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HomeMy WebLinkAboutJuneau Hoonah Transmission Line Reconnaissance Analysis 1981HOO 003 JUNEAU-HOONAH TRANSMISSION LINE RECONNAISSANCE ANALYSIS Prepared for: U. S. DEPARTMENT OF ENERGY ALASKA POWER ADMINISTRATION PROPERTY OF: Alaska Power Authority 334 W. 5th Ave. Anchorage, Alaska 99501 A.P.A. ORDER NO. A-81-062 March 18, 1981 E. J. HARRINGTON P.E. A. ALCAT ENGINEERING INC. 12225 - 210th Place S.E. Issaquah, Washington 98027 W. MOODY P.E. 2. 3. 4. 5. 6. 7. 8. 9. 10. aie 12. 13. 14, 15. 16. 17. 18. 19. TABLE OF CONTENTS Introduction Loads and Load Factors Voltage Choice Primary Routes Overhead Line Terrain Discussion of Overhead Line Features Summary of 69 KV Overhead Line Costs Discussion of Cable Routes Type of Cable Substations Diesel Generator Back-up for Line Outages Cost of Maintenance Cost of losses Fuel Cost of Replacement Power Alternative Routes Cost of System to Serve Hoonah Only Advanced Technology Advanced Planning Conclusion Tables Summary of 69 KV Transmission Line Costs Alternative Overhead Transmission Line Cost Calculations Electric Power Transmissions Costs Figures Proposed One-Line Diagram for Transmission System to Serve Hoonah and Noranda Exploration Impedance Diagram for 34.5 and 69 KV System Chatham Strait Crossing Profile Map of Transmission Line Route Map of Alternative Transmission Line Route amo noaooaouw fF FB Ww W NY NY HF FH PrPrP FP o wr OO 14 18 19 - 12 - 17 JUNEAU-HOONAH TRANSMISSION SYSTEM RECONNAISSANCE ANALYSIS Introduction. The village of Hoonah is dependent on diesel engine generated electric power. Hydro power is available in Juneau and would save money and conserve oil if it could be transmitted to Hoonah. This analysis, authorized by APA, was made to determine the cost of a suitable transmission system and the cost per KWh of electric energy transmitted. In addition to the load at Hoonah, Noranda Exploration is consid- ering a mining operation on Hawk Inlet on Admiralty Island which is near the middle of the proposed transmission line. The mine load was included in this cost analysis. The loads, load factors, land use and other input data were sup- plied by APA, then further discussed and modified at a meeting in Juneau January 7, 1981. The following organizations were repre- sented at the meeting: Alaska Power Administration Noranda Exploration U. S. Forest Service Tlingit-Haida REA Alaska Electric Light and Power Co. Sealaska Corp. Alcat Engineering From other similar studies it is known that the most economical solution to the electric power supply problem is to build a single circuit, non-redundant transmission line and back it up with diesel generators at the load, which run only when the line is out of service. Thus no attempt was made to design a transmission line with more than normal reliability. Load values and Load Factors. The following loads were used in calculating the capacity, losses and voltage drop for the trans- mission system proposed in this report. Hoonah Noranda Mine Domestic Industrial Peak Load (KW) 1500 3000 5000 Average Load (KW) 750 1050 3790 Load Factor 50% 35% 75 8% The total peak load is 9500 KW and the total average load is 5590 KW Section 2 (continued) for the system. The load factor is 58.8%. The annual energy con- sumption for the entire system is 48,968,00 KWh. The load factor of the combined domestic and industrial loads at Hoonah is 403. The total annual energy requirement at Hoonah is 15,768,000 KWh. Voltage Choice. Loads of the magnitude of those at Hoonah and the Noranda Mine could be served at 34.5 KV or 69 KV. At 34.5 KV the voltage regulation would be in the order of 15%, thus requiring step voltage regulators or regulating transformers at both Fish Creek and the Cannery Tap. For this reconnaissance study, both the 69 KV and the 34.5 KV transmission systems were assumed to be using 4/0 ACSR for the overhead and 2/0 copper equivalent for the submarine cable. Impedance diagrams for both systems are shown in Fig. 2. The losses at 69 KV come to about 171 KW or 1.8%. At 34.5 KV they would increase to about 7%. At 34.5 KV the system would be approaching its upper limit of load carrying capability. At 69 KV the load carrying capability would be at least double that at 34.5 KV and as much as four times if adequate conductors were used. The 2000 HP chipper proposed for use at Hoonah could not be run from the power system at 34.5 KV without causing excessive voltage fluctu- ation and hence, light flicker. At 69 KV, the chipper could be supplied and probably without excessive light flicker. The flicker problem should be investigated further when all the parameters are known. It was decided to use 69 KV as the transmission voltage for this analysis. Primary Route. As shown on the map, Fig. 4, the transmission line was assumed to start at the end of a future 69 KV transmission line in the vicinity of Fish Creek on the north end of Douglas Island. A circuit breaker would be installed at this point and the line would follow the present highway R.O.W. to the end of the road. At this point the line would proceed to the water's edge and enter a 3 conductor sub- marine cable under Stephens Passage to Admiralty Island. The cable would terminate on the shore of Admiralty Island north of Youngs Bay. A 69 KV overhead line would cross the narrow isthmus opposite the head of Hawk Inlet. From here the line would proceed along the west side of Hawk Inlet to a point opposite the old cannery site located on the east shore. Switchgear to sectionalize the line and permit a tap to the Cannery site (mine load) would be installed at this place. The Section 4 (continued) line would then proceed along the west side of Hawk Inlet to the ness at the mouth on Chatham Strait. At this point it would enter a sub- marine cable which would terminate on Chichagof Island at Whitestone Harbor near the mouth of Suntaheen Creek. Here, a 69 KV overhead line would begin and after a short roadless stretch, follow the plan- ed logging road. (See "The ALP 1981-86 Timber Sale Operating Plan Final E.1I.S.", U. S. Forest Service). The line would terminate in the vicinity of the airport at Hoonah. Overhead Line Terrain. As near as could be determined from the air, the line route selected traversed terrain where the following comments apply: Footings (Pole holes) Muskeg - backhoe excavation required Rock under shallow soil - blast and hand dig Top soil, machine inaccessable - hand dig Soil (roadless) - auger Rock (roadside) - blast and auger Clearing Muskeg - little to no clearing Timber, machine inaccessable - helicopter Timber (roadside) - assumed only minor clearing Chichagof Island - assumed all clearing by lumber company Discussion of Overhead Line Features. For the purpose of this study it was assumed R.O.W. clearing involved falling and helicopter clean- up on Admiralty Island. On Douglas Island R.O.W. was assumed to follow the edge of the road and only minor clearing would be necessary except for a short portion from the end of the road to the shoreline. On Chichagof Island, except for a short piece of muskeg at Whitestone Bay, all R.O.W. was assumed parallel to a road to be constructed in connec- tion with logging operations. Furthermore, it was assumed that R.O.W.. clearing for the road would be of sufficient width to accomodate the transmission line. From the air, the quality of the muskeg areas could not be deter- mined but it has been assumed that they can be traversed by backhoes mounted on wide tracked vehicles. The backhoes would excavate the pole holes and backfill around steel culvert casings inside which the pole will be placed by helicopter. The space between pole and casing would be filled by helicopter transported rock. Detailed design after on-the-ground surveys may dictate some other type of structure, such as a swamp frame, but cost should be less in such cases. 7. Section 6 (continued) For cost estimates it was assumed that this line would be designed for energy transmission only. During outages the replacement capa- city would be furnished by diesel generators. While good design practices were followed as to the terrain traversed and weather ex- posure, no extra features, such as danger tree removal, access roads, etc. were included in the estimate. This means that the line may be subject to outages during windstorms, snow and icing conditions. On Douglas and Chichagof Islands the line will be essentially road accessible, so repairs should be easily and quickly accomplished. On Admiralty Island no access roads were included in the estimate. All maintenance there would be by heli- copter, float-plane or boat to the shoreline and by foot from there to the R.O.W. Outages on this section could be quite long. Outage time on the Admiralty Island section could be shortened to the equivalent of that in the other portions by construction of an access road along the route. Forest Service estimates for wad costin such terrain are $150,000 to $250,000 per mile. This would be offset somewhat by reduced line construction and maintenance costs. Summary of 69 KV Overhead Line Cost. Included in Table 1. are the primary design cost figures for the 69 KV overhead line used in this report. This 69 KV design utilized 380 foot spans, 50 foot R.O.W. and oversized post type insulators. The conductor was priced at a value more conservative than necessary. An alternative lower cost design utilizing 350 foot spans, 25 foot R.O.W., Standard 69 KV post type insulators, up-dated hardware costs and a reduced conductor price is included as Table 2. of the report. The more conservative cost figures of Table 1. were used in all the calculations. The alternative design would result in a cost about 11% below that utilizing the primary design. Discussion of Cable Routes. The Stephens Passage and Chatham Strait cable routes have already been described under the heading "Primary Route". Before finally selecting the entry points and exact loca- tion of the proposed cables, a sonar route survey including TV monitoring, bottom sampling and precise location methods must be made of the two crossings. It is extimated that such a survey would require two weeks of vessel time at $12,000 per day. In- cluding administration and overhead this survey of both crossings would cost $250,000. The Chatham Strait crossing involves laying cable at depths as great Section 8 (continued) as 2200 feet. Neither cable manufacturers nor the cable laying firms expressed any great concern over this. It is pointed out that it is important that a route be selected (aided by the route survey) that is free of underwater cliffs or sharp ridges in the cable path. The profile of a possible cable route across Chatham Strait from Hawk Point to Point Augusta has been included as Fig. 3 of this re- port. The fathometer readings used for this profile were taken by NOAA on the vessel Davidson October 20, 1980. The route is a little to the south of the proposed cable crossing especially at the Pt. Augusta end but it gives a good idea of the actual conditions in Chatham Strait. The maximum slope measured on the fathometer pro- file was 36 degrees. It is proposed to bury the underwater portion of the line ends out to a depth of at least 30 feet at low tide. The shore ends will also be buried up to a location well above the high tide line. Here the cable will emerge from the ground and go up a wood pole structure supporting a 3 conductor pot head. Also located on this structure will be 3 station type surge arresters to protect the cable from over voltage. In the alternative routes the cable crossings across Gastineau Channel and Hawk Inlet will be treated the same as the longer cross- ings described above, except that it is proposed to bury the under- water portion to a depth of 3 or 4 feet for the entire crossing. Type of Cable. The 69 KV cable price used in this study covers a paper insulated, oil filled, lead covered, 72 KV (rated), 3 x 95 mm cable with 42 single layer steel armour wire each 5.6 mm diameter. The 95 mm* conductor is aluminum and is equivalent to 187.4 MCM in U. S. units. The resistance of .51 ohms per mile is equivalent to a copper conductor between 1/0 and 2/0 in size. This 3 conductor cable weighs 14.8 lbs./foot. Its current rating is 230 amps in 15° C soil. This is equivalent to 27,500 KVA at 69 KV. Its shunt capacitance is .434 mfd./mile. The cable has an outer covering of polypropylene yarn and asphalt. The outer diameter is 3.66 inches. 2 Single phase cable could be used for these crossings instead. The installed cost of 3 single phase cables would be in the order of 25% more than the 3 phase. If 4 single phase cables (1 spare) were installed the cable crossings would cost approximately 65% more than the 3 phase. Since this transmission system does not provide firm power with four single phase cables, it does not seem worthwhile to pay extra for the spare or the single phase option. When a more reliable source of power is required a second three phase cable could be laid and either one could carry up to 27.5 MW continuously. 10. iis Section 9 (continued) Polyethelene type of insulation could be used for these cables at some reduction in cost but until it is more thorougly proven, the paper and lead type is preferred by many engineers. At 34.5 KV, polyethelene insulated cables are more generally accepted and would cost only about 65% as much as the paper and lead insulated cable described above for 69 KV service. If paper and lead cable is specified for 34.5 KV it would cost approximately 85% as much as the 69 KV cable described above. For the line to serve Hoonah only, (described later in this report) it was assumed that paper and lead cable would be used for 34.5 KV at 85% of the 69 KV cable cost. Substations. The l-line diagram, Fig. 1 shows the transformers, switchgear and reactors planned for the substations. Table 1 gives the estimated installed price of the major items in the substation. Note that a 12,500 KVA shunt reactor has been shown at the Cannery Tap substation along with a circuit switcher to remove it from the line without shutting down the system. The shunt capacitance of all the 69 KV cables used in the primary plan supplies 13,659 KVAR of reactive power to the system. This will cause about 5% rise in the voltage at Hoonah under no load without the shunt reactor. With the reactor, there will be almost no voltage rise on the line at no load. The voltage-regulation with the specified loads at 69 KV is so low that no voltage regulating devices should be needed. The standard transformer taps should be adequate to set the voltage at the desired level. Diesel Generator Backup for Line Outages. Previous work has indicated that it is less costly to obtain a reasonably reliable power supply by providing local backup generator capacity than by adding addi- tional lines. The forecasted peak load for Hoonah is 1500 KW domestic and 3000 KW industrial. The present generator capacity is under- stood to be 1700 KW. The proposed industrial load includes a 2000 HP chipper. This type of machine is subject to wide fluctuations in load, possibly from zero to 2500 KW. It is not possible to supply such a load from a diesel power plant of matching size without irritating light (voltage) flicker. For this reason it is assumed in this study that no diesel generating capacity will be provided for supplying the chipper during such times as the transmission system is out of service for repairs. The Hoonah domestic load of 1500 KW plus 1000 KW of the industrial load remains to be supplied by local diesel capacity. The present 1700 KW of diesel capacity would then have to be augmented by about 1000 KW of additional capacity. The cost of a 1000 KW diesel gener- ating plant delivered in Seattle is about $200/KW. The Hoonah plant 12. Section 11 (continued) has space for such a unit and it is estimated that the installed cost is $400/KW for a total of $400,000, It was assumed that Noranda Exploration would provide its own emer- gency generators if shut downs are costly enough to justify the expense. The cost of the added generating capacity at Hoonah is not included in the transmission cost analysis in Table 3. Cost of Maintenance. For this study the overhead line outage rate was assumed to be the same as the Snettisham-Juneau line (after the relocation) which is .178 outages per mile per year. For 30 miles of line there would be 5.34 outages per year. Assuming $22,000 as the average cost to repair an overhead line failure, the maintenance cost would be $117,000/year. For submarine cable, the outage rate was assumed to be the same as for DC submarine cables for which reasonably good outage data is avail- able.* This rate developed is .24 outages per 100 miles per year.** Since the cable considered here is 3 conductor cable the outage rate has been arbitrarily doubled to .48. For 18.1 miles of cable we might expect 18.1 x .48/100 = .087 failures per year, or one failure every 11.5 years. If the average cable repair time is estimated to require one month the cost would be about $475,000 per repair.** The annual cost of cable maintenance would be .087 x $475,000 = $42,000. It is estimated that substation maintenance plus annual inspections and testing would add another $20,000 per year. The estimated cost of maintenance for the system is then: Overhead lines $117,000 Submarine cable 42,000 Substations 20 ,000 Total Maintenance cost $179,000/year * Cigre Paper 14-08 " A Survey of the Performance of HVDC Systems Throughout the World during 1975 - 1978," ** See "Snettisham-Ketchikan Transmission System" March 1980 by Harstad Associates, Pages 18 - 19, 13. 14, Cost of Losses. To approximate the transmission losses on this system it was assumed that all loads operated at 0.95 power factor and that line charging current could be ignored. The estimated losses follow: Line Section Load Amps Ohms Peak % % KW Res. KW Load Loss Loss Factor Factor Fish Creek to Cannery Tap 9500 83.7 9.91 208.3 58.8 40 Cannery to Hoonah 4500 39.6 14.49 68.3 40 23 Total effective line loss As shown above, the effective line loss for the whole line is 99 kW, To this must be added the losses in the transformer at Hoonah and the shunt reactor at the Cannery Tap. The transformer would have a total loss of about 50 KW and an effective loss at 40% load factor of about 12 KW. Adding an estimated 60 KW continuous loss for the 12,5000 KVA shunt reactor brings the estimated total loss to 171 kW. If we assume the cost of fuel oil in 1981 to be $1.25/gal. and diesel generator output of 12 KWh/gal. then the fuel to generate a KWh would be about 10.4¢. The annual cost of 171 KW of average loss would then be 171 x 8760 x $.104 = $156,000. Fuel Cost of Replacement Power. During the portion of the year that the transmission system is shut down for repairs it will be necessary to run the diesel generators to supply power at Hoonah and the Noranda Mine. These loads and outage times should be analysed separately but for this reconnaissance study a brief analysis on the system as a whole was made. Overhead line, estimated .178 outages/mile/year: 30 miles x .178 = 5.34 outages/year for system 5.34 x 13 hours/outage = 70 hours/year For the submarine cable the estimated outage rate is .24/100 miles/year for single phase and .48/100 miles/year for 3 phase cable. It was further assumed that each cable outage required 30 days to repair. «48/100 x 18 miles x 30 days x 24 hours = 63 hours/year. The estimated outage time for the substations is 20 hours per year. The total annual outage time is then 70 + 63 + 20 = 153 hours. The annual energy consumption of the system is 48,968,000 KWh. The cost of replacement energy would, then, be the difference between 10.4¢ KWh for diesel fuel cost and the cost of power at Fish Creek (assumed to be 3¢/KWh) times the KWh used during the outage: 48,968,000 x (153/8760) x (.104 - .030) = $64,000/year for the fuel cost of replacement power. Eff. Loss KW 83.3 15.7 99.0 os Alternative Routes. A great many major and minor route variations were considered during the analysis. One which involves running the line down the east side of Hawk Inlet would not add much distance and would save Noranda Exploration the cost of a cable or overhead crossing of Hawk Inlet. The preliminary maps of the Monument indicate that such a power line would cross a portion of the Monument non-wilderness area and possibly a corner of the wilderness area too, if it con- tinued down the east shore of Hawk Inlet to Chatham Strait. It might be possible to run the line down the east side of Hawk Inlet and enter the water just north of the Monument entrance without going through any part of the Monument. If this could be done, the cable would probably have to be buried in Hawk Inlet till it reached deeper water in Chatham Strait. The cost of burying about two miles of cable is not known, If it saved a cable crossing of Hawk Inlet it would be worth investigating after the Monument limitations are precisely known, since it could be a more economical approach. A second alternative route involves running the line from Fish Creek, on Douglas Island, past the end of the road to the vicinity of Middle Point, thence to Youngs Bay on Admiralty Island via cable. This could shorten the cable route by as much as 1.5 to 2 miles and leng- then the overhead route by about the same amount. Since the cable cost is about $500,000 per mile, (neglecting the terminations) and the overhead line, in roadless areas, around $250,000 per mile there should be a modest saving by doing this. It has the disadvantage of using up more forest land for R.O.W. or possibly creating an eye sore if the overhead portion is run along the shore. A third alternative is to start the Hoonah line at Thane Substation rather than Fish Creek. (See map Fig. 5). From here it would go overhead directly to Gastineau Channel. It should be buried under water in the channel. After leaving Gastineau Channel it would follow the shore around the south end of Douglas Island to Pt. Hilda where it would go via cable to Pt. Young on Admiralty Island. On Admiralty Island an overhead line would follow the shore generally, to one of the passes over the isthmus to Hawk Inlet, then down the east shore to the Cannery Substation, and across Hawk Inlet to the original route. This alternative route around the south end of Douglas results in 16 miles additional overhead line and 2 miles less submarine cable. The total added cost is about $3,950,000. It results in two major advan- tages as follows: A. Eliminates wheeling charge over the AEL&P system. B. Serves the mine load on the east side of Hawk Inlet without requiring Noranda to provide its own cable crossing of Hawk Inlet. The estimated cost of a 69 KV, 2/0 cable across Hawk Inlet is $1,100,000. In the primary route study where the line went down the west side of Hawk Inlet it was assumed that Noranda would pay for this 16. ks Section 15 (continued) crossing to the east side. This third alternative route around the south end of Douglas Island eliminates this added cost for Noranda because the overhead line across Admiralty Island goes down the east side of Hawk Inlet right past the old cannery. The added cost of $3,950,000 would result in an increase of about 0.8¢ per KWh at the interest rate of 8.5%. Cost of System to Serve Hoonah Only. A very short investigation was conducted to determine the approximate reduction in total transmission system cost if only the Hoonah load was to be served. A modest cost reduction would result from reducing the transmission voltage to 34.5 KV. Elimination of the Cannery Tap substation would further reduce the cost. The addition of a 69/34.5 KV transformer would be required at Fish Creek to reduce the voltage to 34.5 KV. The estimated total project cost would be reduced from $20,427,000 to $17,554,000 including interest during construction at 8.5%. The Hoonah load used for this study is 4500 KW at 40%load factor or 15,768,000 KWh per year. Sub- tracting the energy generated by local diesel generators during 153 hours of estimated line outage time results in a total energy transmitted of 15,493,000 KWh. The resulting cost of energy transmission from Fish Creek on north Douglas Island to the Village of Hoonah is 12.6¢ per KWh including carrying charges on the investment, maintenance, cost of losses and replacement power during line outages. Advanced Technology. For a 50 mile transmission line (with 18 miles in submarine cable) connecting two 60 Hz power systems, it is felt there is presently no economic competitor to the conventional AC transmission tie. If the line were all in cable and all going to the same place a DC tie would no doubt save money. Non-conventional low frequency AC tie lines have been proposed by some, but the authors are convinced that a new system such as this, requiring converters at each end, could not pay off. Single phase tie lines might be considered for small loads, but for loads this size single phase to 3 phase converters would have to be added at each end. The cable laying cost using single phase cable would not be significantly lower than 3 phase. If a DC system is later built in S. E. Alaska the proposed AC Juneau- Hoonah tie line could be integrated with it. The two systems are compatible even to the extent of paralleling a DC and an AC trans- mission tie line as is done on the Pacific Intertie. In conclusion, it appears that the conventional 3 phase, 60 Hz, AC system is the most economical choice. 10 18. Advanced Planning. Following is a schedule of tasks necessary for a detailed technical feasibility investigation and design, including estimated time schedules and costs. It should be noted that the time schedules could be overlapping and that some tasks should be done in the summer. 1. Overhead line environmental information to be collected. A. Wind velocities B. Ice and snow loads C. Temperature extremes D. Contamination effects Time: 1 month $ 20,000 2. Line routeing A. Layout proposed route and discuss with all concerned. B. Tentative agreement with land owners C. Environmental report preparation D. Permits and license applications as required. E. On site check of route. Time: 2 months $ 50,000 3. Surveys (land portion) A. Survey and stake route. B. Make plan and profile maps. C. Stake pole locations. Time: 2 months $230,000 4. R.O.W. Procurement A. Easements and/or title aquisition Times 6 to 12 months $ 30,000 5. Line design A. From environmental information, route information, experience of others and construction experience in similar areas, select the line mechanical parameters. B. From load flow,loss and voltage regulation studies select the line electrical parameters. C. On basis of selected parameters: Locate structures on plan and profile map Prepare material list Prepare stringing, sag information etc. Time: 4 months $100,000 6. Procurement information (Overhead lines) A. Material list B. Material specifications C. Construction specifications Time: 6 weeks $ 30,000 11 Section 18 (continued) 7. Cable Routing A. Terminal site selection B. Terminal land surveys C. Bottom survey (both crossings) D. R.O.W. easements for cable E. Permits as required Time: 3 months $315,000 8. Cable procurement A. Determine suitable cable design B. Write procurement specification Time: 1 month $ 10,000 9. Cable terminations A. Pothead specifications B. Terminal station design C. Installation specifications Time: 1 month $ 10,000 10. Cable laying A. Job specifications Time: 1 month $ 10,000 11. Bid evaluation on all jobs Time: 2 months $_ 25,000 Subtotal $830,000 Contingencies @ 20% 166,000 Total $996,000 The above steps are proposed for the complete transmission system engineering and design. Construction, construction supervision and inspection services are not included. It is estimated that construction of the entire transmission system would require the better part of 2 years. The clearing for the overhead line and the underwater route survey (if not already completed) could be done during the summer of the first year. The building of the overhead line and the laying of the cables could be done simultaneously during the good weather portion of the second year. If APA wished to reach a final decision as to feasibility without financing the complete system engineering and design at $996,000 the authors suggest that the cable route survey is probably all that is required. This survey is discussed in Section 8, "Discussion of Cable Routes", and would cost about $250,000. 12 9. Conclusion The recommended voltage for this transmission system is 69 KV. At 34.5 KV (the next lower standard voltage) the 2000 HP chipper load would undoubtedly cause voltage fluctuations and irritating light flicker. The higher voltage also makes possible substantial future load growth without any major system modifications. The route as shown in Fig. 4 is close to the optimum route which completely avoids the Monument. When Monument boundaries are accurately known and the pos- sibility of running a line through the non-wilderness area of the Monument is known, it may be more economical to run the transmission line down the east shore of Hawk Inlet. The alternative route around the south end of Douglas Island, shown in Fig. 5, will not be economically attractive unless wheeling charges are greater than expected. The total cost of the transmission system is estimated at $20,427,000 using an 8.5% interest rate. The average cost of transmitting electric energy over the proposed system is 4,98¢per KWh. This is based on a 25 year system life and an 8.5% interest rate. Costs for other interest rates are included in Table 3. The estimated cost of a transmission line to serve Hoonah only (without the Noranda mine) is $17,554,000 including interest during construction at 8.5%. The cost of transmitting energy to Hoonah is approximately 12.6¢ per KWh. 13 Table I SUMMARY OF 69 KV TRANSMISSION LINE COSTS Submarine Cables Stephens Passage From Douglas Island South of Outer Point to Admiralty Island just north of Youngs Bay. Distance 6.07 miles Using 69 KV, 3 conductor armored cable 187.5 MCM conductor, paper and lead insulated suitable for 230 amps in 15° C ambient, including freight from Oslo, Norway to Juneau, Alaska at $28,333.00 per mile of cable shipped. Cable cost, 6.07 miles of cable @ $245,000/mile Installation cost Cable termination cost (installed) including surge arresters Subtotal Engineering and administration @ 20% Subtotal Contingencies @ 25% Total cost for Stephens Passage crossing Chatham Strait From Hawk Point on Admiralty Island to Whitestone Harbor on Chichigoff Island. Distance 12.02 miles Using same 69 KV Cable as was used for Stephens Passage Cable cost 12.02 mi at $245,000/mile Installation cost Cable termination cost (installed) including surge arresters Subtotal Engineering and administration @ 20% Subtotal Contingencies @ 25% Total Cost for Chatham Strait Crossing 14 $1,487,000 671,000 120,000 2,278,000 456,000 2,734,000 683,000 $2,945,000 1,329,000 120,000 4,394,000 879,000 5,273,000 1,318,000 $6,591,000 Table 1 (cont) Overhead Transmission Line Voltage: 69 KV, 4/0 ACSR Conductor, 380' span, Single wood pole, standoff insulators with extra creep. R/W = 50° 14 poles/mi., H Frame Dead Ends, Length: 30 miles. Surveys Design Materials: Poles Crossarm & Hdwr, Conductor Conductor Hdwr. Insulators Guys & Anchors Misc. Materials Stores Exp. Total: Materials Construction: Pole Excavation Pole Setting Stringing Guy & Anchor Inst. Inspection Subsistence Exp. Equip. Rental Totals: Construction Land Clearing & Access Roads Subtotal Administration & Overhead @ 22% Subtotal Contingency @ 25% Mobilization & Demobilization Total Line Cost 25: $260,400 28,319 365 ,904 35,772 259,056 25,267 50,000 70,000 $464,160 383,525 547,912 35 245 250,000 270,000 268,160 $3,756,000 4,583,000 $ 238,000 104,000 $1,095,000 $2,219,000 0 $ 100,000 827,000 1,146,000 1,500,000 $7,229,000 Table 1 (cont.) Substations Fish Creek l= 69 KV oil circuit breaker complete with overhead structure, disconnects, relays, station service supply, surge arresters. Installed price including fence and ground mat. $ 130,000 Cannery Tap__(Noranda Mine) 3- 69 KV oil circuit breakers complete with overhead structure, disconnects, relays, station service supply, surge arresters. Installed price including fence and ground mat. $ 320,000 1- 12,500 KVA, 3 phase, outdoor oil filled shunt reactor, installed 300,000 1- 1200 amp, 3 pole, 69 KV Circuit Switcher, installed 60,000 Total for Cannery Tap Sub 680,000 Hoonah Sub 1- 5000 KVA, 3 phase, 69 KV to 12.5 KV LTC Transformer, installed 200,000 1- 15 KV, 1200 amp outdoor OCB with accessories 50,000 Total for Hoonah Sub 250,000 Substation Summary Materials and Installation Cost (Fish Creek, Cannery Tap, Hoonah) 1,060,000 Engineering and Administration @ 20% 212,000 Subtotal 1,272,000 Contingencies ¢ 25% 318,000 Total Substation Cost $1,590,000 16 Table 1 (cont.) Project Cost Summary Stephens Passage Cable Crossing Chatham Strait Cable Crossing Overhead Lines (Douglas Island, Admiralty Island and Chichagof Island) Substations (Douglas Island, Cannery Tap, Hoonah) Grand Total 17 $ 3,417,000 6,591,000 7,229,000 1,590,000 $18,827,000 Table 2 Alternate Overhead Transmission Cost Calculations Line Voltage: 69 KV, 4/0 ACSR Conductor, 350' span Single wood pole, standoff insulators R/W = 25' 17 poles/mi., 1 deadend & 1 angle pole/mile. Length: 30 mile Surveys Design Materials: Poles Crossarms & Hardware Conductor Conductor Hardware Insulators Guys & Anchors Misc. Materials Stores Expense Total: Materials Construction: Pole Excavation Pole Setting Stringing Guys & Anchors Inspection Subsistence Exp Equipment Rental Total Construction Land Clearing & Access Roads Subtotal Administration & Overhead @ 22% Subtotal Contingency @ 25% Mobilization & Demobilization Total Line Cost 18 $329,310 38,288 176,850 10,930 98,220 8,340 50,000 50,000 $279,865 328,972 628,419 85,742 198,449 180,000 300,000 $3,238,000 $3,950,000 Single pole dead ends $ 250,000 125,000 $ 762,000 $2,001,000 0 $100,000 712,000 988,000 1,500,000 $6,438,000 Table 3 ELECTRIC POWER TRANSMISSION COSTS Load at Noranda Mine 5000 KW @ 75.8% load factor Load at Hoonah 4500 KW @ 40% load factor Sum of the Mine and Hoonah loads 9500 KW @ 58.8% load factor Total transmission system capital cost $18,827,000 (Plus interest during constr.) Annual energy transmitted* 48,113,000 KWh Interest Rate 5% 8.5% 12% System Life : 25 years 25 years 25 years Capital Recovery Factor 07095 09771 «42750 Interest during Construction $ 941,000 $1,600,000 $2,259,000 Investment (Capital + I.D.C.) $19,768,000 $20,427,000 $21,086,000 Annual Charges on Investment $1,403,000 $1,996,000 $2,688,000 Annual Cost of Maintenance 179,000 179,000 179,000 Annual Cost of Losses 156,000 156,000 156,000 Annual Cost of Replacement Power 64,000 64,000 64,000 Total Annual Cost $1,802,000 $2,395,000 $3,087,000 Cost per KWh (transmission only) 3.74¢ 4.98¢ 6.42¢ * The forecasted load for the entire system is 48,968,000 KWh as stated in Section 2. The energy transmitted is obtained by subtracting the make-up energy generated by local diesel standby plants during the 153 hour outage time forecasted in Section 14. The make-up energy is equal to 153 x 5590 KW average load or 855,000 KWh. 19 PROPOSED ONE-LINE DIAGRAM FOR TRANSMISSION SYSTEM TO SERVE HOONAH AND NORANDA EXPLORATION CANNERY TAP FISH CREEK HOONAH 69 KV TO AEL &P SYSTEM DOUGLAS |S CIRCUIT SWITCHER 5,000 KVA 12.5 MVA 3 PHASE REACTOR 12.5 KV BUS AT HOONAH NORANDA 10,000 KW IMPEDANCE DIAGRAMS JUNEAU - HOONAH LINE 6.42 + JIU 130+J2.25 3.15+J 5.44 3.34+J5.78 12.02 Mi -J2 - J2900 | 5.95+J2.99 CANNERY TAP T 3.00 + JI.5I -si4ea TL -viae4 T? sooo kw 0.95PF = ee CHATHAM ST STEPHENS PAS FISH CREEK 4500 KW 0.95 PF 34.5 KV SYSTEM 6:42 + J12.1 1.304J32.45 3.15 +J5.94 3.34+ J 6.32 12.02 MI. - 32013 “vlog 6.77+J 2.90 T caNNery TAP _ 3.42+ J1.46 HOONAH CHATHAM ST. STEPHENS PAS. FISH CREEK 69 KV SYSTEM OH 34.5 KV, 4/0 ACSR, Z=.440 +J.761 OHMS/MI., SHUNT CAPACITIVE REACTANCE NEGLECTED CABLE 34.5 KV, 2/0 CU, Z= 495 + J.249 OHMS/MI., SHUNT CAPACITIVE REACTANCE 8800 OHMS/MI. OH 69KV, 4/0 ACSR, Z=.440 + J.831 OHMS/MILE, SHUNT CAPACITIVE REACTANCE NEGLECTED CABLE 69 KV, 187 MCM AL, Z=.563 + J.241 OHMS/MI., SHUNT CAPACITIVE REACTANCE 6110 OHMS/MI. SEA LEVEL \ DEEPEST POINT, 2200FT YS . ~~ MAX. SLOPE 36 C_NEAR MIDCHANNEL SEA LEVEL ee aes HAWK INLET ¢ “—— _ NEAR MIDCHANNEL 2.27 NAUTICAL MILES r- CHATHAM STRAIT CROSSING-NOAA DATA SCALE APPROX |"1g00)] “PFROVED BY DATE JAN 25,198! RECORDED BY VESSEL DAVIDSON, OCTOBER 24, 1980 ALCAT ENGINEERING ve PRINTED OM MO 100M 8 CLEAMPRINT FADE OUT 5% : Ban yy ss Hump % Valley ne XS Island % t on pen ont oo Nugget Creek ve Se" Nugget Mtn “fh. © ASA Re £\ OLN, PI Retreat Behn We on 20) False Pt Retreat Aid 2° (455 ~ ASand Pt Louisa \ Coghlan ' \ 5, Island Ss enSymdqds , he ce BL portland N a ¢ Island “ Island Naked! Horse fre kitense!. ) ¢8 Clear Pa Funter Station If *¢ v : Piping Station eS 8 Pt Hilda Couverden ‘ i Vo 4 Rock \ > HR to Ge eo Scull gySeutl Ansley 14974 Ye Island”? Entranct® 0 Gouverdac DonA % ‘ght Rocky | 'The Sisters Lehig Spasski | Lignt® Hanus Reet AD Neck Pt ski Bay a S~Pulizzi | FIGURE 4 t, nan TRANSMISSION LINE _ ROUTE SCALE 1: 250,000 a4 °o N5800 - W13400/60x120 1962 Dewew . Valley ; RS. 2 : w Mtn -, Nugget_Creek _/ Mendenhall ; Glacier tM. - ~ zt n Lake 5 ‘ ast Nugget ti j uisa 3 ae Pt Lo ie Strauss Rk > b. 4) RS y aS Coghlan S By Xe Q Island -: S¥e¢t : ‘ Symdads ‘ y | Unt NO Ww Spuh vi) OY 4 e a — Island. © (ct @ ¢ [sland 3 = Gibby : § iB Ree The Kittensii®.. ag Cleat PRE oy aed Pa Funter oh N Ledge. . Station IMO) 4 Se ae 1. Lv ® Md? Couverden \ Lv » i ‘ Rock Scull seu Entrancé S894 et Couverden sland "2 t \ Sisters Reef QUAL ant z " ae Sisters Rocky | k } ia a iF ade Spasski | cent ee he chek. : ~ \} Neck Pt : Spasski Bay CROSSING assets Se. ePulizzi | r% t e ALTERNATIVE LINE ROUTE => THANE TO HAWK INLET acy SCALE 1: 250,000 Bu 2. =. JUNEAU, ALASKA-CANADA N5800 - W13400/60X120 MI 1962 MINOR REVISIONS 1971