The renovation and mordernisation (R&M) of hydroelectric projects (HEPs) is one of the easiest, fastest and cost-effective ways to augment hydropower capacity in the country. Besides, R&M requires less investment and fewer clearances. Hydro power is a clean energy source that can be implemented on a large scale and offers a host of benefits including fast ramp up and down rates and low load operation. However, setting up new HEPs is challenging in view of the various statutory and land clearances, rehabilitation and resettlement issues, resistance from the local population, etc. Such issues do not exist in the R&M of HEPs.
The R&M of existing HEPs is one the most cost-effective solutions to ensure optimal resource utilisation, efficient operations and better availability. The cost of uprating the HEP is very low as compared to setting up new plants. In R&M, only select components such as turbine runners and generator windings of hydro units are replaced. Computer-aided design techniques and advancements in material science have made it easier to uprate an HEP without much change to the existing civil structure. Besides, no additional land and statutory clearances are required for undertaking R&M works at HEPs.
Typically, the R&M of an HEP is undertaken towards the end of its useful life, that is, after 30-35 years. The actual life of an HEP varies on a case-by-case basis depending on the operating conditions of generating units, the actual running period, operations and maintenance practices followed by the project developer, etc. In India, HEPs located in the Himalayan region are subject to silt erosion, which damages its various components such as runner blades, guide vanes, bearing bodies, top cover, shaft gland and static and rotating labyrinths. These HEPs may face frequent choking of strainers, choking and puncturing of cooler tubes and damage to cooling water pumps. Therefore, they need to undergo R&M much earlier. While the HEPs located in the Himalayan region may require R&M before completing 35 years, the HEPs located in the Southern region can operate problem-free for 40-45 years.
Another factor driving the need for R&M at HEPs is technological advancements. In order to ensure efficient power generation, utilities need to adopt newer technology solutions. This is also necessary to maintain the cost competitiveness of power generation. In some cases, HEP equipment is rendered obsolete with no spares available in the market.
Progress on R&M
The Central Electricity Authority (CEA) has a dedicated hydro wing, which identifies various R&M schemes, examines technical and financial proposals, and monitors R&M works. During the period 2012-17, around 21 projects (two central and 19 state) aggregating 4,149 MW underwent R&M, yielding a cumulative benefit of 549 MW.
During 2017-22, 53 schemes (10 central and 43 state) with a combined capacity of 9,983 MW are expected to be completed. The total cost of these projects is estimated at Rs 66.85 billion for an expected benefit of 5,171 MW. Of these, 27 projects are at the implementation stage, 18 at the tendering stage and two have been completed. Detailed project reports (DPRs) are under preparation for another six projects.
For the period 2022-27, the government has identified a total of 22 projects (one central and 21 state) aggregating 2,518 MW for R&M works. The accrued benefits from R&M works are expected to be nearly 2,549 MW.
Issues and the way forward
One of the key challenges in the implementation of R&M at HEPs pertains to the lack of uniformity and detail in the DPRs prepared by utilities. This leads to complexities at the bidding stage and delays in R&M works. Utilities need to prepare good quality DPRs since this not only helps in getting quicker approvals, but also allows timely execution of works. Experienced consultancy firms should be appointed for DPR preparation, framing of technical specifications and other related works for the re-commissioning of a plant. This is expected to yield better results and ensure timely completion. Equipment manufacturers could also assist in framing comprehensive DPRs.
Another challenge in undertaking R&M at HEPs is the lack of experienced contractors and consultancy firms. As a result, often the contract for R&M work is awarded to incompetent agencies, which results in a significant delay in the implementation of projects and poor quality work. Besides, sometimes the contract needs to be re-awarded in the middle of project execution since the contractors fail to deliver the desired outcome. Therefore, the utilities must ensure that resourceful and competent agencies are hired for undertaking R&M. The contract packages need to be designed in a manner that the best executing agency is hired at the lowest cost.
Another requirement for the successful implementation of R&M projects is adequate financial resources. The utilities need to be provided with timely budgetary allocations to enable them to firm up the financial requirement in the DPR. Meanwhile, since an increase 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.
Further, proper planning is required to identify plants for renovation. To this end, residual life assessment studies must be conducted as a mandatory technical requirement. Apart from this, in order to prevent technological obsolescence of equipment, the utilities need to adopt state-of-the-art technology, which is expected to remain in operation for the next 15 to 20 years.
Overall, for the successful implementation of R&M projects, good project management is required. This includes obtaining necessary approvals, managing the delivery of supply orders for equipment, monitoring erection and commissioning, shutting down generating units, and ensuring timely completion of work.
To conclude, to obtain the desired outcomes from the R&M of HEPs, it is required to identify the best suited plants for R&M, ensure timely implementation and award of contract work, and undertake efficient project management, among other things.