GOLDEN VALLEY ELECTRIC ASSOCIATION

Transcription

1 January 7, 21 GOLDEN VALLEY ELECTRIC ASSOCIATION Eva Creek ind Data Tw inute ean ind Speed Analysis Revisin PROJECT NUBER: PROJECT CONTACT: IKE ALBERT, PE EAIL: PHONE: PROJECT CONTACT: KEITH STUP, SEE EAIL: PHONE:

2 Tw inute ean ind Speed Analysis Prepared by POER Engineers, Inc. fr Glden Valley Electric Assciatin Eva Creek ind Data Fr additinal infrmatin cntact: ike albert (28) Keith Stump (678) Issue Issued Prep Chkd Appd Rev. Ntes Date Fr By By By 1/7/21 Impl KBS A VFP POER apprved sent t GVEA Issued Fr Definitins: - Prelim means this dcument is issued fr preliminary review, nt fr implementatin - Appvl means this dcument is issued fr review and apprval, nt fr implementatin - Impl means this dcument is issued fr implementatin - Recrd means this dcument is issued after prject cmpletin fr prject file

3 TABLE OF CONTENTS 1. SUARY INTRODUCTION TO INUTE IND DATA ONTHLY IND DATA OCCURENCES OF TO INUTE POER LEVELS IND POER RAP RATE DISTRIBUTION AVAILABLE IND POER TIE PROFILES IND INTEGRATION APPROACHES LIST OF FIGURES Figure 1: Prspective wind turbine and meterlgical twer lcatins... 2 Figure 2: ind turbine pwer versus speed characteristic... 4 Figure 3: Tw minute interval bar chart f available wind farm pwer, September Figure 4: Tw minute interval bar chart f available wind farm pwer, Octber Figure : Tw minute interval bar chart f available wind farm pwer, Nvember Figure 6: Tw minute interval bar chart f available wind farm pwer, December Figure 7: Tw minute interval bar chart f available wind farm pwer, January Figure 8: Tw minute interval bar chart f available wind farm pwer, February Figure 9: Tw minute interval bar chart f available wind farm pwer, arch Figure 1: Tw minute interval bar chart f available wind farm pwer, April Figure 11: Tw minute interval bar chart f available wind farm pwer, ay Figure 12: Tw minute interval bar chart f available wind farm pwer, June Figure 13: Tw minute interval bar chart f available wind farm pwer, July Figure 14: ind farm frequency f pwer ccurrences versus available wind pwer Figure : Frequency f ccurrence f lw amplitude pwer ramps Figure 16: Frequency f ccurrence f high amplitude pwer ramps Figure 17: Tw minute average available wind pwer during September Figure 18: Tw minute average available wind pwer during Octber Figure 19: Tw minute average available wind pwer during Nvember Figure 2: Tw minute average available wind pwer during December Figure 21: Tw minute average available wind pwer during January Figure 22: Tw minute average available wind pwer during February Figure 23: Tw minute average available wind pwer during arch Figure 24: Tw minute average available wind pwer during April Figure : Tw minute average available wind pwer during ay Figure 26: Tw minute average available wind pwer during June Figure 27: Tw minute average available wind pwer during July i

4 1. SUARY Available wind farm utput frm a 24 prspective wind farm lcated in the EVA Creek area has been measured with tw minute average samples using wind speed data cllected frm a meterlgical twer. The measurements are presented in five sectins f this reprt. Frequency f ccurrence data has been scaled up t accunt fr missing data (due t anemmeter icing) t represent data fr a cmplete year. Average mnthly available wind farm utput pwer has been cmputed frm available valid wind speed measurement data. Tw minute wind data has been cllected frm nly ne meterlgical twer. Hence, the effect f wind speed diversity amng the prspective sixteen turbine wind farm culd nt be determined. The analysis in this reprt assumes that all sixteen wind turbines distributed acrss tw 2. km east-west ridges get the same wind speed at the same time. Bar charts shwing wind farm utput indicate that Nvember, December, February and arch had the mst available wind pwer with wind farm average utputs exceeding 1. Octber had the lwest available average utput f.4. The frequency distributin f available wind farm utput levels shws that the number f tw minute average ccurrences f zer available wind farm pwer was 46,48 (92,816 minutes r apprximately 1,47 hurs r 17.7% f the time) and the number f tw minute average ccurrences f full 24 available utput pwer was 39,63 (76,36 minutes r apprximately 1,322 hurs r.1% f the time). Tw minute average pwer ramp rates varied frm zer when there was n change in available wind pwer between measurement intervals t 12 /minute when the available wind farm pwer changed frm zer t 24 r 24 t zer in a tw minute sample interval. There were mre lw ramp rate intervals than high ramp rate intervals. A ttal f 121,687 tw minute intervals (46% f the ttal) had lw ramp rates between +.1 /minute and -.1 /minute. Of the ttal 262,8 yearly tw minute intervals, 76,9 (29%) were zer (n wind speed change). There were a ttal f nly 1, tw minute high ramp rate intervals (2 minutes r 33.3 hurs r.4% f the time) during the year that ramp rates were greater than +6 /minutes and less than - 6/minute. Actual tw minute available pwer measurements are pltted versus time fr fur selected three hur perids during each mnth f cntinuus measurement. Typical tw minute wind farm pwer variatins tend t be between apprximately 1 and 4. Hwever, many tw minute available pwer variatins are higher. The tw minute samples shw many small pwer reversals that appear as a. cycle/minute pwer variatins superimpsed upn slwer pwer changes. Sme traces shw the. cycle/minute pwer variatins superimpsed upn a general increase r decrease in pwer that ccurs ver a perid f apprximately ne hur. At ther times the available wind farm pwer changes ver large ranges f apprximately t 2 within five t fifteen minutes. Data frm the tw minute available pwer averages frm the meterlgical twer measurements indicates that any wind speed variatin between zer and full rated wind farm utput is pssible within the sample interval. 2. INTRODUCTION Glden Valley Electric Assciatin, GVEA, has had wind measurements made with meterlgical twers at the site f a ptential wind farm in the Eva Creek area. This reprt dcuments the analysis f wind samples frm a single meterlgical twer averaged ver tw minute intervals starting 1

5 August 31, 27 and ending August, 28. Other wind measurements in the Eva Creek area have been made, but tw minute samples have nly been cllected frm ne meterlgical twer. A prspective wind farm near Eva Creek presently cnsists f sixteen GE-1.sle wind turbine generatrs fr a wind generatin facility rated at 24. Prspective turbines are lcated n tw parallel east-west ridges. The turbines are spaced alng a distance f apprximately 2. km (1. miles) n each east-west ridge and the ridges are apprximately 2. km apart. Figure 1 shws a tplgical map f the EVA Creek area and the prspective wind turbine lcatins. The prspective turbines are numbered 1 thrugh 8 n alng the nrthern ridge and 9 thrugh 16 n the suthern ridge. Figure 1 is marked with Xs at lcatins where meterlgical twers are lcated. Data analyzed in this reprt was cllected frm metrlgical twer 3-1 lcated in Sectin 12, at the east end f the nrthern ridge near prspective wind turbine number 8. etrlgical twer 3-1 is lcated at latitude 64⁰ nrth and 148⁰.277 west. Elevatin f the ridge is 9 meters (2,97 feet) and the measured wind data is extraplated fr a turbine hub height f 8 meters (263 feet). Figure 1: Prspective wind turbine and meterlgical twer lcatins 2

6 3. TO INUTE IND DATA The tw minute wind data frm meterlgical twer 3-1 was supplied by GVEA in tw icrsft Excel data files. One file had 122,7 recrds and the ther file had 122,771 recrds. The tw files were cmbined int a single file with a ttal f 244,841 recrds fr analysis. A cmplete 36 day file f tw minute recrds wuld have 262,8 recrds. Due t early anemmeter mechanical prblems and icing prblems during the measurement perid, gd data culd nt be btained fr every single tw minute interval during the measurement perid. issing data was indicated in the data files by the wrd ICE r the letter in the available energy utput clumn f the data recrds and a negative wind velcity f -98 m/s r -99 m/s in the wind velcity clumns. This infrmatin was used during data prcessing t differentiate mechanical and icing measurement recrds frm valid data. Figure 2 shws available wind pwer utput frm a single GE-1.sle wind turbine versus wind speed. This wind turbine characteristic was prvided by GVEA alng with the wind speed data and the cnversin t available wind turbine pwer. The turbine has a 77 meter (3 ft) rtr diameter. Air density fr this characteristic is 1. kg/m 3. The figure indicates that the full k turbine rating utput is available when the wind speed is m/s (33. mph). Full rated pwer can be prduced fr wind speeds between m/s and m/s (~6 mph). Results pltted in the fllwing sectins t summarize the tw minute data recrds are scaled up by a factr f sixteen t represent the ttal prspective utput pwer frm a 24 wind farm cnsisting f sixteen wind turbines. This prcedure assumes that all turbines in the wind farm get the same wind speed distributin at the same time. Presently tw minute wind speed data is available nly frm a single meterlgical twer at a single lcatin. The effect f tw minute wind diversity n the ttal available wind farm utput pwer cannt be estimated frm the single twer data. There were many recrds f zer pwer utput availability frm the prspective wind turbine. Zer utput will ccur fr wind velcities less than 3 m/s (6.7 mph) r greater than m/s (~6 mph). any recrds indicate zer wind velcity withut the anemmeter icing r mechanical prblems. These zer wind velcity recrds are treated as valid measurements with zer pwer utput during the data analysis. 3

7 16 k A v a i l a b l e P w e r Available Pwer Vs. ind Speed 1.sle GE Turbine 77m Rtr Diameter 1. kg/m 3 Air Density ind Speed meters/secnd Figure 2: ind turbine pwer versus speed characteristic 4. ONTHLY IND DATA Table 1 indicates time duratins f the varius mnthly wind and measurement cnditins fr the tw minute data samples. Lw wind cut-ff is the duratin f valid wind speed measurements belw 3 m/s (6.7 mph) when the wind turbine will nt prduce pwer as shwn n the left side f Figure 2. High wind cut-ff is the duratin f valid wind speed measurements abve m/s (~6 mph) when the wind turbine will nt prduce pwer as shwn n the right side f Figure 2. N data is the time duratin when the anemmeter at the meterlgical site was nt serviceable due t mechanical prblems r icing and n wind speed data was cllected. Prductin time is the time duratin when the cllected wind speed data was abve 3 m/s (6.7 mph) and belw m/s (~6 mph) when wind turbine generatrs culd prduce real pwer (k). Table 1 indicates that the mnthly time was 72 t 17 hurs (.8 t 1.9% f the time) when wind pwer generatin was nt pssible due t lw wind speed. In sme mnths, there culd be mre time than shwn in Table 1 when n wind generatin was pssible, depending upn the actual wind speed during the time when n wind speed data culd be cllected. Similarly, the mnthly time when wind pwer prductin was pssible culd be higher than shwn in Table 1 depending upn the actual wind speed when the anemmeter was ut f service. 4

8 The average available ttal wind farm pwer in the last clumn f Table 1 was cmputed frm the valid wind speed measurements each mnth. Hence, the average culd be a little higher r lwer depending upn the actual wind speed when measured wind speed data was nt available and depending upn the ability t generate during icing cnditins.. The lwest measured mnthly average was.37 in Octber and the highest mnthly average was 12.7 in February. The average available pwer utput frm a 24 wind farm cmputed frm all the valid measurement data including the partial mnth f August is Figures 3 thrugh 13 summarize the available tw minute wind farm utput pwer levels fr each cmplete mnth f measurements. Valid measurement data fr each mnth was used t cmpute the mnthly average available utput pwer. These mnthly averages are indicated n each figure. All cmplete mnths when tw minute measurements were made except June and July f 28 had sme measurement perids where measurement data was nt available due t anemmeter icing. Fr mnths with missing data, it was assumed that the missing data samples have the average available mnthly pwer level and this level is pltted n the figures at the missing sample times. Figure 6, December f 27, and Figure 7, January f 28, are mnths with the mst missing data (due t anemmeter icing). issing data is indicated by the cnstant average pwer levels f the between December 12 and December 2 n Figure 6 and 9.24 between January 4 and January 14 n Figure 7. Similarly, ther mnths with missing measurement data have the missing intervals pltted as the average f the valid data fr that mnth. The lwest mnthly average prspective wind farm utput f the tw minute measurements is.37 in Octber f 27. The highest mnthly average prspective wind farm utput f the tw minute measurements is 12.7 in February f 28. Bar charts in Figures 3 thrugh 13 cntain every tw minute sample in each mnth and they give a gd verview f the available wind pwer. Hwever, since there are 72 (24*6/2) tw minutes data pints fr every day, higher pwer levels tend t verwrite lwer levels and may make the mnthly pwer charts appear t have higher and/r mre cnstant pwer levels than the actual measurements. Figure 12 indicates that June 28 is the mnth with the mst wind variatin f the mnths measured with the tw minute samples. The available wind pwer did nt stay at maximum fr any extended time (hurs r days) during the mnth. Available pwer did nt get t the maximum 24 level anytime between June 14 and June 2.

9 Table 1: easurement ind Cnditins and Average Available ind Farm Output Pwer nth Year Lw ind Cut-ff High ind Cut-ff N Data Prductin Time Ttal Time Average Available Farm Pwr. Hurs Hurs Hurs Hurs Hurs September Octber Nvember December January February arch April ay June July September Average Recrded Available Pwer: 8.4 Day f nth Figure 3: Tw minute interval bar chart f available wind farm pwer, September 27 6

10 . Octber Average Recrded Available Pwer:.37 Day f nth Figure 4: Tw minute interval bar chart f available wind farm pwer, Octber 27. Nvember Average Recrded Available Pwer: 1.64 Day f nth Figure : Tw minute interval bar chart f available wind farm pwer, Nvember 27 7

11 . December Average Recrded Available Pwer: Day f nth Figure 6: Tw minute interval bar chart f available wind farm pwer, December 27. January Average Recrded Available Pwer: 9.24 Day f nth Figure 7: Tw minute interval bar chart f available wind farm pwer, January 28 8

12 . February Average Recrded Available Pwer: 12.7 Day f nth Figure 8: Tw minute interval bar chart f available wind farm pwer, February 28. arch Average Recrded Available Pwer: 1.71 Day f nth Figure 9: Tw minute interval bar chart f available wind farm pwer, arch 28 9

13 . April Average Recrded Available Pwer: 7.6 Day f nth Figure 1: Tw minute interval bar chart f available wind farm pwer, April 28. ay Average Recrded Available Pwer: 8.16 Day f nth Figure 11: Tw minute interval bar chart f available wind farm pwer, ay 28 1

14 . June Average Recrded Available Pwer: 7.26 Day f nth Figure 12: Tw minute interval bar chart f available wind farm pwer, June 28. July Average Recrded Available Pwer: 7.2 Day f nth Figure 13: Tw minute interval bar chart f available wind farm pwer, July 28 11

15 . OCCURENCES OF TO INUTE POER LEVELS The f number valid tw minute available wind pwer measurements at each k level fr a single wind turbine were determined and placed in bins between and k (the rating f ne turbine). The number f ccurrences in each bin were then scaled up by the rati f the number f tw minute samples in a year t the number f valid measurement pints t btain enugh samples t represent a cmplete year. The k single turbine bin size levels were scaled up by a factr f sixteen, t prduce.8 bin sizes, s that the bin pwer levels represent the available pwer utput f a 24 wind farm. Results f the available yearly wind farm pwer level frequency f ccurrences are pltted in Figure 14. The number f tw minute average ccurrences f zer available wind farm pwer is 46,48 (92,816 minutes r apprximately 1,47 hurs r 17.7% f the time) The number f tw minute average ccurrences f full 24 available utput pwer is 39,63 (76,36 minutes r apprximately 1,322 hurs r.1% f the time). There are a ttal f 262,8 tw minute perids (8,76 hurs) in a 36 day year. Data scaling results in 262,8 fr the sum f all the ccurrence pints (y-axis) in Figure 14. This represents the predicted number f ccurrences fr a cmplete year. Number f 2 inute Occurrences per Year Number f Available 2 inute Average Occurences Per Year Vs. Available Output Pwer Ttal 24 ind Farm Available Output Pwer Figure 14: ind farm frequency f pwer ccurrences versus available wind pwer 12

16 6. IND POER RAP RATE DISTRIBUTION Pwer measurements fr each tw minute interval are cnverted t ramp rates by dividing the difference between tw successive available pwer averages by the measurement interval, tw minutes. The ramp rates are cnverted t /minute fr a 24 wind farm by multiplying the 1. single turbine rating by 16 (ttal number f turbines). The number f ramp rates in each bin was scaled up by the rati f the ttal tw minute samples in a 36 day year t the number f cmputed ramp rates t get a frequency distributin f rates representing a cmplete year. Intervals where the pwer did nt change prduce zer ramp rates. These zer ramp rates ccur when the wind speed is belw the minimum r abve the maximum fr turbine pwer prductin (belw 3 m/s [6.7 mph] r abve m/s [~6 mph]). Zer ramp rates als ccur fr wind speeds between m/s and m/s when rated turbine pwer is available and when the wind speed des nt change between cnsecutive tw minute sample intervals. Figure 2 shws the available utput pwer versus wind speed (meters/secnd) curve fr a single 1.sle-GE wind turbine-generatr cnsidered fr the Eva Creek applicatin. Psitive ramp rates indicate the available pwer ut was increasing and negative ramp rates indicate that the available pwer utput was decreasing during the measurement interval. aximum and minimum pssible ramp rates frm this data fr a 24 wind farm are +12. /minute and -12. /minute. These extreme rates ccurred when the available wind farm pwer went frm zer t maximum (24 ) in a tw minute measurement perid r frm maximum t zer in a tw minute measurement perid. The cmputed pwer ramp rates were srted int. /minute bins between +12 /minute and -12 /minute. The number f tw minute intervals in each bin were tabulated. Figures and 16 shw the frequency distributin f tw minute ramp rates pltted frm the binned data. any f the ramp rates were either zer r very near zer. Figure shws the number f lw ramp rates at each level between +2. /minute and -2. /minute. There were a ttal f 121,687 tw minute intervals when the ramp rates were between +.1 /minute and -.1 /minute (46% f the ttal). Of the ttal 262,8 yearly tw minute intervals, 76,9 (29%) were zer (n wind speed change). There are mre lw ramp rate intervals than high ramp rate intervals. There were a ttal f nly 1, tw minute high ramp rate intervals during the year when the ramp rates were greater than +6 /minute r less than -6 /minute. Hence, Figure 16 is pltted with a smaller vertical frequency f ccurrence scale and a higher hrizntal ramp rate scale t shw the number f high ramp rate ccurrences. The peaks at the ends f Figure 16 shw that the number f tw minute available intervals where the available pwer ges frm maximum t zer r frm zer t maximum is apprximately 26 times each per year. The figures shw that the magnitudes f psitive and negative ramp rates are abut equal. Fr example, plus and minus 4 /minute rates each ccurs in apprximately 7 tw minute intervals per year. 13

17 High Occurrences Ramp Rate Yearly /sec. Occurrences.1 8,11. 1, ,9 +., , Frequency Occurences/Year Frequency f Occurence (2 minute intervals) Vs. Ramp Rate (Lw Ramp Rates) Ramp Rate /inute Figure : Frequency f ccurrence f lw amplitude pwer ramps Frequency Occurences/Year Frequency f Occurence (2 minute intervals) Vs. Ramp Rate (High Ramp Rates) Ramp Rate /inute Figure 16: Frequency f ccurrence f high amplitude pwer ramps 14

18 7. AVAILABLE IND POER TIE PROFILES In additin t the frequency f the pwer ramps due t wind changes, the actual time prfiles f the available wind pwer is f interest. System lads tend t be relatively cnstant ver hurly perids. If the generatin pwer varies due t wind, sme generatin in the system must als vary in an ppsite manner t maintain a pwer balance in the system between ttal generatin and ttal lad. T illustrate expected dynamic requirements f nn-wind generatin r t determine hw t perate the wind turbines, sme representative available wind pwer variatins versus time are pltted during each f the eleven mnths in which tw minute wind data was recrded. Figures 17 thrugh 27 are selected plts f available wind farm pwer versus time during September f 27 thrugh July f 28. These plts assume that all sixteen wind turbines in a 24 wind farm get the same wind speed as that measured by the anemmeter n meterlgical twer 3-1 where the tw minute measurements were taken. The charts are intended t be representative f wind pwer variatin that can be expected during variable wind perids. The figures each cntain fur plts f cntinuus three hur available wind pwer measurements. All pints pltted are frm the actual tw minute data measurements and indicate valid available pwer levels fr the prspective 24 wind farm. ajr time divisins n the charts in the figures are 2 minutes apart s there are 1 tw minute measurement pints per divisin as indicated by the markers n each pwer traces. The chart legends indicate the day and time f each data series pltted. Typical tw minute wind farm pwer variatins tend t be between apprximately 1 and 4. Hwever, many tw minute variatins are higher. The tw minute samples shw many small pwer reversals that appear as a. cycle/minute pwer variatin superimpsed upn slwer pwer changes. any traces shw the. cycles/minute pwer variatin superimpsed upn a general increase r decrease in pwer that ccurs ver a perid f apprximately ne hur (Figures 17 18, 19 and 22). At ther times the available wind farm pwer changes ver large ranges f apprximately t 2 within five t fifteen minutes (Figures 17, 18, 2, 22 and 24). Figure 24, April 28, has tw intervals n the 4/8 trace where the available pwer changed by apprximately in ne tw minute sample interval (7. /minute). The mst unusual available pwer variatin selected fr pltting is shwn by the 1/22 (January 22) traces n Figure 21, January, 28. Initially the trace is mstly at zer available wind pwer, but jumps t 24 in ne interval fr single tw minute perids between apprximately 123 and 14. Then the available pwer stays mstly at 24, but drps t zer fr single tw minute sample perids between apprximately 14 and 1. There was anemmeter icing in the January 28 raw data. Hwever, n anemmeter icing was reprted between January 14 and February 11. Zer available wind pwer measurements (n anemmeter icing reprted) have been treated as valid data n the figures and fr the wind analysis in this reprt. Figure 21 als shws a three hur pwer trace later in the same day, January 22, 28 frm 173 t 23. During this time the available wind farm pwer stayed near 24 except fr a frty minute perid between apprximately 19 and 194 when the available pwer drpped t apprximately 1. The traces fr selected three hur perids in February 28, Figure 22, shw sme high available wind pwer perids. The 2/14 trace indicates that the pwer reduced frm near full pwer (24 ) t apprximately 6 fr a perid f apprximately frty minutes between 17 and 174. The 2/8 trace n the figure als shws that the available pwer slwly increased frm apprximately 7 t

19 near full pwer ver a tw hur perid between 9 and 11. Similarly, the 2/ trace shws the available wind pwer decreasing frm near full pwer t apprximately 14 ver a tw hur perid between 14 and 16. ay and June f 28, Figures and 26, were mnths f cnsiderable variatin in available wind pwer. The traces in these tw figures shw a tendency fr lw (2 t 3 ) medium (1 t ) and high (2 t 24 ) pwer levels with the nrmal. cycle per minute variatins during different time perids. The /31 trace n Figure indicates sme high (1 r mre) sample t sample variatins. The /6 trace shws a three hur perid f available pwer belw 4. Figure 26 shws tw three hur perids with available pwer mstly belw abut in June f

20 T t a l 2 Sept. 27 ind Pwer Vs Time P w e r 1 9/ 12 9/ / / Time inutes Figure 17: Tw minute average available wind pwer during September 27 17

21 T t a l 2 Octber 27 ind Pwer Vs Time P w e r 1 1/ / / / Time inutes Figure 18: Tw minute average available wind pwer during Octber 27 18

22 T t a l 2 Nv. 27 ind Pwer Vs Time P w e r 1 11/ / / / Time inutes Figure 19: Tw minute average available wind pwer during Nvember 27 19

23 T t a l 2 Dec. 27 ind Pwer Vs Time P w e r 1 12/ / / / Time inutes Figure 2: Tw minute average available wind pwer during December 27 2

24 T t a l 2 January 28 ind Pwer Vs Time P w e r 1 1/ / / / Time inutes Figure 21: Tw minute average available wind pwer during January 28 21

25 T t a l 2 February 28 ind Pwer Vs Time P w e r 1 2/ / / / Time inutes Figure 22: Tw minute average available wind pwer during February 28 22

26 T t a l 2 arch 28 ind Pwer Vs Time P w e r 1 3/ / / / Time inutes Figure 23: Tw minute average available wind pwer during arch 28 23

27 T t a l 2 April 28 ind Pwer Vs Time P w e r 1 4/ 6 9 4/ / Time inutes 4/ Figure 24: Tw minute average available wind pwer during April 28 24

28 T t a l 2 ay 28 ind Pwer Vs Time P w e r 1 /6 18 / / Time inutes / Figure : Tw minute average available wind pwer during ay 28

29 T t a l 2 June 28 ind Pwer Vs Time P w e r 1 6/6 18 6/ / Time inutes 6/28 18 Figure 26: Tw minute average available wind pwer during June 28 26

30 T t a l 2 July 28 ind Pwer Vs Time P w e r 1 7/ /9/ 8 7/ Time inutes 7/ Figure 27: Tw minute average available wind pwer during July 28 27

31 8. IND INTEGRATION APPROACHES A wind farm prducing 24 is apprximately 9% f the 217 prjected 263 peak lad f the GVEA system and will be a much higher percentage f light system lading. This much wind pwer penetratin will require prper generatin resurce scheduling and cntrl due the variable nature f the wind. A pwer balance must be achieved between generatin plus imprt pwer and lad in the GVEA system. At lw levels f wind penetratin, wind farms can be perated as wind dependent generatin. Hwever, when wind generatin becmes higher than nrmal lad fluctuatins, cmpensatin ther than what is nrmally used t cmpensate fr variable lads must be emplyed. Several pssible aids t cmpensate fr the variable nature f the wind are as fllws: 1. Available ind Predictin: A gd predictin f available wind will allw reserve generatin t be started and available when the wind pwer drps ff and allw generatin t be shut dwn when wind pwer is expected t be available fr an extended perid f time. ithut gd wind predictin mre spinning reserve with existing generatin may be required. 2. Turbine Blade Pitch Cntrl: By perating the turbine belw the maximum available pwer level using cntrl f the blade pitch angle, wind generatin can be maintained when wind speed drps. The amunt f additinal pwer that shuld be made available by blade pitch cntrl will depend upn the predictin f available wind, the size f randm wind fluctuatins, expected lad variatins, ther available lad cmpensatin facilities and ther items that affect the ladgeneratin balance. ind plant cntrl may allw significant smthing f the wind farm utput pwer. 3. Energy Strage Systems: GVEA s battery energy strage system, BESS, at the ilsn substatin culd ptentially d a lt fr keeping the net pwer prduced by the cmbinatin f a wind farm and the BESS nearly cnstant. Pwer frm the BESS in cmbinatin with blade pitch cntrl culd be used t smth wind turbine pwer variatins (perhaps n the rder f +/- ). hen wind predictins indicated that wind pwer wuld be lw fr an extended perid f time, pwer frm the BESS culd allw reserve generatin t be brught n line and relieve the BESS pwer requirement. Cmmunicatin between the wind farm and the BESS culd allw an integrated cntrl t limit pwer ramp rates t defined limits. Additinal cntrl design wrk wuld be required t determine the feasibility, benefits and reliability f this apprach. 4. re Energy Strage: An upgrade f the pwer utput time duratin capability f the BESS t supply 24 fr a perid f an hur r mre culd be very helpful. Pwer frm the BESS culd fill in many f the lw pwer times shwn n Figures 3, 6, 7, 8, 9, 1 and 11 (September and December thrugh ay). This upgrade wuld allw a ttal wind farm plus BESS t be scheduled fr utput lwer than the available wind pwer. Output frm the wind farm in excess f the scheduled ttal wuld be used t charge the BESS when available wind farm pwer is greater than the scheduled net BESS-turbine system utput pwer. The cmbinatin f the BESS and the wind farm culd be perated tgether as a single generatin resurce.. ind Speed Diversity: It is pssible that the. cycles/minute available wind pwer variatins bserved in the single meterlgical twer measurements may be smthed ut by the wind speed diversity acrss the wind farm area and nt be a system peratinal cncern. The prspective wind farm twers span a significant distance (tw apprximately 2. km [1. miles] rws, rws apprximately 2. km apart) acrss uneven terrain. The wind velcity is 28

32 prbably different frm twer t twer at the same instants f time even if it averages the same ver a perid f time (secnds t minutes). If a wind speed change traveled at the maximum useful speed f m/s (~6 mph), it wuld take 1 secnds fr it t get frm ne wind twer ridge t the ther r frm ne end f a turbine rw t the ther. 6. Lad-ind Farm Cmbinatin: This idea may nt be feasible, but if there were large lads that were nt dependent upn the time that they were pwered, they culd be scheduled fr peratin when wind pwer is available and help keep utput pwer frm wind farm nearly cnstant. A pumped strage facility may be such a lad. aybe sme prcess that needs heat and has a lng cling time cnstant culd als be such a lad. Perhaps a grinding prcess frm a quarry r mine culd bring ut the prduct during nrmal wrk hurs and grind it with an autmatic cntrl when wind pwer is available. 29