Hydropower development along Teesta river basin: opportunities for cooperation

The aim of this research is to examine the hydropower development potentials and identifying major hydropower projects along the Teesta river basin that is shared by Bangladesh and India. The upstream of Teesta river basin is located mostly in hilly areas of Sikkim where India plans to produce electricity of over 6,500 MW by developing the hydropower potential of the basin. The downstream basin is densely populated, mostly flat land and has no hydropower potential. As of today, Bangladesh and India have been unable to agree on an integrated development plan for the Teesta river basin. Previous negotiations on Teesta river basin management have focused only on sharing water rather than sharing the wide range of benefits from water resources including hydropower. This paper identified the existing, ongoing and upcoming hydropower development projects. The hydropower sharing opportunity exists between the two riparian countries and this type of natural resource development could reduce economic tensions and provide a platform for sustainable agreements.


Introduction
In many parts of the world, the international political boundaries were drawn without considering the watercourses and basins. Presently, about 261 rivers are being used by two or more sovereign entities. Transboundary river basins cover about 45% of the total Earth surface shared by 145 countries (Tiwary, 2006). The Teesta is a transboundary river shared by Bangladesh and India, which has a steep slope and high seasonal flow variability. Flash flooding occurs from May to September during the monsoon

Data and information sources
Primary data have been collected from relevant government reports of Bangladesh and India, official websites of government organizations of Bangladesh and India and other international organizations (e.g., World Bank, International Energy Agency, etc.). Secondary data have been collected from various international, national and local organizations as well as published articles, books, documents and reports. The data of hydropower projects have been collected and cross-matched from CEA (2016), EDPS (2019), India-WRIS WebGIS (2018), NHPC (2019) and NTPC (2019). To improve the accuracy of the schematic diagram of the Teesta river system (Supplementary material, Figure A1) and the locations of the hydropower projects, data have been collected from several sources, e.g., EnvIS (2019), BWBD (2011), SANDRP (2019), etc. Great emphasis has been placed on the accuracy and reliability of the data.

Major human interventions along the Teesta river basin
From the earliest civilizations, river basins have played a vital role in sustaining communities, economic and social development, and also the accessibility and dependability of water. Human intervention along the river basin is a common issue for this era. When a river crosses two or more countries, the situation could become worse (cf., Rahaman, 2009a;Rahaman & Varis, 2009). Riparian countries have tried to use the water of the river for electricity generation, irrigation, drinking purposes and to serve other needs. The situation of the Teesta river basin of South Asia is no exception.
The Teesta river is prone to flash flooding which contributes a huge amount of sediment and water every year to the huge Brahmaputra river. However, a vast area of the northern part of Bangladesh suffers from a scarcity of water for irrigating agricultural land throughout the year, even during the monsoon. In an effort to resolve the water scarcity, the idea of gravity irrigation with water from the Teesta river was conceived in 1945 during British rule. After achieving independence, the government of Pakistan finished the feasibility survey and took an initiative to start this irrigation project. According to the Project Proforma (PP) of Teesta Barrage Project, the proposed date of commencement was 1960/ 61. After the independence of Bangladesh, the engineers of Bangladesh Water Development Board (BWDB) and Bangladesh University of Engineering and Technology (BUET) reviewed the previous feasibility survey and redesigned the project and selected Doani, Nilphamari for the barrage (BWBD, 1990). The construction of the barrage was started in 1979 and completed in 1992. Phase-I of the Teesta Barrage Project was completed in 1998, and was located 20 km south of the border with India . The total command area of Phase-I and Phase-II of the Teesta Barrage Project are about 111,406  hectares and 448,774 hectares, respectively. The construction of Phase-II began in 2005, but due to insufficient water flow in the non-monsoon period, the project is still incomplete (Wirsing & Jasparro, 2007). The Government of West Bengal planned the Teesta Barrage Project at Gajaldoba in 1975/76 to create new irrigable land in six northern districts of West Bengal, supply drinking water to Shiliguri municipality and generating hydropower. This is one of the largest irrigation projects of the northeastern region of India. The Teesta Barrage Project was under the Accelerated Irrigation Benefit Program (AIBP) of India and the funding proportion varied from 1:1 to 1:3 (Central:State). The project has three different phases: the target for the first phase is irrigating 922,000 hectares of land, generating 650 MW of electricity in the second phase and finally linking the Ganga and Brahmaputra together in the third phase. The first phase consists of three stages: to irrigate 545,000 hectares of land under the first stage, 223,000 hectares of land under the second stage and 153,000 hectares of land under the third stage (Mukherjee & Saha, 2016). The Central Water Commission (CWC) finalized the estimated cost for the Teesta Barrage Project in the first phase, first stage, first sub-stage as Rs. 2,988.61 Crore in 2008, which was about Rs. 69.72 Crore at the time of commissioning in 1975 (IWD, 2019). The expected completion time for the first phase was March 2015 but the construction is still ongoing.
In 1983, an ad-hoc agreement was signed between Bangladesh and India. According to that agreement, India and Bangladesh share 39% and 36% of water, respectively. The remaining 25% of water was allocated for the environment. The 1983 ad-hoc agreement was extended until 1987, but the governments of Bangladesh and India were unable to sign any treaty over sharing of water of the Teesta river. As well, India took initiatives for inter-basin water transfer projects that could increase the water scarcity of Bangladesh during the non-monsoon season (Abbas, 1984;Nishat & Faisal, 2000;Rahaman & Varis, 2009). Through the Brahmaputra-Ganges link canal, known as Jogighopa-Teesta-Farakka, India plans to create a series of dams to divert water from the Brahmaputra through the Jogigopa barrage in Assam to the Ganges at Farakka via the Teesta river (Rahaman, 2009a;Rasul, 2014).
The following section discusses hydropower development in the Teesta river basin in detail.

Hydropower development along Teesta river basin
In 2004, the Central Electricity Authority of India prepared a preliminary feasibility report of 162 new hydroelectric schemes with a total potential of over 50,000 MW, where Sikkim has ten schemes with an installed capacity of 1,469 MW (CEA, 2015). In 1974, a committee was formed to study the hydropower potential in Sikkim. Sikkim welcomes private developers for developing and exploiting its hydropower potential, which has been assessed as 8,000 MW peak with a firm base of 3,000 MW. Total hydropower potential in the state so far is 5,352.7 MW and there are different stages of implementation (EPDS, 2019).
About 47 hydropower development projects are in different stages. Existing hydropower projects in the Teesta river basin of Sikkim and West Bengal are listed in Table 2. Currently, 15 hydropower development projects are at different construction stages. According to the Draft National Electricity Plan 2018, all of these projects will be completed by 2022. The present status of all ongoing projects is listed in Table 3. The hydropower development projects which have faced financial issues or are in the planning phase are listed in Table 4.
The locations of hydropower development projects are shown in Figure 2. Figure 2 reveals that the majority of the hydropower development projects are located in the northern part of Sikkim, India. In Sikkim, some projects have been cancelled as they are located in areas in the vicinity of Kanchanjonga National Park. Since 1995, because of the anti-dam movement, Sikkim's government has cancelled at least eight dam projects (Bosoni, 2017). Rammam II, Teesta Low Dam III and Teesta Low Dam IV are the major hydropower development projects of West Bengal. The West Bengal government signed a Memorandum of Understanding (MoU) with National Hydroelectric Power Corporation (NHPC) in 2015 for constructing Ramman I, Teesta Lower Dam I and II (combined) and Teesta Lower Dam IV.

Concerns for future electricity demand: Bangladesh and India
As of 2014, the electricity consumption per capita of Bangladesh and India is about 311 KWh and 806 KWh, respectively (WB, 2018a). As both countries are part of the developing world, the consumption of electricity increases rapidly (Table 5). In every five years, the percentage of increased electricity consumption varies from 120% to 135% from the previous five years. To fulfil the increasing demand, both countries have undertaken several initiatives.
In 2017, the electricity production of Bangladesh and India was about 57.28 TWh and 1,206.31 TWh (Table 6). Currently, the main source of electricity production in Bangladesh is gas (53.48%) (BPDB, 2019). On the other hand, India depends on coal (54.3%) based power plants (MoP, 2019). India has taken some initiatives to switch their main source of electricity from coal to renewable energy (hydropower, wind, solar, etc.) to fulfil the future demand for electricity. About 47 major hydropower projects (each above 25 MW) throughout India are under construction. It is expected that these projects will contribute to around 14,000 MW additional electricity in the Indian national grid by 2022 (CEA, 2019).
Bangladesh has a GDP growth rate of 8.13 in the economic year 2018/19 (BBS, 2018). High GDP growth rate means more development and purchasing power, which indicates the rapidly increasing demand for electricity. The government of Bangladesh expects that electricity generation capacity will be 16,495 MW by 2020 (BPDB, 2018). However, the electricity demand of Bangladesh will be 66,804 MW by 2030 and the gap between electricity demand and generation capacity will be 50,309 MW (Mondal et al., 2010).  Mondal et al. (2010) forecasted that the electricity demand of Bangladesh will be 131.58 TWh by 2035 in a low GDP growth scenario which is about eight times higher than the electricity consumption of 2005. In the average and high GDP growth scenarios, the demand will increase by about 11 to 16   (Table 7). Bangladesh has a natural gas reserve of 27.12 TCF (trillion cubic feet) and, unfortunately, about 15.22 TCF of gas has already been used by the end of 2017. To meet the future electricity demand, regional hydropower cooperation is needed.

Cooperation: hydropower trade in South Asia
There are very few electricity trade agreements among South Asian countries (see Table 8). Bangladesh and India have an agreement to share electricity from India to Bangladesh that includes about 500 MW electricity, which could be extended up to 1,000 MW. Under the CASA-1000 project, Afghanistan and Pakistan have imported electricity from Central Asia. The transmission line of CASA could be extended up to India and Bangladesh. After fulfilling its own demands, Bhutan exports about 75% of its total electricity generation to India (Singh, 2013). India has invested in several power projects in Bhutan. Under the agreement between Bhutan and India, India committed to importing a minimum of 5,000 MW electricity from Bhutan (Singh et al., 2015). Under a high growth scenario, by 2027, the power development projects of Nepal will earn huge revenues by developing a total hydropower capacity of 22,000 MW, including 15,000 MW for exports (Srivastava & Misra, 2007). Sri Lanka is expected to import around 1,000 MW of electricity from India.

Why hydropower sharing (India-Bangladesh) in the Teesta river basin?
Hydropower sharing between Bangladesh and the state of Sikkim, India, in the Teesta river basin, India could be beneficial for both countries for the following reasons: • The electricity demand of the state of Sikkim, India, is about 264.7 kWh per capita (as of 2016/17) (EnvIS, 2019). It is expected that by 2022, the hydropower projects that are under construction and under survey and investigation will be completed (Table 2 and CEA, 2016). This will add about 3,500 MW of electricity to their grid. After fulfilling the state of Sikkim's local demands, India could export electricity, which could give a strong base to the economy of Sikkim.
• Due to close proximity, exporting electricity from the Teesta river basin to Nepal, Bhutan and Bangladesh is feasible for the state of Sikkim. However, Bhutan already exports electricity and Nepal is also expected to be an electricity exporter by 2022. Hence, exporting hydropower to Bangladesh is the most feasible option for Sikkim.
• According to international law, as a riparian of the Teesta river basin, Bangladesh deserves first priority to import hydropower from the state of Sikkim, India (Helsinki Rules, 1966).
• Government of the state of Sikkim, India, aims to export hydropower to Bangladesh. The Power Trading Corporation (PTC) has been tasked to explore possibilities for exporting electricity to Bangladesh from Teesta III (1,200 MW) hydropower project (Dahal, 2016). Sikkim could export the generated hydropower for a negotiable rate to downstream Bangladesh that could help to ensure the energy security in the basin.   • This is an excellent opportunity for Bangladesh to improve existing capacities and use clean energy to meet the climate change and other environmental targets. It could reduce tension due to future demands of electricity in Bangladesh.

Potential benefits from coordinated development: Teesta river basin
In the past, river basin management was looked after by hydraulic engineers, who managed the river for a single purpose only, such as navigation or hydropower. Nowadays, river basin management is often based on multi-purpose uses and basin-wide approach and involves many more actors (Ridder et al., 2005). Coordinated development of the Teesta river basin can change the present scenarios and reduce tension for both Bangladesh and India by reducing water-related tension, increasing irrigation, food security and energy security that could also potentially open a new path of broader water cooperation in other river basins in South Asia. Below these potential benefits are summarized.

Optimal water sharing: reducing tension
Bangladesh and India have negotiated several times to sign a treaty to solve the Teesta river dispute. Most recently, in 2011, the governments of Bangladesh and India were supposed to sign a 15-year interim deal in a water sharing ratio of 37.5% (Bangladesh):45.5% (India). However, the state government of West Bengal and Sikkim of India opposed the interim deal and since then the deal remains unsigned (Salman & Uprety, 2018).
In most cases, the upper riparian of an international river basin has tended to prefer the 'Harmon Doctrine' or 'theory of absolute territorial sovereignty' that claims every nation can utilize the waters of an international river flowing through its territory, as it likes; whereas the downstream riparian countries tend to favour the 'theory of absolute territorial integrity' that ensures the right to claim the continued and uninterrupted flow of water from the territory of the upper riparian (Wolf, 2007;Rahaman, 2009b; Melesse et al., 2014). But, until now, all the disputes that have been solved are not rights based, but needs based (e.g., irrigable lands, population or specific projects). For example, the Nile River Treaty (1929 and 1959) was based on existing uses and development projects; the Johnston Accord (1956) of the Jordan river was based on irrigable land in the riparian countries; the Israel-Palestinian shared aquifers Interim Agreement (1995) was also based on population pattern and irrigation need; the Indus river treaty (1960) has provided a framework for irrigation and hydropower development (Wolf, 2007;WB, 2018b). In 1961, Canada and the USA signed a treaty to share benefits of the Columbia river which could be an excellent example for Teesta river cooperation. Canada has storage tanks in the upstream and USA has developed flood control systems and hydropower dams in the downstream and both countries share benefits equally (Krutilla, 1969;Islam & Higano, 2001). An optimal benefit sharing treaty based on needs over the Teesta river basin could reduce water and energy scarcity and increase food security.

Increasing irrigation and food security
The riparian people of the lower Teesta basin are economically affected due to the rising cost of groundwater lifting and rising installation cost of deep tubewell compared to past years as a result of the declining groundwater table. The declining groundwater table has also created water quality problems in the lower Teesta basin (e.g., Lalmonirhat, Rangpur and Nilphamari districts of Bangladesh) (Raihan et al., 2017). A cooperative development of the Teesta river basin could ensure the water for cultivation of about 750,000 hectares in the lower Teesta basin in Bangladesh and about 922,000 hectares in the upper Teesta basin in India (Mukherjee & Saha, 2016;Islam, 2016). Irrigated crops from both Teesta barrage projects located in Bangladesh and India (see Figures 1 and 2) could be shared to fulfil the needs of the riparian people of the Teesta river.

Regional energy security: New path for broader cooperation
Bangladesh and Sikkim (India) could develop hydropower in a cooperative manner following the example of India-Bhutan cross-border electricity trade. With financial assistance and cooperation from India, Bhutan has developed several hydropower projects and is exporting hydropower to India. India has invested, as loans, about 57 billion INR and 88% of the investment is targeted at the development of the power sector of Bhutan. Under the existing agreements between India and Bhutan, around 10,000 MW hydropower will be produced in Bhutan by 2020 (Tortajada & Saklani, 2018). Hydropower cooperation over the Teesta river basin could also open the door for cross-border electricity trade of Bangladesh-Bhutan by following the same pattern as the Bhutan-India hydropower cooperation.
The Teesta dispute is a bilateral issue of Bangladesh and India and if the cooperation along the Teesta becomes successful, it could enhance the possibility of broader multilateral water and hydropower cooperation in the Brahmaputra basin (Bangladesh-China-India-Bhutan) and Ganges river basin (Bangladesh-India-Nepal) (cf., Rahaman & Varis, 2009;Rahaman, 2012) (see Table 9).

Conclusion and recommendations
This paper assessed the present condition of hydropower development within the Teesta river basin. The total hydropower potential of the basin is over 8,000 MW, mostly located in the states of Sikkim and West Bengal of India. Currently, a total of 47 hydropower projects of Sikkim and West Bengal within the Teesta river basin are in different stages and have a total installed capacity of around 6,753.5 MW (see Tables 2-4). The governments of the states of Sikkim and West Bengal, India, are taking numerous initiatives to explore more hydropower potential within the Teesta river basin.
Hydropower plays an important role in achieving Goal 7 of the Sustainable Development Goals (SDGs), which has a target to ensure universal access to affordable, reliable and modern energy services by 2030 (Target 7.1) (UN, 2015). Hydropower is an affordable, reliable, sustainable and modern technology that can help the communities or regions to acquire a reliable supply of electricity. Coordinated hydropower development could increase the access to electricity at an affordable rate and, in turn, help the countries to achieve target 7.1 of SDG 7. As SDG 7 is closely interlinked with SDG 6 (Clean Water and Sanitation) and SDG 13 (Climate Action) (UNFCC, 2018), coordinated hydropower development in the Teesta basin could also help both countries to mitigate the challenges related to climate change (e.g., reducing greenhouse gas emissions).
To have an effective hydropower sharing agreement, the governments of Bangladesh and India should consider the following issues: • After fulfilling its own electricity demand, the state government of Sikkim could export electricity to Bangladesh which would improve the economic condition of Sikkim.
• The state of Sikkim, India, should have a clear policy to export hydropower to Bangladesh.
• The cost of electricity should be based on market price, which will ensure both parties are in a winwin condition.
• Agreement should be for the longer term as short-term agreement often does not produce effective cooperation due to lack of continuous commitment.
• The socio-economic and socio-political conditions of both countries should be considered. • A feasibility study should be conducted, which will reduce the risks to financial investment, environment and society.
Management of transboundary water resources has evolved gradually according to changing social needs, increasing demands for water resources and climatic effects. Bangladesh and India already have an agreement for electricity sharing (see Table 8). The effectiveness of the agreement could influence the future hydropower sharing opportunities between Bangladesh and India. The findings of this study should be carefully interpreted. If political leadership shows a strong will and strengthens regional cooperation and electricity trade, hydropower development along the Teesta river basin could significantly contribute to economic development in the riparian countries, i.e., Bangladesh and India.

Supplementary material
The Supplementary Material for this paper is available online at https://dx.doi.org/10.2166/wp.2020. 136.