India Paving the Way for Green Grid
India’s Union Power Minister, Mr. R. K. Singh said, “The power sector is witnessing an increased demand which is further expected to go up in the near future. The current consumption of 1200 units per capita is expected to grow 2-3 times at par with the international consumption after each and every individual of the country has access to electricity.” Mr. Singh was addressing the gathering at Indian Power Stations (IPS) 2019, an international operation and maintenance conference organized annually by National Thermal Power Corporation (NTPC), held on February 13, 2019 in Raipur. Mr. Singh reiterated that with initiatives being undertaken by the government to augment power generation and distribution in the country, like the Saubhagya Scheme and flexibilization of power plants, the government’s directive to fulfil 40% of power requirements through non-fossil fuels by 2030 is on track. The conference was attended by over 500 delegates including Union Power Secretary Mr. A. K. Bhalla, NTPC Limited’s Chairman and Managing Director, Mr. Gurdeep Singh, dignitaries from Central Electricity Authority (CEA), Central Electricity Regulatory Commission (CERC), Power System Operation Corporation Limited (POSOCO) and other power utilities.
Variable and intermittent output from renewable energy (RE) sources requires load generation balance. Adding renewable energy to the electric grid means that conventional sources of electricity, such as coal power plants, need to be ‘flexible’ enough to respond rapidly. NTPC, India’s central generating utility, has been proactively piloting flexibility at a number of its coal-generating plants, including the units at its Dadri, Simhadri, Farakka, Jhajjar and Ramagundam stations. The latter two are being implemented under the USAID’s GTG-RISE initiative. Under the same initiative, the techno-economics feasibility of flexible operations in two (2) units of Gujarat State Electricity Corporation Limited (GSECL), the state generation utility of Gujarat, is also being undertaken. The damage cost modelling exercise for the units at both utilities have been completed and both NTPC and GSECL are now eager to formulate fleet-wide strategies for their coal-based power stations. Key learnings from the damage cost modelling study under the initiative was also presented in a paper titled ‘Techno-economics of Flexibilization in Regulated Indian Market’ during the IPS 2019 conference. This paper discussed the proposed regulatory pathway for supporting flexibilization in the country and will also be submitted to the Hon’ble CERC of India. The GTG-RISE will continue to provide strategic support to both NTPC and GSECL, including helping both utilities analyse investment costs and options, and develop plans to obtain regulatory approval from the CERC, Gujarat Electricity Regulatory Commission (GERC), and the CEA.
Indian Perspective and Readiness Towards Flexible Generation
India is in the middle of a clean energy revolution, and the power sector is working to develop and deploy RE to help bring affordable and reliable electricity to everyone and meet the country’s growing energy needs. To support this effort, India is changing its energy policies and reforming both the government and private sector energy markets. In early 2018, the India National Electricity Plan (NEP) set a new target for 40% of India’s total electricity to come from RE by 2030. The previous target was expressed as a specific amount (175 GW by March 2022), and as of October 2018, India was almost halfway there. Because RE is growing so fast, it is hard for India’s utilities, including the system operators, to make necessary changes and keep pace with it. One of those key changes is to make coal power plants more flexible.
The transition to a high variable renewable energy (VRE) grid presents several challenges to generation utilities and system operations and necessitates flexible grid operations to manage VRE. This shall require coal-based generating stations to be more responsive to flexibility requirements.
India’s coal power plants have for long periods operated under deficit conditions, requiring them to maximize their output and operate as baseload stations. Over the 12th five-year plan period (2012 to 2017), their operating conditions have changed dramatically in Indian states as surplus power conditions emerge and RE capacity is deployed rapidly. CERC has mandated that central generating stations should go down to a technical minimum of operation at 55% of maximum continuous rating (MCR) loading or installed capacity (CERC, April 6, 2016).
Utilities that operate several coal power plants, like NTPC, will need to be able to ramp down and then ramp up their power plants on demand. Many coal power plants have multiple units; some of those units will need to start and stop more frequently to keep the power grid stable. Such stop-start operation costs money and stresses the equipment. NTPC and other utilities are modifying their plants to make them ready to ramp up and down, coordinating with regulators like CERC and GERC.
Flexing of coal units in India would certainly result in additional costs due to factors such as loss of units’ and equipment’s useful life, modification/retrofit costs to make units ready for cycling, increased Operation & Maintenance (O&M) expenses, decreased efficiency due to heat rate degradation, and increased auxiliary power consumption. Compensation mechanisms for the resulting additional costs need to be designed with the approval of regulators to ensure financial sustenance of the generating companies. These financial mechanisms also should address the unique challenges that plant operators would face while retrofitting thermal power plants in India.
Coal-based generation utilities in India need to start from identifying the units within their fleet for cyclic operations in the future and work on addressing the requirements of flexible operations in such units.
GTG-RISE Initiative - Pilot on Flexible Power Generation
USAID’s GTG-RISE initiative is undertaking a range of pilots to help establish the coal flexibility framework in India. The ongoing pilots at NTPC and GSECL shall be able to provide learnings for the country for meeting the flexing requirements from coal units and create awareness through successful use cases.
The pilots are leveraging international experience under the GTG-RISE initiative to implement flexibility across a representative range of power generating units in India. The damage cost modelling studies at the NTPC’s Ramagundam (200 MW), Jhajjar (500 MW) and GSECL’s Ukai TPS (200 MW & 500 MW) have been completed and key recommendations from the studies have been shared with NTPC and GSECL. The major recommendations include modifications of operations procedures, carrying out test runs to determine system limitation, specific interventions such as nitrogen cap on condensate tanks, flame monitors, installation of asset health monitoring equipment, etc. NTPC has already moved ahead with one of the suggested recommendations on retrofitting of Nitrogen Sparging and blanketing system in demineralised (DM) storage and condensate storage tanks across its NTPC stations.
“Indian power sector has entered into a new regime characterized by fusion of significant amount of Renewable Energy, which requires conventional power stations to operate more flexibly and at part load operations. The impacts and capital requirements resulting from flexible operations are not known and this pilot study, conducted under USAID’s GTG-RISE Initiative, will guide NTPC’s strategy for its entire fleet.”
Mr. Prakash Tiwari
Director (Operations)- NTPC
“India has set huge targets for deployment of large-scale RE and states such as Gujarat with high wind and solar potentials have an important role to play in achieving these targets. Integration of significant amount of RE can pose challenges for both utilities and the SLDCs. USAID India’s GTG RISE pilot on coal flexing, implemented at Ukai unit, would be useful in making overall strategy to implement flexible operation in our own units”.
Mr. P. R. Dahake
Managing Director – GSECL
The GTG-RISE, through its experts, also supported the successful pilot test run at NTPC’s Mauda Unit in Maharashtra (February 15 – 17, 2019) and moving forward will help in determining the system limitations for flexible operation and lowering the stable minimum load level. The test run will help in preparing standardizing operational procedures for flexible operation which will be developed under the project.
In addition to the pilot implementation, GTG-RISE is also preparing a paper to advise India’s regulators on what they can do to support coal power plant flexing in India, including necessary compensation mechanisms for regulated power plants and changes required to market mechanisms to accommodate various costs of start-up and load-following.
To know more about GTG-RISE Initiative on Flexible Power Generation, please visit https://www.gtg-india.com/flexible-power-generation/