How stupid we Nepalese people, government and also the elected bodies would look like in the eyes of the international community once they learn that our government on the one hand is desperately calling international institutions for help to protect us from hazardous consequences of the global warming even by holding a highly symbolic cabinet meeting at a very high location “ KALAPATHAR” close to the Everest summit itself in Himalayan mountain to draw the attention of the whole world, and ridiculously on the other hand we are now going to build just few kilometers away from the very place, where the historic cabinet meeting was held, on the site identified based on past surveys to be highly vulnerable to disastrous glacier lakes outburst floods (GLOF) consequent upon the global warming the giant Upper Tamakosi hydropower project, which will have installed capacity exceeding the total installed capacities of almost all existing hydropower plants built so far in Nepal- Kaligandaki A, both Marshyangdi hydropower plants and both Kulekhani hydropower plants combined together.
We are going to take the horrendous risk despite the fact that the small-scaled alternative of the NEA proposed project would have not only been safer from the GLOF but it would also have been far more suitable to match against the nature of the present demand for power in our country. The small-sized alternative project could have been implemented within a much shorter period to provide quick relief from the present acute power shortage crisis, and it would also be producing at almost one third of the investment by comparison with that of the NEA proposed variant even more energy during critical dry season periods if the seepage losses are not discounted.
Danger in Consequence of Global Warming
There are several rapidly growing glacier lakes near the project site in Tibet in consequence of the global warming. The great risk of glacier lakes outburst floods (GLOF) to high gated barrage and other structures of the NEA proposed Upper Tama-Kosi project should not be underestimated. We already have a bitter experience of the 1984 Digcho GLOF when the Namche hydropower built on the upper reach of the Dudh-Kosi river was completely washed away.
Let us not forget that the Kulekhani high dam was also on the verge of collapse just few years after the completion of its construction. It has been described in an article recently published in the journal “SPOTLIGHT”.
The reconstruction cost could be too much if the barrage and intake structure of the NEA proposed Upper Tama-Kosi project would be seriously damaged by big GLOF. Power supply would be suspended for a very long time which would have terrible consequences for the economy of entire country.
The Mini Upper Tama-Kosi project would be having only un-gated weir across the river. The GLOF would cause only limited damage to the weir. The damage could be repaired within a short period at a relatively small cost.
Less Energy in Dry Season
It is reported that the flat reach of the Tama-Kosi river serving as the floor of the reservoir of the NEA proposed hydropower project is made of 300 meters high porous fill materials lying over the original river bed. The fill materials had accumulated after a big landside dammed the river. There is a great possibility of excessively large seepage of water from the reservoir. As a result of such seepage, there can be a significant reduction in electricity generation in dry seasons.
The mini Upper Tama-kosi project would not require the provision of a reservoir. The question of energy losses resulting from the seepage through the floor of the reservoir does not arise.
Our electricity planners do not appear to take cognizance of the fact that the electricity price (as well as generation cost) varies not only with the seasons but it also widely varies even within a very short period of just one day. The cost of generation of electricity for the supply of peaking demand in the evening hours can be usually about three times more expensive than that of the off-peak hours.
Our country is reeling from acute shortage of electric power. Most of our industries are on the verge of collapse. People are facing great hardship due to long hours of load-shedding reaching up to 16 hours a day and it is expected to increase even further in days ahead. However, during the wet season months quite limited areas are affected by load-shedding lasting only for a very short period in the evening. Even such limited disruption in supply of power might have been to a certain extent the result of transmission lines congestion. It is quite obvious that the NEA is now facing acute shortage of base load energy which could have been produced at exceptionally low cost within a very short period.
Rationalization of Existing Projects
All the NEA owned hydropower projects, like the Kali-Gandaki, both Trisuli, both Marshyangdi, both Kulekhani and others are capable to run at full capacity even during the dry season periods. They have been built at enormous cost to supply electricity to meet the demand for peaking. Obviously, the generation cost of such peaking energy is always very high. Unfortunately at present the full capacity of these hydropower projects built to generate high valued peaking energy has not been fully utilized during the critically important dry season periods. They are now operated to produce a very large proportion of cheap energy to meet the demand for base load. Thus, the reservoirs, high barrages, turbines, generators, transmission lines and civil structures provided to generate and transmit peaking energy have not been utilized to the full extent.
A fifty percent proportion of the base load and the peak load capacities of the power stations operating in a power grid is normally considered to be optimum mix. It implies in our case that the overall firm generating capacity of our power grid should have already grown very high on top of the existing 450 MW firm capacity ( 400 MW peaking capacity and 50 MW base load capacity) in order to effectively use the additional peaking capacity of the NEA proposed 456 MW Upper Tama-Kosi project. Thus, it would be too uneconomic under present circumstances to implement a hydropower project suitable to produce excessively large peaking power such as the 456 MW Upper Tama-Kosi project.
Considering the nature of the present demand for electricity in our country and also the vulnerability of main project structures, the installed capacity of the Upper Tama-Kosi Project must be limited to just over 100 MW based on 95% probable dry season river discharge by targeting to generate mostly the firm energy to meet the demand for the base load. Even after such drastic reduction in installed capacity the total generation of electric energy during the dry season period would still be equal or even exceeding the generation by the NEA proposed 456 MW project ( in case the significant proportion of the dry season flow is lost in seepage) despite the fact that the cost of such mini- project would be only about one third. As the demand for peaking energy grows in future the installed capacity could be raised with ease by providing additional structures if it is found after some years of operation and further observations that the GLOF and the geology of reservoir site would not pose serious threat to the safety of the project.