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HomeMy WebLinkAboutBethel Area Power Plan Feasibility Assessment; Appendix E; Transmission Intertie System 1984i Ate fees esata | Alaska Power Authority LIBRARY COPY App. E c Bethe ( APPENDIX E | Transmission | Intertie System | | | | Bethel Area Power Plan Feasibility Assessment APPENDIX E TRANSMISSION INTERTIE SYSTEM DRAFT Prepared for Harza Engineering Company and the Alaska Power Authority by P.E. Company Anchorage, Alaska Draft April 1984 Chapter Z II Itl IV TABLE OF CONTENTS INTRODUCTION TRANSMISSION INTERTIE CONCEPTUAL DESIGN Introduction Desig Desig n Considerations Possible Causes System Failures Bethel Climatic Data n of Transmission Intertie System General Consideration of SWGR System INTERTIE ROUTE SELECTION COsTS Right Selec Mater Labor -of-Way Selection Criteria Terrain Considerations River Crossings Allotment Considerations Other Considerations tion of Rights-of-Way Bethel-Akiachak-1 Bethel-Napakiak Jct.-2 Bethel-Oscarville-3 Napakiak Jct.-Napakiak-4 Eek Jct.-Napaskiak-5 Kwethluk-Napaskiak-6 Kwethluk-Kwethluk Jct.-7 Kwethluk Jct.-River Crossing- Akiakiak-8 Akiachak-Akiak-9 Kwethluk Jct.-Tuluksak Jct.-10 Tuluksak Jct.-Tuluksak-11 Napakiak Jct.-Tuntutuliak Jct.-12 Tuntutuliak Jct.-Atmautluak Jct.-13 Atmautluak Jct.-Atmautluak-14 Atmautluak Jct.-Akolmiut Jct.-15 Akolmiut Jct.-Akolmiut AVEC Tie Line-16 Tuntutuliak Jct.-Tuntutuliak-17 Eek Jct.-Eek-18 ials It-1 II-1 TI-1 LZ II-4 LE—5) IT=5 EE=5 III-1 III-1 III-1 Et IItI-2 ILi=2Z ELE=3 Tit<-3 III=-3 Tigt=4 III-4 CLE=4 III-4 III-4 LEL=5 III-5 Crr=5 ITI=6 TII-§ III-6 III-6 III-7 ItI-7 Iil-7 III-7 Iv-1 Iv=-1 tv=1 TABLE OF CONTENTS (Cont'd) Chapter Page Transportation and Freight Iv-2 Transportation of Personnel Iv-3 Equipmental Rental IvV-4 Camp Costs Iv-4 Other Costs Iv-4 Cost of Transmission Intertie Line Iv-4 River Crossings Iv=5 -ii- Table No. Iv-1 Exhibit No. 1 LIST OF TABLES Title Estimated Construction Cost of 34.5 kV Transmission Intertie per Mile LIST OF EXHIBITS Title Typical A-Frame Structure Intertie Transmission System Transmission Line Route Segments Estimated Material Cost per 3-Phase Flexible A-Frame Tangential Structure -iii- Page Iv-5 Chapter I INTRODUCTION This appendix describes the potential transmission intertie system between Bethel and the twelve outlying villages. Chapter II presents conceptual design criteria for transmission inter- ties, and a description of two Single Wire Ground Return (SWGR) intertie systems. Chapter III presents the right-of-way selec- tion criteria, and a description of each segment of the trans- mission intertie network. Finally, Chapter IV presents the basis for cost estimates. Ld, Chapter II TRANSMISSION INTERTIE CONCEPTUAL DESIGN Introduction Four major aspects should be considered in the design of a transmission line: economy, reliability, safety, and public acceptance. The economics of a transmission intertie system includes both the economics of construction and the cost of operation. A concern which may not be quite so apparent, however, is the life-cycle cost of the system. The line should be designed to be useful over .its full economic life and not built solely on the basis of present consumer demands. The design of a trans- mission line should also consider the future demands on the entire system. The second aspect, reliability, is very critical. The transmission line is worthless to the owner and to the consumer if it is not reliable - if power is not available to the con- sumer on demand. Every effort must be made to ensure that the transmission line fulfills its function of providing power to consumers. Safety, of course, is an imprtant consideration. The National Electrical Safety Code (NESC) was established to ensure power is provided to consumers at no risk to the consumer or any innocent bystander. Transmission lines must be built according to requirements specified in the NESC. An obscure, but important consideration in transmission lines is public acceptance. The general public must feel com- fortable with the manner in which power is provided to consu- mers. In recent years, more attention is being focused on environmental considerations during the construction phase of transmission lines. Design Considerations In order to choose the most efficient transmission line design, it is necessary to consider some of the variables that will affect the performance. Two important considerations are a) possible causes of failure and b) climatic conditions. IIt-1 Possible Causes of System Failures Meteorological liabilities must be examined when selecting a line route. Three major problems are wind, ice, and winds with ice. Foundation failures, and failure due to flooding and river ice loading are also important. Wind. Wind moves in a horizontal plane, but also contains vertical components. In selecting the design wind speed for a structure, the time interval over which the wind occurs must be specified. The impact of a severe gust may impose a greater load on a rigid structure already strained by a strong, steady wind than it would when the general wind is lighter. In addi- tion to the duration of a strong wind, its vertical and horizon- tal extent must be considered. Measurements of wind force have long been considered in transmission line design and provisions are included in most design codes. Provisions for wind power effects are frequently made only within the safety factor allow- ance on wind loads since the factors are not well understood. The most common wind causing transmission line failure is associated with tornados, having a wind velocity of 40 to 72 miles/hour. Damage is usually quite localized. Separation of circuits on different rights-of-way where possible helps to minimize the system impacts from failure in a given locality. Provisions of longitudinal tower strength sufficient to with- stand the loads caused by the failure of another tower, will also limit the progression of damage. Ice. The major icing problems for transmission systems are caused by either rime or glaze. Usually, wet snow will turn into a form of glaze or rime and is considered an icing problem. Rime (discrete ice crystals) are formed by rapidly freezing, supercooled water drops as they hit an exposed surface. Glaze is a clear, smooth coating of ice usually containing air pockets. It is formed by the freezing of a film of supercooled water deposited on a structure by rain, drizzle or fog. The total amount of ice deposited on a structure is depen- dent upon wind speed. Since wind speed increases with height above ground, larger amounts of ice will form on tall towers and the conductors mounted on tall towers. The total deposit of ice along the conductor is dependent upon the ability of the conduc- tor to twist. Ice will build in a circular deposit on conduc- tors that are free to rotate. Conductors which are stable get ice formations in a pennant shape extending into the wind. Wind and ice occurring simultaneously must be considered as a distinct threat to a transmission line. The probability of Et? this happening can be computed by statistical means, and design precautions can be applied. A condition caused by glaze ice which is potentially damag- ing to transmission lines is conductor galloping. This motion causes insulator breakage and tower damage as well as circuit interruptions due to contacts between wires. Ice formations can impose severe weight loads upon transmission lines causing failures such as broken conductors and collapsed towers. Most wind and ice failure can be avoided with proper evalu- ation of hazards during line design. It is frequently necessary to collect data at carefully selected locations along a proposed route to establish a reliable design basis. Data should in- clude: Maximum wind speeds and associated directions Maximum wind speed return periods Type and magnitude of icing Maximum simultaneous ice and wind Ice and wind return periods o0000 Foundation Failures. "“Adfreeze", or "frost jacking" action, creates an uplift force which acts on tower members embedded in frozen fine-grained soil of high moisture content. The uplift force can be sufficient to shear off light diagonals embedded in the soil and to cause failure at the attachment of a stub angle to either a grillage or rock anchor. Solutions suggested for frost action problems include using backfill that does not retain moisture and improvement of drain- age to reduce ground moisture. A common practice is to wrap pole butts with "Visqueen" plastic sheeting in an effort to reduce frost adhesion to them. Guy anchors grouted in rock may pull out when installation occurs during sub-zero weather. Even though grout is heated during installation, air temperature causes adherence failure. Anchors should be installed during warmer weather to avoid this problem. Failure of earth anchors occurs when clay backfill does not consolidate. Proper foundation design requires the following: ° Adequate soil information including knowledge of the effects of moisture on shear strength of various soils. ° Expected foundation loading and the effect of founda- tion movement on the structure. II=3 ° Knowledge of the relative costs and how various foun- dation types can be expected to perform in the soil and location installed. Good design as well as proper construction and adequate inspec- tion are vital-to ensure satisfactory foundations. Failure Due to Floods and River Ice. Water swirling around unprotected footings can carry away the backfill. If unchecked, the water will undermine and destroy tower footings. Protective measures include pile footings, fenders and rock revetments. A tower base may also be surrounded with a steel piling cell filled with rock. River ice presents a critical problem in severe climates. Where towers must be located in flood plains, use of pile sup- ported concrete footings is recommended. The footings should extend above the level of the highest known flood. Bethel Climatic Data Climate data used in the design of the transmission system for the Bethel area are given below: Wind: 70+ MPH Avg. Annual Temp: 30°F Avg. Low Temp: -3°F Avg. High Temp: 60°F Annual Precipitation/Yr: 19 inches Snowfall/Yr: 60 inches Soil: -Sedimentary (clay, silt & sand) -Permafrost Warmest Month: July Coldest Month: January ri=4 Design of Transmission Intertie System General The design of the transmission intertie system was based on the above considerations and on experience with similar sys- tems. A voltage level of 34.5 kV was selected for the systems This voltage was selected initially based on experience and load flow studies made of the system at this voltage level confirmed that it could adequately serve the load centers without exces- sive losses or voltage drop. Consideration of SWGR System Description. Consideration was given to a Single Wire Ground Return (SWGR) system. Conceptually and theoretically, a SWGR system is ideal for electrification projects in rural Alaska. According to Robert Retherford in "Alaska Business" magazine, April, 1982, "The SWGR system cost less than two- thirds the amount it would cost to build a comparable, three- wire system, which uses wire as the return conductor,. . ." There are problems inherent in a SWGR line, however. The firs is the fact that the SWGR line does not meet the National Elec-— trical Safety Code (NESC) requirements. Other problems are: with only one phase to a particular rural community, a total lack of power in the community is experienced when power is interrupted in the line; intermediate customers cannot tap off the line and; it is difficult to balance the load at the central power generating station with a large single phase tap. The difference between a SWGR distribution system and a conventional distribution system is significant. A conventional system requires two conductors, one bringing the current from the source to the user and one returning the current from the user back to the source. The SWGR system does not return cur- rent from the user to the source. Instead, the earth is used as a ground return path by using round grids. There are presently only two SWGR systems operating in Alaska. Both were funded by the State Legislature to test the concepts of a SWGR line in rural Alaska. One line is located between Kobuk and Shungnak in northwest Alaska; the second is located between Bethel and Napakiak. Each system uses the basic A-frame concept for the line structures (Exhibit 1). The problems related to SWGR systems and the particular problems inherent in electrification projects in rural Alaska require further study to identify the optimum design and con- struction methods for power distribution systems. II=5 Bethel - Napakiak SWGR_ Line. Since the cost of building a transmission line is a primary consideration in electrification projects in rural Alaskan communities, the SWGR concept, espe- _cially coupled with A-frame structures, has the advantage of being less expensive to build than a conventional line. The Bethel - Napakiak project is well documented in "Single Wire Ground Return Transmission System Phase II Report" prepared for the State of Alaska, Department of Energy & Power Develop- ment by Robert W. Retherford Associates, February, 1982. Kobuk - Shungnak SWGR Line. Again, cost was a major con- sideration in construction of this transmission line. Local materials and local labor were used to construct the power line. The Kobuk line was more experimental in nature than the Napakiak line. The Kobuk line was constructed in continuous permafrost, causing some variations in design; and a variation of the A- frame structure was tested. In addition, local spruce trees were used. The Kobuk system design included two important factors lacking in the Bethel-Napakiak system: 1) Two wires instead of one were used; the two wires ensured that the City of Kobuk would be serviced with electricity even if the ground return portion of the line failed. Applications of a SWGR concept in the continuous permafrost were uncertain. 2) Intermediate customers will be able to tie into the transmission line in Kobuk, which is not true of the Napakiak line. The A-frame structure was modified to an X-shape to allow a simple balanced configuration for the second wire while main- taining the required flexibility of the structure. This X-frame is not recommended in future transmission systems in rural Alaska. During a 90 mph+ high wind, a section of X-frames toppled. The support at the intersection weakened the integrity of the pole enough to cause several to break upon impact with the ground. Conclusions. Because the SWGR system does not meet the NESC requirements, this system was not selected for use in the Bethel Region. However, the flexible A-frame with no foundation appears to be an ideal structure for power line construction in the Bethel region. A synthesis of the structures used in two SWGR demonstration projects would be optimal, thereby using the experience gained on both projects. By using the A-frame of the Napakiak line adapted to 2 and 3 phase systems, the structure II-6 could be used economically and efficiently throughout’ the region. The structure could be manufactured and erected with local materials and labor. Because no holes are dug, no heavy equipment is used and no roads are built. The A-frame structure causes no adverse effects to the environment. Adapting the structure to 2 and 3 phase systems allows the distribution sys- tem to meet NESC requirements (See schematic illustration on Exhibit 1). LIK. Chapter III INTERTIE ROUTE SELECTION Right-of-Way Selection Criteria Terrain Considerations The Bethel study area is characterized by relatively flat to rolling terrain which is pockmarked by large and small water bodies and dissected by the Kuskokwim and Johnson Rivers. A major consideration in the selection of the proposed electrical interties was to minimize the number of lake, pond, and river crossings, while at at the same time selecting the shortest and straightest routes. The connection of all the villages with electrical inter- ties consider two major factors: (1) the difficulty of crossing the Kuskokwim River and (2) the desire to avoid any conflict with native allotments that are scattered throughout the entire area. These and other consideration are discussed below, River Crossings The Kuskokwim River, which must be crossed at least once, has several natural and man-caused limitations that must be considered in selecting a suitable crossing: Te Within the study area, the river is between 600 feet and several miles wide. An overhead crossing would have to occur at one of its narrower areas. 2. The river has the ability to erode its banks and change course very rapidly. At Napakiak, the bank has eroded approximately 800 feet in the last 5 years, 3. During spring break-up, there is a tremendous amount of ice build up and flooding which would require that structure locations on the river banks be carefully selected and reinforced to avoid possible damage, 4. Barges that service the communities along the river are sometimes piled as high as 40 feet, requiring exceptionally tall structures on either side of the river. Se Underwater crossings are undesirable due to problems associated with the meandering nature of the river, III-1 constantly shifting sand bars, ice build up problems, and barge and boat anchors. Due to the limiting factors above and observations in the field, it is apparent that the best possible location for an overhead river crossing of the Kuskokwim would be at Akiachak. The river is approximately 600 feet wide at this location, the river bank fairly stable according to locals and there are mini- mum ice build-up problems. Allotment Considerations Native allotments pose a second limiting factor in select- ing the intertie rights-of-way due to delays, additional cost, and uncertainty of the Bureau of Indian Affairs review, which is required by law and can easily take in excess of two years. Hence, the intertie rights-of-way have been selected to avoid all native allotments. However, some alternatives that would be shorter or otherwise preferable, although crossing allotments, have been indicated. Allotments noted on the right-of-way maps prepared have been located from the best available information. However, it should be noted and emphasized that the allotment locations frequently vary in the field. Other Considerations In addition to the above considerations, the rights-of-way were located in areas that would be as accessible as possible to facilitate construction and maintenance. The right-of-way location approaching and entering the village was selected to avoid any conflicts with airstrips or float plane areas while at the same time allowing a convenient hook up with the existing distribution system. Proposed substations and/or ground grids are located in areas as close as possible to the existing village power supply. Ideally, these facilities were located to minimize any impacts on any allotments or existing uses of the land while at the same time being situated on fairly level dry ground. Prior to any final determination of suitable ground grid locations, ground resistivity tests would have to be conducted. Proposed right-of-way entry near each village and locations of other proposed facilities are discussed and shown in detail on the exhibits in the community reports of Appendix G. IIlI~-2 Public participation was also used in the selection pro- cess. During the week of June 7, 1982, all the villages within the study area were visited and the proposed right-of-way and river crossings were reviewed by air. At each village, council members and local residents were consulted concerning the proposed location of the right-of-way and river crossings. Maps showing the proposed rights-of-way and comment sheets were posted and left at each village. Sever- al of the right-of-way segments were adjusted and, in one instance, a new alternative was added. The data and information gathered during this reconnais- sance trip have been incorporated into the right-of-way design and is reflected in the designated rights-of-way. Selection of Rights-of-Way Rights-of-way were selected based on. the above criteria through the use of aerial photography. Recent (1980) high alti- tude infrared aerial photography for the study area was obtained and interpreted. These photographs were particularly valuable in identifying flooded areas, vegetation types, recent man-made features, and changes in the numerous rivers in the area, The proposed intertie rights-of-way intertie are shown on Exhibit 2. Exhibit 2 shows interties between villages that are geographically close to each other and represent logical routes where interties between smaller groups of villages could be explored. The interties between the villages and intertie junctions have been identified and numbered. In the following section, discussion of each segment includes mileage, river crossings, cost information and reasons for route selection. Exhibit 3 presents a summary of intertie data. Bethel - Akiachak-1l This 15.62 mile section of right-of-way would tie into an existing single phase line owned by Rethel Utilities Corpora- tion. The proposed route avoids all native allotments and num- erous ponds and lakes between the two villages and crosses Gweek Slough at one of its narrowest sections (approx. 635 feet wide) As shown on maps prepared by Calista Corporation, this segment of right-of-way passes through land selected by the Bethel Native Corporation and Akiachak Village Corporation. Bethel - Napakiak Jct.-2 This 2.3 mile section of right-of-way is presently estab- lished and occupied by a Single Wire Ground Return line serving ELr=3 Napakiak from Bethel. As shown on maps prepared by Calista Corporation, this segment of right-of-way is located on land selected by the Bethel Native Corporation. Bethel - Oscarville-3 This 4.65 mile section of right-of-way is presently esta- blished and currently being negotiated with land owners, under a state contract supervised by the Alaska Division of Energy and Power Development. As shown on maps prepared by Calista Corpo- ration, this segment of right-of-way is located on lands select- ed by the Bethel Native Corporation and the Oscarville Village Corporation. Napakiak Jct. - Napakiak-4 This 7.05 mile section of right-of-way is presently estab- lished and occupied by a Single Wire Ground Return line serving Napakiak from Bethel. As shown on maps prepared by Calista Corporation, this segment of right-of-way is located on land selected by Bethel Native Corporation and Napakiak Village Cor- poration. Eek Jct. - Napaskiak-5 This 4.3 mile section of right-of-way was selected to avoid conflicts with native allotments and the airstrip at Napaskiak. The alignment parallels an existing winter trail that will allow easier access to the right-of-way for construction and mainte- nance of a powerline. As depicted on maps prepared by Calista Corporation, this segment of right-of-way is located on lands selected by Napakiak Village Corporation, Oscarville Village Corporation, and Napaskiak Village Corporation. Kwethluk - Napaskiak-6 This 14.05 mile section of right-of-way from Kwethluk to Napaskiak was routed to avoid the numerous native allotments in the area and take advantage of the existing road access from an abandoned air strip to the south of Bethel. The two slough crossings selected should present no problems as they are both under 400 feet in width. As shown on maps prepared by Calista Corporation, this segment of right-of-way is located on land selected by the Kwethluk Village Corporation, the Bethel Native Corporation, and the Napaskiak Village Corporation. Kwethluk - Kwethluk Jct.-7 This 3.14 mile section of right-of-way was selected to avoid the numerous native allotments that are present in the III-4 area. The right-of-way require two river crossings, both of which are under 650 feet in distance and suitable for aerial crossings. As shown on maps prepared by Calista Corporation, this segment of right-of-way is located primarily on lands selected by Kwethluk Village Corporation. A small portion of route near Kwethluk Jct. is located on land selected by Akiachak Village Corporation. Kwethluk Jct. - River Crossing - Akiachak-8 This 4.44 mile section of right-of-way was selected to avoid the numerous lakes and flooded areas between the two vil- lages and was routed across Kiktak Island at a point on the Kuskokwim River considered suitable for an aerial crossing. The right-of-way is also the shortest possible route between the two points and avoids conflicts with the Akiachak airstrip and float plane traffic that serves the village. The Kuskokwim River aerial crossing appears very feasible at this location as the distance is not prohibitive, river banks are relatively stable, and the local residents indicate that spring ice jams are usual- ly not a problem. The river crossing will have to accommodate barge traffic some of which are piled as high as 40 feet. Unfortunately, in order to accomplish the above, three native allotments would have to be crossed. In the event this is undesirable or not possible, an alternative route is presented as the next segment. As shown on maps prepared by Calista Cor- poration, this segment of right-of-way passes through lands selected by both of these villages. Akiachak - Akiak-9 This 7.15 mile section of right-of-way was selected as the shortest route between the two villages and avoids conflicts with the village airstrips and numerous water bodies enroute. Unfortunately, the route passes through three native allotments and a longer alternative, avoiding these allotments, is present- ed as the next segment. As shown on maps prepared by Calista Corporation, this segment of right-of-way passes through lands’ selected by Akiachak Village Corporation and Akiak Village Corporation. Kwethluk Jct. - Tuluksak Jct.-10 This 13.68 mile section of right-of-way avoids potential conflicts with the numerous native allotments scattered through- out the area. The only undesirable feature of this segment is the 950 foot crossing of Kuskokwim Slough and the smaller cross- ings of the Kasigluk River, Kisaralik River and Reindeer Slough. Should an intertie from Akiak to Tuluksak Junction across the IIL=5 Kuskokwim River prove feasible, it would be preferable to this longer route. As shown on maps prepared by Calista Corporation, this right-of-way passes through land selected by Akiak Village Corporation, Kwethluk Village Corporation and a very small por- tion by Akiachak Village Corporation. Tuluksak Jct. - Tuluksak-11l This 15.16 mile section of right-of-way avoids native allotments and, where possible, the numerous ponds and lakes enroute. The two crossings of Mishevik Slough do not appear to present any problems. As shown on maps prepared by Calista Corporation, this right-of-way passes through land selected by Tuluksak Village Corporation and Akiak Village Corporation, Napakiak Jct. - Tuntutuliak Jct.-12 This 11.15 mile section of right-of-way was routed to avoid potential conflicts with native allotments as well as allow for manageable river crossings across the Kongeruk River (approx 320 feet) and the Johnson River (approx 790 feet). The Johnson River crossing will have to allow a minimum of 40 feet clearance for barge traffic. The Napakiak Junction allows access to Bethel from this point on an existing right-of-way. As shown on maps prepared by the Calista Corporation, this segment of right- of-way is located on land selected by Napakiak Village Corpora- tion and the Bethel Native Corporation. Tuntultuliak Jct. - Atmautluak Jct.-13 This 7.38 mile section of right-of-way was selected to avoid potential conflicts with native allotments and the num- erous lakes and water bodies that cover the area. As shown on maps prepared by Calista Corporation, this segment of right-of- way is within land selected by the Napakiak Village Corporation and the Nunapitchuk Village Corporation. Atmautluak Jct. - Atmautluak-14 This 5.23 mile section of right-of-way crosses the Johnson River and encompasses a series of islands located in shallow water that surrounds the village. To accommodate these physical features, span lengths will be variable. The Johnson River crossing (approx 530 feet) will have to accommodate barges loaded up to 40 feet in height. As shown on maps prepared by Calista Corporation, this segment of right-of-way is within lands selected by Atmautluak Village Corporation and Nunapitchuk Village Corporation. III-6 Atmautluak Jct. - Akolmiut Jct.-15 This 5.3 mile section or right-of-way was selected to avoid the numerous native allotments along the Johnson River to the east and numerous lakes and ponds in the area. As shown on maps prepared by Calista Corporation, this segment of right-of-way is located within an area selected by Nunapitchuk Village Corpora- tion. Akolmiut Jct. - Akolmiut AVEC Tie Line-16 This 3.77 mile right-of-way was selected to avoid native allotments that cover the area and connects with AVEC's intertie line between Akolmiut, Kasigluk and Nunapitchuk. The route will require a river crossing of approximately 600 feet across the Johnson River. This crassing will have to accommodate barges piled as high as 40 feet. This particular location is a poor choice, however, due to the low, wet nature of the northern shore of the river. During a meeting with the Nunapitchuk Vil- lage Council, the local leaders advised against crossing the river at this location due to frequent flooding in this area. The council and members of the village preferred a right-of-way that would connect with AVEC's proposed intertie line at Akula Heights. This proposed route would be considerably shorter and utilize AVEC's proposed underwater crossing of the Johnson River but would require crossing three native allotments. The propos- al is discussed in the next route segment. As shown on maps prepared by Calista Village Corporation, this segment of right- of-way is located within lands selected by Nunapitchuk Village Corporation and Kasigluk Village Corporation. Tuntutuliak Jct. - Tuntutuliak-17 This 32.1 mile section of right-of-way was selected to avoid potential conflicts with native allotments and the num- erous lakes and ponds that dot the area. In addition, the route allows a manageable aerial crossing of the Kialik River (approx 530 feet). As shown on maps prepared by Calista Corporation, this segment of right-of-way is located on land selected by Napakiak Village Corporation and Tuntutuliak Village Corpora- tion. Eek Jct. - Eek-18 This 42.84 mile section of right-of-way was selected to avoid potential conflicts with native allotments and situated between the Kuskokwim River to the west and an area covered with large and small lakes to the east. Two river crossings across the Eenayarak River and the Eek River are necessary to access Tit? Eek from the north. The right-of-way selected crosses these rivers at locations that are narrow and suitable for an aerial crossing. In addition, the northernmost 6.8 miles of the route takes advantage of an existing winter trail. As shown on maps prepared by Calista Corporation, this segment of right-of-way is located on lands that have been sel- ected by the Eek Village Corporation, and the Napakiak Village Corporation. Part of this right-of-way is on unselected land. III<-8 Chapter IV costs Standard procedure for cost estimates involves breaking the job into all its components, called units, and then applying a labor and material cost to each unit. Then the sum of the units is taken together with other costs, such as transportation and freight, with a percentage for overhead and profit added. Conventional power lines (i.e. R.E.A. specifications) have a standardized system of unit costs. Since the flexible A-frame structure being recommended by this report has never been built, except for the two SWGR lines, a somewhat more general approach was used for cost estimating. Materials Since the majority of these lines will comprise tangential structures, spaced at 15 per mile, a reasonably reliable esti- mate could be based on all tangential structures plus a factor for deadends. Terminations and river crossings over about 900 feet have to be handled individually. An estimate of material costs is given in Exhibit 4. Labor Previous cost experience on the two SWGR lines built at Bethel-Napakiak and Kobuk-Shungnak used a high percentage of unskilled local labor. Under Alaska State law, a local govern- ment body, such as a village, is exempt from Davis-Bacon wage laws and other contractor laws. However, if the proposed village interties are funded and built, it is not very likely the normal electrical contractors and Davis-Bacon regulations will be set aside. It is assumed that all work would be done by a licensed and bonded outside electrical contractor employing only certified linemen paid "Davis-Bacon" scale wages. In 1982, the prevailing "Davis-Bacon" wage rate for a line- man was: IV=5 Straight time basic wage $25.15 Fringe Benefits (1) 5.45 Employer Costs (2) 8.66 $39.26 (1) Fringe benefits include standard union benefits e.g. pension, health and welfare, training, etc. (2) Employer costs are FICA, ESC, workman's comp, other insurances, etc. Rural Alaskan construction projects are normally worked a minimum of 6 ten hour days per week. This overtime has an addi- tional impact on the cost. A composite rate can be formulated as follows: $1,570.40. 40 S.T. hours @ 39.26 = 20 0.T. hours @ 58.89 = 1,177.80 $2,748.20 2748.20/60 $45.80/hour Based on experience with the Bethel-Napakiak SWGR project and the above data: Hours Structure Assembly 4 hrs. each 4 Structure Delivery 2 hrs. each 2 Structure Erection 12 hrs. each 12 Conductor Installation 20 hrs./M 39.4 57.4 Labor cost per structure would average 57.4 hrs x $45.80/hr = $2,630. Transportation and Freight Transportation and freight into the Bethel region involve both barge and air. There are no roads, except when the rivers are frozen they are often used as roads. Typical rates for the 1982 season are: Barge: Seattle to Bethel, Foss, $8.83/100 lbs(C)., earliest Sailing May 10, last sailing, August 30. IV-2 Barge: United Transportation, Bethel to Eek - $4.03/C, Bethel to Tuluksak - $3.78/C, Bethel to Kasigluk - $3.78/C. Air Commercial: Wein, Anchorage to Bethel - $31.20/C, Anchorage to Eek - $52.30/C, Anchorage to Tuluksak - $52.30/C, Anchorage to Kasigulk - $52.30/C. A.I.A., 5,000 lbs., Anchorage to Bethel - $25.71/C, Anchorage to Bethel - 130% oversize, $33.42/C. Air Charter: A.I.A. Hercules 44,000 lbs nominal, Anchorage to Bethel - $12,540 (or 28.50/C, offloading not included). The minimum barge rate for material offloaded at the near- est village would total $12.85/C. Cost per structure would be $12.85 X 21.3 = $273.70. Air freight runs about four times the cost of barge freight. Actual costs would run somewhere in between, since not all material would be barge-shipped and the contractor would have to charge interest on barge-shipped material costs for upwards of three months, since the contractor would not be reimbursed until material was on site. For purposes of this estimate, costs are developed as fol- lows: Assuming the poles and conductors are shipped by barge $12.85 x 19.2 = $246.72. Interest of 2% per month is included at $734.70 x .06 = $44.08. And the remainder of the freight is shipped by air commercially or $52.3 x 2.1 = $109.83. The cost of freight per structure would then total $400.63. Transportation of Personnel Wien Air Alaska fares: Anchorage - Bethel RT $292.00 Bethel - Eek RT 58.00 Bethel - Tuluksak 62.00 Bethel - Kasigluk 48.00 Estimated air fare at 6 RT per 7 mile transmission line segment is $354 x 6 + 7 = $303/mile. IV=3 Equipment Rental Various methods of construction could be used to erect a flexible "A" frame power line. For instance, the Kobuk project used 2 snowmachines, 1 small cat and a 40 ft. sled, 1 gas fired rotary hammer and 4 chain saw winches. The Bethel-Napakiak line used a helcopter. Typical rental rates include: Snow machine (Alpine) $45/day Rotary hammer $25/day Chain saw winch $25/day Helicopter (1000 1b) $260/hr. Helicopter (4000 1b) $1000/hr. For purposes of this analysis, $625/day and 1/2 day per structure have been selected as typical parameters. These are in line with the Bethel-Napakiak estimates which used a heli- copter at $450/hour. For a helicopter to be economical, every hour it works should save about 20 manhours. Camp Costs Room and board is estimated at 5 man-days per structure at $56 per day or $280 per structure, or $4,200 per mile. Other Costs Mobilization includes all the costs of organizing men, material, tools, and equipment to the job site. Indirect costs include job site telephone, etc. These costs were estimated at approximately $1,100 per mile. Contractors overhead and profit is estimated at 25% of all the above costs. A contingency allowance of 15 percent, a right-of-way allowance of 10 percent, and engineering and owner's overhead at 17 percent was added to all the above costs including contractor's overhead and profit. Cost of Transmission Intertie Line The cost per mile is summarized in Table IV-l. Iv-4 Table Iv-l ESTIMATED CONSTRUCTION COST OF 34.5 kV TRANSMISSION INTERTIE PER MILE Material $1150 x 15 $ 17,250 Labor 2630 x 15 39,450 Freight 400 x 15 6,000 Travel 300 x 15 4,500 Equipment Rental 2,500 Room & Board 4,200 Mob & Demob 1,100 Sub-Total $ 75,000 Construction Overhead & Profit (25%) LS i750 Sub-Total $ 93,750 Contingency (15%) 14,000 Right-of-way (10%) 9,350 Engineering (17%) 15,900 Total Construction Costl/ $133,000 1/ Total construction cost excludes excalation and interest during construction. River Crossings The longest river crossing under consideration is 1,050 feet across the Kuskokwim River. The clearance limit is 40 feet above water level. Based on manufacturer's line sag data under heavily loaded conditions, the expected sag in the transmission line is at least 40 feet. With allowance for location at a point 15 feet above mean high water level and a 10 foot pole setting depth, the required poles will be at least 75 feet long. Any pole longer than 40 feet has an additional charge of $120 per foot. IvV=5 To get a 75 foot, class 3 pole to Bethel would cost: 1. Pole (FO Seattle) $ 1,000 2. Barge cost, 3060 lb. @ 8.83 270 3. 35 foot overage @ $150/ft. 5,250 $ 6,520 4. Helicopter time for pole to move from Bethel to site: 2 Hr. @ $1,000 $ 2,000 Total river crossing costs would exceed: Material: (4) 75' poles $34,080 (4) 40' poles. 1,000 6000' 16M Alumoweld 1,572 Misc. cross arms, etc. 2,000 $38,652 Labor: Dig and set 8 poles, string and tension conductors, 500 man-hours @ 45.80 $22,900 Other Costs: Estimated @ 30% 18,018 TOTAL $80,018 Estimated total river crossing costs: $80,000 These river crossing expenses apply to navigable river crossings only, i.e. the Kuskokwim at Akiak, Akiachak, and Napaskiak. Crossing the Johnson River involves a much shorter Span length and would cost less. Other river crossings under about 900 feet in length use standard structures with no signi- ficant cost impact. IV-6 EXHIBIT 1 1-0" 5” DIA. POST INSULATOR ] 10’ x 4" x 4" x 1/4" ANGLE IRON 4.75" DIA. WOOD POLE 30’ — 0” 31-8” 10” DIA. | ns =a ALASKA POWER AUTHORITY BETHEL AREA POWER PLAN FEASIBILITY ASSESSMENT TYPICAL ‘A — FRAME STRUCTURE P.E. COMPANY ELECTRICAL ENGINEERS HARZA ENGINEERING COMPANY P.O. Box 42543 hecrorege Atesia Prone (907) 276-3442 oes08 December 1982 20 MILES Le) ee I 1" =6 MILES li i it lt it EXHIBIT 2 Page 2 of 4 *; 6) L} i +? 4 ALASKA POWER AUTHORITY BETHEL AREA POWER PLAN FEASIBILITY ASSESSMENT INTERTIE TRANSMISSION SYSTEM HARZA ENGINEERING COMPAN' EXHIBIT 2 Page 3 of 4 \ i eae BETHEL AREA POWER PLAN FEASIBILITY ASSESSMENT ¥ = i ; ‘ t ‘ - Q ce f ATMAUTLUAK | « F ws ep TS ATMAUTLUAK m a” ask ALASKA POWER AUTHORITY BETHEL AREA POWER PLAN FEASIBILITY ASSESSMENT INTERTIE TRANSMISSION SYSTEM Route Segements 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. ll. 12. 13. 14. 15. 16. 17. 18. TRANSMISSION LINE ROUTE SEGMENTS Mileage Bethel - Akiachak Bethel - Napakiak Jct. (existing SWGR) Bethel - Oscarville Napakiak Jct. - Napakiak (existing SWGR) Eek Jct. - Napaskiak Kwethluk - Napaskiak Kwethluk - Kwethluk Jct. Kwethluk Jct. - River Crossing - Akiachak Akiachak - Akiak Kwethluk Jct. - Tuluksak Jct. Tuluksak Jct. - Tuluksak Napakiak Jct. - Tuntutuliak Jct. Tuntutuliak Jct. - Atmautluak Jct. Atmautluak Jct. - Atmautluak Atmauluak Jct. - Akolmiut Jct. Akolmiut Jct. - Akolmiut AVEC Tie Line Tuntutuliak Jct. - Tuntutuliak Eek Jct. - Eek 15.62 2.3 4.65 7.05 4.3 14.05 3.14 4.44 Tei 13.68 EXHIBIT 3 River Crossings 635+' None None 110+" None 350+' 3704" 250+! 792+' Gweek Slough Napakiak Slough Tupuknuk Slough Napakiak Slough Kwethluk Slough Kuskokwim River 1050+' Kuskokwim River None Numerous small cross- ings of Kasigluk River, Kisaralik River, & Reindeer Slough 480+' 270+! 790+° 320¥' None 530+' None 600+' 530+' 635+' 620+" Mishevik Slough Mishevik Slough Johnson River Kongeruk River Johnson River Johnson River Kialik River Eek River Eenayarak River Several Small Creeks EXHIBIT 4 ESTIMATED MATERIAL COSTS 3-PHASE FLEXIBLE A-FRAME TANGENTIAL STRUCTURE Estimated Estimated Description Weight, lbsUnit Pricel/ Cost Weight, lbs 2 Predrilled, treated poles 700 $ 832/ $166 1400 2000 Alumoweld 16M 262/M 288/m3/ 571 520 1 Pole top saddle 60 125/ea4/ 125 60 assembly 2 Post top insulator- horizontal 30 54/ea5/ 108 60 1 Post top insulator- vertical 25 33/ea5/ 33 25 3 Clamps 7 6/eaS/ 18 3 lot Misc. hardware, bolts, etc. 6 164/ 16 6 2 Rebar anchors 10 4/ea4/ 8 20 3 Dampers 12 35/ea4/ 105 36 Total $1,150 2,130 1/ Unit prices are F.O.B. Seattle or Anchorage. 2/ Cascade, Seattle quotation for 200 penetrated, predrilled, gained, 35 ft., class 6 poles delivered F.0O.B. Seattle dock. 40 ft., class 6 poles were $120.80/ea, 885 lbs. 3/ Copperweld Bimattalics, manufacturers list prices 50,000+ foot quantity, F.O.B. Reno, Nevada. 4/ Engineers estimate. 5/ A.B. Chance, list prices C903-1402, $32.10; C903-1602, $53.00; C903-9510, $6.00.