Otter Creek Hydroelectric Feasibility Report
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VERMONT MARBLE COMPANY, J' PROCTOR, VERMONT : j+' - OTTER CREEK HYDROELECTRIC FEASIBILITY REPORT HUNTINGTON FALLS DAM - BELDENS DAM CENTER RUTLAND DAM FEBRUARY 1979 INTERNATIONAL ENGINEERING COMPANY, INC. A MORRISON-KNUDSEN COMPANY DISCLAIMER This report was prepared as an account of work sponsored by an agency of the United States Government. Neither the United States Government nor any agency Thereof, nor any of their employees, makes any warranty, express or implied, or assumes any legal liability or responsibility for the accuracy, completeness, or usefulness of any information, apparatus, product, or process disclosed, or represents that its use would not infringe privately owned rights. Reference herein to any specific commercial product, process, or service by trade name, trademark, manufacturer, or otherwise does not necessarily constitute or imply its endorsement, recommendation, or favoring by the United States Government or any agency thereof. The views and opinions of authors expressed herein do not necessarily state or reflect those of the United States Government or any agency thereof. DISCLAIMER Portions of this document may be illegible in electronic image products. Images are produced from the best available original document. VERMONT MARBLE COMPANY, PROCTOR, VERMONT : COTTER CREEK HYDROELECTRIC FEASIBILITY REPORT HUNTINGTON FALLS DAM = BELDENS DAM = CENTER RUTLAND DAM FEBRUARY 1979 - INTERNATIONAL ENGINEERING-- COMPANY, INC. --- \ - A MORRISON-KMUDSEN COMPANY wgl!mmm EXECUTIVE SUMMARY Vermont Marble Company (VMCO) owns and operates four hydroelectric projects in a 50-mile reach of Otter creek in west central Vermont. This study con- cerns three of the installations - Center Rutland, Beldens, and Huntington Falls. The fourth site is known as Proctor and will be studied separately. All four plants operate as run-of-river stations, and the limited reservoir storage capacity places severe limitations on any other type of operation. VMCO has been aware for some time that the physical condition of the' installa- tions is poor and that the concrete has suffered deterioration due to its age, repeated freezing and thawing, and the effects of trash. VMCO also recognizes that rehabilitation, upgrading, and replacement of many of the facilities is now necessary .to restore the structures to a satisfactory condition and to maximize energy production at each plant. The plants are presently operating at much lower outputs than can be obtained, because they do not use .the avail- able discharge and head. ... The results show that, under the assumptions made in this study, Beldens and Huntington Fa1 1s can be economically improved. The rehabi 1i tation of the Center Rutland plant did not look economically attractive. However, the improvement of Center Rutland should not be eliminated from further considera- tion, because it could become economically 'attractive if the cost of energy starts escalating at a rate of around 10 percent per year. The study included a brief appraisal of the existing generating facilities and condition of existing concrete structures, a geological reconnaissance of the sites, analysis of the power potential, flood studies, technical and economic investigations and comparative evaluations of the a1 ternati ves for developing the streamflow for power generation, selection of the, most suitable a1 ternative, financial analysis, preparation of drawings, and preparation. of detailed quan- tity and cost estimates. The sites and nearby surrounding'areas were inspected, and the condition of existing structures and equipment were appraised. The concrete needs repair; and the equipment is old, obsolete,- and in need of replacemer~t. The generating units are inefficient and a.re .undersized for economical exploi.tati,on.of the avai 1able hydraul i,c resources. No . .geological proh- lems were found during the field ins.pecti.ons that would prohihit construc- tion and the structure sites appear sound. Th.ere is some leakage at all sites that can he easily control led by presently available techniques. In general, the time has arrived when improvements and rehabilitation are, or soon will be, necessary. The environmental conditions were evaluated and found to be mostly favor- able. The few conditions that cannot be classified as favorable require only simple measures to rectify. No environmental impact was found that precludes proceeding with the contemplated improvements. Three basic pbi.losophies were.considered in formulating development alternatiyes. The first makes'maximum use of existing facilities and results in theminimum capital investment; however, it does not fully 'exploit the avail able hydraul ic resources. The second ful ly exploits the hydraulic resources, but requires the largest capital expenditure. The third philosophy is:intermediate between these two and, consequently, results in inte-rmediate capital investment. and .energy production. Four alternatiyes embodying these ph.ilosophies were.formulated and are shown in Table S-1. Technical evaluations were made of the components of each alternative to* eliminate the least feasible and reduce them to a more manageable number. The evaluations considered the unit size, number of units, total installed capacity, energy produced, topograp.hic and physical conditions of the site, and the upstream and downstream limitations. One large unit would be inoperative for almost half the time and was eliminated from consideration on an energy production basis. The unit size and upstream urbanization resulted in selecting a single development for Center Rutland. Upstream conditions restricted the leyel of the Beldens reservoir, and.the relocated. powerhouse was eliminated on a cost basfs. Huntington Falls r,emained as originally conceived. The nine components shown in Table S-2 remained after completion of these evaluations. TABLE S-1 DEVELOPMENT ALTERNATIVES ALTERNATIVE I Upgrade existing facil ities, minimum cost and energy. 1. Center Rutl and Reservoir El. 507.0 2. Be1 dens Reservoir El. 284.0 3. ~untingtonFalls Reservoir El. 218.0 ALTERNATIVE I1 Maximum dam-raise, maximum costs and energy. 1. Center Rutl and Reservoir El. 514.0 2. Beldens Reservoir El. 284.0 3. Huntington Fa1 1s Reservoir El. 241.0 ALTERNATIVE I11 Intermediate -dam raise, intermediate costs and energy .- Condition A. 1. Center Rutl and Reservoir El. 509.0 2. Beldens Reservoir El'. 284.0 3. Huntington Fa1 1s Reservoir El. 230.0 ALTERNATIVE IV . Intermediate dam raise, intermediate costs and energy - Condition B. 1. Center Rutl and Reservoir El. 514.0 2. Beldens Reservoir El. 284.0; relocate powerhouse one mile downst ream. 3. ~untingtonFall s Reservoir El. 230.0 TABLE S-2 PROJECT SELECTION ELIGIBLE PROJECTS CENTER RUTLAND 1. Reservoir El. 509.0; 2-1,200 kW units. Identification Symbol CR/2-2.4-509 BELDENS 1. Reservoir El. 284.0; 3-2,100 kW units. Identification Symbol BEL/3-6.3-284 2: Reservoir El. 284.0; 2-2,100 kW units. Identification Symbol BEL/2-4.2-284 HUNTINGTON FALLS 1. Reservoir El. 241.0; 3-3,700 kW units. Identification Symbol HF/3-11.1-241 2. Reservoir El. 241.0; 2-3,700 kW units. Identif icat ion Symbol HF/2-7.4-241 3. Reservoir. El. 230.0; 3-3,100 kW units. Identification Symbol HF/3-9.3-230 " 4. Reservoir El. 230.0; 2-3,100 kW units. Identif icat i on Symbol HF/2-6.2-230 5. ~eservoirEl. 218.0; 2-2,300.k~ units. Identification Symbol HF/3-6.9-218 . 6. Reservoir El. 218.0; 2-2,300 kW units. Identification Symbol HF/2-4.6-218 Quantity and cost estimates were prepared, and the average annual eneryy production was computed for the nine projects. able' 5-3contains a summary of the data. The cost per. kilowatt. hour is discussed later. -. Economic evaluations were made for the nine eligible projects using the present worth method of analysis. The evaluations used 3, 5, and 7 per- cent escalation rates; 35-, 40-, and 50-year analysis periods; and dis- count rates from 6 through 11 percent. A computer was used to analyze a total of 81 cases for which the benefit/cost ratios and' internal rates of return were computed. These.eval.uations Were used on'ly to select a recommended .devel opment , which was subsequently further analyzed using oth.er methods of analysis . No analysis was made for zero escalation, because it is considered to be unrealistic; and th.e three rates selected are indicative of the escala- tion range to be expected. Escalation was uniformly applied to all costs and benefits for the first half of the analysis period and no further es- calation was used for the second half.. The minimum analysis period cor- responds to the useful life of some major project parts, especially the generating units. The l.ongest. represents .a usual ly acceptable standard .:. for hydroelectric economic-evaluation. The discount rates are considered to be .appl i cab1 e .to t.his type of development. Benefits are the value of energy that does not have to be purchased from an outside supplier and, accordingly, are based- on the price.recently paid. The demand charge, transmission charge, and energy mill rate were combined on a weighted average basis and resulted i 6 25 mi 11s per kilowatt hour. This rate was escalated after the first year on the same basis as the costs'. System energy losses were subtracted from gross generation in computing.the total annual.benefit, or revenue. The range of the benefit/ cost ratios and internal rates of ,return is shown in Table .S-4., . TABLE S-3 -. SUMMARY .OF PROJECT COSTS AND ENERGY RECOMMENDED DEVELOPMENT Item Total Capital Investment ($) Average Annual Energy (kwh) Installed Capacity (kW) Cost Per Installed kW ($) Total CapC tal Investment ($) Average Annual Energy (kwh) Installed Capacity (kW) ' Cost 'er Installed kW ($) Total Capital 1nvestmen.t ($) 8,760,800 9,079,700 6,936,000 Average Annual Energy ('kwh) 26,740,000 23,275,000 20,225,000 Installed Capacity (kW) 6,200 6,900 4,600 Cost Per Installed kW (8) 1,413 1,316 1,508 TABLE S-4 RANGE OF BENEFITICOST RAT,IOS AND INTERNAL RATES OF RETURN SELE,CTION OF RECOMMENDED DEVELOPMENT 3% Escalation B/C Ratio Center Rutland Be1 dens Huntington Falls :.--- .:."..- .