Modelling of mini hydro plants in long term planning studies : a Sri Lankan case study

The development of green energy and cutting down fossil fuel fired brown energy is now matured from the voluntary commitment stage up to a level of fixing national policy targets even in developing countries [1], [2] including Sri Lanka [3]. Thus, the share of Non Conventional Renewable Energy (NCRE)in electricity generation is becoming crucial in modern generation planning studies. As a result, many advanced research studies have been conducted around the world [8]-[13].In particular, no national level detailed study has yet been conducted to model the macro impacts of large numbers. of distributed mini hydro plants, in long term planning studies. Owing to the increasing share of contribution from mini hydro power plants, especially as embedded, non-dispatchable generation, simplified models such as the thermal equivalent model with high Forced Outage Rate (FOR)which is the current practise will no longer be justifiable. A suitable model should accommodate the seasonal variation of energy availability as well as the operational aspects specific to embedded generation. This study proposes a.probabilistic model to meet this vital requirement of the entire group of mini hydro plants. The operational aspects of the model have been verified by using the optimisation tool Wien Automatic System Planning (WASP), the same planning tool used by the Ceylon Electricity Board (CEB)and many other utilities worldwide for generation planning. Special attention has been paid to ensure that the model will be suitable for conducting sensitivity studies. The predictability of the model has been checked with past data. Although a Sri Lankan case study was applied to validate the model, the technique is more general and can be adapted for any other case studies as well