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HomeMy WebLinkAboutPetersburg-Wrangell Power Needs Forcast 1979PET 003 ve APRIL 1979 U.S. DEPARTMENT OF ENERGY ALASKA POWER ADMINISTRATION P.O. Box 50 Juneau, Alaska 99802 PETERSBURG-WRANGELL POWER NEEDS FORECAST Se L PROPERTY OF: Alaska Power Authority 334 W. 5th Ave. Anchorage, Alaska 99501 CONTENTS TITLE PAGE NO. Introduction .cccccccccccccccccvcccccccvcvcccsccssccssccscces 1 Basic Data cececcecccsccccvcvcvvvncceccccncceccnrsccesessseee 1 Previous Studies .cceccccccccccccccccccccceccsscecsccece 1 Historic Data and Existing Generation ...eeeeseeeeeceoes A Monthly load Distribution ....cceccccccccccccvcccccccecs D Residential Use ..ccececccccccccccccccrcenscccecvccccccee 5 Methodology and AssumptionS ...eeeceecccececccccccceccccssecs 8 Residential ...cccccccccccccccccccccccesessesescccsceces 8 Commercial and Industrial ....cccecececceccccccccccccces 8 Electric Heat ...ccccccccccccvcccccccessvccssecescscvces 10 System Capacity Factors ceccecccccccccccccccccccccsccece 10 REGULES co c.ccciccsccsccwccccioncccccccccccceccee sess eescecceeee 10 TABLES NUMBER PAGE NO. 1 Summary Previous and Present Estimated Future Energy Requirements (2 2 Energy and Peak Demand a 3 Existing Power Generation Sources 4 4 Monthly Load Distribution 6 5 Residential Use/Customer 7 6 Assumptions on Future Energy Use 9 7 Estimate of Future Power Needs 12 FIGURES NUMBER PAGE NO 1 Historic and Projected Energy Needs Petersburg and Wrangell Separate is 2 Historic and Projected Energy Needs Petersburg and Wrangell Combined 14 3 Historic and Projected Capacity Needs Petersburg and Wrangell Combined 15 PETERSBURG-WRANGELL POWER NEEDS FORECAST Introduction The Alaska Power Administration has assessed the future power needs of the Petersburg and Wrangell areas as part of the power market analysis for the "Interim Feasibility Report on Hydroelectric Power and Related Purposes for Sitka, Petersburg/Wrangell and Ketchikan, Alaska," prepared by the U.S. Army, Alaska District, Corps of Engineers. Authorities for this work include Section 5 of the Flood Control Act of 1944, concerning transmission and marketing of power from Corps of Engi- neers projects and the Act of August 9, 1955, concerning investigations of Alaska water and power development potential. The future power needs of the Petersburg and Wrangell areas were esti- mated for several levels of use. These levels include low, medium, and high growth rates and a high growth rate combined with increasing use of residential electric heating systems. Parameters utilized in predicting future demands include historic and recent trends in residential and industrial uses, industrial/commercial growth, conservation, and fuel displacement. This report presents the basic data and assumptions used in the forecasts and summarizes the results of the analyses by this agency. During the period of this analysis, the communities of Petersburg and Wrangell, through the Thomas Bay Power Commission, proceeded with in- vestigations of the Tyee Lake hydroelectric project, leading toward li- censing by the Federal Energy Regulatory Commission. This project is expected to be in operation in 1984. This power market analysis indi- cates that the Tyee Lake Project will meet the power needs of Petersburg and Wrangell through the year 2000. Basic Data The basic data used in preparing the forecast came from APA files and included monthly residential, commercial, and industrial energy and capacity use. Studies of previous energy need forecasts and the existing generation systems are presented to give a perspective on the existing situation. Previous Studies Table 1 presents a summary of previous estimated future power require— ments and the results of this study for comparison purposes. Historic Data and Existing Generation Table 2 contains the historic energy and capacity used for both Peters- burg and Wrangell. The data is from APA files, collected from utili- ties, local industry, and the Federal Energy Regulatory Commission. Table 3 contains existing generation data, also including the date of installation. Industrial generation shown would be converted to standby if hydropower became available, according to local information sources. 1 Table 1 Summary Previous and Present Estimated Future Energy Requirements Petersburg P j ; and PETERSBURG WRANGELL Wrangell Historic Period Historic Period Data of Percent Data of Percent Period Projection Growth Period Projection Growth 1974 Alaska Power Estimate 1972-1982 2.3 Estimate 1972-1982 3.1 . Survey by the i; by the Utility Utility 1972 - s : 1972 '. 1974 (1976) Alaska. : _ 1980-1990 Power Survey I : at 6.7% a ie 5 : 1990-2000 : 5.6% Thomas Bay Appraisal 1968-1974 1975-1995 27.5 1968-1974 1975-1995 7.5 7.5 Report — R.W. Beck, ; z : : ; November 1975 . “Virginia Lake : - 1968-1976 1976-1996 6. / - Appraisal Report - (Some data preliminary) R.W. Beck, Aug 1977 ‘ “Institute of Social = 9.25, 6.75 Economic Research i ; June 1977 S.E. Intertie APA 1976-1980 7.5 - 1976-1980 8 (unpublished) 1980-1990 6 : 1980-1909 8.5 : 1990-2000 4 1990-2000 4 Preliminary Tyee 1968-1977 1979-1988 3.5. 1968-1977 1978-1988 4.2 1978-1988 Appraisal Report, . i -3.8 Retherford, 1973 i 1988-1998 2.6 : 1988-1998 3.0 1988-1998 -- : : : “1/7 : aad) ‘Alaska Power / 1968-1977 1980-2000 He 9.7 2/ 1968-1977 1980-2000 He 8.6 He 2/ 7.5 Administration~ ~ H 5.4 . H 7.24 6.1 = M 2.8 Mo 3.5M 3.1 L 2.5 L 3.1L 2.7 ; a Average percent of the composite increase. Actual estimate was made by projecting residential, commercial and industrial, and electric heat ‘Separately. 2/ High case including some home electric heat. Table 2 ENERGY AND PEAK DEMAND Petersburg and Wrangell Energy — Million KWH (GWH) - Total Petersburg Petersburg Wrangell and Wrangell 1968 12.191* 6.663 18.854 1969 12.434* 6.662 19.096 1970 13.777 7.199 20.976 1971 16.314 8.275 24.589 1972 16.798 8.998 25.796 1973 17.286 9.724 27.010 1974 18.735 10.305 29.040 1975 18.371 10.753 29.124 1976 19.307 11.651 30.958 1977 20.366 12.405 122 32.771 1978 20.124 Peak Demands - MW Petersburg Wrangell Total 1970 2.65 1.7 4.35 1971 2.95 2.05 5.0 1972 3.0 2529 5.25 1973 3.2 2625 D955 1974 3.5 z.15 5.65 1975 br | 2.6 5.85 1976 3.67 2065 6.32 1977 3.95) 2.65 6.75 1978 3.49 Data Source: APA files for all data except as indicated by "*" which is from Tyee Lake Appraisal Report, Sept. 1978, Retherford and Associates. Gross generation figures shown which include 2 percent to 5 percent station service use above net generation. Table 3 EXISTING POWER GENERATION SOURCES 1979 Petersburg and Wrangell Petersburg Municipal Light And Power DATE NAMEPLATE PLANT INSTALLED CAPACITY (KW) Hydro 1/ Crystal Lake 1974 2,000— (Blind Slough) Diesel Z 1965 15250 2 1972 350 > 1972 2,100 4 1977 885 Total 6,585 Wrangell Municipal Light And Power Diesel 1 1964 500 2 1970 500 3 1970 500 4 1970 1,245 5 1972 1,250 6 1972 1,250 7 1973 1,250 8 1973 1,250 Total 7,745 Industrial Diesel os -_ 300 Steam Turbine —_ - 1,000 a _ 1,800 Total 3,100 Capable of only 1,900 KW due to limiting penstock. An additional 1.1 GWh was purchased from the utlity. Ink ~~ ANNUAL GENERATION 1976 (GWH) 12.3 7.0. 11.6 Generation 1978 (GWh) Monthly Load Distribution The monthly load distribution shown on table 4 is based on 1970 to 1976 Petersburg and Wrangell loads combined. Future loads of the combined system may be distributed significantly different due to increasing industrial use and potential electric heating. Residential Use Table 5 shows historic residential use, number of customers, and KWh use per customer for Petersburg and Wrangell. For comparison purposes, a summary of use per customer for other Southeast Alaska towns is presented. Table 4 . MONTHLY LOAD DISTRIBUTION Petersburg-Wrangell Monthly peak as percent of annual peak load. Month Percent Annual Oct 8.0 Nov 8.2 Dec 8.9 Jan 8.7 Feb 7.9 Mar 8.9 Apr 7.2 May dod. Jun 7.7 Jul 8.6 Aug 9.3 sep 9.1 Total 100.0 Data Source: APA data, 1970-76 Table 5 PETERSBURG AND WRANGELL Residential Use/Customer Residential Use Petersburg - Wrangell , Residential Use | Number KWh Per Residential Use Number KWh Per Million (KWh) Customers Customer Million (KWh) Customers Customer 1970 5.65 749 7,540 2.78 536 5,190 1971 5.74 744 7,715 2.97 543 5,465 1972 S.32 801 6,640 3.22 706 | 4,560 1973 5.73 827 6,935 3243 715 4,790 1974 5.89 826 7,125 3.60 750 4,795 1975 6.23 840 7,410 3.83 775 4,940 1976 5.89 858 6,865 3.87 769 5,030 1977 6.61 922 7,170 1978 7.25 985 7,360 Average Rounded 7,200 5,000 Other Southeast Alaska Towns KWh Per Residential Sitka Ketchikan Juneau 1970 6,309 8,845 5,995 1971 6,725 9,159 6,144 1972 7,140 9,570 6,305 1973 7,328 8,674 6,477 1974 7,208 8,292 6,745 1975 8,011 8,558 6,931 1976 8,079 8,723 6,687 Average Rounded 7,300 8,800 6,500 Petersburg KWh use per customer increased 1.7 percent per year 1972-1978. Number of customers increased at the same 1.7 percent rate for the repre— sentative period 1972-1976. Wrangell KWh use per customer increased 2.5 percent per year 1972-1976. Number of customers increased 2.2 percent per year. Methodology and Assumptions The forecast of power needs was prepared using a component method whereby residential, commercial industrial, and electric home space heat were estimated separately and then combined. High, medium, and low cases were prepared using these components. Electric heat was considered a significant amount for the high case only. Detailed assumptions for the components are presented subsequently and summarized on table 6. Residential - The residential component of the future needs was projected using the number of customers and use per customer as variables. Table 6 shows the historic and assumed future trends. The number of customers was extended, using 1972 to 1976 trends of an average 2 percent growth per year for the medium case and adjusted up and down 1 percent for high and low case, respectively. The energy use per residential customer was extended, based on the 1972-1976 trends also. For conservation purposes, the assumption was made for the medium case that the increase in use per customer would continue at the present trend through the mid-1980's, and then still increase, but at a lower rate, through the year 2000. The high case was assumed to increase at the present rate through the year 2000, and still not exceed reasonable limits. The low case was assumed to increase at half the past trend. Commercial and Industrial - Commercial and industrial estimated needs were increased to become a larger percent of the total system load, based on the 1970-1976 data and the current economic expansion plans expressed by industries in both towns. Petersburg commercial and in- dustrial loads increased from 47 percent to 62 percent of the total system use between 1970 and 1978. For the Petersburg high growth case, considering a cautious expansion of commercial fisheries, the loads could easily increase to 70 percent of the total load (excluding electric heat) by the year 2000. The resulting annual growth was estimated at 5 percent through 1985 and 6 percent through 2000. For the medium growth case, continuation of past trends would include some expansion of the bottom fisheries and fish processing, but no major off-shore ships delivering to Petersburg. The commercial and industrial use was assumed to remain at the same 62 to 65 percent of the total commercial, industrial, and residential use. For the low growth case, commercial and industrial loads were assumed at 90 percent of the medium estimate and would amount to roughly 70 percent of the total low load forecast. Table 6 ASSUMPTIONS ON FUTURE ENERGY USE Petersburg and Wrangell Petersburg Historic Residential 1972-1976 Number of Customers High Medium 1.7% Low Use Per Customer High Medium 1.7% Low KWh Per Customer 1970-1976 High Medium 7,200 (Average) Low Commercial and Industrial High Medium Low Electric Heat Percent of homes electrically heated 0 10 1980 1985 ly Includes self-supplied industry Assumed Future 1977-1985 1985-2000 3% 3% 2% 2% 1% 1% 1.7% 1.7% 1.7% 0.85% 0.85% 0.85% 1985 2000 8,240 10,620 8,240 9,350 7,710 8,750 1977-1985 1985-2000 5% 6% 4.2% 2.6% 90% of Medium Loads 1990 1995 on 25 50 Wrangell Historic Assumed Future 1972-1976 1977-1985 1985-2000 3% 3% 2.2% 2% 2% 1% 1% 2.5% 2.5% 2.5% 2.5% 2.5% 1.25% 1.25% 1970-1976 1985 2000 6,280 9,080 5,000 (Average) 6, 280 7,570 6,670 5,600 1977-1985 1985-2000 10% 17 C«S AY 3% 90% of Medium Loads 1980 1985 1990 1995 on 0 10 25 50 assumed to use utility by the mid 1980's. or The Wrangell commercial and industrial loads were roughly 67 percent of the total system needs from 1970 to 1976. This percent is expected to remain the same until a hydro project becomes operational in the mid-1980's. At that time, the local utility would have the capability of picking up a major portion of the timber industry energy needs, which are currently self-supplied. For the high growth case, the residential use was assumed 25 percent of the total system load, with commercial and industrial making up the remaining 75 percent for the period 1985-2000. For the medium growth, loads were assumed to continue on the basis of straight-line extension of past trends where commercial and industrial energy use is roughly 67 percent of the total system use. For the low growth case, use will increase, but will be roughly 90 percent of the amount assumed for the medium case where past trends were extended. Electric Heat - Residential customers use of electric heat in their homes is assumed to start in 1985 due to increased oil prices and incentives to use hydropower energy. Assume the following schedule: 10 percent of homes use electric heat in 1985, 25 percent in 1990, and 50 percent in 1995 and thereafter. The use per home is estimated at 2.7 KWh per degree day based on experience in the Anchorage area. Petersburg has 8,300 degree days per year, which would require 22,400 KWh to heat an average home for a year. Wrangell has 7,750 degree days per year, which would require 21,000 KWh. System Capacity Factors - System capacity factors were projected based on past trends. Petersburg has a historic average 60 percent factor while the recent annual average for Wrangell was 50 percent (rounded from 47 percent). Capacity needs for each town were estimated based on energy needs at the appropriate system capacity factor and combined for a new factor. Due to load diversity, the combined Petersburg and Wrangell system capacity factor may be somewhat higher. Results Results of estimated future power needs are presented in table 7 for high, medium, and low cases. Electric heat is included for the high case only. Figures 1, 2, and 3 show the results graphically. The medium to low load forecasts seem to be the most likely paths the utilities would follow if diesel generation is the only source of future generation. This conclusion is based on: (1) the continued rising diesel cost will keep the residential use per customer in Wrangell at the current much lower level than Petersburg (5,000 KWh vs. 7,200 KWh/customer) . (2) the lumber mills in Wrangell will continue to generate with oil and small, wood-fired steamplants; (3) if a hydro project is available by the mid-1980's, as the community is planning, the most likely pattern would be somewhere between the medium and high forecast. Using diesel generation for home electric heat is unlikely. With hydro power available, the Wrangell lumber mills could have an adequate supply of hydro power; electric heat could become a 10 Tt Petersburg Wrangell TOTAL Petersburg Wrangell TOTAL Petersburg Wrangell TOTAL Petersburg Wrangell TOTAL 1980 MW GW 4.5 2h, 3.3 14, 7.8 38. HIGH 4,5 2h, 3.3 14, 7.8 38. MEDIUM 4.5 2h, ano 14. 7.8 38. LOW 4.1 22. 2.9 12. 7.0 34, Table 7 ESTIMATE OF FUTURE POWER NEEDS Petersburg and Wrangell 1985 1990 Md Gwh MNGi High - Including Electric Heat 6.2 33.0 9.0 47.0 6. 27.0 8.9 39.0 12.4 60.0 17.9 86.0 5.7 30.0 7.5 40.0 5.8 25.0 7.5 32.0 115: 55.0 15.0 72.0 5.3 28.0 6.2 33.0 4.0 18.0 4.8 21.0 9.3 46.0 11.0 54.0 4.8 25.0 5.5 29.0 3.4 15.0 4.0 17.0 8.2 40.0 9.5 46.0 1995 vil Sint 13.3 70.0 13.1 57. 26.4 127.0 9.9 52.0 9.9 43.0 19.8 95.0 Jel 37.0 5.6 24.0 12,7 61.0 6.1 32.0 4.5 20.0 10.6 52.0 2000 Mia Gin 16.9 89.0 16.6 73.0 33.5 162.0 13.0 69.0 12.9 56.0 25.9 125.0 8.0 42.0 6.3 28.0 T4.3 70.0 6.8 36.0 5.1 22.0 9 58.0 possibility; and residential use per customer in Wrangell could become more comparable to other towns. Industrial loads could well be a large portion (75 percent) of future needs. An adequate supply of power at a stable price would tend to encourage industries to substitute the hydro power for oil-fired generation, thereby increasing use toward the the © high load forecast. 12 (GWH) MILLION KWH (GWH) MILLION KWH Figure 1 HISTORIC AND PROJECTED ENERGY NEEDS PETERSBURG AND WRANGELL COMBINED 80 A PETERSBURG Yy 60 1970 1975 | Is80 1985 1990 1995 2000 80 60 WRANGELL A 40 20 {970 1975 1980 1985 1990 1995 2000 Figure 2 HISTORIC AND PROJECTED ENERGY NEEDS PETERSBURG AND WRANGELL COMBINED 180 - 160 (G WH) 120 80 MILLION KWH * 40 0 ! { f 1 I 1970 . 1975 1980 1985 1990 1995 2000. YEAR APA 4/79 Figure 3 HISTORIC AND PROJECTED CAPACITY NEEDS PETERSBURG AND WRANGELL COMBINED / 30 25 nN ° MEGAWATTS (MW) a 10 Oo 1970 | 1975 I 1980 1985 YEAR 1990 1995 2000 APA 4/79