Unveiling the Factors Affecting the Energy Generation of Hydropower Plants in Nepal

ABSTRACT: Despite having substantial hydropower potential, only a fraction of Nepal’s capacity is harnessed, with numerous plants struggling to meet their estimated energy outputs. This paper delves into the factors affecting the energy generation of hydropower plants in Nepal, a critical element in the country’s energy sector. The study identifies key factors through a series of structured interviews with industry experts, including project developers, managing directors, and CEOs of various hydropower projects. The interviews revealed four primary challenges: delays in transmission line construction, frequent transmission line outages, inadequate hydrological assessments, and internal outages due to poor maintenance practices. These factors significantly hinder the optimal performance of hydropower plants, leading to substantial energy generation shortfalls. The study underscores the urgency for formulating strategies to optimize energy production, improve reliability, attract investment, and ensure sustainable development in Nepal’s hydropower sector.
Keyword: Hydropower Potential, Energy Generation, Transmission line, Outage

1. Introduction

Hydropower is a renewable energy source that harnesses the power of moving water, typically from rivers or dams, to generate electricity. By converting the kinetic energy of flowing water into mechanical energy through turbines, which in turn drives generators, hydropower plants produce clean and sustainable energy. This form of energy generation is pivotal for reducing greenhouse gas emissions and combating climate change, making it an essential component of the global energy mix.[1]

Hydropower stands as a cornerstone in Nepal’s energy sector, harnessing the abundant water resources available due to the country’s mountainous terrain and numerous rivers. As of recent years, hydropower contributes to more than 90% of Nepal’s total electricity generation, making it a critical component of the nation’s energy infrastructure.[2] Nepal has an estimated hydropower potential of approximately 83,000 MW. The economically viable potential is estimated at around 42,000 MW of which only around 2,684 MW has been developed and connected to the national grid.[3] Despite the extensive utilization of hydropower, several factors affecting the efficiency and consistency of energy generation in these plants remain insufficiently explored. Existing studies have primarily focused on the technical aspects, such as turbine efficiency, dam design, and water flow management.[4]

Focusing on the challenges faced by hydropower plants in Nepal is crucial for several reasons. First, understanding these challenges can help in formulating strategies to optimize energy production and improve the reliability of hydropower as a renewable energy source. Second, addressing these issues is essential for attracting investment in the sector, which is critical for scaling up capacity to mitigate energy demands. Lastly, improving the performance of hydropower plants can greatly help in developing skills and introducing new technologies in the sector.[5]This paper aims to investigate the obstacles encountered by operating hydropower plants in Nepal in meeting their estimated energy. The study will be conducted through a series of interviews with project developers, providing an in-depth perspective on the operational, technical, and environmental challenges. By gathering insights directly from those involved in the development and management of hydropower projects, this paper seeks to offer a comprehensive understanding and identification of the issues so that a foundation can be laid for reasonable solutions in the near future. 

2. Data Sources

The data for this paper was collected through a combination of primary and secondary sources, ensuring a comprehensive understanding of the factors affecting the annually estimated energy of hydropower plants in Nepal. Detailed questionnaires were developed to conduct interviews.

The primary sources of data include structured interviews with hydropower developers, consulting engineers, CEOs of hydropower companies and plant managers. The interviews aimed to gather insights and relevant data into the operational challenges, strategic decisions, and technical factors that play a key role in hydropower plants not being able to meet their average estimated energy annually. A comprehensive and consistent questionnaire was prepared, focusing on the technical and managerial aspects of hydropower production. The information and responses obtained from the interview are checked and verified with the company’s monthly produced data.

The secondary sources of data were based on research papers and online data. A thorough review of various research papers was conducted. These papers and journals provided theoretical foundations relevant to hydropower production optimization. Data published by the Nepal Electricity Authority (NEA) and academic sources were accessed. Similarly, official reports and publications from the Ministry of Energy, Water Resources, and Irrigation of Nepal were reviewed. These reports offered valuable data on Nepal’s hydropower potential, project status, and regulatory requirements.

3. Results 
The responses obtained from the interviews revealed four key factors affecting the energy generation of hydropower plants in Nepal, which are thoroughly detailed below: 

a. Delay in construction of transmission line: 
Numerous hydropower projects in Nepal face significant challenges due to the incomplete construction of transmission lines by the Nepal Electricity Authority (NEA), as stipulated or planned in the connection agreement. The development of transmission lines in Nepal is not keeping up with the rapid pace of the hydropower project’s construction schedule. This delay in infrastructure development prevented many hydropower plants from reaching their annual energy production targets. As a result, these projects were only able to generate between 30% and 70% of their total potential energy output, leading to substantial financial loss to the developer (company). For instance, among the most affected were:

1. Sipring Khola Hydropower Project (9.96 MW) (delay in construction of 132 kV Barabise-Singati line in 2076/77 BS)

 2. Tungun-Thosne Khola (4.36 MW) (Malta-Matatirtha 33 kV line in 2076/77 BS)

 3. Khani Khola Hydropower Project (2 MW) (Malta-Matatirtha 33 kV line in 2076/77 BS)

There are several projects on the Marsyandi, Dordi, and Nyadi-Khudi rivers having a combined potential of more than 500 MW which were to be evacuated through Udipur-Bharatpur transmission line. Their present status is:

1. 220/400 kV Udipur-Khudi Hub substation is still under construction. So, the operating projects in this area are currently running in “Contingency condition” i.e. based on dispatch instruction from LDC (Load Dispatch Centre).

 2. Udipur-Khudi transmission line section is still under construction.

3. Udipur-Markichok-Bharatpur 220 kV transmission line has not been constructed yet.

These lines were to be constructed and connected by the year 2021 AD but are still under construction and showing slow progress but the projects which were planned to evacuate through these lines have already been established and not being able to generate to their maximum potential. In some areas like Karnali, due to the delay in the construction of the transmission line, many project developers are hesitant to start or continue with the construction work. Some possible causes of delay in construction are: 
• Delay in approval from the Ministry of Forest (Right of Way problems). 
• Local and political issues. 

A particular case in point is Upper-Syange in which the local dispatcher is forced to generate “0 MW dispatching” during the wet season due to transmission line constraints. The contract conditions in the PPA (power purchase agreement) which is on a “Take or Pay” basis are violated. Similar to this, 49 projects are operating in take and pay basis. So, unless transmission lines and substations are completed in time, the energy to be generated by around 800-1200MW every year during the wet season is being spilled. The major spill is observed during July, August and September. 

b. Transmission line outage: 

In electricity buying-selling negotiation (PPA drafting), normally, 3-5% of transmission outages are envisioned for large to small hydropower projects. However, power outages in lines with a capacity of 33 kV or less; have recorded a high percentage of outages due to the following reasons: 
• Overload and insulation failure
• Poor construction standard of transmission lines resulting in frequent damage to hardware and structures due to external causes
• Delay in maintenance of lines caused by external fault 
• Exceeding the standard length or distance of the transmission line 

Due to delay in construction of Udipur-Khudi transmission section, Radhi Khola (4.4 MW), Siuri Khola (5 MW), Khudi HPP (4 MW), Upper-Syange (2.4 MW), Chhangdi 1 & 2 (6 MW) and other projects are connected to 33 kV Damauli-Udipur-Chame line resulting in overload and overvoltage causing high transmission outage experiencing number of tripping. 

c. Hydrological Assessment 

Operating a power plant requires a designed water flow. The projects so far designed/licensed are “run-of-river” and “peaking run-of-river” type hydropower plants. The natural flow of water is estimated with sufficient historical data to study the flow patterns. For dependable technical assessments in hydrology, it is essential to consider at least 30 years of data on flow patterns during wet and dry seasons before predicting a river’s energy generation potential. However, for small rivers in Nepal, there is a lack of adequate hydrological and meteorological data. Most of the projects are developed from the ungauged river. So, the developers have unfortunately relied only on their 3-5 years of monthly data, leading to inaccurate hydrological predictions and a failure to meet the declared energy output.

The Department of Electricity Development (DoED) emphasizes that project designers should adhere to specific guidelines for predicting hydrology using software like the Hydest, Modified Hydest, MHSP 1997, Modified Dickens, PCJ, Rational and Specific discharge method, among others. While these methods suggest higher project capacities, during operation they often fail to generate the expected energy, resulting in unmet estimated energy targets. Consequently, the accuracy of these proposed guidelines is being questioned. Many projects fall short, producing less energy than anticipated. Moreover, with increasing global warming and climate change, the level of water is also decreasing every year. 

d. Operation management and maintenance issues (internal outage): 

Hydropower plants that have been operational for a long time often begin to show signs of aging, necessitating thorough maintenance and the replacement of worn-out components when necessary. A major challenge in maintaining the projected energy output is the lack of a well-structured maintenance plan. Manufacturers set maintenance requirements based on the equipment’s intended use and service life, and these cannot be replaced by regulatory maintenance guidelines. However, many power plants in Nepal have failed to carry out timely maintenance, or any maintenance at all in some cases. This negligence has resulted in decreased efficiency, performance, and capacity.

For hydropower plants operating for over 5-6 years, capital maintenance becomes necessary. This process involves stripping down the entire system and replacing worn-out or defective components as needed. The plant is then recommissioned according to the original commissioning practices. In Nepal, hydropower equipment is sourced from other countries, requiring meticulous tracking of maintenance schedules to ensure the timely availability of spare parts. However, due to the negligence of operators and developers, this tracking has been poorly managed, leading to equipment failures without available spare parts and ultimately poor performance with lower energy generation.

Additionally, Nepal has limited service providers and lacks appropriate training for operators. Many projects in Nepal are commissioned on a “water-to-wire” basis from countries like India and China. Due to the lack of technical manpower and the manufacturing industry in this sector, many projects face maintenance challenges, resulting in power plant shutdowns for months or even years.

4. Discussion 

The detailed interviews revealed critical factors such as delays in transmission line construction, transmission line outages, inadequate hydrological assessment, and internal outages due to poor maintenance practices and operation management.

The delay in constructing transmission lines exhibited a significant barrier to the optimal performance of hydropower projects. The Udipur-Markichok-Bharatpur 220 kV transmission line which was supposed to be completed by 2020 has not been completed yet due to the slow work progress of the contractor, and the delay in cutting down of trees that fall under the alignment of the transmission line. [6] The construction work of the 30 MW Khani Khola Hydroelectric Project in Dolakha is facing delays due to the incomplete construction work of the 16 km long transmission line running from Singati to the project’s powerhouse which was originally set for completion in September of 2023.[7]

The transmission line outages further complicate the situation, particularly for lines with a capacity of 33 kV. According to the report published by the Ministry of Energy in 2077 BS, of 35 private small hydropower projects, projects with more than 5% outage were found to be 15, from available data, and the maximum outage recorded was 40% of Puwa Khola HEP.[8]

Hydrological assessment inaccuracies posed another substantial challenge. According to the report of MOE, 2077 BS, out of 35 only 2 projects recorded less than 10% of hydrological issues and the remaining recorded 20-30% of hydrological issues with maximum of 30.2% of Mailung Khola HEP. [8] The NEA’s hydropower plants also generated only 2,930 GWh of electricity in FY 2022/23, a 10.10% decrease compared to the highest recorded annual energy of 3,259 GWh in FY 2021/22. This reduction was primarily due to the unexpected decrease in river discharge during the dry season months due to climate change.[3] This trend underscores the importance of long-term, accurate hydrological studies and adaptive planning to address the impacts of climate change on water resources.

Internal outages due to aging infrastructure and inadequate maintenance practices further exacerbate the challenges faced by hydropower plants. The MOE report indicates that 15 out of 35 projects experienced internal outage rates of 5 or less, while 20 projects had rates exceeding 5%, with Upper Hadi Khola HEP recording the highest at 13%.[8]

5. Conclusion 

The investigation into the operational challenges faced by hydropower plants in Nepal reveals critical insights into the factors hindering optimal energy production. All interviewees, 100%, identified that the availability of transmission lines and substations as the predominant issue impacting energy generation. Additionally, 75% of the interviewees mentioned hydrological issues as significant, while 50% highlighted transmission line outages/non-dispatch spills, and 50% pointed to internal outages as contributory factors. These findings underscore the major need for infrastructural improvements in transmission line construction and better resource management to enhance the reliability and efficiency of hydropower plants in Nepal.

While 75% of the respondents were very adamant that hydrology contributes as a significant factor, 2 out of 8 i.e. 25% mentioned that hydrology is inherently influenced by natural phenomena and global warming worsens these challenges which are beyond our control, ultimately resulting in lower energy generation. Then 62.5% of the respondents mentioned that transmission line outage plays a significant role in insufficient energy generation. Finally, only 50% mentioned that due to the unavailability of the manufacturing industry in this sector, technical manpower lacks “know-how” resulting in unmanaged or inadequate operation management and maintenance issues.

The study’s reliance on interviews with only eight participants may not capture the full range of perspectives and experiences within Nepal’s hydropower sector. A larger sample size could offer a more thorough understanding of the issues. The responses are subjective and may be influenced by personal biases. Additionally, the varied expertise and focus areas of the interviewees might lead to an incomplete or unbalanced view of the factors affecting energy generation. The factors affecting energy generation are dynamic and can change over time due to policy changes, technological advancements, and environmental conditions. The insights gathered from the interviews reflect the situation at a specific point in time and may not capture future developments or past trends comprehensively.

Thus, addressing these multifaceted challenges requires a comprehensive approach that includes improving infrastructure development timelines, enhancing hydrological assessment accuracy, implementing rigorous maintenance strategies, and resolving external impediments through better policy frameworks. Only through such coordinated efforts can Nepal’s hydropower projects achieve their full energy generation potential and contribute effectively to the nation’s energy security and economic growth.

6. References

1. International Hydropower Association, “World Hydropower Outlook,” International Hydropower Association, 2023.

2. Nepal Electricity Authority, “Annual Report 2021/2022,” Nepal Electricity Authority., Kathmandu, 2022.

3. Nepal Electricity Authority , “Annual Report 2022/2023,” Nepal Electricity Authority , Kathmandu, 2023.

4. S. S. R. &. D. S. Khanal, “Technical Efficiency of Hydropower Plants in Nepal: A Data Envelopment Analysis,” Energy Economics, pp. 81, 55-67, 2019.

5. M. Shrestha, “Prospects of Hydropower in Nepal: Challenges and Opportunities,” Renewable Energy, pp. 150, 29-37, 2020.

6. “Urja Khabar,” 15 February 2023. [Online]. Available: https://www.urjakhabar.com/en/news/1502542042.

7. “RepublicaNepal,” 1 April 2024. [Online]. Available: https://myrepublica.nagariknetwork.com/news/construction delay hits khani-khola-hydropower project-due-to-incomplete-transmission-line/.

8. “निजी क्षेत्रबाट संचालन भएका आर्थिक रूपले सङ्कटग्रस्थ जलविद्युत आयोजनाका समस्या सम्बन्धमा अध्ययन गर्न गठित समितीको प्रतिवेदन,” २०७७ असार ३१।

Interview Questions: 

1. What do you recognize as the primary factors contributing to the inability of hydropower plants in Nepal to meet their energy generation targets?
2. What is your opinion on:
a. What are the underlying causes of these challenges? 
b. To what extent do you believe these issues stem from the internal management practices of the hydropower companies versus external factors such as governmental support and regulatory frameworks?

The Writer of this article is a graduates (BE Industrial Engineering) from Thapathali Campus, Institute of Engineering. This article is taken from the 6th issue of urja khabar, a bi-annual magazine. Which was published on 15 june, 2024.