The sun powers the hydrologic cycle which provides water to the earth. The power of the sun and water are synchronous, and the electricity we harvest from the sun (solar power) and water (hydropower) complement each other. However, in Nepal, there is much resistance from policymakers and policy implementors against solar power and other non-hydro forms of energy for fear of disrupting the current regime. While companies are struggling to interconnect large-scale solar plants and industrial rooftop solar, the Nepal Electricity Authority (NEA) is reverting to importing power from India generated from dirty resources, i.e., coal and oil. The secretive nature of the price per kWh at which NEA imports dirty electricity is a reason to be wary of its intentions. Given its current and future power generation capacity, Nepal will import electricity from India, especially during the dry months.

Solar power can complement hydropower to help fulfil seasonal/daily electricity requirements and reduce reliance on electricity imports. This will eventually allow Nepal to achieve its long-term net zero emissions goal, which should be a national priority.

Nepal produced surplus energy this past wet season and successfully exported electricity to India worth Rs10.38 billion. As per the managing director of NEA, Kul Man Ghishing, the authority targets to sell electricity worth over Rs30 billion to the Indian market in 2023-24. If NEA’s strategy is built around selling electricity to India, why rely on a single generation source? Diversifying the generation mix will allow NEA to sell in various seasons and at different hours of day. Solar generates less during the wet season and more during the dry season which compensates for less hydro generation during the dry season. Nepal has only one 100 percent storage hydro in Kulekhani with a capacity of 92 megawatts and a few large hydros with peak capacity (PROR) of approximately four hours storage capacity in full power in the Upper Tamakoshi, Kali Gandaki, Middle Marshyangdi and Lower Marshyangdi. The limited readily available stored power that can be dispatched as required is a major constraint for any power grid operator. As a result, NEA must revert to imports and even load-shedding during peak hours. Imports aren’t always reliable. For instance, this winter, as some thermal plants in Bihar failed, NEA was forced to shed load in many industrial belts across Nepal.

Floating solar

NEA has considered different technologies for years, with battery storage and hydrogen technologies, in particular, gaining popularity on paper. As a monopoly and a vertically integrated utility, NEA’s reluctance to introduce and scale newer technology does not come as a surprise. But technologies such as floating solar photovoltaic (FSPV) that would complement the existing hydropower plants have not been considered. Floating solar could be instrumental in increasing the much-needed storage capacity for Kulekhani and other large peak run of the river hydropower plants in Nepal.

One MWp of floating hydro could prevent water evaporation loss of 8000-metre cube per year. If 50 percent of the area is utilised for FSPV in Kulekhani dam, it could install approximately 100 megawatts conserving 800,000-metre cubes of water annually. In short, with a 100 megawatts FSPV, the total generation capacity of Kulekhani would go from 315 GWh per year to 461 GWh per year (an increase of 146 GWh). The added 40 percent generation capacity would dramatically help Kulekhani maximise its much-needed storage capacity to manage intra-day peak and seasonal variance. If a few large PROR hydros add FSPV to their generation mix, NEA would significantly decrease its reliance on imported electricity. A feasibility study on FSPV for Kulekhani published in 2019 needs to be updated to better reflect today’s context. Hence, the NEA should shortlist the top 10 peak run of the river hydros and conduct a detailed feasibility study to implement FSPV if feasible from multiple perspectives, including economic, energy independence, strategic etc.

Studies conducted in various regions of the world have shown great potential for floating solar photovoltaic (FSPV) and hydropower hybrid systems. Gonzales et al.’s study in Africa has shown a generation increase of up to 58 percent of hydropower plants by implementing FSPV in existing hydropower plants. The existing transmission infrastructure in the hydropower plants significantly decreases power evacuation risk and financial loss faced by standalone solar power systems. The water helps cool the solar panels, maximising generation, and FSPV also avoids using fertile cultivatable land typically used for land-based solar systems. The intermittent nature of solar generation is instantaneously balanced by constant and reliable generation from the hydropower plant. The FSPV will generate maximum electricity during the daytime, which will help the hydro plant store water to be used during the evenings and mornings peak when the solar system is not active. Similarly, both generators will complement each other to manage the wet and the dry season variances.

The argument is not against land-based solar power plants or any other technology. Nepal needs generation diversification as well as massive storage capacity in the form of battery energy storage systems and hydrogen storage. But implementing floating solar photovoltaic (FSPV) is an obvious solution in the short run, a low-hanging fruit. The implementation timeline and investment requirements are favourable for the implementation of FSPV. NEA has full ownership of the Kulekhani hydropower plant and many other large peak run of the river hydropower plants. Therefore, multiple modalities could be adopted by NEA to add FSPV to these hydropower plants. With sufficient financial and technical resources, NEA could implement FSPV independently. Otherwise, a private-public partnership model with an interested private sector could also be adopted. Alternatively, since the NEA is going public soon, it could invest in FSPV using initial public offering funds.

A good case study for the NEA is the floating solar photovoltaic (FSPV) installed in the Da Mi Hydro Power Plant reservoir in Vietnam. Da Mi hydropower plant is owned by DHD, a Viet Nam Electricity Power Generation Company subsidiary, which owns more than 600 megawatts of hydropower across Vietnam. The hydropower plant has a capacity of 175 megawatts, and the FSPV installed has 47.5 megawatts, occupying only 8 percent of the reservoir and leaving ample room for future expansion. The project came into operation in May 2019 and was completed within nine months of construction. In a few years of operation, the plant has exceeded the planned generation by 7 percent. The power plant was built with a total investment of $60 million. The financing package of $37 million included a concessional loan from the Asian Development Bank (ADB) with the help of the Canadian Climate Change Fund (CCCF) and the Japanese International Cooperation Agency (JICA). The investment helped leverage $23 million of private investment in climate change mitigation and adaptation.

In the past, CCCF and ADB have jointly financed hydro projects in Nepal. Historically, JICA has been one of the better development partners assisting Nepal with multiple national priority projects. If NEA and these development partners join hands in successfully building a model floating solar plant on a hydropower reservoir in Nepal, it would be an exemplary project for others to follow and for the private sector to invest in.