ral g

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at pl

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Fig. 9. Analysing 1 p ‘AZEP85 % (400MW) Method: Eco-indicator 99 (H) V2.07 / Europe EI 99 H/A /Single score

Fig .10. Analysing 1 p ‘NGCC (400MW) Method: Eco-indicator 99 (H) V2.07 / Europe EI 99 H/A /Single score

Table 6. Comparing 1 p ‘Life cycle AZEP100%’, 1 p ‘Life cycle AZEP85%’, and 1 p ‘Life cycleNGCC’Method: Selected LCI results V1. Indicator: Characterization (400MW)

Impact category Unit Life cycle AZEP100%

Life cyc le AZEP85%

Life cycle NGCC

NMVOC kg 21853.981 22566.673 25920.419 Carbon dioxide fossil kg 27636454 29348681 37405562 Sulphur dioxide kg 129772.91 130391.17 133306.27 Nitrogen oxides kg 71098.875 72204.554 77410.575 Particulates, <2.5 m kg 32127.573 32151.153 32299.169 Land occupation m2 1134838.7 1135914.5 1141244.4 BOD kg 42844.845 42961.601 43514.316 Cadmium kg 0.003472432 0.00347964 0.003514453

µ

810

Ataei, A. et al.

Tabl

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naly

zing

1 p

‘A

ZE

P100

% (

400M

W)’

Met

hod:

Eco

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) V

2.07

/ E

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H/A

Ind

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or:

Wei

ghti

ng

Impa

ct

cate

gory

Unit

Total

Chromium steel 18/8, at plant/RER U

Reinforcing steel, at plant/RER U

Copper, at regional storage/RER U

Aluminium, production mix, at plant/RER U

Concrete, normal, at plant/CH U

Rock wool, packed, at plant/CH U

Polyeth-ylene, LDPE, granulate, at plant/RER U

Nickel, 99.5%, at plant/GLO U

Chromium, at regional storage/RER U

Cobalt, at plant/GLO U

Oxygen, burned in industrial furnace >100kW/RER U

Tota

l Pt

62

3648

9.7

2040

706.

2 96

4955

.9

2439

223

2707

40.31

40

816.

852

9471

9.804

33

3833

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4285

3.52

6 20

01.5

883

729.

5693

2 59

09.57

88

Carc

inog

ens

Pt

1879

978.7

72

801.

775

1070

32.7

7 16

2624

1.1

4856

8.48

4 23

81.8

281

4992

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11

17.9

759

1528

9.09

7 18

8.43

539

64.5

2306

6 13

00.32

6

Resp

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s Pt

73

0.79

275

132.

4554

1 24

7.28

525

54.49

2384

34

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16

13.47

189

27.1

4781

6 21

7.502

01

2.521

1893

0.2

4415

407

0.347

2041

3 0.

7022

2054

Resp

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orga

nics

Pt

13

7314

9.3

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50.5

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.23

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1 80

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1193

2.07

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6 16

518.

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489.

5302

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519

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Clim

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16

7694

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4420

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1 70

461.6

06

4542

.369

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40.79

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8 37

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8269

6

Radi

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n Pt

29

38.7

95

913.

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6 11

09.58

6 12

8.728

35

528.6

9299

95

.9850

25

101.

0691

6 0.

9372

5111

8.9

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09

5.733

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1.1

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Ozon

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Pt

34.6

4003

7 10

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169

13.5

0722

4 1.

6873

655

6.13

5867

9 1.

4317

327

0.91

1491

820.

0247

6795

6 0.

1415

1481

0.0

4962

9925

0.0

1164

694

0.12

9626

65

Ecot

oxic

ity

Pt

9964

60.69

63

6275

.12

6271

6.493

28

0176

.42

1112

0.57

6 80

8.875

39

1246

.2596

26

6.64

29

3112

.578

6 32

4.19

364

14.5

9208

2 39

8.94

49

Acid

ifica

tion/

Eu

troph

icati

on

Pt

4580

7.40

1 11

509.

052

1427

5.984

94

80.2

287

3808

.569

9 13

90.9

084

1485

.4709

27

35.8

76

950.

4760

8 24

.444

3 36

.607

091

109.

7830

8

Land

use

Pt

32

210.

408

1016

5.20

6 10

990.8

05

5198

.709

1 24

92.5

31

611.4

7116

24

96.27

13

12.42

0231

13

6.41

811

16.9

1746

9 39

.586

898

50.0

7086

9

Min

erals

Pt

9360

01.77

58

2943

.86

4630

1.517

27

7794

.92

2247

9.17

8 42

4.386

99

1306

.8969

4.

2938

776

4550

.269

71.0

5065

7 9.3

5127

02

116.

0332

4

Foss

il fu

els

Pt

8014

82.22

16

2903

.77

2082

14.1

2 23

110.

039

8056

9.80

8 14

603.

131

2120

4.433

28

6328

.27

1910

.774

3 73

9.72

88

152.

1701

2 17

45.98

45

811


Tabl

e 8. A

naly

zing

1 p

‘AZ

EP8

5 %

(400

MW

)’ M

etho

d: E

co-in

dica

tor 9

9 (H

) V2.

07 / E

urop

e EI 9

9 H

/A I

ndic

ator

: Wei

ghtin

g

Impa

ct ca

tegor

y Unit

Total



Copper, at regional storage/RER




Polyethylene, LDPE, granulate, at plant/RER U




Oxygen, burned in industrial furnace >100kW/RER U

Natural gas, burned in industrial furnace >100kW/RER U

Total

Pt

63

5350

6.2

2040

706.

2 96

4955

.9 24

3922

3 27

0740

.31

4081

6.85

2 94

719.

804

3338

33.3

3 42

853.5

2620

01.5

883

729.5

6932

48

73.4

838

1180

52.64

Carc

inog

ens

Pt

1880

123.

3 72

801.7

75

1070

32.77

1626

241.

1 48

568.4

84

2381

.828

1 49

92.3

807

1117

.975

9 15

289.0

9718

8.43

539

64.52

3066

10

72.3

467

372.

5292

3

Resp

. org

anics

Pt

75

0.210

94 1

32.45

541

247.2

8525

54.4

9238

4 34

.623

216

13.4

7189

27

.1478

16

217.5

0201

2.

5211

893

0.244

1540

0.34

7204

1 0.5

7910

3919

.541

3

Resp

. inor

gani

cs

Pt

1377

148.

1 51

8850

.51

4435

92.23

2124

94.3

1 80

833.6

85

1193

2.07

2 57

818.

173

2867

5.23

6 16

518.5

9348

9.53

026

378.5

7519

12

91.74

2 42

73.4

662

Clim

ate c

hang

e Pt

17

7568

.38

4420

0.291

70

461.

606

4542

.3698

20

298.0

24

8553

.290

5 40

40.7

903

1447

4.14

8 37

3.66

579

141.

2605

732

.6920

88

475.

6949

699

74.5

496

Radi

ation

Pt

29

41.1

515

913.

5463

6 11

09.5

86

128.

7283

5 52

8.69

299

95.9

8502

5 10

1.069

16

0.93

7251

0 8.

9906

109

5.733

3798

1.11

2670

1 36

.626

4 10

.143

263

Ozo

ne la

yer

Pt

40.78

0478

10.

6091

69

13.50

7224

1.68

7365

5 6.

1358

679

1.431

7327

0.9

1149

18

0.02

4767

9 0.

1415

148

0.049

6299

0.01

1646

9 0.1

0689

996.

1631

685

Ecot

oxici

ty

Pt

9965

47.7

3 63

6275

.12

6271

6.49

328

0176

.42

1112

0.576

80

8.87

539

1246

.259

6 26

6.642

89

3112

.5786

324.

1936

414

.5920

82

329.

0000

215

6.98

048

Acid

ifica

tion/

Eu

troph

icatio

n Pt

46

351.

119

1150

9.052

14

275.

984

9480

.2287

38

08.56

99

1390

.908

4 14

85.4

709

2735

.876

95

0.47

608

24.4

443

36.60

7091

90

.535

394

562.

9657

7

Land

use

Pt

32

622.

714

1016

5.206

10

990.

806

5198

.709

24

92.53

54

611.

4710

5 24

96.2

714

12.42

0006

13

6.41

811

16.9

1747

239

.5868

98

41.2

9221

142

1.08

037

Min

erals

Pt

93

6037

.87

5829

43.8

6 46

301.

517

2777

94.9

2 22

479.1

78

424.

3869

9 13

06.8

969

4.29

3866

8 45

50.2

69

71.0

5065

79.

3512

702

95.6

8975

256

.445

7

Foss

il fu

els

Pt

9033

74.8

9 16

2903

.77

2082

14.12

2311

0.039

80

569.8

08

1460

3.13

1 21

204.

433

2863

28.2

7 19

10.77

4373

9.72

88

152.1

7012

14

39.8

703

1021

98.78

812

Tabl

e 9. A

naly

zing

1 p

‘NG

CC

(400

MW

)’ M

etho

d: E

co-in

dica

tor 9

9 (H

) V2.

07 / E

urop

e EI 9

9 H

/A I

ndic

ator

: Wei

ghtin

g

Impa

ct ca

tego

ry

Unit

Total



Copper, at regional storage/RER U




Polyethylene, LDPE, granulate, at plant/RER U




Natural gas, burned in industrial furnace >100kW/RER U

Total

Pt

69

0486

2.8

2040

706.

2 96

4955

.82

2439

223

2707

40.3

2 40

816.

852

9471

9.80

6 33

3833

.33

4285

3.52

6 20

01.58

83

729.5

6932

67

3337

.3

Car

cinog

ens

Pt

1880

849.7

72

801.

773

1070

32.76

16

2624

1.1

4856

8.486

23

81.8

281

4992

.380

9 11

17.9

759

1528

9.09

7 18

8.43

54

64.52

3066

21

24.79

63

Res

p. or

gani

cs

Pt

841.5

9128

13

2.455

41

247.2

8524

54

.492

384

34.6

2321

9 13

.471

89

27.1

4781

6 21

7.50

201

2.521

1893

0.2

4415

408

0.347

2041

3 11

1.45

779

Res

p. in

orga

nics

Pt

13

9666

6.1

5188

50.5

44

3592

.2

2124

94.3

1 80

833.6

9 11

932.

072

5781

8.17

4 28

675.

236

1651

8.59

3 48

9.53

027

378.5

7519

24

374.5

85

Clim

ate c

hang

e Pt

22

4027

.82

4420

0.29

1 70

461.

604

4542

.3698

20

298.0

25

8553

.290

5 40

40.7

904

1447

4.14

8 37

3.66

579

141.

2605

7 32

.6920

88

5689

1.876

Rad

iatio

n Pt

29

52.7

052

913.5

4635

11

09.5

86

128.

7283

5 52

8.69

3 95

.985

025

101.

0691

7 0.9

3725

086

8.990

6109

5.

7333

799

1.11

2670

1 57

.854

164

Ozo

ne la

yer

Pt

69.67

2863

10

.6091

68

13.50

7222

1.

6873

655

6.13

5868

1 1.4

3173

27

0.911

4918

4 0.0

2476

7955

0.1

4151

481

0.04

9629

926

0.011

6469

435

.152

887

Ecoto

xici

ty Pt

99

6972

.11

6362

75.1

2 62

716.

484

2801

76.4

2 11

120.5

78

808.

8753

4 12

46.2

598

266.

6429

3 31

12.5

786

324.

1936

4 14

.5920

82

895.3

701

Acid

ifica

tion/

Eu

troph

icati

on

Pt

4891

2.00

3 11

509.

052

1427

5.98

2 94

80.22

87

3808

.5702

13

90.9

084

1485

.471

27

35.8

76

950.

4760

8 24

.444

301

36.60

7091

32

10.98

99

Land

use

Pt

34

570.

348

1016

5.20

7 10

990.

805

5198

.7089

24

92.53

24

611.

4710

9 24

96.2

719

12.4

2011

4 13

6.41

811

16.9

1748

4 39

.5868

98

2401

.7177

Min

erals

Pt

93

6214

.83

5829

43.8

6 46

301.

508

2777

94.9

2 22

479.1

8 42

4.38

694

1306

.897

4.2

9390

5 45

50.2

69

71.0

5066

9.

3512

702

321.

9495

2

Foss

il fu

els

Pt

1382

786

1629

03.7

6 20

8214

.1

2311

0.039

80

569.

811

1460

3.13

1 21

204.

433

2863

28.27

19

10.7

743

739.

7288

1 15

2.170

12

5829

11.5

6


CONCLUSIONThe different uncertainties arising from the options

given during the development of the LCA of a combinedcycle power plant (or AZEP) have been analyzed inthis study, using the Eco-indicator99 LCA method. Inaddition, the impact that these scenarios may presenton the ûnal LCA has also been assessed. Undoubtedly,the choices made at the turbine maintenance stagehave an important effect on the results of the LCA.Therefore, it is necessary to precisely analyze theaverage of major corrections that a model of combinedcycle power plant (or AZEP) may experience along its20 years of life. Another issue that signiûcantlyinûuences the ûnal results of the LCA study of anAZEP is the considerations made about recycling andreuse of components and materials from anenvironmental point of view. Compared with aconventional CCGT the optimized AZEP concept forthe 50 MW size gives 4.5 percentage points reductionin thermal efficiency (LHV) with 100% CO2 captureincluding pressurization of CO2 to 100 bar. In the AZEP50 MW case with a CO2 capture of 85% the penalty inthermal efficiency is less than 3.0 percentage pointscompared to a standard CCGT. The 400 MW size hasmore penalty for the 100% CO2 capture case andtherefore needs a sequential combustion before theexpander to improve the thermal efficiency. In an AZEP400 MW case with 85% CO2 capture the penalty inthermal efficiency (LHV) is 4.5 percentage points. TheLCA study shows a very good environmental rank forthe systems based on the AZEP concept. This isparticularly evident for two global effects, theGreenhouse Effect (Global Warming Potential) and theAcid Rain Potential, and for two impacts, the CO2 andNOx emissions. For all studied impacts and impactcategories, the AZEP power plants have fewer impacts.However, compared to the conventional CCGT plantsthe total consumption of primary energy is bigger forboth the CO2 capturing concepts due to lower electricefficiencies for these concepts.

Abbreviation

AZEP Advanced Zero Emissions PlantLCA Life Cycle AssessmentLCI Life Cycle InventoryLCIA Life Cycle Impact AssessmentBFW Boiler Feed Water SystemCCGT Combined Cycle Gas TurbineHP High PressureLP Low PressureHRSG Heat Recovery Steam GeneratorMCM Mixed Conducting MembraneTIT Turbine Inlet TemperatureHTP Human Toxicity Potential

PMFP Particulate Matter Formation PotentialBOD Biological Oxygen DemandNMVOC Non-Methane Volatile Organic CompoundsWFC Fuel cell electrical workWexp , WC Thermodynamic work of gasturbines, steam turbines, and gas turbine compressorsWAD/AC Losses related to DC to AC conversionWconsumers Work related to auxiliaries, pumps,ejectors, CO2 compression, O2 production andcompression.ήt → e Electricity grid efficiency

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Documents

Life Cycle Assessment of Advanced Zero Emission Combined