Printer Friendly

Ghazi-Barotha hydropower project.

Over the past decade, shortage of energy has emerged as one of the main constraints in the economic and industrial growth of the country. With the ambitious plans for accelerated development launched by the present government, the growth of demand for energy will receive a further impetus, and our ability to instal power generation facilities at a matching rate will be a key factor in achieving the objective of rapid economic development.

Let me briefly review the power generation situation with which we are faced. The total installed generation capacity in the country is approximately 11,000 MW. It is estimated that a minimum of about 6,000 MW of additional generation capability is required to be installed by the Year 2000. As far as possible, these additions to the generation capacity should be such that a reasonable mix of hydro and thermal generation is maintained. Pakistan is already importing a major part of its oil requirements from abroad, and continued expansion in thermal generation is bound to result in a crippling burden on our balance of payments.

In view of these factors, the Government of Pakistan has decided on a rapid implementation of the Ghazi-Barotha Hydropower Project which is well-suited to the requirements of the Pakistan power system since it provides maximum power generation during early summer months when the system is particularly short of generating capability due to low water levels in our reservoirs.

The Project was taken up for detailed study in 1989. Detailed feasibility, engineering, and preparation of the civil works tender documents have been completed under a study carried out by an international group of consultants with the World Bank as the executing agency and WAPDA as the counterpart agency. The study was jointly financed by the UNDP and the Government of Pakistan. The feasibility and designs have been reviewed by a panel of international experts, who have cleared the Project for tendering.

A detailed environmental impact assessment of the Project has been carried out, and reviewed by an international panel of environmental experts. This assessment shows that there are no significant adverse effects of the Project.

The economic studies have clearly demonstrated that the Project offers highly attractive economic returns. The economic internal rate of return (EIRR) of the project is over 20 per cent.

The PC-I for the Project has been approved by the Technical Committee on Energy, and a high-level steering committee has been appointed to oversee its implementation.

Work on pre-construction activities has already started. It is planned to commence prequalification process for civil works in March 1994, which would be followed by tendering. Award of the main contract is scheduled for May 1995, with the first power unit becoming available in 1999.

The estimated cost of the Project is US $ 2.25 billion. The Government of Pakistan has already made a request to the World Bank and other prospective donors for financing of the Project.

The Project

The Ghazi-Barotha (Ghazi-Gariala) Hydropower Project is a major run-of-the-river environmentally sustainable power project (1450 MW installed capacity), designed to meet the acute shortage of peak power demand in the country. The Project is based on utilisation of the head available in the Indus river between Tarbela dam and its confluence with the Haro river. In this reach, the Indus river drops by about 76 m in a distance of 63 km.

The Project studies (comprising of Project feasibility, detailed design, Project cost estimates, environmental studies, and preparation of prequalification and tender documents for civil works) have been financed by the UNDP and the Government of Pakistan, with the World Bank as the Executing Agency and the Pakistan Water and Power Development Authority (WAPDA) as the Cooperating Agency. These studies were undertaken in February 1990 by Pakistan Hydro Consultants, a joint venture of 5 engineering firms (3 expatriate and 2 local) and were completed during 1992. The Government of Pakistan has recently decided to proceed with the implementation of this power Project on priority.

The Project will have three main components; a barrage, a power channel and a power complex. The relatively flat slope of the power channel will permit most of the river drop to be utilized for power generation.

Barrage

The barrage, located about 7 km downstream of Tarbela dam, will regulate the daily discharges from Tarbela and divert water into the power channel. Compensation water during the low-flow season and excess flows during the high-flow season will be released downstream of the barrage. The barrage will be able to pass the flood of record through its 20 standard bays and 8 undersluices at normal pond level. A fuse plug will help pass extreme floods up to the capacity of Tarbela's spillways and tunnels. The barrage will include a public road crossing of the Indus river.

Power Channel

The concrete-lined power channel will convey up to 1,600 cumecs (56,500 cusecs) from the barrage to the power complex. The channel will be 52 km long with a bed slope of 1 in 9,600, a water depth of 9 m, a base width of 58.4m and a velocity of 2.33 m/s. There will be 32 road bridges, including a dual lane bridge for the Grand Trunk Road, a railway bridge and 45 cross drainage structures.

Power Complex

The power complex will be located near the confluence of the Indus and Haro rivers. It will comprise a forebay, a siphon spillway, two headponds, a power intake structure, penstocks, a powerhouse with five 290 MW turbo-generators, and a tailrace channel. The headponds will allow daily peaking operations. The power will be transmitted by 500 kV circuits to WAPDA's national grid system.

One of the most important features of the Project is that it provides power peaking capacity throughout the year, with full power generation during the months of May and June when there is reduced generation from other large hydropower projects as a result of low reservoir levels.

Environmental Aspects

The Project will not have any significant environmental impacts. Environmental considerations have been important in the development of the layout and design of the Project components.

The area to be taken by the barrage pond is almost entirely confined within the river banks and is Government-owned land. There are no river-bank villages between Tarbela dam and the barrage. The barrage will reduce the attack of the Indus river on the left bank villages downstream of the barrage site and would thus provide protection and stability to the left bank and the adjacent villages.

The selected channel alignment (though comparatively costlier) avoids all villages, graveyards and shrines. Only about 100 dwellings will have to be locally relocated. This alignment results in the channel being largely in cut. Part of the excess spoil will be used to increase the channel freeboard. The rest will be used to form low, wide spoil banks which will be covered with topsoil from the necessary excavations, provided with tubewell irrigation and sold back to the local farmers. There will be negligible impact on the existing groundwater table or the quality of water. On the other hand, the concrete channel underdrainage system will help to partly alleviate the existing waterlogging problem in the Project area.

The Project will replace a small irrigation system disrupted by the tailrace channel. The area occupied by the headponds does not contain any dwellings and is poor quality rain-fed land.

An environmental assessment study has been carried out by the Project Consultants to meet the World Bank guidelines and requirements. This has been reviewed by an international Panel of environmental experts established for the Project. The Panel's review found general acceptability of (a) the approach used in the environmental and social impact analysis of the structural elements of the Project, including siting and design approach for the barrage, power channel and power complex; (b) the recommended mitigation plan for resettlement and compensation; (c) the proposed mitigation plan for archaeological, historical and religious sites.

Supplementary studies have also been carried out, on the recommendation of the Panel, to develop operational criteria for discharge of compensation water and for the management of the created impoundments. A detailed draft resettlement plan has been prepared by WAPDA in accordance with the World Bank guidelines and the advice of the Panel. This plan is presently under review.

Operation

The Project will have an installed generating capacity of 1,450 MW. This power will be available during the critical months of May and June when the system is short of power. The average annual energy output will be about 6,600 GWh, with relatively little variation due to dry and wet years. The power channel is designed not to require regular dewatering for inspection and maintenance. Other pans of the Project can be isolated for maintenance during the low-flow season.

Costs

Detailed estimates have been prepared of the costs of the various elements of the Project, using the crew-up method. The total capital cost of the Project, at January 1992 price levels, is estimated by the Project Consultants at US$ 2,030 M including the transmission links to the national grid, physical contingencies, price contingencies and engineering. The cost will have a local component of US$ 580 M and foreign component of US$1,450 M. The Project cost estimate is being updated for September 1993 price levels.

Project Economics

The economic studies have demonstrated that the Project forms part of the least-cost expansion of the Pakistan power system, resulting in savings to the power system of capital and operating cost with a present value of about US$ 870 M, at a discount rate of 10%. The least-cost status of the Project remains valid for the full range of sensitivity analyses performed, including the timing of other projects.

The Project has an EIRR of 20.19% and an FIRR of 14.1%.

Project Implementation

The feasibility study of the Project, completed in April 1991, demonstrated the technical, environmental and economic feasibility of the Project. An independent Panel of Experts, established for the Project, has been involved in the review of various technical aspects of the Project from the very beginning of the studies, and the Panel has endorsed the Project as technically sound and economically highly attractive.

The tender documents for civil works (already completed) are presently being processed and it is envisaged that the ICB Civil Works Contracts will be awarded in May 1995, with the first unit to be commissioned by the end of 1999.

The activities for land acquisition and the preliminary works (including access roads, staff colonies, transmission and telephone lines etc.) are being started soon by WAPDA.

Contracts Packaging Civil Works

The layout of the Project civil works lends itself to adoption of either a single contract or three separate contracts. The separate contracts would be:

* the barrage and ancillary works, including erection of gates;

* the power channel and ancillary works and;

* the power complex and ancillary works, including erection of powerplant equipment and gates.

Tender documents have been prepared for these three separate contract packages. Prospective tenders will be prequalified for one or more packages. Contract award would then be based on the combination which results in the least evaluated cost to the Owner. There may thus be one, two or three civil works contractors.

Mechanical and Electrical Works

For the mechanical and electrical equipment, the following separate contracts are foreseen:

ME 01 Turbines and auxiliaries ME 02 Generators and auxiliaries ME 03 Transformers and reactors ME 04 Cranes ME 05 HV switchgear, control and protection equipment ME 06 MV and LV switchgear ME 07 Elevators ME 08 Diesel generating standby sets ME 09 Gate equipment ME 10 Generator isolated phase bus ME 11 Switchyard steel structures and powerhouse take-off masts ME 12 Cables and accessories ME 13 Miscellaneous auxiliaries ME 14 Control & instrumentation, SCADA and telecommunication equipment

The first ten will be supply and supervise contracts, the next three will be supply only contracts and ME 14 will be supply and install contract.
COPYRIGHT 1994 Economic and Industrial Publications
No portion of this article can be reproduced without the express written permission from the copyright holder.
Copyright 1994 Gale, Cengage Learning. All rights reserved.

 Reader Opinion

Title:

Comment:



 

Article Details
Printer friendly Cite/link Email Feedback
Author:Kazi, Asif H.
Publication:Economic Review
Date:Jul 1, 1994
Words:1992
Previous Article:Industrial energy consumption pattern.
Next Article:Gas use for electricity generation.
Topics:

Terms of use | Copyright © 2014 Farlex, Inc. | Feedback | For webmasters