Adopting advanced studies can help improve the reliable performance of operating hydel plants, says Narayan Bhat.At the end of 2011, CEA data showed that installed capacity of 186.65 GW, of the total about 122.96 GW is fossil-fuelled power plants including coal, lignite, gas and oil-fired capacity. Grid-connected hydroelectric power is around 38.74 GW, while nuclear is 4.78 GW and other renewables are around 20.16 GW. In spite the large growth in the capacity addition, India is yet to meet the voracious electricity demand. At times the available capacity has been below the demand. Past data of performance shows that whenever there have been good rains in the monsoon and water storage levels are high, the hydel performance has been consistently good. Fossil-fired plant performance which mostly depends on fuel availability is currently facing challenges of fuel supply especially oil and gas-fired power plants. In the last few five year plans, it has been seen that coal-based generation has been given greater emphasis over other sources, which currently figures around 55 per cent of the energy mix.Globally installed hydroelectric power accounts for around 16 per cent of the total energy mix. China tops the list with almost 200 GW of installed capacity, followed by Canada with around 89 GW. India ranks 7th in the world in hydro-electricity generation. It is estimated that by the end of the 11th Plan period in March 2012, a total of 6.2 GW hydro capacity will be added, which will take installed capacity to 40.8 GW. The ministry plans to add about 9 GW hydro power during the 12th Plan period (2012-17). With the pace at which hydro power is growing and in view of the challenges that are being faced it may take another 30-40 years to harness its fullest potential.The worldwide experience of civil construction and fail-safe construction of dams across rivers has made it more promising. However, there is a lot of potential that is still to be exploited and may need more attention to overcome challenges with mitigating measures. More studies may need to improve the construction of electro-mechanical equipment and improve the performance of plants.Potential and challengesAs per CEA’s assessment, India has exploitable hydro-power potential of around 150 GW. In addition to this, identified pumped storage capacity of around 90-94 GW and small and micro hydro potential of 7-8 GW has been reported, taking the hydro potential of India to the range of around 250 GW. So far the installed capacity has been around 38.7 GW which is almost 15 per cent of its potential.It has been always a question as to why India is unable to harness the fullest potential of hydro. Like in the Lower Subansiri mega dam project, hydro-power in India has always faced issues of public protest, mostly due to submergence of fertile forest land, refusal to relocate or the potential fear of flooding in the event of dam failures. Some frequently cited issues for the delay in projects are time-consuming processes for obtaining environmental clearances, lack of state government concurrence and poor quality environmental assessments. Large projects have been identified in Arunachal Pradesh. It remains to be seen when, and whether, they will actually be completed.Technical challengesWater-to-wire has a lot of technical challenges in conversion apart from social and environmental issues. Mostly the geological and topological factors are most important in dam location and design. The electromechanical component design and their life-time reliability is vital in view of components experiencing extremely abrasive and erosive conditions and depends on the water quality, particles etc. Vibration and noise are also of concern for such large rotating equipment and its components which experience fatigue during their long operation. This is not only a challenge for an initial plant but also a problem to be handled during its lifetime of operations. So strengthening the assessment of quality during construction and periodic assessment of plants may be essential.Benefits of hydro• Hydroelectricity is a non-polluting source of power, has better climate compatibility than other forms of energy like coal and gas and can lower greenhouse emissions• It has a long plant life. Some projects completed over a century ago are still in operation.• Technically, it has a higher efficiency (over 90 per cent) as compared to thermal which is 35-40 per cent and does not require any raw material and the operating costs are low.• The cost of hydropower is relatively low, in fact one of the cheapest, making it a competitive source of renewable electricity. The average cost of power from a hydro plant, larger than 10 MW, is 3 to 5 US cents per kilowatt-hour.• Hydropower is also a flexible source of electricity since plants can be ramped up and down very quickly to adapt to changing energy demands. It is one of the best suited for India in view of the wide power fluctuations.• The associated benefits like better irrigation for the surrounding lands, creation of a tourism centre indirectly lend value to the project.Negative aspects• Dams interrupt the natural flow of rivers and can harm local ecosystems. Dams and river diversion can impact freshwater, as well as marine fisheries.• Large dams often involve displacing people.• Dams and reservoirs due to disruptions in flow may increase siltation and evaporation.• Run-of-river often face problems like downstream flows are considerably reduced or even completely stopped at times. Drastic variability in water flow impacts aquatic life and leads to increased sediment transport.• Freshwater reservoirs may emit greenhouse gases like methane and carbon dioxide as organic matter submerged in a reservoir decays under anaerobic and aerobic conditions. • The most disputed negative impact of reservoirs is the possibility of inducing earthquakes. Many believe that seismic activity can be attributed to the creation of dams and their adjacent storage reservoirs.Going forwardIt is critical to explore and anticipate all social and environmental impacts early in the planning process so appropriate steps can be taken to avoid, mitigate or compensate for such an impact.Project feasibility assessment can be strengthened by experts including validation by independent experts in seismic assessment and ecological impact at potential sites.Appropriate and effective mitigation measures by local authorities can address resettlement issues, sustainable livelihoods, cultural impact and flood control at the planning stage itself. Educating locals with facts and benefits like employment opportunities may make it more acceptable.May be an option of adopting small and medium-sized dams rather than big dams can make it viable and gain local confidence and involve small population relocation. Generally plants with smaller dams are considered less environmentally damaging than those with larger dams. More run-of-river (ROR) hydropower plants can be another alternative, which are generally considered as less damaging than reservoir power plants, due to small upstream flooding area for storage.To enhance the plant’s performance, quality should be ensured during its construction and periodic assessment, vibration analysis etc., can help. Maybe adoption of technically advanced studies like RAMS can help identify the gap areas and strengthen the plant’s reliability.Certainly any development inevitably involves some degree of change. The construction of dams and their associated reservoirs and hydroelectric power plants, creates certain ecological and social impacts.Attention has mostly been focused on the negative impact and less attention is paid to the benefits of hydropower. There is a need to overcome the negatives by anticipating it early in the planning stage with proper mitigatory measures. It is indeed a requirement for India to harness the maximum potential of hydro. So there should be a proper assessment and careful balance between energy and environmental security.Our company offers vibration analysis and reliability studies and has been associated with some of the hydro projects in India for assessment of quality of electro-mechanical components.The author is Head Power - Asia, Lloyd’s Register.Views are personal.
I wish to start pvc / pp electric wire unit in Delhi. What kind of information I can get if I subscribe for your magazine
Pls invite me all auction in gujarat
we are doing business developing for solar power ,thermal power , customer supporting and we have 45 mw splar power on hand needs investors.....
pls call +910842559230