Cost of Geothermal Power and Factors that Affect It

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1 Proeegs Worl eohermal Cogress 005 Aalya, Turkey, 4-9 Aprl 005 Cos of eohermal Power a Faors ha Affe I Subr K. Sayal eohermex, I., 51 Ceral Aveue, Sue 01, Rhmo, Calfora, 94804, USA mw@geohermex.om Keywors: power os, geohermal power, apal os, operaos a maeae os, levelze os ABSTRACT Ths paper preses a aalyss of he sesvy of he os of geohermal power o: (a apal os; (b operaos-amaeae (O&M os; ( make-up well rllg os; ( resoure haraerss (well prouvy a s rae of ele; (e evelopme a operaoal opos (salle pla apay, umber of years of make-up well rllg, a proje lfe; a (f maro-eoom lmae (eres a flao raes. The power os here represes levelze os ( US es per klowa-hour over he proje lfe, he apal os beg amorze over 30 years; ay royales, ax bure, or ax re are gore. A rage of evelopme szes, from 5 o 150 MW, wh 50 MW as he base ase, s osere. The eoomy of sale boh apal os a O&M os, as well as he hgher prouvy ele rae ue o rease salle apay, are ake o aou. The apal os oes o lue rasmsso le os or ay uusually se-spef oss of regulaory omplae or evromeal mpa mgao. Power os s sharply reue f full geerao apay s maae, by rllg make-up wells, for a leas he frs 10 years or so followg pla sar-up; however, oug make-up well rllg beyo abou 0 years oes o reue power os ay furher. The mmum ahevable power os s sesve o pla apay; s o he orer of 3.4US / kwh. There are sgfa opporues o reue power os as se-spef experee s gae resoure maageme a power pla operao hroughou he proje lfe. Power os s mos sesve o u O&M os followe by u apal os, eres rae a flao rae he ereasg orer of sesvy; s relavely sesve o well prouvy, rllg os per well a well prouvy ele rae. The maro-eoom lmae has relavely mor mpa o power os. Operag small power plas beyo her ypal amorzao pero of 30 years a subsaally reue power os; hs reuo s sgfa for plas of 50 MW or larger apay. Power os oes o ele sgfaly wh reasg pla apay exep he ulkely suao of well prouvy ele beg sesve o pla apay. I he uusual suao of a absee of eoomy of sale, power os reases wh pla apay, he mmum ahevable level sll beg 3.4US / kwh. I he very ulkely suao of boh well prouvy ele as well as u apal a O&M oss beg sesve o pla apay, he mmum ahevable power os woul be o he orer of 3.6US / kwh. For a 50 MW power pla oay, he levelze power os woul be he rage of 3.6 o 4.1 US /kwh. 1. INTRODUCTION Boh apal os a operaos-a-maeae ( O&M oss of geohermal power have ele subsaally over he las eae (see, for example, Egh a MVegh, 003. I lgh of hs evelopme, s worhwhle 1 assessg he overall os of geohermal power oay. The power os osere here s levelze os es per klowa-hour (US /kwh over he proje lfe, he al apal os beg amorze over a pero of 30 years; make-up well rllg os s o apalze a s osere a operag expese. The apal os lues he os of moey (ha s, he umulave prese value of all fuure eres paymes bu oes o lue ay rasmsso le os or ay uusually se-spef oss of regulaory omplae or evromeal mpa mgao. Ths paper osers power os raher ha power pre or proje profably beause, ulke pre or profably, os s subsaally epee of he orporae ulure of he eveloper a operaor, fag mehasm, loal marke fores a goverme poles. Furhermore, os alulaos hs paper gore ay royaly bure, ax lably or ax re. Therefore, alhough he values of eoom parameers assume hs paper refle he prese seg he Ue Saes, he olusos arrve a shoul be applable a leas qualavely, f o quaavely, o geohermal power projes worlwe. I he urrely fashoable ebae over he relave vrues of varous forms of reewable eergy, power os s a objeve rero ha shoul favor geohermal; ye here s oserable fferee of opo as o wha ruly s a a be. Hee he jusfao for hs aalyss. The aalyss osers a power apay rage of 5 o 150 MW wh 50 MW as he base ase. Power os oss of hree ompoes: (a apal os ompoe (lug os of moey, (b O&M os ompoe (o oug eb serve, whh s lue uer he apal os ompoe, a ( make-up well rllg os ompoe, as esrbe he Appex.. FACTORS THAT AFFECT EOTHERMAL POWER COST These faors a be groupe o four aegores: (a eoomy of sale, (b well prouvy haraerss, ( evelopme a operaoal opos, a ( maroeoom lmae. I geeral, eoomy of sale allows boh u apal os ( US ollars per kw salle a u O&M os ( US /kwh o ele wh reasg salle apay. Base o he aa presee by Egh a MVegh (003, he u apal os s esmae o vary from US$1,600/kW o US$,500/kW epeg o proje sze a oher proje-spef rera. For he smalles proje sze of 5 MW osere here, we have assume a u apal os of US$,500/kW a for he larges osere proje sze of 150 MW a os of US$1,600/kW; however, base o eohermex s ree experee wh projes he U.S., we beleve Egh a MVegh (003 s oss are slgh ueresmaes. We have furher mae he permssve assumpo ha wh he above rage of values, u apal os eles expoeally wh pla apay. Ths assumpo leas o he followg orrelao

2 Sayal bewee u apal os US$/kW ( a pla apay kw (P: 0.003( P 5 = 500e. (1 For he 50 MW base ase he u apal os s esmae from (1 a US$,184/kW; as sae before, hs esmae followg he work of Egh a MVegh (003 s somewha low. Base o eohermex s experee, we beleve he represeave u O&M os approxmaely rages from.0us /kwh for a 5 MW pla o 1.4US /kwh for a 150 MW pla. Assumg a expoeal ele u O&M os US /kwh ( o wh pla apay kw (P, we ge: 0.005( P 5 o =.0e. ( For he 50 MW base ase he u O&M os s esmae from ( a 1.79US /kwh. Well prouvy haraerss affe geohermal power os maly wo ways: a f well prouvy s hgher, fewer wells are eee o supply a pla, hus reug power os; a b a hgher rae of ele well prouvy wh me alls for more make-up well rllg, a herefore, leas o hgher power os. For he purposes of hs paper, a average al prouvy of 5 MW per well was assume; hs s a ypal value. eohermal wells geerally uergo harmo ele well prouvy wh me (Sayal, e al, 1989: W W =, (3 1 + D where W s al prouvy, D s al aual ele rae prouvy a W s prouvy year. The harmo ele re mples a ele rae ha slows ow wh me, he aual ele rae (D prouvy year beg gve by (Sayal, e al, 1989: D D = (4 1 + D If he oal prouo rae from a fel s small eough o be erely ompesae by aural reharge or f oly a small frao of he prouve reservor s beg exploe, he ele rae well prouvy woul be sesve o reases pla apay. These suaos are muh less ommo. I mos ases ele rae reases wh reasg salle apay. Ths sesvy of prouvy ele o salle apay s oo se-spef o be quafe by a geerally-applable orrelao. Neverheless, Sayal, e al (000 aempe a approxmae formulao: W D = W l W D, (5 lw where D s al aual harmo ele rae whe oal prouo rae s W a D s al aual harmo ele rae whe oal prouo rae s hage o W. Assumg a ypal al harmo ele rae of 5% per year for he 50 MW base ase, he al aual harmo ele rae for ay oher pla apay was esmae from (5. There are era resoure evelopme a operaoal opos ha affe power os. The eveloper of a geohermal proje has he opo o sze he power pla whle he operaor of he proje has he opo o eher allow geerao o ele wh me or o maa geerao by make-up well rllg; he operaor a also ru he pla beyo s amorze lfe. The sesvy of power os o hese erwe opos has bee sue hs paper. The resoure evelopme opo has bee osere by varyg he pla apay wh he rage of 5 o 150 MW. The operaoal opo has bee osere by assumg make-up well rllg for varous peros of me followg pla sar-up, a searos of pla operao boh up o a beyo he amorzao pero. Whle he u apal os for a gve pla apay, as gve by (1, lues al rllg os, he u O&M os gve by ( oes o lue make-up well rllg os. I orer o esmae he make-up well rllg os as a fuo of me, s eessary o esmae frs he al umber of wells requre for a gve pla apay. Ths esmae was base o a ypal al prouvy of 5 MW per well plus he usomary ee for a leas oe sa-by well a a mmum of 10% reserve prouo apay a all mes. Wh he above assumpos follows ha he salle pla apay a be maae whou ay make-up well rllg for up o years followg pla sar-up, as gve by: = 1 W N w D (1 + r /100 P 1, (6 where D s al aual harmo ele rae, W s al prouvy per well (MW, N w s al umber of wells (lug a leas oe sa-by well, P s pla apay (MW, a r s mmum prouo apay reserve requre (%. 3. CALCULATION OF LEVELIZED POWER COST Fgure 1 shows he shema geerao a make-up well rllg hsores of a ypal power proje. eerao a be maae whou make-up well rllg up o year, as gve by (6. The geerao s maae by make-up well rllg up o year respose o ele well prouvy aorg o (3, he al aual harmo ele rae beg gve by (5. Afer year, o make-up well s rlle a geerao s allowe o ele as per (3 a (5.

3 Sayal Aual eerao No Makeup Well Drlle Make-up Wells Drlle No Make-up Well Drlle 0 year Fgure 1. Shema eerao a Make-up Well Drllg Hsores of a Proje ve he geerao a make-up well rllg hsores represee Fgure 1, he levelze os of geohermal power ( US /kwh s gve by (see Appex: = 100D( { D( + l[ 1 + D( ( ]} C( 1 + (1 + I (1 + 1 I(1 + I of D( + ( + ( { D( + l[ 1 + D( ( ]} ov + 100C w N w D( D( ( +, (7 where D( s aual prouvy ele rae year ; s al aual geerao (kwh; N s power pla lfe (assume o be 30 years base ase; C s oal apal os, ha s, P (US$; o s u aual O&M os (US /kwh; s aual eres rae (assume o be 7% base ase; I s aual flao rae (assume o be 3% base ase; of s fxe poro of he aual O&M os a pla sar-up ve by al aual geerao (US /kwh; ov s varable poro of he aual O&M os ve by aual geerao (US /kwh; N w s umber of al prouo wells; a C w s rllg os per al prouo well (assume o be $ mllo he base ase. Capal os lues explorao os, power pla os, gaherg a jeo sysem os a os of apal. Aual O&M os lues persoel os, geeral a amsrave os, surae os, supples / osumables / egeerg a laboraory serves os, wellfel maeae os, geeraor a urbe maeae os a oher equpme a maeae os. of The varable poro of he aual O&M os represes oss ha vary wh he level of geerao, suh as, oss of supples, osumables, e, whh rema proporoal o geerao; hs os ve by aual geerao gves ov. The fxe poro of he aual O&M os represes oss ha are epee of he geerao level; hese lue oss of persoel, amsrao, surae, wellfel maeae, geeraor a urbe maeae, oher equpme maeae, e., whh may o ele respose o ay ele geerao. Ths fxe aual os ve by aual geerao gves of. For he purposes of hs paper 0% of he aual O&M os was assume o vary wh geerao a pla sar-up; however, resuls are fou o be relavely sesve o he frao of O&M os ha s varable. As geerao eles, ov remas osa bu of reases from s al value of of. A ypal pla apay faor of 90% was assume esmag aual geerao. I (7, he oal apal os (C s assume o be amorze over he pla lfe of years a a eres rae (aual ompoug. The alulae power oss fuure years are soue for flao o arrve a a levelze power os prese ollars (. 4. RESULTS I shoul be oe ha f here were o eoomy of sale apal a O&M oss (ha s, a apal os of US$,184/kW a a O&M os of 1.79US /kwh, as he base ase a f prouvy ele rae were sesve o salle apay (remag a 5% al aual harmo rae as he base ase, levelze power os from (7 woul be 3.6US /kwh rrespeve of pla apay. Table 1 lss all parameers for he rage of evelopme searos aalyze, assumg he eoomy of sale apal a O&M oss as well as he sesvy of prouvy ele o pla apay. 3

4 Sayal Table 1. Developme Searos Aalyze Pla Capay (MW U Capal Cos (US$/kW Toal Capal Cos (Mllo US$ U O&M Cos (US /kwh Ial Harmo Dele Rae (% No. of Ial Prouo Wells Years before Make-up Well Drllg s Requre ( 5, >30 10, >30 0, , , , , , , Fgure shows he alulae power os US /kwh for varous levels of salle pla apay as a fuo of (ha s, he umber of years of make-up well rllg uerake o maa pla apay. Ths fgure akes o aou he eoomy of sale as reflee (1 a (, as well as aelerao well prouvy ele, as gve by (5, wh rease salle apay. Fgure aes ha power os eles wh he umber of years of makeup well rllg, he ele rae beg seeper for a hgher pla apay. Fgure also aes ha f make-up well rllg s soue oo early (pror o abou 10 years, power os woul be hgher for a larger pla. Ths fgure also shows ha for ay pla apay, a relavely mor reuo power os s aheve by oug make-up well rllg afer hs pero, a oug make-up well rllg beyo abou 0 years may aually rease power os. Therefore, here s lle reaso o oue make-up well rllg beyo abou 0 years uless he power sales ora mposes sgfa peales for ay shorfall pla apay. Fgure 3 shows he mmum ahevable power os for varous pla apaes as rea from Fgure. Ths fgure shows ha he mmum ahevable power os s raher sesve o pla apay; vares from 3.7US /kwh for a 10 MW pla o 3.4US /kwh for a 150 MW pla, a 7.6% ele power os for a 1400% rease power apay. Irrespeve of he pla apay a he umber of years of make-up well rllg, power os oay ao be lowere sgfaly below 3.4US /kwh. Fgure 4 shows he hree ompoes of power os (apal, O&M, a make-up well rllg as fuos of pla apay assumg make-up well rllg o be soue afer 0 years. Ths fgure shows ha he apal os ompoe s approxmaely equal o he O&M os ompoe for all pla apaes whle he make-up well rllg ompoe assumes greaer sgfae wh reasg pla apay (exep for very small apaes. Furhermore, he sum of O&M a make-up well rllg ompoes osues he major par of power os. Capal expeure s urre he frs few years of a proje, whe se-spef kowlege of he resoure s sll lme; herefore, aequae opmzao of apal vesme a be a hallege. Afer pla sar-up lle a be oe o reue he apal os ompoe of power os, exep perhaps refag he eb shoul he eres rae ele. O he oher ha, O&M a make-up well rllg oss, beg urre graually as prouo oues, shoul reue wh me ue o he learg urve effe. As more uersag of he resoure haraerss a reservor performae s gae wh operao, O&M a make-up well rllg oss a be reue, lowerg power os. Fgure 5 s a plo of power os versus pere evao he values of he varous epee varables from her base ase (50 MW values. I hs fgure, a seeper urve hrough he base ase po mples a hgher sesvy of power os o he varable represee by he urve. Fgure 5 shows ha u O&M os a u apal os have he hghes mpa o power os; hese wo varables are also subje o eoomy of sale. O he oher ha, power os s relavely sesve o resoure-relae varables (suh as well prouvy, rllg os per well a prouvy ele rae. Fgure 5 aes a levelze power os of 3.6US /kwh for a 50 MW pla. However, shoul be oe ha ree experee of eohermex aes ha he esmaes of apal os he U.S. base o Egh a MVegh (003 s somewha low. For he base ase, he apal os he U.S. may be as muh as 30% hgher ha US$,184/kW. Therefore, Fgure 5 shows ha he levelze power os for a 50 MW pla he U.S. may be as hgh as 4.1US /kwh. Ieresgly, power os s oly moesly sesve o maro-eoom varables (eres a flao raes, beause eres a flao raes affe power os by abou he same mague bu oppose reos (Fgure 5. Fgures 6 shows power os versus pla apay for several verse mro-eoom suaos: (1 a hyperflaoary evrome, ( a hgh flaoary evrome, (3 he urre eoom evrome he U.S., a (4 a eflaoary evrome; approprae eres raes ( a flao raes (I assume for he varous ases are show o he fgure. Fgure 6 mples ha, relave erms, he sesvy of power os o he maroeoom lmae s o sgfa. For example, he varao power os over he apay rage of 5 o 150 MW s of smlar mague as he varao power os he base ase over he exreme rage of maro-eoom lmaes osere. 4

5 Sayal MW 30 MW 50 MW 75 MW 100 MW 15 MW 150 MW Year Make-up Well Drllg s Dsoue Fgure. Power Cos versus he Year Make-up Well Drllg s Dsoue 3.7 Mmum Pla Capay (MW Fgure 3. Mmum Power Cos versus Pla Capay 5

6 Sayal 4 Toal Power Cos 3 1 Make-up Well Cos O&M Cos Capal Cos Pla Capay (MW Fgure 4. Power Cos Compoes versus Pla Capay (Assumg 0 Years of Make-up Well Drllg U O&M Cos U Capal Cos 4. Ieres Rae Base Case Ial Well Prouvy/ Cos per Make-up Well Prouvy Dele Rae Iflao Rae % -40 % -30 % -0 % -10 % 0 % 10 % 0 % 30 % 40 % 50 % Chage Iepee Varable Fgure 5. Sesvy of Base Case Power Cos o Chages Iepee Varables 6

7 Sayal Hyper-Iflaoary Evrome (=13%, I=7% Hgh Iflaoary Evrome (=10%, I=5% Curre Eoom Evrome (=7%, I=3% Deflaoary Evrome (=4%, I=1% Pla Capay (MW Fgure 6. Power Cos versus Pla Capay uer Varous Maro-eoom Coos (For 0 Years of Make-up Well Drllg Year Pla Lfe wh a 30-year amorzao (o make-up well rllg afer 0 years Year Pla Lfe wh a 30-year amorzao (o make-up well rllg afer 0 years Pla Capay (MW Fgure 7. Effe of Pla Lfe o Power Cos (0 Years of Make-up Well Drllg 7

8 Sayal Hsory of operao of geohermal power plas Ialy, New Zeala, El Salvaor, Mexo a U.S., where some plas have ow operae for more ha 30 years, aes ha s possble o oue operag a geohermal pla beyo s ypal amorzao pero of 5 o 30 years. Ca power os be reue f a geohermal pla were amorze for 30 years bu operae for a loger pero? Fgure 7 ompares power os versus pla apay as show before (for 30 years operao a as alulae for a 50-year operag pero, he al apal os sll beg amorze over 30 years. Fgure 7 shows ha for smaller plas, os may be reue sgfaly, by as muh as 0% for plas of 10 MW or smaller apay. For plas larger ha abou 50 MW, hs reuo power os s o sgfa, parularly oserg he aoal rsk of operag a agg power pla a ppeles, a possbly eerorag wells. The above aalyss akes o aou he usual aelerao well prouvy ele ue o reases pla apay. How woul he resuls hage he uusual ase of well prouvy beg sesve o salle pla apay? Fgure 8 ompares levelze power os as a fuo of pla apay, as alulae before, wh he ase of a osa al aual harmo ele rae of 5% rrespeve of apay. Fgure 8 shows ha f prouvy ele rae were sesve o pla apay, power os woul ele wh pla apay muh more raply ha he usual ase, he mmum power os beg oly.8us /kwh (for a 150 MW pla. However, a sa-aloe proje of a apay larger ha 100 MW s a rary he geohermal usry. The exsg fels wh a geerao level greaer ha 100 MW ypally rely o mulple, epee us of up o 100 MW eah; as suh, he eoomy of sale ejoye by hese projes woul amou o ha for a apay of 100 MW or less. Therefore, f well prouvy were sesve o pla apay, a power os of less ha 3.US /kwh (esmae for a 100 MW pla s ulkely o be realze. Fally, how woul he resuls hage f eoomy of sale apal a O&M oss were eglgble? Oe suh oevable suao oul be he sallao of mulple, moular a frasruurally-epee power plas he same fel. Fgure 9 preses power os versus he umber of years of make-up well rllg for varous pla apaes gorg eoomy of sale. The resuls hs fgure assume ha u apal a O&M oss rema he same as he base ase rrespeve of salle apay, bu prouvy ele sll reases wh salle apay as gve by (5. Fgure 9 aes ha f eoomy of sale were eglgble, power pre woul rease wh salle apay o maer how log oe oues makeup well rllg, a power pre woul be ossely hgher ha he usual ase wh eoomy of sale. The mmum ahevable power os hs ase s sll o he orer of 3.4US /kwh (esmae for a 0 MW pla Dele rae vares wh pla apay Dele rae epee of pla apay (D=5% Pla Capay (MW Fgure 8. Power Cos versus Pla Capay (For 0 Years of Make-up Well Drllg 8

9 Sayal MW 30 MW 50 MW 75 MW 100 MW 15 MW 150 MW Year Make-up Well Drllg s Dsoue Fgure 9. Power Cos versus he Year Make-up Well Drllg s Dsoue ( No Eoomy of Sale Case 5. CONCLUSIONS 1. Power os s sharply reue by maag full geerao apay, by rllg make-up wells, for a leas he frs 10 years or so followg pla sar-up; oug make-up well rllg beyo 0 years oes o reue power os.. The mmum ahevable power os s sesve o pla apay; s o he orer of 3.4US /kwh. There are sgfa opporues o reue power os as se-spef experee s gae resoure maageme a power pla operao hroughou he proje lfe. 3. The levelze os of power from a 50 MW pla s he rage of 3.6 o 4.1 US /kwh. 4. Power os s mos sesve o u O&M os followe by u apal os, eres rae a flao rae he ereasg orer of sesvy; s relavely sesve o well prouvy, rllg os per well, well prouvy ele rae a he maroeoom lmae. 5. Operag small power plas beyo her ypal amorzao pero of 30 years a sgfaly reue power os; hs reuo s o sgfa for plas of 50 MW or larger apay. 6. The mmum ahevable power os oes o ele sgfaly wh reasg pla apay exep he ulkely suao of well prouvy ele beg sesve o apay, whe may be as low as 3.US /kwh. I he uusual suao of a absee of eoomy of sale, power os reases wh pla apay, he mmum ahevable level beg 3.4US /kwh. I he very ulkely suao of boh well prouvy ele as well as u apal a O&M oss beg sesve o pla apay, he mmum ahevable power os woul be o he orer of 3.6US /kwh. ACKNOWLEDMENT The auhor s graeful o Iwaa-sa, Prese of Aka eohermal Compay of Yuzawa, Japa, for hs k eourageme o wre hs paper. Thoughful ommes o he paper from Da Egh of Preo Eergy Resoures Ieraoal a he auhor s oseous olleagues a eohermex have bee mos helpful. REFERENCES Egh, D. J. a J. F. MVegh (003. Hsoral Improvemes eohermal Power Sysems Coss. Tras. eohermal Resoures Coul, p Sayal, S. K., A. J. Mezes, P. J. Brow, K. L. Eey a S. Eey (1989. A Sysema Approah o Dele Curve Aalyss for The eysers Seam Fel, Calfora. Tras. eohermal Resoures Coul, Saa Rosa, Calfora, p Sayal, Subr K., A Roberso-Ta, Chrsopher W. Kle, Seve J. Buler, James W. Lovek, Phlp J. Brow, Sayog Suarma a Syafe Sulama (000. Assessme of Seam Supply for he Expaso of eerao Capay from 140 o 00 MW, Kamojag eohermal Fel, Wes Java Ioesa. Tras. 9

10 Sayal Worl eohermal Cogress, Beppu a Moroka, Japa, p APPENDIX: CALCULATION OF LEVELIZED POWER COST Toal geerao over he pla lfe ( s: = = + l 1 + [ + D( ( ] 1 [ + D( ( ] D(, D( 0(A-1 Assumg aual ompoug, aual payme (US$A o amorze he oal apal os (US$C for years s gve by: C(1 + A = (A- (1 + 1 Iflao-soue sum ( A of aual paymes of US$A per year s gve by: = 1 A 0 I A = (1 + C (1 + (1 + I 1 (A-3 (1 + 1 I (1 + I = 1 The apal os ompoe of levelze power os ( CAP US /kwh s gve from (A-1 a (A-3. A ( CAP 100 = = 100D( { D( + l[ 1 + D( ( ]} C (1 + (1 + I 1 1 (A-4 (1 + 1 I(1 + I Up o me, geerao remas osa a so oes he uflae value of he u O&M os ( o. As geerao eles afer me, ov (expresse US /kwh remas osa bu of (expresse US /kwh reases as geerao eles from o as : of of =. (A-5 Assumg harmo ele, from (3, of = 1 + D( ( ] (A-6 of[ Therefore, he O&M os ompoe of levelze power os ( O&M US /kwh, gorg flao, s gve by: 1 O& M = ov + of + of = ov + of + of ( { 1 + D( ( } D( + ( (A-7 No make-up well s rlle up o year ; herefore, he oal umber of prouo wells servg he pla s sll N w. Afer me, make-up wells are rlle o maa geerao. The oal umber of prouo wells (N servg he pla a me s gve by: N [ + D( ( ] = N (A-8 w 1 The oal umber of make-up wells rlle ( N bewee me a s, herefore, N = N D ( (A-9 w ( The oal os of make-up well rllg over he pla lfe ollars s ( N (C w for he oal lfeme geerao gve by (A-1. The make-up well os ompoe of levelze power os ( MW US /kwh, gorg flao, s he gve by: MW 100CwNwD( D( ( =, D( 0. (A-10 { D( + l[ 1+ D( ( ]} Fally, levelze power os ( s gve by: + = CAP + O& M MW (A-11 Usg (A-4, (A-7 a (A-10 (A-11, we ge (7. 10