THE FEASIBILITY OF HYDROGEN STORAGE FOR MIXED WIND-NUCLEAR POWER PLANTS

Transcription

1 THE FEASIBILITY OF HYDROGEN STORAGE FOR MIXED WIND-NUCLEAR OWER LANTS G. Taljan, Student Member, IEEE, C. Cañzares, Fello IEEE, M. Fowler, G. erbč, Member, IEEE Abstract A novel methodology for economc evaluaton of hydrogen storage for a mxed wnd-nuclear power plant s presented n ths artcle n a context of a Hydrogen Economy. The smulaton of the operaton of the combned nuclear-wnd-hydrogen system s dscussed frst, where the sellng and buyng of electrcty and the sellng of excess hydrogen and oxygen s optmzed to maxmze profts. Ths smulaton s done n two phases: In the pre-dspatch phase, the system operaton s optmzed accordng to stochastc wnd and prce forecasts to obtan optmal hydrogen charge levels for the operatonal horzon. In the second phase, a real-tme dspatch s carred out on an hourly bass to optmze the operaton of the system to maxmze profts, and to follow the storage levels of the pre-dspatch phase. Based on the operaton plannng and dspatch results, an economc evaluaton s performed to determne the feasblty of the proposed scheme for nvestment purposes. The results of these studes demonstrate that hydrogen for the sole purpose of storage of electrcty s not economcally feasble at the current state of hydrogen technology development, unless hydrogen s sold to the market for other purposes such as transportaton, as n the case n a Hydrogen Economy, or n the case of lmted electrcty transmsson capactes,.e. transmsson congeston. Index Terms wnd power, nuclear power, hydrogen storage, Hydrogen Economy, power generaton plannng, optmzaton, nvestment evaluaton. I. NOMENCLATURE A. arameters and constrants μ c : hydrogen effcency of electrolyzer (kg/mwh) μ d : hydrogen effcency of fuel cell (kg/mwh) μ O : oxygen effcency of electrolyzer (Nm 3 /MWh) H c : hydrogen sellng prce (CAD/kg) O c : oxygen sellng prce (CAD/Nm 3 ) Accepted for publcaton n IEEE Trans. ower Systems, Feb Ths work was supported by Bruce ower, Ontaro Centres of Excellence (OCE), NSERC and Ad Futura. G. Taljan and G. erbč are wth Unversty of Ljubljana, Faculty of electrcal engneerng, Ljubljana, Slovena (e-mal: gregor.taljan@fe.unlj.s, gregor.verbc@fe.un-lj.s). C. Canzares and M. Fowler are wth Unversty of Waterloo, Waterloo, Canada (e-mal: ccanzar@uwaterloo.ca, mfowler@cape.uwaterloo.ca). max : transmsson lne capacty (MW) max : maxmum storage level (kg) max mn : maxmum fuel cell power (MW) : mnmum fuel cell power (MW) max : maxmum electrolyzer power (MW) mn c mn : mnmum electrolyzer power (MW) : mnmal bd prce at the Ontaro electrcty market (CAD/MWh) N : number of wnd scenaros w N p : number of prce scenaros T : number of tme steps B. arables W : wnd power plant producton (MW) N : nuclear power plant producton (MW) C : electrolyzer consumpton (MW) D : fuel cell producton (MW) M : power exchange wth the market (MW) charge : electrolyzer hydrogen producton (kg) dscharge : fuel cells hydrogen consumpton (kg) : hydrogen exchange wth the market (kg) hsell WIND w p,, : wnd-nuclear power consumed for wnd scenaro w and prce scenaro p n hour (MW) w p,, : electrolyzer electrcty consumpton for wnd scenaro w and prce scenaro p n hour (MW) w p,, : fuel cell electrcty producton for wnd scenaro w and prce scenaro p n hour (MW) : hydrogen storage level n hour (kg) HSELL w p,, : hydrogen exchange wth the market n wnd scenaro w and prce scenaro p n hour (kg) OSELL w p,, : oxygen producton n wnd scenaro w and

2 α β w, w, WIND ˆ prce scenaro p n hour (Nm 3 ) : on/off status of fuel cells for wnd scenaro w and prce scenaro p n hour : on/off status of electrolyzers for wnd scenaro w and prce scenaro p n hour : actual wnd-nuclear power used n hour (MW) ˆ : actual electrolyzer electrcty consumpton n hour (MW) ˆ : actual fuel cell electrcty producton n hour (MW) ˆ : actual storage level n hour (kg) HSELL ˆ : actual hydrogen exchange wth the market n hour (kg) OSELL ˆ : actual oxygen producton n hour (Nm 3 ) αˆ : actual on/off status of fuel cells n hour βˆ : actual on/off status of electrolyzers n hour END ˆ d : storage level n the last hour of the day d (kg) Rˆ : revenues from hydrogen subsystem n hour (CAD) Rˆ WH : revenues wthout hydrogen subsystem n hour (CAD) C. Input data p w : probablty of wnd scenaro w p : probablty of prce scenaro p p M c p, : electrcty prce forecast for scenaro p n hour (CAD/MWh) W w, : wnd-nuclear generaton forecast for wnd scenaro w n hour (MW) : actual electrcty prce n hour (CAD/MWh) M ĉ Wˆ : actual wnd-nuclear generaton n hour (MW) II. INTRODUCTION HERE s a growng concern about the negatve T envronmental mpacts assocated wth the use of fossl energy sources (FES) n partcular global warmng mpacts. In ths context, some of the man real emsson-free and sustanable optons for FES n electrcty generaton are nuclear and renewable energy sources (RES) [1]. Nuclear technology s already well developed and s a sgnfcant part of the energy mx n several jursdctons around the world (e.g. France, Ontaro). RES, on the other hand, are stll at the development stage; however, some technologes, especally wnd, are already takng a consderable part of the energy mx n several markets (e.g. Denmark, Germany). Wth respect to transportaton, there s stll a lack of an energy carrer that would replace FES as an effcent and feasble storage opton. In ths context, the concept of a Hydrogen Economy, whch s a hypothetcal economy where energy s stored and carred as hydrogen (H 2 ), has been proposed [2]. arous Hydrogen Economy scenaros can be envsaged, usng hydrogen n a number of dfferent ways; a common feature of these scenaros s the use of hydrogen as an energy carrer for moblty applcatons (e.g. cars, ral, arcrafts) as well as electrcty generaton. Thus, the generaton, storage and usage of hydrogen have recently ganed sgnfcant attenton. There has been some research carred out nvestgatng dfferent hydrogen producton and usage optons. The possble use of nuclear power plants for the sole purpose of producton of hydrogen through novel thermo-chemcal cycles and hgh temperature electrolyss, as dscussed n [3], show that those technologes wll enable producton of hydrogen at effcences as hgh as 50-60%, nstead of less than 30% effcency wth conventonal electrolyss; ths wll result n lowerng the costs of hydrogen producton. In [4], the techncal and fnancal feasblty of hydrogen as an energy carrer s presented for a stand-alone applcaton of RES n Australa; the results show that electrcty produced by such system s more expensve than the electrcty for domestc customers connected to the grd (2.52 AUD/kWh compared to 0.13 AUD/kWh). It s further shown n [5], that hydrogen storage s not yet fully compettve compared to battery storage due to ts low round-trp effcency (about 0.37% presented n the artcle), and hgh nvestments, operaton and mantenance (O&M) costs. The two latter studes are only lmted to electrcty storage capabltes of hydrogen and do not nclude other possble applcatons of hydrogen, wthn the context of a Hydrogen Economy, such as ts possble use n the transportaton sector. There has also been some research done n the feld of optmal generaton schedulng wth electrcty storage. In [6], the optmal operaton of hydrogen storage together wth ntermttent RES on the European electrcty markets s dscussed. The results suggest that hydrogen storage wth ntermttent RES, such as wnd, can consderably ncrease the ncome of the producer, and byproducts of electrolyss and fuel cell usage, such as oxygen and heat, mght mprove the hydrogen system economc performance. However, a comprehensve economc analyss consderng the nvestment and O&M costs of such a system s mssng n ths artcle. In [7], the economcs of nuclear power for electrolytc hydrogen producton n the context of the electrcty market n Alberta, Canada, s analyzed. The results are compared wth common steam-methanereformng (SMR) hydrogen producton processes, wth costs assumptons for the hydrogen subsystem beng relatvely low and wthout consderng an adequate system operaton optmzaton.

3 Wnd farm G Nuclear power plant G W N M μc C H2 tank REGIONAL ENERGY HUB μd D Transmsson lne ELECTRICITY MARKET M Real wnd speed data arameters Generaton of wnd scenaros N producton arameters Generaton of j prce forecasts Electrolyzer charge hsell Hydrogen dstrbuton dscharge Fuel cell Σ Industral market Moblty market Hydrogen powered dstrbuted generaton market Fg. 1: Structure of a regonal energy hub ncludng hydrogen as energy storage and energy carrer. The notaton used s detaled n Secton I. The paper results show that hydrogen producton s a favorable opton; however, a proper senstvty analyss of possble nvestment scenaros s mssng. The present paper tres to broaden these studes by consderng realstc hydrogen producton costs as well as uncertantes, and performng varous senstvty analyses. Thus, t tres to answer the queston of whether the use of hydrogen for energy storage n a mxed wnd-nuclear generaton plant, consderng hydrogen producton wthn the context of a Hydrogen Economy, s economcally justfable. A varety of system optmzaton models and studes are performed, usng varous economc ndces such as nternal rate of return and net present value to evaluate the feasblty and worth of the proposed ntegrated Nuclear-Wnd-Hydrogen system. The rest of the paper s structured as follows. In Secton III, the proposed models and analyss methods are descrbed n detal. The system data used for the proposed studes s dscussed and justfed n Secton I, n the context of the Ontaro electrcty market. Secton presents and dscusses the results obtaned from the proposed models and data, and the man contrbutons and conclusons of the presented studes are summarzed n Secton I. III. SIMULATION METHODOLOGY The proposed system conssts of a nuclear power plant (N) and a wnd farm sellng electrcty n the Ontaro electrcty market, whch s a realstc scenaro beng currently faced by the Bruce ower company. The system ncludes hydrogen storage and dstrbuton facltes accordng to the model depcted n Fg. 1. Hydrogen generaton and storage s consdered for the followng potental benefts: art of the electrcty producton can be stored as hydrogen n perods of low electrcty prces and then sold to the electrcty market at hgh-prce perods. When there s not enough lne capacty to sell the whole electrcty producton to the market, the excess electrcty may be stored as hydrogen and then sold to re-dspatch optmzaton for every (,j) combnaton of scenaros Real-tme evaluaton Revenues wth H 2 Fg. 2: System operaton procedures. Revenues wthout H 2 the market when there s suffcent lne capacty. Hydrogen may be sold drectly to a hydrogen market when the prce of hydrogen s greater than the costs of producng t, and/or when proft s hgher than sellng t nto the electrcty market. Hydrogen wthn the hub can be used as a storage mechansm to releve some of the electrcal grd operatonal challenges assocated wth the varablty of wnd generaton, n partcular power dspatch and frequency control. The system operaton and market bddng, for the system depcted n Fg. 1, s optmzed based on a mxed nteger stochastc lnear programmng (MISL) model. In ths model, wnd producton and electrcty prces are the stochastc nput parameters, and the opton of sellng O 2 and H 2 s also consdered. The flowchart of the system operaton and bddng processes used for the studes presented here s shown n Fg. 2. Several artcles about bddng of electrcty from ntermttent energy sources and consderng prce forecasts n European electrcty markets are avalable (e.g. [8], [9]); these artcles use stochastc programmng technques to ncorporate the stochastc varables such as prce and wnd forecasts n the optmzaton process. In [8], the objectve functon s the mnmzaton of mbalance costs due to devatons of wnd producton from bds to the market. In [9], a smlar methodology s used to ncorporate the electrcty storage n form of pumped-storage unts n the optmzaton process n day-ahead European electrcty markets, wth a balancng market for devatons of actual productons from bds. A novel approach s presented here for the Ontaro electrcty market, based on the models proposed n [8] and [9]. A two-level study approach s used; thus, dspatch levels are frst obtaned one-day ahead based on a stochastc optmzaton model, and the system's realtme operaton s then smulated based on real-tme data, so that fnancal parameters, such as energy sold, energy

4 purchased, ncome, etc., can be calculated based on the real-tme operaton results. A. re-dspatch The followng optmzaton model for obtanng one-day ahead dspatch levels consders that the only varable that lnks operatng hours and days together s the storage content; hence, the storage content varable s fxed n ths model, makng t tme dependent but not scenaro dependent, as t can be seen from the defnton of the storage content varable: max s.t. Nw w Np M WIND pw p p ( c ( w, + w, = 1 p= 1 = 1 (1) H HSELL O OSELL ) + c + c ) max max 1 WIND T + 0 c WIND W (2) (3) = + μ μ d HSELL END 0 = ˆ d 1 α mn w, α max mn w, β 0 max OSELL = μow, max (4) (5) (6) β (7) (9) All varables above are properly defned n Secton I. In ths model, M M c and p W are stochastc parameters, wth, wp,, c p, representng the electrcty prce at the locaton beng consdered, whch n markets based on locatonal margnal prcng t would be affected by lne congeston; however, for the case studed here, whch s located n Ontaro, a unform prce market, ths prce s not consdered to be affected by lne congeston. The bnary varables wp,, (8) α and β for on/off modelng of the electrolyzer and fuel cells wp,, n equatons (6) and (7) make ths model a mxed nteger stochastc lnear programmng (MISL) model. The producton and consumpton lmts of the model are defned by the lne capactes n equaton (2). Equaton (3) restrcts the actual wnd producton dependng of the wnd forecast w at hour. Equatons (4)-(8) model the operaton of the hydrogen subsystem. Fnally, equaton (9) descrbes the producton of oxygen dependng on electrolyzer utlzaton. The optmzaton functon consders only a lmted operaton horzon of one day, wth hourly resoluton and no start up tme for electrolyzers. Two consecutve operaton perods are lnked va the hydrogen storage content equaton (4) at the end of the frst perod. Fnally, observe that the model consders the smultaneous producton and consumpton of hydrogen, snce, as per Fg. 1, there s a hydrogen demand from a market drven by Hydrogen Economy consderatons, wth hydrogen beng sold for transportaton applcatons,.e. the hydrogen system s not only used to smply store electrcty. The forecastng horzon s set to 24 h, snce a longer horzon would not mprove the overall performance of the system, snce the forecastng error of electrcty prces and wnd speeds ncrease wth forecastng length [8], lmtng the ablty to properly asses the optmal operaton of the system. On the other hand, a shorter pre-dspatch optmzaton horzon would mean only ncreased number of local optmums, wthout havng the ablty to make use of all the wnd power and prce fluctuatons. B. Real-tme Dspatch A smple real-tme operatng strategy that follows the scheduled hydrogen storage obtaned from the soluton of the MILS problem (1)-(9) s used. The excess hydrogen s sold as electrcty from statonery fuel cells or to a hydrogen market to maxmze profts. The optmzaton s done on an hourly bass. The constrants are the same as n the prevously descrbed optmzaton model. Thus, the realtme dspatch problem s modeled as a mxed-nteger lnear programmng (MIL) optmzaton problem as follows, wth all varables beng defned n Secton I: s.t. M ˆWIND max ( ˆ ( ˆ ˆ c + ) H ˆ ˆHSELL O ˆOSELL + c + c ) (10) ˆWIND ˆ ˆ max + max (11) WIND 0 ˆ Wˆ ˆ = ˆ + ˆ ˆ μ μ 1 c d HSELL ˆ ˆ 1 = END ˆ ˆ 0 d 1 ˆ α ˆ β mn mn 0 ˆ max OSELL ˆ = μoˆ END ˆ d = ˆ T w (12) (13) (14) = (15) ˆ ˆ α max (16) ˆ ˆ β max (17) (18) (19) (20) Observe that ths model s very smlar to the pre-dspatch model (1)-(9); however, n ths case, there are no stochastc parameters and the optmzaton model corresponds to one-

5 hour only, whch s solved on an hourly bass for 24 h. C. Economc Evaluaton The economc evaluaton of projects s based on the calculaton of one or more numercal ndces whch bear the nformaton about the economcal vablty of a project. The net present value (N) and the nternal rate of return (IRR) are ndces most commonly used n the ndustry [10]. The N s the sum of the dscounted cash flows durng the lfetme of the project, and the IRR s the margnal dscount rate for whch the N s zero [11]. The components whch are taken nto account when calculatng the cash flow n ths artcle are the followng: ntal nvestment costs ncludng transportaton and nstallaton; replacement nvestment costs (for replacements of worn-down assets); O&M costs; revenues; deprecaton (amortzaton); taxes; and salvage value. It s assumed that the cash flow s already expressed n nomnal monetary unts wth respect to the tme of evaluaton of the frst project cash flo so that the nflaton rates are taken nto consderaton. The ncome or proft obtaned from the hydrogen subsystem s the dfference between total ncome of the wnd-nuclear system wth hydrogen and wthout hydrogen, where the ncome wth hydrogen system s calculated usng: ˆ M ˆ WIND ˆ (ˆ ( ˆ R = c + ) + (21) H ˆ HSELL O ˆ OSELL + c + c ) The ncome wthout fuel cells s calculated usng the followng equaton: ˆ WH M ˆ mn(, ˆ WIND R = c max ) (22) I. ACTUAL SYSTEM SETU The system s assumed to be located n Bruce County n Ontaro, Canada. Ths locaton was chosen because of Bruce ower s N currently operatng n the regon, together wth a growng wnd capacty n the regon such as Huron Wnd s wnd farm. Any nvestment or O&M costs assocated wth exstng unts are dsregarded n the economc analyss, snce these unts are already operatonal, regardless of whether the hydrogen storage opton s consdered. All locaton-specfc parameters are consdered to be those for Ontaro; thus, the chosen currency s Canadan dollars (CAD), whch s converted from US dollars (USD) at a rate of 1 USD per CAD. From some ntal studes, t was observed that the number of wnd scenaros dd not mpact the operaton of the system, due to suffcent capacty of the transmsson network and the fact that the energy producton from Bruce ower s N s suffcent to run the electrolyzers; hence, only one wnd scenaro s consdered here n the optmzaton procedure. Even n the case of nsuffcent lne capacty, wnd forecasts wll not mpact system proftablty due to the observed low fuel cell utlzaton. Ths assumpton s further justfed based on the results presented and dscussed n Secton. To represent the stochastc prce behavor, 30 prce scenaros are generated for each optmzaton perod, whch s consdered to be 24 h wth hourly resoluton. The proft calculaton s done for one year, whch s then used n economc evaluatons. The project lfetme s assumed to be 20 years. The dscount rate used n the calculatons of the N s 8%, as per typcal values rangng from 5% to 10% [10]. There are two governmental/provncal tax rates n Canada dependng on yearly ncome. For ncomes less than 300,000 CAD, an 18.62% tax rate apples, and for ncomes above ths fgure a 34.12% tax rate s used. A provncal tax ncentve s assumed, because of producton of hydrogen from RES, thus an 18.62% tax rate s used here regardless of ncome [12]. Furthermore, a government nvestment support from the Ontaro ower Authorty (OA), due to emsson free hydrogen producton from RES and N, n the form of a standard offer program [12], s assumed to cover 25% of the ntal nvestment costs; ths support does not nclude replacement costs for worn-down equpment after ts lfetme. The unformed salvage value of equpment at the end of ts lfetme s assumed to be 10% of the nvestment costs [13]. The operaton and mantenance costs are assumed to be 2% per year of ntal nvestment [13]. A. Ontaro Electrcty Market The model was developed consderng the Ontaro electrcty market rules [14], [15], [16]. Hence, the followng assumptons for the developed models are based on a N and a wnd farm operatng n Ontaro: The producer s a prce taker n the electrcty market, due to the relatvely small scale of the hydrogen facltes. The market bds are c mn =-2000 CAD/MWh, so that the unts are always dspatched. The N producton s added to the wnd-power producton, and the aggregated producton s used as an nput to the model. The N producton s greater than the maxmum electrolyzer demand; thus, there s always enough electrcty to feed the electrolyzer. For real-tme operaton, the wnd farm s consdered as an ntermttent generator accordng to [15]. Intermttent generators supply the Independent Electrcty System Operator (IESO) wth producton forecasts, but are not oblged to actually delver the forecasted power, and do not have to follow the IESO's dspatch nstructons. These types of generators may not regster for the provson of any physcal servce, other than energy and reactve support and voltage control servces. Qualfyng large-scale wnd energy generaton projects are also elgble for a Wnd ower roducton Incentve [12]. An ntal ncentve payment of 12 CAD/MWh of producton, gradually declnng to 8 CAD/MWh, s avalable for the frst ten years of producton.

6 TABLE I: ELECTROLYZER ARAMETERS ARAMETER ALUE Number 32 rce (CAD per module) Lfetme (years) 10 Max. capacty (MW/module) Mn. capacty (MW/module) Hydrogen effcency (kg/mwh) 18.7 Oxygen effcency (Nm 3 /MWh) 119 TABLE II: COMRESSOR ARAMETERS ARAMETER ALUE Number 40 rce (CAD per module) Lfetme (years) 20 Capacty (Nm 3 /h) 48 TABLE III: STORAGE ARAMETERS ARAMETER ALUE Number 101 rce (CAD per module) Lfetme (years) 20 Max. capacty (kg/module at 400 bars) Intal hydrogen n tank (kg) 0 TABLE I: FUEL CELL ARAMETERS ARAMETER ALUE Number 141 rce (CAD per module) Lfetme (years) 20 Max. capacty (MW/module) Mn. capacty (MW/module) Hydrogen effcency (kg/mwh) 68.1 B. Wnd Subsystem Huron Wnd s Ontaro's frst commercal wnd farm, and s located on the shore of Lake Huron n Bruce County, Ontaro. The ste s seven klometers northwest of Tverton n the muncpalty of Kncardne. The wnd farm conssts of fve estas MW wnd turbnes, whch gves a total output power of 9 MW [17]. The wnd speeds for 2005 were obtaned from the desgn proposal for renewable energy generaton facltes n Kncardne [13]. C. Nuclear Subsystem Bruce ower s Canada s frst prvate nuclear generatng company, and the source of more than 20% of Ontaro s electrcty. It s located approxmately 250 km northwest of Toronto and currently operates sx reactor unts, wth nstalled capacty of 4820 MW. Because Bruce ower s prvately owned, the actual producton profle and ncome data are confdental. In 2004, Bruce ower produced 33.6 TWh of electrcty [18], whch gves them a capacty factor of 82%, equal to MW of constant electrcty producton. It s assumed that 3000 MW of constant electrcty s sold to the IESO on a blateral contract, and the remanng MW capacty s bd nto the electrcty market or may be converted to hydrogen. D. Transmsson Lne Capacty A smplfed model of the lne capacty s used here, whch s an adequate approxmaton for the purpose of the present feasblty study. Thus, transmsson capacty lmts are represented through the use of max n equatons (2) and (11) of the pre-dspatch and dspatch models, respectvely. Observe that f the wnd power plant were located afar from the N, to generalze the proposed optmzaton models, the transmsson lne lmts could be readly ncluded nto the model by smply separatng the power lmts on the output of the wnd, nuclear and hydrogen subsystems nstead of representng them n the proposed aggregated manner. Furthermore, note that the transmsson lne capacty model can be readly changed to accommodate hourly changes n transmsson capacty; ths can be accomplshed by replacng max by max, n equatons (2) and (11). Fnally, t should be mentoned that the transmsson losses are not consdered n the model snce ths s a partcular transmsson system ssue under the purvew of the system operator (Ontaro's IESO n ths case), and s handled centrally and ndependently from the power producers, based on mechansms such as system balancng servces and/or network charges, whch do not have a sgnfcant nfluence on the proposed models, analyss methodologes and results. For the partcular case study dscussed here, the majorty of the power s transmtted va the 500 k Bruce-Mlton lne wth total capacty of 5000 MW, runnng from the Bruce area to the load centre n the eastern part of Ontaro around Toronto. In prncple, there s abundant lne capacty accordng to the IESO data, and hence thermal, voltage and other IESO managed constrants should not mpact the system operaton and proftablty. Ths assumpton can be further justfed by consderng the relatvely low nstalled capacty of hydrogen subsystem, whch leads to the free lne capacty beng lower than the fuel cell capacty for only 17 hours a year n 2006, for example. Fnally, the refurbshment of Bruce A reactors 1 and 2 wll add an addtonal 1500 MW of nstalled capacty n ; however, ths should not mpact the system operaton and revenues, as t wll be accompaned by an expanson of the Bruce-Mlton transmsson lne. In spte of these observatons, congeston of the Bruce-Mlton transmsson corrdor s stll studed n ths paper, as dscussed n detal n Secton -C. E. Hydrogen Subsystem The hydrogen subsystem s dmensoned to have the same capacty as the wnd subsystem. The N s assumed to provde requred electrcty n perods of low electrcty producton from wnd. The test system s comprsed of 32 Hydrogencs HySTAT-A IMET 1000 Electrolyzers [19],

7 wth total nstalled power of MW and a maxmum producton rate of hydrogen of 1920 Nm 3 /h. Because the prces of equpment are confdental, the prces reported n [20] were used here. Thus, electrolyzer prces are assumed to vary from 1370 USD/kW to 3693 USD/kW, dependng on nstalled power and economes of scale; hence, a prce of 1590 USD/kW ( CAD/kW), assumng a largescale economy and medum szed unts, was used here. All electrolyzer parameters are lsted n Table I. A hydrogen effcency of 4.8 kwh/nm 3 or kg/mwh was consdered accordng to [19]; ths fgure represents the amount of hydrogen produced by 1 MWh of electrcty, and results n an effcency of 62.5%, ncludng rectfer and auxlares, and consderng the energy value of 1 kg of hydrogen to be equal to kwh [2]. Hydrogen producton s consdered here to be solely from tradtonal and commercally avalable electrolyss processes, snce the use of thermo-chemcal processes for hydrogen producton would requre the replacement of the exstent nuclear reactors, as ths s not techncally feasble wth current low-temperature Canadan nuclear technology. Nevertheless, observe that the proposed optmzaton models could be n prncple modfed to consder ths possblty; n ths case, dfferent converson effcences and assocated parameters would have to be consdered accordngly. A compressor array comprsed of 40 I 3 stage metal daphragm compressors [21], wth total capacty of 1920 Nm 3 /h, s assumed to be used to compress the hydrogen to 400 bar (6000 psg), whch s the storage pressure of the storage tanks, allowng the dstrbuton to the hydrogen market. The effcency of the compressors s assumed to be practcally 100%. rces for compressors vary from USD/kg/h (900 USD/Nm 3 /h) to USD/kg/h (2440 USD/Nm 3 /h) for ths sze daphragm compressors [20]. A medum prce of USD/kg/h was chosen here, whch s equal to CAD/kg/h (1698 CAD/Nm 3 /h). All compressor parameters are lsted n Table II. The hydrogen storage conssts of 101 hydrogen storage vessels, assumed to be provded by C Industres, wth total capacty of kg of hydrogen at 400 bars. Ths provdes enough storage to store the hydrogen produced n 12 consecutve hours. Ths sze was chosen on the assumpton that the system wll be optmzed n 24 h ntervals, and that peak prces are reached n the afternoon. The prce of one CI tank s USD (22033 CAD), accordng to the producer nformaton. The storage parameters are shown n Table III. The statonery fuel cell array ncludes 141 Hydrogencs HyM 500 seres fuel cells of 65 kw each; ths adds up to MW of total nstalled capacty for the entre array. The techncal parameters are depcted n Table I, as per reference [22]. rces are confdental and vary n the lterature. In [20], the prce range stated s 297 USD/kW USD/kW. In [23], the lowest prce s 3000 USD/kW, whch seems to be reasonable from the dscussons n [20], and s hence used here. The mnmum capacty of the array s equal to the maxmum capacty of a sngle fuel cell power module. The hydrogen effcency of the fuel cells n Table I represents the amount of hydrogen needed to produce 1 MW of electrcty; hence, the overall fuel cell effcency s 44%, whch gves a round-trp effcency (.e. generaton of electrcty from hydrogen and then use of hydrogen to produce electrcty) of 27.50%. Observe that ths means that the sellng prce of electrcty should be about four tmes the buyng electrcty prce for the hydrogen subsystem to be able to proft from the storng of electrcty. The total ntal nvestment costs are 5238 CAD per kw of nstalled capacty. The hydrogen sellng prce s taken as bulk hydrogen prce produced from natural gas n 2020, whch s half of the assumed lfetme of the system. Natural gas s currently the prmary energy source for producton of hydrogen as well as the lowest cost source, [23]; therefore, t s assumed that the prces of hydrogen wll be mostly dependant on natural gas prces n the system s lfe-tme. The bulk pre-tax prce of hydrogen for dfferent natural gas prces s reported n [23]; f natural gas prces vary between USD/GJ, the hydrogen prces vary between USD/kg for a 22 tons/day hydrogen producton plant. Snce nomnal gas prce forecasts n [24] for are USD/MBtu, the prce at 2020 s assumed to be 9.16 USD/MBtu, whch s equal to 8.68 USD/GJ. Hence, accordng to ths prce of gas, the hydrogen producton prce s assumed here to be 2.74 USD/kg. If a carbon tax of 0.35 USD/kg s added as n [23], the converted end-prce s 3.24 CAD/kg. If Canadan and Ontaro tax rates of 34.12% are added, the wholesale hydrogen prce becomes 4.35 CAD/kg. Hydrogen transportaton costs are consdered external costs for the present studes, and are hence not factored n the hydrogen sellng prce. Usually, gaseous hydrogen can be transported usng hgh-pressure cylnders, tube tralers or ppelnes [25]. Compressed-gas truck delvery would be the cheapest opton for the producton rate consdered n the present artcle, costng around CAD/kg/km for an 80 km dstance, or CAD/kg/km for 800 km. Because there s no ready market for the volume of oxygen produced, the oxygen prce s assumed to be 0 CAD/Nm 3. Ths s a conservatve assumpton, snce future market potental for oxygen, such as those assocated wth oxy-combuston processes, would mprove the overall economcs of the dscussed system. F. Electrcty rce Forecasts A smple electrcty prce forecastng module was developed, assumng a normal dstrbuton of electrcty prce forecasts around actual electrcty prces. The prce forecasts are generated here by addng random numbers from normal dstrbuton, wth mean value μ = 0 CAD, and a standard devaton of σ = 13.8 CAD, to the hourly Ontaro energy prce (HOE); the maxmum relatve error s lmted

8 p W w, TABLE : THE RE-DISATCH RESULTS FOR THE SIMLE TEST CASE M WIND HSELL c p, w, w, p, w, p, w, p, OSELL w, p, Wˆ M ĉ WIND ˆ TABLE I: THE REAL-TIME RESULTS FOR THE SIMLE TEST CASE HSELL ˆ ˆ ˆ ˆ Rˆ TABLE II: RESULTS FOR BCS CONSIDERING FC AND FE FACTOR FC/FE NFC/FE FC/NFE NFC/NFE roft [CAD/year] 2 964, , , ,138 N [CAD] , , , ,602 IRR [%] Negatve 9.60 Negatve 9.60 Utllzaton FC [%] Utllzaton EL [%] Investment costs [CAD] , , , ,561 O/M costs [CAD/year] 965, , , ,134 TABLE III: RESULTS FOR CONGESTION SCENARIO CONSIDERING FC AND FE FACTOR FC/FE NFC/FE FC/NFE NFC/NFE roft [CAD/year] , , , ,309 N [CAD] , , , ,172 IRR [%] Utllzaton FC [%] Utllzaton EL [%] Investment costs [CAD] , , , ,486 O/M costs [CAD/year] , , , ,052 Rˆ WH Total roft to 30% of the HOE. Ths procedure yelds the same mean absolute error (MAE) as the transfer functon forecastng model dscussed n [14]. The electrcty prces were based on HOE values for 2005, whch have a mean value of CAD/MWh [26].. RESULTS AND DISCUSSION The smulatons were performed usng AML [27], and a CLEX solver [28]; hence, a Branch and Cut approach was used to deal wth the nteger varables, formng subproblems, that are then solved by a smplex optmzaton algorthm. The economc evaluaton was all done usng Matlab [29]. A. Smple Test Scenaro To demonstrate how the pre-dspatch and real-tme procedures are appled, a smple test case scenaro s frst used. Thus, the system descrbed n Secton I was used, wth a tme horzon of 4 h and wth two prce forecast scenaros. The results of solvng the optmzaton models (1)-(9) and (10)-(20) are shown n Tables and I. The proft made n ths case due to the hydrogen subsystem utlzaton s 1,330 CAD. It should be hghlghted, that the utlzaton and the resultng profts of the hydrogen subsystem are manly dependent on three factors: electrcty prces and electrcty prce profles; the effcences of the components; and the hydrogen sellng prce. Investment and other costs are not a factor n ths case. One can easly calculate that f there are no prce forecast errors, and the hydrogen sellng prce s 4.35 CAD/kg, and the effcency of the electrolyzer s 18 kg/mwh (60%), the electrolyzer would be utlzed when the prces of electrcty drop below 78.3 CAD/MWh. Ths s consstent wth the results obtaned n Table, where one can observe that w, p, s

9 2 x CCF wth fuel cells CCF wthout fuel cells 20 0 % reducton 25 % reducton 50 % reducton CCF [CAD] IRR [%] % Years Fg. 3: Cumulatve cash flow (CCF) wth and wthout fuel cells. roft [CAD/year] 6 x Electrolyzer utlzaton roft Electrolyzer utlzaton [%] Electrolyzer effcency [%] Fg. 5: IRR wth fuel cells for varous electrolyzer effcences and equpment prce reductons. IRR [%] % reducton 25 % reducton 50 % reducton Electrolyzer effcency [%] Fg. 4: roft and electrolyzer utlzaton wth respect to electrolyzer effcency. zero for c M p, values greater than 78.3 CAD/MWh. If a hgher effcency of 27 kg/mwh (90%) s consdered, the electrolyzer would be dspatched at prces below CAD/MWh. Smlarly, the fuel cell would be utlzed when the prce of electrcty exceeds CAD/MWh, for a hydrogen sellng prce of 4.35 CAD/kg and an effcency of 50 kg/mwh (60%), or when the prce exceeds CAD/MWh, f the effcency s kg/mwh (45%). Snce the prce of electrcty rarely reaches these levels, the fuel cell utlzaton would be very lo as shown n Tables and I ( w, p,, ˆ ). Notce that an ncrease n the hydrogen sellng prces decreases the utlzaton and proftablty of electrcty generatng statonary fuel cells, whereas an ncrease of effcency of the fuel cells ncreases them. B. Base Case Scenaro The base case scenaro (BCS) s based on the system data mentoned n the prevous secton. Ths s the most probable scenaro n practce, and s further dvded nto four subscenaros based on prce forecasts, wth and wthout error, for the system wth and wthout statonary fuel cells. The nvestment evaluaton results obtaned excludng fuel cells Electrolyzer effcency [%] Fg. 6: IRR wthout fuel cells for varous electrolyzer effcences and equpment prce reductons. (NFC) and ncludng them (FC), wth (FE) and wthout (NFE) forecast errors are presented n Table II. The governmental support s already consdered n the nvestment costs, so that the ntal nvestment costs stated n ths table are 75% of the actual ntal nvestment costs. Nether forced outages of electrolyzers nor the scheduled outages for mantenance were consdered. Observe that the hydrogen subsystem wth statonary fuel cells s not proftable, due to the hgh costs and low utlzaton of those fuel cells; ths s reflected n negatve values for N and IRR. The electrolyzer utlzaton s consderably hgher, at about 93%. The forecastng error s shown to have only lmted mpact on proftablty of the system wth fuel cells, and no mpact on the system wthout fuel cells; ths s due to effcency of fuel cell power modules and the relatvely hgh hydrogen sellng prces compared to electrcty prces. Thus, the hydrogen s produced and sold when prces of electrcty fall below the aforementoned 78.3 CAD/MWh, almost regardless of the results of the pre-dspatch phase. Notce that by omttng the under-utlzed statonary fuel cells, the projects IRR s 9.6%, makng t proftable enough 8%

10 10 x Electrolyzer utlzaton roft % reducton 25 % reducton 50 % reducton roft [CAD/year] Electrolyzer utlzaton [%] IRR [%] % Hydrogen sellng prce [CAD/kg] Fg. 7: roft and electrolyzer utlzaton wth respect to hydrogen sellng prces. to nvest on t. Fgure 3 shows the cumulatve net cash flows (CCF) wth and wthout fuel cells ncludng prce forecast errors. The cash flows are nomnal values,.e. no dscountng to present value s consdered. The scenaros wthout prce forecast errors result n smlar cash flows. It s evdent from the fgure, that the hydrogen subsystem wth statonary fuel cells never becomes proftable, snce the cumulatve cash flow never exceeds the zero margn. The scenaro wthout statonary fuel cells, on the other hand, s shown to be proftable. Observe the consderable change on cash flows n year ten; ths s due to replacement of electrolyzers at full costs n that year. In the last year of the project, the effect of salvage values s clearly vsble. It should be hghlghted that because the system s manly utlzed for hydrogen producton nstead of electrcty storage, due to low fuel cell utlzaton, the prce and wnd forecasts do not have any sgnfcant mpact on the system proftablty. For dfferent hydrogen and electrcty prces and effcences, these forecasts may have a more sgnfcant effect on the system economcs. C. Senstvty Analyss The senstvty analyss s based on the BCS, and concentrates on studyng the followng man ssues: 1. Effect of effcency of electrolyzers and fuel cell power modules. 2. Effect of hydrogen sellng prce. Impacts of equpment prces, prce forecastng errors and excluson of fuel cells are also consdered n all these studes. Senstvtes wth respect to other parameters, such as the hydrogen subsystem dmensons, were not studed due to the fact that, from the results presented n the prevous two sectons, one can conclude that ther effects would not be sgnfcant on the system under study. 1) Fuel cell and Electrolyzer Effcences In ths secton, the effcences of fuel cells and electrolyzers were assumed to vary from 45% to 60% for the fuel cell power modules, and 60% to 90% for the Hydrogen sellng prce [CAD/kg] Fg. 8: IRR wth fuel cells wth respect to on hydrogen sellng prces. electrolyzer subsystem. The results obtaned ndcate that the utlzaton of statonery fuel cell power modules s near zero for all studed effcences; ths s due to the fact that electrcty prces should exceed CAD/MWh, dependng on the effcency of the fuel cells, for the fuel cells to be utlzed, whch rarely happens n the current market, as prevously dscussed. Based on ths, the proft, electrolyzer utlzaton and nternal rates of return depend solely on electrolyzer effcency. In Fg. 4, the proft and electrolyzer utlzaton are shown wth respect to the electrolyzer effcences. The results show almost lnear dependency of proft and electrolyzer utlzaton wth respect to effcences. The prce and wnd forecast errors do not have any consderable mpact on the proftablty and utlzaton of statonary fuel cells and electrolyzers, as well as on nternal rates of returns, smlar to what s reported n the prevous secton. The IRR of the project wth respect to electrolyzer effcences are depcted n Fg. 5. Dfferent equpment prce reductons are consdered here, consderng also a governmental ntal nvestment support of 25%. Observe that equpment prces strongly mpact the proftablty of the hydrogen subsystem; the hgher the reducton, the hgher the proftablty of the hydrogen subsystem. If one assumes an IRR of 8% to be the margnal value for the nvestment to be proftable, then 50% prce drops wth effcences of above 60%, or 25% prce drops wth effcences above 75%, are suffcent for the subsystem to be attractve to potental nvestors. A smlar study wthout statonary fuel cells s depcted n Fg. 6. Ths fgure shows hgher economcal benefts f fuel cells are omtted, as expected. 2) Hydrogen Sellng rce The second part of the senstvty analyss was devoted to hydrogen sellng prces, assumng a range of 3 CAD/kg to 8 CAD/kg. Agan, a very lmted mpact of prce and wnd forecast errors on proftablty of the system was observed. The effect on proft and utlzaton of electrolyzer versus hydrogen sellng prce s llustrated n Fg. 7.

11 IRR [%] % reducton 25 % reducton 50 % reducton The results for the congeston scenaro studes are shown n Table III. They show hgher proftablty of the hydrogen subsystem compared to other scenaros, due to the use of energy for hydrogen producton, whch would otherwse be lmted by transmsson lne congeston. Ths further constrants the use of statonery fuel cells, resultng n no utlzaton of these devces, snce ther electrcty producton cannot be transmtted. However, the overall proftablty of the Nuclear-Wnd-Hydrogen system s hgher than n the prevous case, where there was no transmsson lmtaton Hydrogen sellng prce Fg. 9: IRR wthout fuel cells wth respect to hydrogen sellng prces. Observe that utlzaton s close to 100% for prces above 6 CAD/kg. The proft s almost lnearly dependent on hydrogen prces, wth an approxmate slope of 1 420,000 CAD per each CAD/kg hydrogen sellng prce ncrease. The mpact of the hydrogen sellng prces on the proftablty of the subsystem wth respect to equpment prce costs s depcted n Fg. 8. These results show that the IRR of the hydrogen subsystem ncreases as hydrogen prces ncrease. The complete subsystem becomes economcally vable at hydrogen prces above 6 CAD/kg n the base case scenaro; at lower equpment prces the system becomes proftable at lower hydrogen prces. The economc vablty of hydrogen subsystem wthout statonary fuel cells s presented n Fg. 9. D. Transmsson Congeston Scenaro In addton to the base case scenaro wth senstvty analyses, a scenaro consderng lmted transmsson lne capactes s consdered here, addressng possble delays n the planned transmsson expanson n the Bruce area [30]. Therefore, the possblty that the energy produced by Bruce ower and wnd generators s not gong to be entrely transferable to end-users s nvestgated. The lne capacty s assumed to reman unchanged wth regards to the base-case scenaro. The refurbshed Bruce power plant s foreseen to ncrease ts capacty by 1500 MW, resultng n a total capacty of 6320 MW. Any other potental generaton developments n the area are not consdered. Wth same capacty factor used n the base case scenaro, ths capacty expanson would result n 5207 MW of constant electrcty producton by the N. Wth the addton of 9 MW of Huron Wnd s wnd power, the nstalled capacty of the hydrogen subsystem to supply for the potental lack of transmsson capacty s assumed to be 216 MW. The sutable hydrogen subsystem for storng ths amount of excess electrcty s presumed to consst of 750 electrolyzers wth total hydrogen producton capacty of kg/h. The compressor, storage tank and fuel cell arrays are assumed to be comprsed of 939, 2355 and 914 unts, respectvely. 8% I. CONCLUSIONS The feasblty of a wnd-farm and nuclear power plant n the context of a Hydrogen Economy has been studed n ths artcle. A novel methodology has been developed takng nto account all mportant factors n the economc evaluaton of projects for nvestment purposes. The proposed methodology was used to study the feasblty of a realstc wnd-nuclear-hydrogen system located n Ontaro, Canada. The results show that for the gven realstc assumptons, hydrogen s not a vable opton for electrcty storage at ths tme for the current electrcty market and prcng. It s also shown, that prce and wnd forecastng errors do not play a major role n the feasblty studes presented. The hydrogen subsystem for producng hydrogen s shown to be proftable, f a hydrogen demand (e.g. for transportaton applcatons) s consdered; n that case, one can conclude from these studes, that t mght be vable to produce hydrogen from electrcty and nvest n hydrogen producton equpment n an exstng mxed wnd-nuclear energy hub. The proftablty of such system s ncreased when lmted transmsson capactes prevent the sellng of all the electrcty produced to the electrcty market, snce n ths case, the electrcty s converted to hydrogen and sold to the hydrogen market. Thus, the hydrogen producton opton, n ths context, may also be an alternatve for grd expanson, especally n locatons where such expanson s not an opton due to envronmental, local or other reasons. In future research, there s a need to focus on the applcaton of the proposed models and analyss methodology to other possble system confguratons and ssues. For nstance, the sellng of byproducts such as oxygen from the electrolyzer and heat from the fuel cells may add economc value to the hydrogen subsystem. II. REFERENCES [1] A. I. Mller, R. B. Duffy, "Integratng large-scale co-generaton of hydrogen and electrcty from wnd and nuclear sources (NUWIND )", IEEE EIC Clmate Change Technology, pp. 1-9, May [2] Natonal Research Councl and Natonal Academy of Engneerng, "The Hydrogen Economy: Opportuntes, Costs, Barrers and R&D needs", The natonal Academes press, Washngton, [3] R. R. Sadhankar, J. L, H. L, D. K. Ryland, S. Suppah, "Future Hydrogen roducton Usng Nuclear Reactors", IEEE EIC Clmate Change Technology, pp. 1-9, 2006.

12 [4] B.D. Shakyaa, Lu Aye,. Musgrave, "Techncal feasblty and fnancal analyss of hybrd wnd photovoltac system wth hydrogen storage for Cooma", Internatonal Journal of Hydrogen Energy, ol. 30, pp. 9-20, [5] D.B. Nelson, M.H. Nehrr, C. Wang, "Unt Szng of Stand-Alone Hybrd Wnd//Fuel Cell ower Generaton Systems", IEEE ES General meetng, ol. 3, pp , June [6] M. Korpas, A. T. Holen, "Operaton lannng of Hydrogen Storage Connected to Wnd ower Operatng n a ower Market", IEEE Transactons on Energy Converson, ol. 21, No. 3, 2006 [7] A. Mller, R. Duffey, "Sustanable and economc hydrogen cogeneraton from nuclear energy n compettve power markets", Energy, ol. 30, pp , [8] J. Matevosyan, L. Soder, "Mnmzaton of Imbalance Cost Tradng Wnd ower on the Short-Term ower Market", IEEE Trans. On ower Syst., ol. 21, No. 3, August, [9] J. Gonzales, R. Moraga, L. Matres, A. Mateos, "Stochastc jont optmzaton of wnd generaton and pumped-storage unts n an electrcty market". [10] Internatonal Energy Agency, "Gudelnes for the economc analyss of renewable energy technology applcatons", ars, [11] D. Allen, "Economc evaluaton of projects", Insttuton of chemcal engneers, Thrd edton, [12] Renewable Energy Development n Ontaro (REDO), "General nformaton for potental developers", [13] Mchael Fowler, "Renewable Energy Generaton Faclty Desgn Report", Unversty of Waterloo, [14] H. Zarepour, "rce Forecastng and Optmal Operaton of Wholesale Customers n a Compettve Electrcty Market", hd thess, [15] Independent Electrcty System Operator, "Market Manual 9: Day- Ahead Commtment rocess Operatons and Settlement", Issue 4.0, March [16] Independent Market Operator (now IESO), "Market Manual 4: Market Operatons art 4.0: Market Operatons Overvew", Issue 9.0, June [17] Huronwnd, "Facts and fgures", [Onlne]. Avalable: [18] Bruce ower, "2004 year revew", [Onlne]. Avalable: [19] Hydrogencs Corporaton, "Hystat-A Hydrogen plants brochure". [Onlne]. Avalable: [20] J. X. Wenert, T. E. Lpman, "An Assessment of the Near-Term Costs of Hydrogen Refuelng Statons and Staton Components", Insttute of transportaton studes, Unversty of Calforna, Davs, [21] resure product ndustres, "Fuel cell staton compressor -brochure". [Onlne]. Avalable: l.pdf [22] Hydrogencs Corporaton, "HyM 500 seres power module fuel cell brochure". [23] F. Doty, "A Realstc Look at Hydrogen rce rojectons", Doty Scentfc, Inc. Columba, [Onlne]. Avalable: [24] Internatonal Energy Agency, "World energy outlook 2006", [25] W. A. Amos, "Costs of storng and transportng Hydrogen", NREL, November [26] IESO, "Hourly Ontaro Energy rce (HOE)", [Onlne]. Avalable: [27] R. Fourer, D. M. Gay, B. W. Kernghan, "AML: A Modelng Language for Mathematcal rogrammng", Duxbury ress, 2 edton, November, [28] ILOG, "ILOG AML CLEX System erson 10.0 User s Gude", January, [29] MATLAB, "Matlab Onlne Manuals". [Onlne]. Avalable: [30] Ontaro Clean Ar Allance, "A new Bruce transmsson lne: Does t make sense for Ontaro?", Ar Qualty Issues Fact Seet #23, [Onlne]. Avalable: systems. III. BIOGRAHIES Gregor Taljan (SM 06) receved hs Electrcal engneer dploma from the Unversty of Ljubljana, Slovena n He s a hd student at the Faculty of Electrcal Engneerng, Unversty of Ljubljana, workng as young researcher n the Laboratory for ower Systems and Hgh oltage. He s currently a vstng scholar at the Unversty of Waterloo, Canada. Hs research nterests are n power system operaton and economcs and relablty evaluaton of power Mchael Fowler receved hs B.Eng. n Fuels and Materals Engneerng from Royal Mltary College of Canada (RMC) n 1986, MASc n Engneerng Chemstry from Queen s Unversty n Followng a career as Mltary Engneer n the Canadan Forces and workng as an Envronmental Management Consultant he completed a hd at RMC n Dr. Mchael Fowler s currently an Assstant rofessor n the Department of Chemcal Engneerng at the Unversty of Waterloo wth a research nterests n fuel cell system desgn and relablty, fuel cell materals durablty and green power systems. Claudo Cañzares (S'86, M'91, SM 00, F 07) receved the Electrcal Engneer degree from Escuela oltecnca Naconal (EN), Quto- Ecuador, n 1984 where he held dfferent teachng and admnstratve postons from 1983 to Hs MSc (1988) and hd (1991) degrees n Electrcal Engneerng are from Unversty of Wsconsn-Madson. He has been wth the E&CE Department, Unversty of Waterloo snce 1993, where he has held varous academc and admnstratve postons and s currently a full rofessor. Hs research actvtes concentrate n the study of stablty, modelng, smulaton, control and computatonal ssues n power systems wthn the context of compettve electrcty markets. Dr. Cañzares has been the recpent of varous IEEE-ES Workng Group awards, and currently holds and has held several leadershp appontments n IEEE-ES techncal commttees and subcommttees, as well as workng groups and task forces. Gregor erbc (S 98, M 03) receved n December 1995 the Electrcal Engneer dploma from the Unversty of Ljubljana, Slovena. He joned Korona ower Engneerng n 1995 where he worked for three years. Hs MS (2000) and hd (2003) degrees n Electrcal Engneerng are from the Unversty of Ljubljana. Dr. erbc s now an Assstant rofessor at the Unversty of Ljubljana, Faculty of Electrcal Engneerng. In 2005, he was a NATO-NSERC ostdoctoral Fellow at the Unversty of Waterloo, ON, Canada. Hs research actvtes are power-system operaton, dynamcs and control.