Disappointing PLF

I have been closely following the energy generation trend of recently completed projects, and I must say it is pretty disappointing. Following are the projects with their design PLF and their actual (PLF) generation.

S.N.	Project	Design PLF	Actual PLF
1	Ankhu Khola (8.4 MW)	63%	47% to 55% in the last two years.
2	Radhi Hydropower (4 MW)	68%	Around 57% in the last two years.
3	Lower Modi -1 (10 MW)	70%	Around 57% in the last two years.
4	Charnawati Hydro (3.52 MW)	66%	Around 55% in the last two years.
5	Siuri Khola (4.95 MW)	74%	Around 59% in the last two years.

PLF (Plant load factor) is the percentage of energy generation against its full capacity. To calculate it, take the total amount of energy the plant produced during a period of time and divide by the amount of energy the plant would have produced at full capacity. Higher PLF is always better as it ensures higher energy production leading to higher revenue.

Unfortunately, no hydropower project (recently completed) has been able to operate at its designed PLF. Not only this triggers the revenue loss but also may end up in paying penalty to NEA.

What may be the causes for such variation?

1) First of all, we do not have mature data. Except the major rivers, none of our rivers/rivulets are gauged. In such case, prediction of hydrology becomes a guess work only. Reference of rainfall analysis in the similar catchment areas becomes the main tool for forecasting the river flow.

Some developers establish their own gauging station to measure the actual discharge, but 1 or 2 year data is simply not enough to do the prediction.

2) Developers are obsessed with MWs. I have seen many developers going for higher MWs only without considering the energy generation/energy revenue aspect compared to its installed capacity. Project optimization is completely neglected. NEA buys energy from the project that is designed at Q40% (up to). Hence, manipulation of hydrological data becomes quite obvious. 

3) 8 months is considered as wet season while the remaining 4 months is termed as dry season. However, NEA requires at least 15 percent of the total contract energy as dry energy. So developers may have manipulated on purpose to meet this requirement.

4) One of the causes is the water seepage, and it happens due to low quality design/construction of structures.