At present about 160 countries use hydropower for energy generation and the world has in excess of 1270 GW of installed hydro capacity. A unique aspect of hydropower is that apart from energy production, it creates other opportunities – hydro reservoirs are used for irrigation, providing drinking water, flood risk mitigation and even recreation. Evidence suggests that hydropower plays a role in mitigating the effects of global warming as well. It is important to highlight a very important advantage of hydropower in contrast to other renewable energy sources like wind and solar – hydropower can be dispatched very quickly at any time enabling a balancing of load variations in the s
A particularity of hydropower technology is its large variability in scale. Hydropower stations range from the “pico” scale stations with a nominal power capacity of few kilowatt (KW) to projects of huge scale and several gigawatt (GW) power capacity. Although the principles among these very different in scale stations are similar or even identical, the technological and market maturity is not the same. This offers interactions and allows synergies among different scientific disciplines i.e. the natural sciences and the applied sciences. It also creates challenges and trade-offs that require a wider spectrum of research.
Essentially hydropower stations are a sum and system of components in complex set-ups which incorporate a wide spectrum of technologies. The operational characteristics and capabilities of each system rely on technological features of its alignments. I must underline the fact that each hydropower station is a unique system specifically designed for a particular site. Overall, however, hydropower technology development includes trans-technology knowledge transfers since hydropower is uniquely capable of gaining from new concepts and latest advances in other sectors.
India’s hydropower infrastructure is dated having been built first in the 1950s and then successively replenished. Broadly, the modernization of any infrastructure, including hydropower, is an essential part of its life-cycle and must be a constant work-in-progress. As I see it, we should execute the following : the first is monitoring and oversight. To keep the entire plant at peak efficiency and safety, it must be maintained and monitored regularly. Digitization of hydropower operations is another key aspect of modernization.
A key challenge for modern hydropower plants is to enhance their flexibility drastically by providing storage capacity and advanced system services which then must be developed further to support the integration of variable renewable energy (VRE). We need to gather and elaborate real world data on actual workings of turbines to enhance the capacities of our hydropower plants, while providing advanced grid supporting services without compromising safety and reliability. The objective of black start in emergencies will be optimally served by digitization of hydropower plants which will transform the way in which plants are designed, developed/upgraded, operated and maintained. Apart from prolonging the life of plants, digitization helps address overall efficiency and output besides operational savings and reduction in greenhouse gas emissions. Digitization will also optimize response time in generating additional units or reversible pump turbines.
It will allow assessment of the economic impact of offering additional reserve flexibility besides supporting high level safety and reliability standards of hydropower plants. I strongly believe in digitization because requirements of extended operating ranges and faster dynamics are stressing out the reliability and safety of hydropower plants. Only a disruptive approach, therefore, can address this risk by linking physical engineering and data science. Another aspect to consider is of hydro generators with current controlled motors to mitigate instabilities in flow. Modern hydraulic turbines meet challenges associated with variable demands of the energy market and the limited energy storage capacities. This results in substantial flexibility.
Both active and passive control flow techniques can be applied. In addition, state-of-the-art methodologies for engineering and operating hydro-electric units include advanced electro-magnetic, flow and structural numerical simulants for different hydraulic, mechanical and electronic components of machinery. These assist in optimal reliability for commercial operations. The operating conditions of a hydropower plant can be highly variable. These variations result in lowering the plant’s efficiency and lead to flow instabilities, cavitation, etc. – impacting the life of the hydropower unit. There is technology available to vary rotational speeds of the hydropower plant’s units with respect to synchronous speed. With this the plant can better adapt to the hydrological regime of the river.
There are several more technological advancements in addition to the more visible ones I have outlined here. As we assess, adopt and integrate the best suited solutions, hydroelectric infrastructure will become more compliant to changing and dynamic context conditions – climate, market and environmental safeguards — through new design and operational paradigms which are inclined towards renewal and development. Over the years hydropower equipment has been optimized for high performance, availability and flexibility. Significant improvements have been enabled by computer technologies in different areas – design, construction, monitoring, diagnostics, protection and control. We have also seen innovative measures to mitigate environmental impacts. Perhaps the most significant is fish friendly interventions like fish ladders for low head dams, these are far more effective than the older lateral channel designs. This is complemented by fish elevators for high head dams and fish passes for medium head dams.
The environmental and ecological characteristics of hydropower plants must now increasingly address fish friendly turbines and the development of water lubricated bearings in turbines to mitigate water pollution risks. There is an entire body of work related to water led challenges such as securing the required environmental flows to enable ecological conservation and the water-energy-ecosystem nexus interactions which offer solutions.
I am a firm believer in R&D as a fundamental factor in meeting advances in technology and dealing with market competition. Alongside this, to manage environmental and socio-economic aspects at a regional level, there is need to build links between industry, R&D and policy institutions. Technologies and solutions in the larger frame are baseline references to identify and prioritize actions. As we adopt a wholesome and co-optive approach, we will see markedly improved resilience of electro-mechanical equipment and infrastructure besides better operations, maintenance and outputs.
