Transmission Line Route—Physical Inspection for Afghanistan
The proposed transmission line route, developed during Phase 1, runs from a proposed new converter/substation adjacent to Sangtuda HPP, in Tajikistan, to a proposed new converter/substation near the existing Peshawar 500kV substation in Pakistan.
The Project Terms of Reference require that the entire route be inspected on the ground in Phase 2 and refined in accordance with the findings of the inspection. SNC-Lavalin requires the Route Sub-consultants to carry out this physical inspection in Afghanistan and make recommendations as to revisions required to be made to the Phase 1 route. In addition, identification of suitable locations for proposed converter/substations near Kabul is required.
The Phase 1 route was developed based on information shown on 1:250,000 topographical maps, published by the Defense Mapping Agency, USA. These maps are up to 25 years old, therefore extensive use was made of satellite imagery to identify more recent developments around towns and villages. The route was based on the following criteria:
Minimize the total length of the line,
Avoid difficult terrain and extreme altitudes,
Access from existing roads for construction and maintenance, and
Minimize negative environmental and social impacts.
The Terms of Reference require that the final recommended route be shown on 1:50,000 topographical maps. SNC-Lavalin has identified the source of these maps and it is expected that these will soon be available to SNC. After acquiring these maps, SNC will develop the transmission line route on these maps.
Phase 1 Route
Copies of the 1:50,000 and 1:250,000 topographical maps, showing the Phase 1 route, will be given to the Sub-consultants. Description of the route is included in Sections 6.2 and 6.3 of the Draft Pre-Feasibility (Phase 1) Report and is included for information at the end of this document.
The Phase 1 route should be considered as a corridor approximately 2 km wide. Generally the route follows a road and is often indicated as long straight sections on one side of the road, especially in sections of relatively flat terrain.
The Sub-consultants are required to consult with the relevant authorities (Ministries, utility companies etc) in Afghanistan to collect information on other projects, either in advanced stages of planning or already under implementation, which may interfere with the CASA-1000 transmission line route. These projects may be other transmission lines or major industrial developments—for example it is known that there are some other proposed transmission lines from Tajikistan to Afghanistan, at least one of which is at the construction stage.
The entire route is to be inspected on the ground and refined to produce the final, Phase 2, corridor approximately 500m wide. The EPC contractor will be responsible for selecting the final alignment within this corridor and for carrying out the final detailed survey.
The criteria for route selection are stated above. The Route Sub-consultants will need to have close coordination with the environmental Sub-consultants. The Route Sub-consultants shall make recommendations as to revisions to the route based on their findings—always considering the route selection criteria. For example, Phase 1 route may show the alignment, for a significant length, as straight line on one side of the road. During the field inspection it may be determined either that crossing the road somewhere along the straight or staying on the same side and introducing an angle is a better option. Alternative routing should also be investigated for sections of the line where improvement can be achieved i.e. through extremely difficult terrain.
All important features such as locations of converter/substations, angle points, river/road crossings etc need to be identified by their coordinates---latitude, longitude and altitude. It is suggested that a portable GPS instrument should be used for this purpose.
SNC-Lavalin requires that the Route Sub-consultant collect and provide general data on soils expected to be found along the route. The information should be sufficient in order for SNC-Lavalin to make an assessment of the general foundation conditions expected along the route. It is anticipated that the tower foundations will generally be reinforced concrete spread type to resist both uplift and compression loads. Piled or other special foundations may be required in areas with very weak soils. Some suggested sources for this information are publications, local engineers, local contractors, university faculty and residents of the area of the route.
Typical data required are:
Granular (sand, gravel—loose, medium, dense),
Silt /clay (soft, firm, stiff etc),
Deep organic soil deposits
Depth of ground water table, probability of flooding
Approximate locations and extent of the various soil types along the route
Presence of corrosive soils
The following deliverables are required from the Route Sub-consultants:
Phase 2 route and updated information regarding new projects marked on topographical maps,
Coordinates of major features,
Description of the whole Phase 2 route,
Sections 6.1 to 6.3 from the Draft Pre-Feasibility (Phase 1) Report are reproduced below for information:
TECHNICAL ASSESSMENT OF TRANSMISSION LINE OPTIONS
The analysis of the export potential of the Tajikistan/Kyrgyz systems, described above, indicates that the total surplus available is as shown in Table 6-1 below.
Table 6.1 Surplus Power available from Tajikistan/Kyrgyz Republic
In the above table, the surplus shown for each country is the individual monthly maximum surplus for that country in each year. The total surplus shown is the coincident monthly maximum for both countries. Since the individual surpluses in each country may not occur in the same month, the total surplus will be equal to or less than the sum of the individual surpluses.
The base case option defined in the Terms of Reference for the study consists of an interconnection between Tajikistan and Pakistan to deliver up to 1 000 MW to Pakistan at the Peshawar 500 kV substation and 100 MW to Afghanistan at Kabul, starting in the year 2010 (taken as the first year of operation of the interconnection). The above table shows that this level of export can be achieved in 2010, the maximum transfer level being 1 552 MW in the year 2010 rising to 1 734 MW by the year 2012. After the year 2012, the available surplus increases, reaching a maximum level of 8 878 MW by the year 2023, then decreases until by the year 2030 the maximum surplus is 6 289 MW. The individual surpluses in Tajikistan and the Kyrgyz Republic follow a similar pattern. It is noted that in 2013, the surplus in Tajikistan alone is sufficient to provide the base case export level of 1 100 MW. The maximum transfer from the Kyrgyz Republic to Tajikistan to support the export to Pakistan could be as low as 653 MW or as high as 4 710 MW depending on the level of participation by the Kyrgyz Republic once Tajikistan has sufficient surplus to supply the base case export levels from its own resources.
For the purposes of this study, the transfer levels defined in the Terms of Reference have been used to develop the basic characteristics of the transmission interconnection. However, in developing the options for the base case interconnection, account has been taken of the opportunities for increased transfers in the future. The options have been developed in such a way as to allow expansion of the interconnection capacity in a reasonably simple and cost-effective manner.
Transmission Line Routing
Before developing options for the interconnection, it is necessary to first consider the available routing for any transmission lines to determine the distances involved and the terrain to be traversed. At this stage, it is normal to define the transmission line route in terms of a corridor of 1-2 km width. At the detailed design stage, when route surveys and detailed environmental analysis has been carried out, the final line route is selected within the defined corridor. Of particular importance in the selection of a corridor is the range of altitudes that the transmission lines will pass through since altitude has a direct bearing on the design characteristics of any transmission line.
In selecting a transmission line corridor, the following criteria are normally considered:
Minimize the total length of the line,
Avoid difficult terrain and extreme altitudes,
Access from existing roads for construction and maintenance,
Minimize negative environmental and social impacts.
The available corridors considered in this study are based on work carried out in previous studies and are shown in Figure 6-1.
Figure 6.1 Available Transmission Line Corridors
The eastern corridor proceeds from Sangtuda in Tajikistan, following existing roads to Kulob. From Kulob, the corridor cuts across the northeast corner of Afghanistan to Khorugh back in Tajikistan and follows existing roads to the Tajikistan-Afghanistan border. The corridor then passes across the Shawat Pass into Pakistan where it then follows existing roads to Peshawar via Chitral, alongside the Pakistan-Afghanistan border.
The western corridor follows existing roads for its entire length, crossing the Tajikistan-Afghanistan border near Nizhny and proceeding in a southerly direction via Kunduz, Pul-e-Khumri, the Salang Pass and Raqi to Kabul. From Kabul, the corridor follows the existing road via Jalalabad to Peshawar in Pakistan.
Both corridors are similar in terms of route length (approximately 750 km). Whereas the western corridor follows existing roads for its entire length, the eastern corridor consists of significant sections where no roads presently exist. The maximum altitude associated with the western corridor is 3 750 masl encountered in the area of the Salang Pass in Afghanistan and difficult terrain will be encountered for approximately 160 km (20% of the total route length). The maximum altitude associated with the eastern corridor is above 5 000 masl. and difficult terrain will be encountered for approximately 200 km (30% of the total route length).
The eastern corridor does not pass close to any existing or future load centres in Afghanistan. Thus a supply to the Kabul area would have to be provided separately using another corridor either south from Nizhny in Tajikistan or west from Peshawar in Pakistan.
The western corridor passes through the Kabul area as well as passing by the towns of Kunduz, Baghlan, Pul-e-Khumri, Raqi, Mehtar Lam and Jalalabad. This routing offers a range of possible connection points in the future as the load in Afghanistan increases.
The above considerations of the two corridors lead to the selection of the western corridor for more detailed analysis, based on the following:
Lower extremes of altitude,
Proximity to existing roads for easier construction and maintenance access,
Proximity to existing load centres in Afghanistan
Description of the Selected Corridor
The selected corridor is approximately 2 km wide and is shown on the attached 1:250 000 scale topographical maps published by the Defence Mapping Agency, U.S.A. These maps were used for this initial analysis for the following reasons:
The 1:250 000 scale is more manageable for environmental and socio-economic data collection and physical route inspection,
The maps are in English, the working language of the study,
A source of 1:50 000 scale topographical maps has been identified for Pakistan and Afghanistan. A source of 1:100 000 scale topographical maps has been identified for Tajikistan. The maps for Afghanistan and Tajikistan are in Cyrillic script.
Efforts are continuing to acquire 1:50 000 scale topographical maps for the entire transmission corridor.
The selected corridor is shown on six 1:250 000 scale maps (Figure 6-2) as indicated on the following key plan.
Map Ref: NJ42-10
Map Ref: NJ42-14
Map Ref: NI42-2
Map Ref: NI42-3
Salang Pass, Charika
Map Ref: NI42-7
Map Ref: NI42-8
The Phase I corridor was selected based on the information shown on the 1:250 000 scale maps, supplemented by extensive use of satellite imagery. The maps are up to 25-years old and the satellite imagery was used to determine the current extent of urbanization. The total length of the Phase I corridor is approximately 750 km with lengths in each country as follows:
Tajikistan 117 km
Afghanistan 562 km
Pakistan 71 km
Total 750 km
A description of the Phase I corridor, by map section is given below.
Map NJ42-10: The northeast corner of the map is approximately 18km south of Sangtuda Hydro Station. The map showing Sangtuda was unobtainable. The route follows, generally, a southerly direction to the Tajikistan-Afghanistan border near Shir Khan and thereafter follows the road to Kunduz. Sections of the route which will require in-depth investigation during Phase II are the first approximately 18km south from Sangtuda, the communications installation near Voroshilovabad airfield, the area between Dusti and Pervomayski and the border/river crossing. The total length of the route shown on this map is approximately 127km, which together with the approximately 18km from Sangtuda not shown total 145km from Sangtuda to the southern boundary of the map. The elevation of the whole 145km is less than 1,000m.
Map NJ42-14: The route shown on this map follows the road to Kunduz and onto Mahajer and Baghlan. The route is located on the west side of the road. Phase II investigation will include the exact extent of the development around Kunduz, Mahajer and Baghlan to ensure that the line is located a sufficient distance from the road to minimize socio-economic impacts. The total length of the route shown on this map is approximately 124km all of which is under 1,000m elevation.
Map NI42-2: The route continues generally south alongside the road to Pul-e-Khumri and Dowshi. At Dowshi the route turns to run east to Khanjan where the road and the line route turn south towards the Salang Pass. The section between Khanjan and the Salang Pass passes through some of the most severe terrain of the whole route, passing between mountain peaks up to nearly 5,000m elevation, and will be studied carefully in Phase II. The total length shown on the map is approximately 96km of which approximately 60km is below 1,000m elevation; 25km is between 1,000m and 2,000m with the remainder above 2,000m.
Map NI42-3: The section of the route shown on this map is that from just north of Salang Pass, through Jabal-Os Saraj to Charika. The route generally follows the road. The section from Salang Pass to Jabal-Os Saraj is through terrain of similar severity as that north of the Slang Pass and will be investigating in detail during Phase II. The approximate line route length on this map is 58km. The elevation ranges from a peak of 3,750km to 1,500m at Charika, the breakdown being approximately 3km above 3,500m, 10km between 3,500m and 3,000m, 15km between 3,000m and 2,000m and 30km between 2000m and 1500m.
Map NI42-7: The section of the route shown is that south from Charika to outskirts of Kabul and then east to Jalalabad. The route generally follows the road south to Kabul and then east to Jalalabad, passing approximately 5km north of Kabul airport and similar distance north of Jalalabad. The distance from these two cities are to minimize the socio-economic impacts on these urban areas and in the case of Kabul to provide a suitable location for a converter and/or substation in an uncongested area. The focus during Phase II will be the two urban masses of Kabul and Jalalabad and any impact on the Kabul River, which parallels the Kabul-Jalalabad road. The total line length on this map is 183km of which approximately 135km is at elevations between 1,000m and 2,000m with the remaining 48km at less than 1,000m.
Map NI42-8: The line section on this map is from north of Jalalabad to Jamrod approximately 15km west of Peshawar. From Jamrod the route will have to go in a wide semicircular arc, to the south, to avoid the city of Peshawar in order to enter the existing 500/220kv Peshawar Substation located south of Peshawar near Matanui. The length of the line shown on the map is approximately 104km. The length of the semicircular section from Jamrod to the substation is estimated to be approximately 40km in length. This section is not shown, as the applicable map is unavailable. Of the total length of approximately 144km from Jalalabad to Peshawar Substation approximately 134km is at elevations of less than 1,000m with the remaining 10km (mainly through the Khyber Pass) at elevation between 1,000m and 1,300m. In Phase II concentration will be on the alignment through the Khyber Pass and the section from Jamrod to Peshawar Substation.