Former Soviet states, such as Tajikistan, are having to overhaul their hydroelectric plants in order to keep up with power demands. David Hayes reports
THE collapse of the Soviet Union has had a wide reaching impact on the water power and water supply industries of many former Soviet republics. More than a decade after gaining independence many of these are still making a transition from a centrally administered economy and political system, in which they were merely satellite states, to becoming independent market economies able to attract foreign investment and forge their own destinies.
For several former Soviet republics, including Tajikistan and Georgia, plans to modernise and expand their electricity industries involve a major overhaul of their water power and dam facilities due to a high dependence on hydroelectric power. Tajikistan, for example, is using a US$34M Asian Development Bank (ADB) loan to cover foreign exchange costs of rehabilitating and upgrading two major hydro power plants. Funds approved by the Manila-based ADB are also being used to reinforce the republic’s war damaged electricity transmission and distribution facilities that supply hydroelectricity throughout most parts of the country.
Tajikistan ranks among the poorest countries in the world and is the poorest of the former Soviet Union economies. According to United Nation’s statistics, 83% of the population live below the poverty line and 33% live in absolute poverty. Six years of civil conflict and natural disasters, including an earthquake in 2000, have severely damaged the energy sector’s infrastructure, particularly in rural areas that lack electric power and safe, reliable water supplies.
Tajikistan is estimated to have 527TWh of annual hydro power generation potential of which only about 19TWh, equivalent to 4%, is being used. The country’s extensive mountain ranges, including the Pamir and Fan mountains, are among the highest in the world and have a layer of glaciers that melt in the summer, resulting in a large flow of melt water of which only a small volume is currently used for hydroelectric generation. Even so, hydro power accounts for 90% of electricity generated in Tajikistan and consequently plays a major role in the economy.
According to government records, between 1995-98 melt water flows produced an average electric power generation surplus of about 4.2TWh each summer that was mostly exported to Kazakhstan, Turkmenistan and Uzbekistan. In winter, when the glaciers were frozen, Tajikistan experienced a net power supply deficit of about 1TWh. The shortfall was met by importing electricity from Kyrgyzstan, Turkmenistan and Uzbekistan.
Because of the seasonal nature of its current hydro power resources, Tajikistan depends on imported oil, gas and coal to meet its energy requirements during periods when insufficient hydro is available. As part of efforts to promote economic growth and social progress, the government aims to implement policy changes to attract private sector financing to develop the nation’s hydro power, coal, oil and gas resources.
Regional energy trade will continue to be important to Tajikistan. Due to its dependence on hydro power and neighbouring countries, the government is prioritising the negotiation of long term contracts for hydro power exports on equitable terms with traditional neighbouring hydro importing Central Asian countries.
Electricity exports can be unstable, however. From the mid-1990s to 1999, net exports of electricity fell to 0.18TWh due to a decline in electricity demand in neighbouring Central Asian countries on account of their own economic problems.
Although current annual electricity sales of about 13.5TWh are substantially below electricity demand of about 18TWh recorded in the early 1990s, electricity consumption in Tajikistan has been rising for several years as the cost of imported energy from neighbouring countries has risen towards international levels. This has caused households to switch from imported oil, gas and coal to electricity, largely generated by hydro power, for heating and cooking.
Tajikistan’s electricity industry comprises three separate power grids – the north, the south and the Gorno-Badakhshan systems. All three are operated by Barki Tajik, the state-owned power company. Barki Tajik has a combined installed power generating capacity of 4354MW of which 4000MW is hydro power capacity accounting for 92% of total capacity. The power utility’s hydro power plants generate an average of 15TWh annually, accounting for about 90% of total power output.
Barki Tajik is responsible for power generation, transmission and distribution countrywide along with heat supply to Dushanbe and Khujand. Since Tajikistan’s independence in 1992, the utility has been a state joint stock holding company and enjoys autonomous status in spite of being wholly government owned.
Under its present organisational, structure Barki Tajik consists of a network of ten subsidiary power generation companies, 11 subsidiary distribution companies and eight supporting companies including a research institute and several construction companies. The utility’s management is due to carry out a reorganisation programme in due course to corporatise and restructure the operational business units to focus on power generation, transmission and distribution.
Meanwhile, although the northern region of Tajikistan is the most industrially developed part of the country, it has only one hydro power plant. The 130MW Kairrakumskaya hydro power dam on the Syr Darya river is operated for irrigation purposes in summer to supply the agricultural water needs of Tajikistan, Kazakhstan and Uzbekistan. As the dam generates only limited power supplies during winter, Tajikistan is obliged to import electricity from Kyrgyzstan, Turkmenistan and Uzbekistan to overcome the power shortage.
Due to topographical and geographical reasons, Barki Tajik’s northern transmission grid is not connected directly to the southern grid but instead is connected to the south through neighbouring Uzbekistan’s power grid. This arrangement results in significant technical losses of electricity during transmission and expensive wheeling charges. As a result, northern Tajikistan suffers a major power deficit and depends on electricity imports from Uzbekistan.
Although a direct north-south grid interconnection would enable Barki Tajik to supply the northern region with electricity more efficiently, high mountain ranges separating the north and south regions make the construction of a direct grid interconnection difficult and expensive under present circumstances.
In contrast to the power deficient in the northern region, Barki Tajik‚s southern grid system boasts 4194MW installed generating capacity and contains most of Tajikistan’s hydroelectric dams. All major hydro power plants in the south are located on the Vaksh river.
Hydro power details
The 3000MW Nurek dam is the largest hydro dam in Central Asia and represents 69% of Barki Tajik’s total installed capacity. Constructed in stages from 1962 to 1979, Nurek dam regulates the Vaksh river flow for irrigation needs in the Amu Darya basin countries of Turkmenistan and Uzbekistan during the annual May to July agricultural growing season.
Elsewhere, Baipinskaya hydro power plant with an installed capacity of 600MW, is the second largest dam in the southern grid region and has been in operation since 1985.
Also in the south, the Vaksh river cascade of three dams, including Tajikistan’s Central hydro power dam, provides a combined total of 285MW installed capacity and has been in operation since the early 1960s. Meanwhile, the Varzob cascade in the south has three small dams and provides a combined total of 25MW installed capacity and was built between 1932-1952.
Barki Tajik’s Gorno-Badakhshan power grid is much less developed than either the northern or southern grids and serves about 220,000 people in the eastern mountainous part of Tajikistan. Consisting of several isolated network systems and a number of small and mini hydro power schemes with a combined installed capacity of about 30MW, the Gorno-Badakhshan power grid includes the 14MW Pamir One dam and the 7MW Khorog dam. Construction of the Pamir One dam was supported by the Aga Khan Foundation which in 1996 provided financial assistance amounting to US$12M for the Pamir I and II hydro power dams.
In March 2000, the Aga Khan Foundation, the International Finance Corporation and the government of Tajikistan reached agreement to establish a privately owned company to operate the 14MW Pamir II hydro station and the electricity system in Gorno-Badakhshan region under a 15 year concession.
Mini and micro potential
Mini and micro hydro power schemes also are being used to provide electricity in Gorno-Badakhshan and other regions. The Swiss Agency for Development Cooperation is supporting the Aga Khan Foundation with funding for nine micro hydro schemes in Gorno-Badakhshan, while the United Nations Office for Project Services has installed 13 micro hydro projects involving rehabilitation of war damaged infrastructure in Khatlon region, south of Dushanbe.
One major problem facing almost all electricity and other public utilities in Tajikistan and other former Soviet republics is that their infrastructure was designed and built to serve the Central Asian region rather than the individual republics. Prior to the break up of the former Soviet Union, Tajikistan’s power system was operated as part of the electricity pool of Central Asia by which Tajikistan, Kyrgyzstan, Uzbekistan, Turkmenistan and southern Kazakhstan were linked by 110kV, 220kV and 500kV transmission lines for synchronous operation.
Tajikistan supplied the Central Asian region with low cost hydroelectric power that was used for peak load capacity and reserves to regulate voltage and frequency in the region. In return Tajikistan received oil and gas imports through net resource transfer system arrangements.
Changes in trading relations and energy supply requirements among the neighbouring countries after the break up of the Soviet Union and their independence have complicated energy sector operations in the various countries. As a result Tajikistan, which used to generate about 4.2TWh of surplus during the summer, is usually not able to export all its surplus power to offset energy imports during the winter period.
The regional imbalance in electricity supply and consumption also affects other Central Asian countries. To try and rectify the situation, the ADB is providing technical assistance consultancy services to improve regional cooperation for power transfers between electricity grids of the Central Asian republics. The ongoing technical assistance programme is intended to optimise Central Asian republics‚ use of their power generation resources and improve the stability and reliability of their power systems.
While Tajikistan will benefit from improved regional cooperation in electricity supply transfers, Barki Tajik’s ADB-funded power rehabilitation scheme will provide the nation’s three power grids with a long awaited overhaul designed to upgrade power plant generation activities and revive power transmission and distribution operations.
Power shortages are commonplace today. Residential power supplies have been cut as a result of insufficient electricity supplies due to Barki Tajik prioritising supplies to industrial and agricultural sectors. Power cuts are scheduled on a rotational basis for urban and rural households, particularly during winter, due to mechanical problems affecting power plants and insufficient water supply for hydro power generation.
The recently launched power network rehabilitation project is getting underway at a critical time as power cuts have become increasingly frequent owing to a lack of spare parts and funds for maintenance.
According to the ADB, rehabilitating the Barki Tajik power networks will take five years and is due for completion by the end of 2005. Rehabilitation work on two major dams is due to begin shortly. Scheduled over 30 months, work on Nurek dam and the central hydroelectric dam on the Vaksh cascade is due for completion by mid-2004.
Plans call for Barki Tajik to rehabilitate Nurek hydro power plant and associated transmission facilities to improve the reliability of power supplies from Tajikistan’s most important power plant. In addition to being the largest hydroelectric dam in Central Asia, Nurek is the world’s largest rock filled dam.
During the Soviet era, the stability of Nurek dam was analysed on a regular basis. Although monitoring is essential for safety reasons, Barki Tajik has not been able to monitor the dam properly due to a lack of technology and equipment. The ADB project will include computer hardware, software and training to ensure the dam monitoring system is fully operational.
Siltation has been a problem at Nurek for a number of years. According to an ADB consultants report, the tailrace water head at Nurek is 6m higher than the design head, due to sediments deposited downstream from the power house. Dredging of the tailrace section of the river will be completed as part of the rehabilitation project that plans to increase power generation by 320GWh annually.
Under ADB loan conditions, the environmental impact of all project components has to be assessed and approved before loan financing can be granted. An estimated 500,000m3 to 1Mm3 of material will have to be excavated from the Nurek dam tailrace. An uninhabited unlevel area of land covering about 7ha has been identified near the project site as being suitable for disposing of material excavated from the dam tailrace.
The area of land belongs to the local government and Barki Tajik has obtained permission to use the excavated material to fill the uneven pockets. The excavated material will consist of rocks and sediments and does not present any environmental risk. Environmental benefits are expected as trees will be planted once the filled area is levelled.
Apart from the dam itself, the condition of the Nurek power house 220kV switchyard has seriously deteriorated over the past decade and requires immediate rehabilitation. According to consultants’ reports, the stability of the switchyard is threatened by large sinkholes that appeared in about 25% of the switchyard‚s area caused by deteriorating subsoil conditions.
While Barki Tajik is taking some remedial measures, the ADB project aims to provide a reliable longterm solution to stabilise the foundations in the affected areas. If the affected part of the 220kV switchyard were to collapse, two transmission lines would be disconnected resulting in a serious disruption to power supplies in Barki Tajik’s southern grid region which includes Tajikistan’s capital Dushanbe.
As part of the switchyard rehabilitation programme, the existing 29-year-old circuit breakers will be replaced with new circuit breakers that are more compact and efficient. This will help reduce the weight loading on the switchyard foundations.
Meanwhile, a significant portion of electricity generated by Nurek dam is delivered through 500kV and 220kV substations at Regar in addition to the main electricity exchange with Uzbekistan through the Central Asia transmission grid. The rehabilitation of these substations will improve the grid’s efficiency and the reliability of power supply. This will involve replacing all seven 500kV and eighteen 220kV circuit breakers, along with the 500kV capacitor couplers and voltage transformers, and protective relays.
Apart from work at Nurek dam, the ADB project also includes rehabilitating Tajikistan’s central hydro power dam, which is one of three dams in the Vaksh cascade which provide a combined total of 285MW installed capacity.
The Central dam has not been operating since about 1992 due to a lack of funds to purchase spare parts. The rehabilitation project will include reconditioning the powerhouse generators, the replacement of auxiliary equipment and the addition of a new 110kV circuit breaker.