Globally, hydropower is recognized as renewable, cheap and reliable resource of energy. It generates electricity with zero emission and produces no waste. There is no requirement of fuel, operating cost is much lower and hydropower stations have longer lives than thermal power plants.
To resolve the power crisis in long term and to sustain economic growth, the optimal development of hydropower in the country is essentially needed. In fact, the development of hydropower is considered a key factor for future progress. Fortunately, enormous potential exists to exploit this unlimited indigenous resource of energy.
The installed capacity of hydropower plants owned and operated by the Water and Power Development Authority (WAPDA) is around 9,538-MW. There are 21 power stations--- large, medium and small. In the year 2019, these power stations achieved the highest-ever electricity generation, having delivered 34.678 billion units (kWh) of energy to the national grid, despite various technical constraints.
Currently, WAPDA is implementing a number of multi-purpose mega and medium water and power projects. These include hydropower generating facilities, either reservoir-based or run-of-the-river type. It has recently embarked upon a series of new hydropower projects. Keyal Khwar Hydropower (128-MW), Mohmand Dam (800-MW), Dasu Hydropower, stage-1 (2,160-MW) are under construction, whereas Diamer Basha Dam (4,500-MW), Bunji Dam (7,100-MW), Harpo Hydropower (34.5-MW), Kurram Tangi Dam, stage-1 (18.9-MW) and Tarbela 5th Extension (1,410-MW) are at advanced stages of kick-start for construction.
On the other hand, WAPDA has set as a strategic priority to carry out major renovation, refurbishing, upgrading and modernization of its existing old hydropower plants, aiming to harness optimal hydropower potential at the sites. Rehabilitation and refurbishment of Mangla power station is being implemented since 2016 though the project is far behind the schedule for completion. Now, stage is set for the construction of Warsak Rehabilitation-II project. Likewise, major repair, overhaul and rehabilitation of Tarbela power station Units 1-14 is being carried under a phased program. All these projects are being financed by the international donor agencies.
WAPDA operates a number of small hydropower stations, with cumulative capacity of over 87-MW, connected to national grid. These are Jabban (22-MW), Rasul (22-MW), Dargai (20-MW), Gomal Zam (17.4-MW), Nandipur (13.8-MW), Shadiwal (13.5-MW), Chichoki Mallian (13.2-MW), Kurram Garhi (4-MW), Renala (1.1-MW) and Chitral hydel power station (1-MW). While their share in total installed hydropower capacity at WAPDA system is just one per cent, these small hydropower stations contribute significantly towards bridging the gap of electricity demand and supply, thus reducing load-shedding, particularly during peak hours. Being connected to the national grid, these small powerhouses not only benefit the region but the entire national economy.
The economic lifetime of a hydropower plant is around 50 years, depending on operating conditions of the installed plant machinery that however needs regular maintenance, periodic overhauls and partial replacement & upgradation of equipment.
However, most of these small power stations were commissioned more than half a century ago, and have not been upgraded or refurbished since then. Therefore, these powerhouses have outlived their designed useful life since long, resulting in loss of power generation.
Nonetheless, despite their being obsolesce and operating much below their rated capacity, these small power stations generate over 300 million of units (kWh) of low-cost electricity each year. The reliability of existing electro-mechanical equipment of these powerhouses has deteriorated, and efficiency reduced from designed values and parameters of the installed equipment. To achieve high availability and reliability of operations of these old power stations, it is essential to undertake major overhaul, rehabilitation, upgrading and replacement of existing hydro-mechanical and electrical equipment. This will also result in enhancing capacity, in a few cases, and increasing profitability and long-term value of these hydropower stations—for another 30-40 years.
Modernization of these old powerhouses is required for achieving higher performance as well as for safety improvements according to international standards. WAPDA has on cards the refurbishment of its small hydropower stations since long, but due to paucity of funds and lack of interest by the government, most of these schemes could not see light of the day. On the other hand, WAPDA priority remained the completion of on-going and launching new mega projects for political gains. The first and only project implemented so far is the refurbishment of Jabban hydropower station located in Malakand District in Khyber Pakhtunkhwa that was installed sometime in 1938.
Reconstruction of the powerhouse, which was de-commissioned in 2006 as a result of a fire accident, started in February 2010. Complete power plant machinery was replaced, utilizing the existing infrastructure of transmission and dispersal of power. Four modern turbines of 5.5-MW each and allied electro-mechanical equipment have been installed, making the up-rated installed capacity to 22-MW against original 19.6-MW. The new power plant is in operation since 2014.
Meanwhile, WAPDA has finalized its program for launching refurbishment of another three small hydropower stations----Dargai, Chitral and Renala. The Dargai (Malakand-II) power station, located on Swat River, has four units of 5-MW each, and was commissioned during 1951-52. The power station is in operation and generates about 90 million kWh for national grid. It is proposed to replace all the electromechanical equipment including turbines, generators, transformers and switchyard equipment etc., which will also enhance the powerhouse capacity to 22-MW.
PC-1 of the project Rehabilitation of Dargai Hydroelectric Power Station was approved by the ECNEC (Executive Committee of the National Economic Council) in November 2018 at a cost of four billion rupees. Implementation period is estimated to be 71 months. Foreign currency portion of the project amounting to Euro 35 million is to be financed by the French Development Agency (AFD). Appointment of the Consultants is in advanced stage.
Currently, WAPDA is in the process of hiring consultants for Capacity Enhancement Project of Chitral Hydel Power station from the existing 1-MW to 5-MW. Chitral powerhouse was completed in two phases in 1975 and 1982. AFD has committed to finance the project under soft loan program.
Renala hydropower — the oldest power station in the country — was commissioned in March 1925. Located on Lower Bari Doab Canal, in Okara District, it has five turbo-generators of total 1.1-MW capacity, and all its units have been in operation since then. After rehabilitation and refurbishment, there is a potential to enhance the power station’s capacity up to 4.4-MW, utilizing full available water discharge. In fact, the existing 1.1-MW powerhouse will be maintained after rehabilitation, and a new power plant of 4.4-MW will be constructed at site.
On completion, the powerhouse will generate 25.6 GwH annually, almost four times its existing power generation. The up-rated project will also involve remodeling of existing power channel off-taking from the canal, and the construction of new spillways. For the purpose, additional land acquisition from the Government of Punjab is in process. The project’s feasibility has been finalized by WAPDA, PC-1 is approved, and financing arrangement is in hand. Total cost of the project is estimated at $16.2 million.
WAPDA also has plans to modernize and rehabilitate the 3.5-MW Kurram Garhi hydel power station which is located on Kuchkot Canal in Khyber Pakhtunkhwa, and was constructed in 1958. On completion of the project, the power house capacity will be enhanced to 5-MW, capable of generating 37 GWh energy. Consultants for detailed engineering & design and construction supervision are to be appointed shortly.
The writer is former chairman of the State Engineering Corporation