Reviving HEPs: RMU&LE of hydro plants offer substantial gains

RMU&LE of hydro plants offer substantial gains

Renovation and modernisation (R&M) of existing hydroelectric plants (HEPs) is a critical process, which helps in enhancing the generation potential of dams, improving efficiency, lowering O&M costs and improving their flood control capacity in addition to extending the life of the plants by 20-30 years. Constructing large hydro projects involves significant capital outlays and long gestation periods of 7-10 years (along with a strong possibility of time and cost overruns). In comparison, renovation modernisation, uprating and life extension (RMU&LE) activities in a hydropower plant can yield returns and help investors break even in three to four years, while infringing minimally on the ecological balance.

The government has been undertaking R&M of several central and state projects since 1992. These projects have been identified, examined and reviewed, and their progress monitored under the aegis of the Central Electricity Authority’s (CEA) hydropower wing. Till 2017, about 104 projects, with a total rated capacity of 20,611 MW, had undergone R&M, with 3,635 MW capacity enhancement achieved by uprating, life extension of deteriorating plants and restoration of obsolete plants. Currently, the government is executing an R&M programme for the period 2017-22, covering 47 projects with 9,294.25 MW of capacity, which is expected to lead to a benefit of 4,527 MW. As such, this R&M programme will add 890 MW more capacity than all the previous programmes combined, therein demonstrating the importance being accorded to it.

Till June 2020, three years from the commencement of the current programme, five projects have been completed, with 132 MW of benefits accrued. About 2,152 MW of addition or restoration is in the process of being commissioned, 968 MW of R&M additions are in the process of tendering, and 1,274 MW of R&M addition is still being finalised and prepared. For the period 2022-27, about 3,428 MW of R&M benefits across 33 projects are being targeted. Of these 33 projects, 29 are being set up by the state sector and the rest are being implemented by the central sector. Of the targeted benefits, 396 MW is currently being implemented.

Issues and the way forward

One of the key challenges in R&M is assessing its scope. Since many of the old hydro plants were built with limited hydrological and geotechnical data, utilities need to undertake a systematic assessment of the actual site conditions while also considering the water flow data over the years, environmental aspects and O&M history records in order to determine the optimal methodology of improving their capacity through R&M. This effectively requires that the utility engage the services of a reputed agency to prepare a detailed project report (DPR). However, due to the contractual complexities involved during the bidding stage, R&M activities get delayed. Additionally, gencos tend to prioritise ad hoc O&M measures, thus escalating R&M costs in the long run. Normally, RMU&LE activities would need to be conducted only after a span of 35 years; however, owing to the unique terrain and silt erosion in the Himalayan region, Indian HEPs need to undergo RMU&LE much earlier than 35 years. In India, these activities are often constrained by the lack of technical expertise to execute complex R&M projects. Moreover, contractors prefer to implement new hydroelectric power plants rather than R&M projects, considering the larger book value of new projects.

Given the critical role of RMU&LE in the hydro sector, proper planning is needed for the identification of plants that require renovation. To this end, residual life assessment studies must be conducted as a mandatory technical requirement. Similarly, experienced consultancy firms need to take up DPR preparation work, framing technical specifications and related work till the recommissioning of a plant. Utilities need to ensure the quality of DPRs, since this not only helps in getting quicker approvals, but also allows timely execution of work. Further, equipment manufacturers need to assist power utilities in framing the scope of DPRs, and provide them with timely budgetary allocations so as to enable utilities to firm up the financial requirements in the DPRs. Since an in-crease in R&M costs can lead to higher tariffs for consumers, the implementing agency should consider the technical aspects, cost benefits and consumer gains of R&M works, while being overseen and regulated by the CEA.