Impact of Operational Constraints on Generation Portfolio Planning with Renewables

Transcription

1 1 Impac of Operaonal Consrans on Generaon Porfolo Plannng wh Renewables P. Vhayasrchareon, Member, IEEE, T. Lozanov, Suden Member, IEEE, J. Resz, Member, IEEE and I. MacGll, Member, IEEE Absrac Increasng varable renewable generaon peneraons wll cause ncreased cyclng operaon for convenonal generang plans. No all of hese plans are necessarly well sued o such operaon. Tradonal long-erm generaon plannng frameworks ofen neglec hese operaonal characerscs and herefore do no reflec he operaonal consrans and coss assocaed wh cyclng of generang plans. Usng a dealed generaon dspach model n PLEXOS, hs sudy assesses he poenal mpac of shor-erm operaonal consrans and coss on fuure hgh renewable generaon porfolos obaned from a long-erm porfolo plannng framework. A case sudy of he Ausralan Naonal Elecrcy Marke (NEM) wh dfferen renewable peneraons, rangng from 15% o 85%, suggess ha he echncal and cos mpacs assocaed wh he operaonal consrans modelled are moderae even a hgh renewable peneraons. The exen of he mpacs also depends parcularly on he level of carbon prce and he mx of generaon echnologes whn he porfolos. Index Terms Generaon plannng, operaonal consrans, cyclng, flexbly, varably, renewable generaon I. INTRODUCTION ARIABLE renewable generaon, parcularly wnd and Vsolar phoovolacs (PV), are fas becomng major generaon sources n a number of elecrcy ndusres. Gven her varable, somewha unpredcable and parly dspachable naure, here are concerns over he poenal operaonal and economc mpacs of negrang such renewable sources no power sysems. In parcular, hey wll ncrease he varably of ne demand o be me by convenonal dspachable generaon necessang more frequen cyclng (ramp up/down, sarup/shudown) operaon of hese uns [1]. Large hermal generaon has parcular echncal lmaons and coss assocaed wh such operaon. As he shares of wnd and solar generaon are projeced o subsanally ncrease n he comng decade, s mporan o ensure ha hs can be accommodaed by fuure elecrcy sysems [2] wh large hermal plans. Hence, long-erm generaon plannng and nvesmen modelng needs o reasonably capure acual operaonal characerscs of generang plans and her ably o respond o rapd and frequen changes n ne demand [3]. Key hermal plan Ths work has been suppored n par by Ausralan Renewable Energy Agency (ARENA) and he CSIRO Fuure Grd Projec. The auhors acknowledge Energy Exemplar and FICO for provdng academc lcenses of PLEXOS and Xpress-MP solver used n hs paper. The auhors are wh he Cenre for Energy and Envronmenal Markes and School of Elecrcal Engneerng and Telecommuncaons, Unversy of New Souh Wales, Sydney, Ausrala (emal: peerapa@unsw.edu.au). operang characerscs nclude mnmum generaon levels, sarup mes and coss, ramp rae lms, and mnmum up/down mes. Gven he assocaed complexes and he long me horzon nvolved, radonal long-erm generaon plannng frameworks ofen gnore hese operaonal consrans, and he coss assocaed wh hem. However, hs may mean ha generaon porfolos calculaed o be opmal under long-erm plannng frameworks may no be operaonally vable or economcally opmal n pracce. Ths paper ams o assess how he echncal lmaons and economc mpacs of generaor operaonal characerscs, especally a hgh renewable peneraons, mgh mpac on he leas cos generaon porfolo oucomes obaned from longerm plannng ools. In parcular, compares overall fuure ndusry coss obaned from a long-erm generaon porfolo plannng and nvesmen modellng ool, MC-ELECT [4], agans hese ndusry coss when operang coss are obaned by solvng a dealed ner-emporal consraned dspach n PLEXOS (a commercal power marke modellng ool) [5]. II. GENERATION PLANNING AND INVESTMENT MODELS A. Mone Carlo based Generaon Porfolo Modellng Tool A long-erm generaon porfolo plannng ool, MC- ELECT, developed n prevous work, exends load duraon curve (LDC) opmal generaon mx echnques by usng Mone Carlo smulaon o ncorporae key unceranes [4]. The expeced coss, cos rsks and CO 2 emssons of a range of generaon porfolos n a gven fuure year are obaned from several housand repeaed scenaros wh probablsc npu parameers. The oupus can be descrbed as an expeced (mean) fuure value of annual porfolo coss. The cos spread can be represened by sandard devaon and s referred o as cos rsk. Fnancal porfolo echnques s hen used o deermne an Effcen Froner ha conans opmal porfolos n erms of expeced coss and assocaed cos rsk [6]. MC-ELECT was employed o analyze fuure generaon porfolos wh dfferen renewable energy peneraons n he Ausralan Naonal Elecrcy Marke (NEM) for 2030 [7]. Fg. 1 llusraes he prevously calculaed opmal generaon porfolos for dfferen renewable peneraon levels, rangng from 15% o 85%. Ths resul forms he bass of he case sudy presened n hs paper (Secons IV. V., whch explores he mpac of shor-erm operaonal consrans on hose porfolos deermned o le on he effcen froner. The man lmaon of MC-ELECT s nherenly lnked o s use of LDC, whch removes chronology and prevens he

2 2 analyss of shor erm operaonal ssues. Ths s common wh oher long erm approaches overlookng un commmen ssues. A pos processng exenson o he modellng ool has been prevously mplemened o assess he mpacs of shorerm operaonal aspecs, bu he dspach smulaons were smplsc and can only handle low o moderae levels of renewable peneraon [8]. The analyss n hs paper herefore addresses he need for more dealed operaonal modellng. Fg. 1. Prevous resuls from an Ausralan case sudy showng he opmal generaon porfolos n erms of expeced cos ($/MWh) and assocaed cos rsks (sandard devaon) for dfferen renewable peneraons n 2030 [7]. B. PLEXOS Inegraed Energy Model PLEXOS s an energy marke smulaon package wh parcular capables n modellng operaonal aspecs of power sysems ncludng solvng opmal un commmen and economc dspach [5]. PLEXOS s wdely used n by ules, consulans and researchers [9-12]. Some of hese sudes also compared capacy expanson plannng under LDC approach wh chronologcal un commmen [12]. In PLEXOS, smulaons can be solved over dfferen meframes, rangng from long erm generaon capacy expanson o shor erm un commmen. Capacy expanson problems are solved usng a Long Term ool based upon he LDC (chronology removed). In conras, chronologcal un commmen problems are solved usng a Shor Term (ST) schedulng ool, akng no accoun ner-emporal consrans ncludng mnmum generaon level, mnmum up and down mes, sarup coss and ramp raes. The hgh level of deal means PLEXOS s capable of hghly precse shor-erm modellng. For he purpose of hs sudy, he ST Schedule ool n PLEXOS has been used o assess he mpac of shor-erm operaonal consrans on he opmal generaon porfolos obaned from MC-ELECT descrbed prevously. III. METHODOLOGY The opmal generaon porfolos for each renewable energy peneraon were aken from MC-ELECT, as shown n Fg. 1. PLEXOS and he Xpress-MP solver was hen employed o solve a year of hourly consraned generaon dspach. Hourly PV and wnd generaon profles are npu no PLEXOS. Hydro generaon was dspached o mnmze annual sysem cos subjec o a hydro energy lm consran. The consrans ncorporaed no he PLEXOS modellng were sar-up coss, mnmum operang levels, ramp raes and synchronous generaon requremens. Techncal and cos mplcaons assocaed wh hese consrans were hen analyzed. Mnmum up/down mes and spnnng reserve were no consdered n he analyss. A mnmum synchronous generaon requremen s also mposed n all dspach perods o provde adequae sysem nera, faul feed-n levels and sysem sably [13]. Ths consran s mporan for hgh renewable scenaros snce some prevalen knds of renewable generaon (wnd and PV) are non-synchronous and herefore do no generally provde nera and faul feed-n curren o he sysem [14]. For he purposes of hs sudy, coal, gas and hydro plans are assumed o provde synchronous generaon (some ypes of renewable generaon such as solar hermal, geohermal and bomass are also synchronous, alhough hese echnology ypes have no been modelled n hs sudy). The mpac of requrng varous synchronous generaon levels va hs consran was examned, as oulned n Secon IV. Generaors were dspached based on her shor run margnal cos (SRMC) wh he objecve of mnmzng oal sysem operang cos (ncludng sarup coss) of meeng demand n a year subjec o generang un and demand balancng consrans as shown n Eq. (1) Eq. (6). SRMC s he sum of he fuel, varable operaons and manenance (O&M) and greenhouse emssons coss of each un. Subjec o: T I mn [ VC.( P, ) S ( )] (1) 1 1, {0,1} (2), Sysem demand, P, D (3) I 1 mn max Capacy P P P (4),.,,. Ramp raes P ) P ( P ) (5) (, 1,, 1 Synchronous requremen P, ( SC 100). D (6) conv where VC s he SRMC of generang un ($/MWh), P, s he oupu of generang un (MW) and, s on-off decson varable ndcang wheher un s onlne or offlne n perod. S s he sarup coss whch nclude fuel, manenance and oher coss as explaned n Secon IV. D s he demand n perod (MW), P and max P are he mnmum and mn maxmum oupu of generang un. P conv, s he oupu of convenonal generang un a perod (MW). SC s he mnmum synchronous requremen (%). IV. THE AUSTRALIAN NATIONAL ELECTRICITY MARKET (NEM) CASE STUDY Ths sudy consders sx dfferen renewable energy peneraon scenaros for he Ausralan NEM n 2030, whch are 15%, 30%, 40%, 60%, 75% and 85% renewable. 1 Egh echnologes were ncluded: coal, combned cycle gas urbne 1 The exsng renewable energy peneraon n he NEM s around 15%.

3 3 (CCGT), open cycle gas urbne (OCGT), co-generaon, dsllae, uly-scale PV (sngle axs rackng), wnd (on shore) and hydro. I was assumed ha new generaon opons only come from CCGT, OCGT, PV and wnd. The opmal generaon porfolos for 2030 under a medum carbon prce obaned from MC-ELECT are he focus of hs sudy. Three carbon prce scenaros are consdered: $20, $91 and $115/CO 2. These prces correspond o medum and hgh projecons of carbon prces for Ausrala n 2030 as modelled by he Ausralan Treasury [15]. Alhough carbon prcng legslaon has recenly been repealed n Ausrala s assumed ha a comparable mechansm wll be appled by 2030 o acheve he necessary emsson reducons, as recommended by he Ausralan Governmen Clmae Change Auhory [16]. A number of mnmum synchronous generaon requremens (from 0% o 40%) are consdered. A. Hourly Demand, PV, Wnd and Hydro Generaon Daa An ndcave hourly elecrcy demand profle for was sourced from analyss by he Ausralan Energy Marke Operaor (AEMO) on a 100% renewables sysem under a moderae economc growh scenaro. AEMO s demand projecons were derved from he hsorcal demand paern n Hourly wnd and solar oupu profles for 2030 were smulaed from hourly races of 1-MW on-shore wnd and solar PV (sngle axs rackng) generaon n dfferen locaons across he NEM provded by AEMO [13]. For hydro generaon an annual hydro energy dspach lm of 13 TWh was appled, based upon he long-erm average hydro generaon esmaed by AEMO [13]. B. Operang Characerscs of Generang Uns Operang and cos characerscs assumed for each echnology are shown n Table I and II. These daa were esmaed based upon a number of consulancy sudes and repors boh n Ausrala and nernaonally [11, 17-19]. 2 TABLE I GENERATOR STARTUP CHARACTERISTICS OF EACH TECHNOLOGY Characerscs Coal CCGT OCGT Un sze (MW) Ho Sarup fuel cos ($ 000/sar) Warm Cold Non-fuel sarup coss (capal & Ho manenance, emssons and oher Warm coss) ($/MW) Cold CO 2 emssons nensy (CO 2) 0.75 a Sarup fuel prce ($/GJ) 20 a a Desel s used for sarng up coal generang uns The key componens of sar-up coss are: fuel coss, capal and manenance coss, greenhouse emssons, and oher coss. Fuel coss are dcaed by he rae a whch fuel s consumed durng sar-up and he fuel prce. Manenance and capal expendures ( wear and ear coss ) are arbued o hermal and pressure sress whch occur durng sar-up and culmnae n equpmen degradaon. The emssons cos s dependen on 2 Only coal, CCGT and OCGT sar-up coss were consdered n he modellng snce he oher hermal echnologes modelled (cogeneraon and dsllae) represen less han 1% of generaon capacy n he NEM n he carbon prce and he hermal effcency. Expendure on un sars owards auxlary power, chemcals and labor are ncluded under oher coss. These coss are nfluenced by he amoun of me ha has elapsed snce he un was las acve. Three me perods (ho, warm and cold) were defned. TABLE II MINIMUM OPERATING LEVEL AND RAMP RATE CHARACTERISTICS Operang parameers Coal CCGT OCGT Cogen Dsllae Hydro Mn. Gen (% of capacy) Ramp rae (MW/hour) V. SIMULATION RESULTS AND ANALYSIS Fg. 2 llusraes an example of hourly dspach of a generaon porfolo wh a 40% renewable peneraon durng a ypcal week. A a low carbon prce ($20/CO 2 ), he low SRMC of coal uns by comparson wh gas-fred CCGT and OCGT sees hem provdng base-load generaon. The sgnfcan coal and renewable generaon capacy of hese porfolos means CCGT and OCGT are no heavly ulzed. Wh hgher renewable peneraons, hermal generaon uns are requred o cycle more ofen. Fg. 2. Example of ypcal weekly generaon paerns for porfolos wh a 40% renewable peneraon a low carbon prce ($20/CO 2). A. The Impac on Number of Sarups/Shudowns The average number of sarups of coal and gas uns for seleced porfolos wh dfferen renewable peneraons facng a medum carbon prce are shown n TABLE III. TABLE III AVERAGE NUMBER OF STARTUPS/UNIT/YEAR FOR EACH TECHNOLOGY FOR SELECTED PORTFOLIOS FOR A MEDIUM CARBON PRICE ($91/TCO 2). RE Average no. of sarups/un/year Porfolo (% share of coal and pen New New Exsng Exsng gas n oal capacy) Coal (%) CCGT OCGT CCGT OCGT 36% coal, 12% CC, 12% OC % 18% coal, 42% CC, 0% OC % coal, 40% CC, 0% OC % 25% coal, 15% CC, 10% OC % coal, 4% CC, 12% OC % 12% coal, 28% CC, 0% OC % coal, 3% CC, 8% OC % 5% coal, 16% CC, 5% OC The hghes number of sarups for CCGT s around 230 sars per year, whch s whn a ypcal desgn range of recenly nsalled and fuure new buld CCGT of around sars per year [20]. The number of coal sarups also appears o be operaonally vable for mos porfolos. Coal uns are conssenly dspached gven her relavely low SRMC compared o gas generaon. For low o moderae

4 4 renewable peneraons, a mes of very low demand coal uns are able lower her oupu raher han swch off compleely. However, for very hgh renewable peneraons, coal uns n porfolos wh consderable share of coal capacy (e.g. 16% coal, 3% CCGT and 8% OCGT) can experence up o around 100 sars per year, whch s arguably hgher han he ypcal desgn range of coal uns a presen. However, coal plans may be able o ncrease her flexbly hrough modfcaons n hardware and operaonal pracce and here are ceranly some examples of flexble coal plans ha whsand daly sarup and shudown [21]. Generally, he number of sarups ncreases wh hgher renewable peneraon. However, as shown n Fg. 3, hs s no always he case as he number of sarups also depends on he mx of convenonal echnologes whn he porfolo. Fg. 3. Average number of coal sars per un per year n a range of porfolos for dfferen renewable peneraons. Percenages ndcae he proporon of nsalled capacy ha s coal, CCGT and OCGT. For each generaon porfolo, he number of un sarups s also nfluenced by he level of carbon prce. Hgher carbon prces resul n reducons n he number of coal sars snce coal uns are less dspached due o her now ncreased SRMC. The reducon n coal sars s offse somewha by a smaller ncrease n he number of gas sarups. The oppose s seen for lower carbon prces. If a small amoun of convenonal generaon s requred for only a shor perod of me, s preferable o sarup CCGT or OCGT and shu down agan gven her flexbly and relavely low sarup coss. B. The Impac of Mnmum Generaon Consran Mnmum generaon consrans mpose addonal coss o porfolos snce ndvdual coal and gas uns mus be dspached a hgher levels (compared o he case whou he consran). However, resuls show ha he ncrease n coss assocaed wh hs consran s very small. The larges cos ncrease observed n any porfolo was $2/MWh (or a 2% ncrease), whch occurs only n generaon porfolos wh 85% renewable peneraon. A low o moderae renewable peneraons, mnmum operang levels have a neglgble effec snce hermal generang uns are already dspached well above her mnmum levels (less han a 1% ncrease n sysem coss for renewable peneraon levels below 60%). Generally, as he renewable peneraon rses, he cos mpacs due o mnmum generaon consrans were observed o ncrease snce hs consran resuls n addonal curalmen of PV and wnd generaon o accommodae ncreased coal and gas generaon. The cos mpacs due operaonal consrans for a number of porfolos wh dfferen renewable peneraons are shown n TABLE IV. C. The Impac of Ramp Rae Lms Of he operaonal consrans consdered, ramp rae consrans have he smalles mpac on boh cos and dspach. All generaon porfolos were found o be able o mee he maxmum hourly ramps requred. Hence, he mpac of ramp rae consrans on overall generaon cos s almos neglgble. However, he dspach smulaon was opmzed on an hourly bass whch does no capure he acual rampng requremens of he sysem over shorer meframes. If he dspach smulaon was carred ou wh a fner granulary, ramp rae lms may be volaed o a greaer exen. As shown n TABLE IV, coss ncurred due o ramp rae consrans ncrease very slghly as renewable peneraon ncreases. TABLE IV COSTS OF SELECTED PORTFOLIOS SUBJECT TO DIFFERENT OPERATIONAL CONSTRAINTS FOR A MEDIUM CARBON PRICE ($91T/CO2) Generaon cos ($/MWh) RE pen Porfolo Whou Wh Mn. Mn. gen & consran gen ramp raes 30% 36% coal, 12% CC, 12% OC % coal, 42% CC, 0% OC % 10% coal, 40% CC, 0% OC % coal, 15% CC, 10% OC % 24% coal, 4% CC, 12% OC % coal, 28% CC, 0% OC % 16% coal, 3% CC, 8% OC % coal, 16% CC, 5% OC D. The Impac of Synchronous Generaon Requremen Dfferen synchronous generaon requremens beween 0% and 40% were mposed. The synchronous requremens ncur sgnfcan addonal coss, parcularly a hgh renewable peneraons and carbon prces, snce n hese scenaros low operang cos renewable generaon mus be curaled o accommodae ncreased hermal generaon. TABLE V llusraes he changes n sysem cos of generaon porfolos wh 40% and 60% renewable peneraon for dfferen carbon prces when varous synchronous requremens (0% o 40%) are mposed. TABLE V TOTAL COST OF PORTFOLIOS WITH 40% AND 60% RENEWABLE PENETRATION FOR DIFFERENT SYNCHRONOUS REQUIREMENTS RE Carbon Toal generaon cos ($/MWh) Porfolo pen Prce ($) 0% 10% 20% 30% 40% 20 25% coal, 15% CC, 10%OC 65 No change % 91 25% coal, 15% CC, 10%OC 104 No change % coal, 15% CC, 10%OC 117 No change % coal, 4% CC, 12% OC % 91 24% coal, 4% CC, 12% OC % coal, 4% CC, 12% OC For porfolos wh low o moderae renewable peneraons (.e. 15% o 40% renewable), he cos mpac of synchronous requremen s neglgble snce a leas 40% of he demand n each perod s already beng served by convenonal generaors (he hghes synchronous requremen modelled s 40%). For renewable peneraons greaer han 40%, he nroducon of a synchronous requremen begns o have sgnfcan cos mpacs, parcularly a hgh carbon prces. Even very low

5 5 synchronous requremens add o sysem cos. A a 60% renewable peneraon, mposng a 40% synchronous requremen ncreases he oal sysem coss by around 7%. For mos porfolos, sysem cos ncreases wh he level of synchronous generaon requremen as llusraed n Fg. 4. The fgure also llusraes he sgnfcan dfferences n he cos arbued o synchronous requremens as renewable peneraon ncreases from 60% o 85%. For all of he porfolos modelled, coss assocaed wh synchronous generaon requremen ncrease wh hgher carbon prces. Fg. 4. Generaon cos of dfferen porfolos wh 60% and 85% renewable peneraon for dfferen levels of synchronous generaon requremens. VI. CONCLUSIONS Ths paper examnes he mpac of shor-erm operaonal characerscs on generaon porfolos obaned under a longerm porfolo plannng modellng. These nclude sarup coss, mnmum generaon level, ramp rae lms and synchronous generaon requremen. Resuls from he Ausralan case sudy wh dfferen levels of renewable peneraons n 2030 sugges ha he ncluson of sarup coss, mnmum generaon and ramp rae consrans do no have a sgnfcan cos mpac on generaon porfolos obaned usng a long-erm porfolo plannng framework ha does no nclude hese facors. Whle here are shfs n he amoun of generaon dspached, ulmaely he oal annual cos does no change by more han 2%, even under very hgh (85%) renewable peneraon. However, he synchronous generaon requremens can resul n sgnfcan ncrease n generaon coss parcularly a hgh renewable peneraons and carbon prces. Generally, coal and gas plans can experence frequen cyclng operaon (ramp up/down and sars/sops) wh hgher renewable peneraon. However, he number of un sarups appears farly reasonable excep for some porfolos wh hgh renewables (hgh share of coal capacy) where coal uns can face up o 100 sars per year. Ths, however, suggess ha coal plans may need o ncrease her flexbly o whsand ncreased cyclng n low-carbon and hgh renewable fuures. The mpacs of he operaonal consrans modelled depend parcularly on he level of carbon prce and he mx of generaon echnologes whn he porfolo. There are some lmaons of hs sudy. Some consrans ncludng mnmum up/down mes of generang uns were no modelled. Transmsson nework consrans were also gnored. The modellng n hs paper does no nvesgae he effecs ha arse when sar-up coss, mnmum operang levels, ramp raes and synchronous generaon requremens are all ncorporaed smulaneously. There s sll much o be done n mprovng our undersandng of he addonal coss assocaed wh more varable operaon of hermal plans. I s of course lkely ha new hermal plan desgns for elecrcy ndusres wh hgh varable renewable generaon wll provde mproved operaonal flexbly and reduced cyclng coss. Furhermore, here are opporunes o address he low sysem nera presen a mes of hgh non-synchronous renewable peneraons oher han mposng a mnmum synchronous generaon lm. All of hese lmaons represen areas for fuure work. VII. REFERENCES [1] A. Shor, J. Kvluoma, and M. O' Malley, "Accommodang Varably n Generaon Plannng," IEEE Trans. on Power Sys., vol. 28, 1, pp , [2] J. Cochran, M. Mller, O. Znaman, M. Mllgan, D. Aren, B. Palmner, M. O'Malley, S. Mueller, E. Lannoye, A. Tuohy, B. Kujala, M. Sommer, H. Holnnen, J. Kvluoma, and S. K. Soonee, "Flexbly n 21s Cenury Power Sysems," 21s Cenury Power Parnershp, CO, [3] B. S. Palmner and M. D. Webser, "Heerogeneous Un Cluserng for Effcen Operaonal Flexbly Modelng," IEEE Trans. on Power Sys., vol. 29, 3, pp , [4] P. Vhayasrchareon and I. F. MacGll, "A Mone Carlo based decsonsuppor ool for assessng generaon porfolos n fuure carbon consraned elecrcy ndusres," Energy Pol., vol. 41, pp , [5] Energy Exemplar, "Plexos Inegraed Energy Model," [6] H. Markowz, "Porfolo Selecon," The Journal of Fnance, vol. 7, 1, pp , [7] P. Vhayasrchareon, J. Resz, and I. F. MacGll, "Usng renewables o hedge agans fuure elecrcy ndusry unceranes An Ausralan case sudy," Energy Pol., vol. 76, pp , [8] P. Vhayasrchareon and I. F. MacGll, "Incorporang shor-erm operaonal plan consrans no assessmens of fuure elecrcy generaon porfolos," Appled Energy, vol. 128, pp , [9] SKM, "Modellng he Renewable Energy Targe: Repor for he Clmae Change Auhory," Snclar Kngh Merz, [10] E. Lannoye, D. Flynn, and M. O'Malley, "Evaluaon of Power Sysem Flexbly," IEEE Trans. on Power Sys., vol. 27, 2, pp , [11] D. Lew, E. Brnkman, A. Ibanez, M. Flora, B.-M. Heaney, H. Hummon, G. Sark, J. Kng, S. A. Lefon, N. Lumar, D. Agan, G. Jordan, and S. Venkaaraman, "The Wesern Wnd and Solar Inegraon Sudy Phase 2," NREL, Techncal Repor NREL/TP , Golden, Colorado, [12] C. I. Nweke, F. Leanez, G. R. Drayon, and M. Kolhe, "Benefs of chronologcal opmzaon n capacy plannng for elecrcy markes," n 2012 POWERCON, 2012, pp [13] AEMO, "100 Per cen Renewables Sudy - Modellng Assumpons and Inpu," Ausralan Energy Marke Operaor, [14] E. Ela, M. Mllgan, A. Bloom, A. Boerud, T. A., and T. Levn, "Evoluon of Wholesale Elecrcy Marke Desgn wh Increasng Levels of Renewable Generaon," NREL, [15] Ausralan Treasury, "Srong growh, low polluon: Modellng a carbon prce," Ausralan Governmen, Canberra, [16] Ausralan Governmen, "Reducng Ausrala's Greenhouse Gas Emssons - Targes and Progress Revew Fnal Repor," he Clmae Change Auhory, [17] AEMO, "2012 Naonal Transmsson Nework Developmen Plan," Ausralan Energy Marke Operaor, [18] BREE, "Ausralan Energy Technology Assessmen 2012," Bureau of Resources and Energy Economcs, Ausralan Governmen, [19] N. Kumar, O. Besuner, S. A. Lefon, D. Agan, and D. Hlleman, "Power Plan Cyclng Coss," Naonal Renewable Energy Laboraory, Subconrac Repor NREL/SR , Golden, Colorado, [20] D. Robb, "CCGT: Breakng he 60 per cen effcency barrer," Power engneerng nernaonal, vol. 18, 3, pp , [21] J. Cochran, D. Lew, and N. Kumar, "Flexble Coal - Evoluon from Baseload o Peakng Plan" NREL, Golder, CO, 2013.