| |JULY 202019sients and other operational factors associated with the flexible operation, have following effects on coal-fired generating assets:· Increased rate of wear on high-temperature compo-nents and BOP components.· Decreased thermal efficiency at low load (high turndown).· Increased fuel costs due to more frequent unit starts.· Difficulties in maintaining optimum steam chemistry.· The Potential for catalyst fouling in NO control equipment.· Increased risk of human error in plant operations.· Cyclic operation/Load Ramping capabilities of ma-chines of different age and technology will pose dif-ficulties in dealing with the impact of RE generation variation. · Part load operation would adversely im-pact the Heat Rate, SOC, and APC. · Damage Mechanisms - Thermal fatigue, Thermal expansion, Corrosion & its Related Issues, Fireside Corrosion and many others.· Impacts on Environmental control equipment - Load following and other modes of flexible operation can affect the performance and reliability of Flue Gas Desulfurization (FGD) equipment and Selective Catalytic Reduction (SCR) systems.COMMERCIAL CHALLENGES:· Cost of start-up fuels· Auxiliary power Consumption· O&M/R&M expenses· Poor efficiency & heat rate The above will increase the cost of generation and affect merit order position in the highly competitive power market.ECONOMIC FLEXIBLE OPERATION (EFO):As India is stepping into Renewable Energy, thermal power plants may likely meet the European scenario of flexibiliza-tion. The approach towards flexibilization should involve an economical commercial solution, focusing on the effi-cient operation, maximizing income and reducing risk. To conquer the challenges of flexibilization, Thermal genera-tors should get acquainted with the mitigation measures of flexibilization and follow the strategies of operation and maintenance of `flexible' operated power plants around the world. EFO is our holistic tool to approach flexibilization. EFO ­ A Toolbox Approach to Improving the Cycling Performance.Flexible operation studies: These studies reduce component damage through procedure optimization and design modification. Included in the studies are an initial appraisal of plant-specific risk areas, installation of addi-tional instrumentation, flexible operation trials, assessment of thermal transients, modifications to operating procedures and design to address issues identified, repeat trials to confirm success, and detailed stress analysis to inform strategy going forward.Operator Coaching: Simplified damage algorithms for creep and fatigue should be developed for operator coaching. Plant data for critical components are screened to iden-tify and understand the most damaging op-erational conditions. Operators can then seek to minimize the extent of such conditions during future unit starts.Maintenance Strategies: Maintenance strategies are developed about every three to four years to allow future budgeting and phasing of component replacement (as in-formed by inspection and experience). These strategies are forward-looking to anticipate requirements of expect-ed operating regimes in terms of hours and starts and are sometimes scenario-based. They include a detailed review of site-specific defect/failure histories to date.Design Modifications: Modifications to the de-sign of replacement components to `design out' damage mechanisms.Damage Estimation: Estimates can be made of dam-age costs per start to inform the plant's trading position based on increased routine maintenance costs, damage to major components, and estimated cost of consumables per start.New-Build Design: Lessons learned are incorporated into specifications for new-build plants. As India is stepping into Renewable Energy, thermal power plants may likely meet the European scenario of flexibilizationAnand Bansal
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