Implementation of the proposed run-of-river  type  900 MW Upper Karnali Project would be extremely harmful  to  Nepal’s western terai irrigation and it would also ruin the prospect to supply abundant cheap peaking energy to India badly needed there to supplement energy generation  from their coal fired, combined cycle and nuclear power stations which can not be economically operated to meet the demand for peaking. The proposed hydropower to meet the demand  for three hourly sharp peaking  energy  without reregulation immediate downstream would lead to very serious land sliding, bank erosion, retrogression  and other types of  flooding problems. There is a far better alternative solution.

Energy Export to India

The 4180 MW mega storage project and the proposed 900 MW run-of-river project are two variants of the same hydropower project to be built at the  Karnali bend site acclaimed for generation of cheap electricity.  Originally the capacity of the run-of-river variant was only 240 MW but recently it has been raised to 900 MW to meet the demand for peaking in India.  Despite these differences the annual firm energy generation of both these variants would be exactly the same which is estimated to be just about 1000 GWH.

In contrast to a mere 1000 MWH annual firm energy generation by the run-of-river type variant, the annual firm energy generation of the 4180 MW storage project would be about 9000 MWH.  Thanks to extremely favourable  topography,  the peaking energy generation cost of the Upper Karnali storage project operating at a head of  about 400 meters is expected to be exceptionally  low  not  only in comparison  with that of its   run-of-river type variant  but also in comparison with other mega storage projects like the Kosi Dam Project and Karnali (Chisapani) Project operating at a  head of just around   200 meters.   Nepal would be able to supply abundant  cheap peaking energy to India if the 4180 MW storage type Upper Karnali Project is implemented.

The firm installed capacity of the Upper Karnali storage project could  be raised even further up to 8000 MW if the peaking hour is limited   to daily 3 hours  as in case  of the proposed 900 MW variant. The increase in installed capacity to 8000 MW could  greatly facilitate to  improve the energy supply situation  in very big areas of  India’s northern grid which is mostly depend on thermal generation.

The Decommissioning

We should not shut our eyes while taking final decision on implementation of the Upper Karnali Project to the fact that we will have to completely decommission  the 900 MW Project if we want to implement in future the 4180 MW Karnali Storage Project .   It has been clearly explained  about  it  in the World Bank financed detailed prefeasibility study report of this project. 

Disastrous to Existing  Irrigation in Nepal

The designed discharge of the 900 MW Upper Karnali Project is expected to be about 750 cumecs and the   90% probable discharge of the Karnali river at Upper  Karnali  project site  is  only 97.6 cumecs.   According to the data recently published in a local newspaper there are already three irrigation canals drawing water directly from the Karnali  to  irrigate 57.5  thousand hectare  lands.     Those canals  in the absence  of diversion  barrage and proper regulating  structures must be having very low conveyance as well as  irrigation efficiency.    If the crop grown in summer is paddy,  the water requirement could  be as high as 2 litres  per  hectares.  Thus  the total diversion from the river could reach up to 100 cumecs  though a substantial proportion of this flow would  come back to the river  immediately downstream in the form of regeneration  due to high  seepage and other losses.   

Bheri river is soon going to  be diverted into Babai river.  If  the limited flow from the West Seti  river  is  not considered the water supply  to existing Karnali  canals would  be completely  cut off  for 21 hours each day during dry season after the completion of the proposed 900 MW storage project.  This will have disastrous consequences for agriculture.

The proposed hydropower to meet the demand  for three hourly sharp peaking  energy  without reregulation immediate downstream would lead to very serious land sliding, bank erosion,   retrogression  and other types of  flooding problems.  Possible retrogression of the river bed could greatly hamper full  entry  of water into irrigation canal intake.

The Alternative Solution

It would be better not to implement the run-or-river type Upper Karnali  Project.   However,  a very low cost variant of this project could also be considered for implementation  in  near future  to resolve our  present  energy shortage problem   if  there is going  to be a very  long delay  in implementation of the storage type project.

A simple 120 MW run-of-river type hydropower without the provision of daily  storage could be the best option for the time being.  This project  would be decommissioned later on  when we intend to implement the storage project.  The  low cost  floating type weir of that project could be later on used as coffer dam and the power tunnel for temporary diversion during the construction of the storage project.

 The proposed 120 MW small Upper Karnali Project would also be able to generate 1000 GWH  firm energy annually as much as the 900 MW variant  though it would be  mostly to meet the demand for base  load.  This project must preferably be built by the government  itself  for greater flexibility in taking any type of appropriate decision in future.

Comparative Investment Cost

The proposed 120 MW Upper Karnali Project with a very short headrace tunnel  just 2.5 km long and a simple floating type weir might be able to generate three times more firm energy  during the dry months when we are  facing acute  energy shortage than the existing 144 MW Kaligandaki A  hydropower with a very complex regulating  barrage  and relatively a long  headrace tunnel. The investment cost of the proposed  120 MW Upper Karnali project could be only half of the latter.

The demand for cheap energy to meet the base load would  remain unfulfilled even after completion of the projects like the Upper Tama-kosi. The proposed 120 MW project could  be quickly implemented  by our Government  to provide   immediate relief for our people from the present power  shortage crisis  at  relatively  a very small  investment.    Moreover, the proposed 120 MW hydropower  would  not have any adverse impact on irrigation in Nepal.