Flexibility for power plants

Most coal-fired power plants (subcritical and supercritical) were designed to run efficiently and cost-effectively when operating at steady baseload. Variable renewable energy (VRE) systems, such as wind and solar, are sporadic in their energy output, following unpredictable weather conditions. The energy from renewable sources is prioritised for input into the grid in many countries, meaning that dispatchable power plants, such as those powered by coal or nuclear sources, must now provide more flexible output to keep the available energy in the network at the required level.

The flexible operation of a coal plant to balance the grid has impacts on plant efficiency, component lifetimes and pollutant emissions. Repeated cycling or ramping of a coal power plant increases the wear and tear of the components. This must be assessed and monitored, especially in older units, to mitigate potential costly damage to the plant and to promote safe, efficient, and problem-free operation. Thus, increased plant cycling can incur cost penalties for maintenance and repair as well as a greater risk of outages and elevated emissions of pollutants. It is therefore vital that the Indian coal fleet prepares to minimise the potential issues which may arise as it is called upon to provide more flexible power as the proportion of VRE supplied to the rid increases. This will require the integration and alignment of people, processes, and technologies to manage major assets, materials, and environmental systems. This challenge will be significantly reduced by the application of a methodology to improve the operational flexibility of the existing coal fleet.

This part of the project builds upon a previous project between the USDOE, USAID, EPRI and NTPC in India which developed a toolkit to maximise the flexibility of coal-fired power plants. The ‘High-Level Flexibility Assessment and Benchmarking Tool’ developed by EPRI is an interactive guide to maximising coal utility power plant performance during flexible operation. Application of the toolkit will ensure that Indian utility managers can ramp the operation of their coal-fired units up and down effectively and efficiently with minimal plant damage. This flexing will help the Indian electricity grid to meet growing power demand as the capacity of VRE increases.

The figure above shows the ten areas of focus within the Flexibility toolkit, including combustion, maintenance, and cycle chemistry.

As a legacy, the ICSC is working with EPRI, CII and the major utility stakeholders in India (NTPC, Adani, Mahagenco and others) to create a new initiative called Flex-India.

Flex-India will coordinate the establishment of a benchmarking and award system for flexible plant operation in India via monthly online meetings. The first annual FlexIndia event is planned to take place in September 2023 in conjunction with the CII-EPRI annual Power Summit Conference. More information will be provided here as it becomes available.