Automatic Generation Control (AGC)



Power system reliability under increased RE penetration is of significant concern to system operators in the country. To achieve this, Indian system operators need to maintain an array of ancillary services to ensure it is possible to balance supply and demand for energy in real-time.

Power system reliability under increased RE penetration is of significant concern to system operators in the country. To achieve this, Indian system operators need to maintain an array of ancillary services to ensure it is possible to balance supply and demand for energy in real-time. A subset of these ancillary services incudes;

  • Regulation,
  • Spinning, and
  • Non-spinning Reserves

The regulation reserves are used to constantly and automatically balance small fluctuations in supply and demand in real time. Generation units that are providing regulation service must be able to respond to AGC signals from the system operator and change their output accordingly on very short time scales, typically 2 to 5 seconds. AGC can provide significant secondary reserve, which in turn would bring down tertiary reserve requirements in the event of prolonged imbalance in demand and supply. As of now, preliminary regulations on tertiary reserves exist in India, and are followed by the Regional Load Dispatch Centres (RLDCs). Considering the future growth of RE to meet the Government of India (GoI) targets, regulation reserves have been identified as necessary to compensate variations due to load and RE in the seconds timeframe.

The Central Electricity Regulatory Commission (CERC) outlined a roadmap in October 2015 for implementing reserves in the country in a phased manner. An important requirement in this regard is the implementation of AGC for enabling Secondary Control. POSOCO has outlined the need to implement AGC pilots across the regions in the grid and covering all forms of generation (thermal, hydel and RE) before regulations and procedures for a nation-wide launch can be framed.

The first pilot on AGC is under implementation in India by POSOCO in collaboration with NTPC in the Northern Region at the Dadri coal-based generation station of NTPC. The AGC pilot setup and test runs have been completed at National Load Dispatch Center (NLDC) and at NTPC, Dadri and a regulatory approval was obtained in December 2017 to transit to commercial operation. POSOCO in discussions with GTG-RISE proposed a pilot in the Southern Region encompassing hydro generator(s), a solar power plant and a wind power plant. This was accepted by GTG-RISE and discussions initiated with state-owned utilities in Karnataka to explore their willingness to be part of this pilot. One of the pilots implemented under USAID’s Greening the Grid (GTG)-RISE Initiative is intended to support adoption of AGC for hydro, solar and wind power plants in the southern region.

Pilot Scope & Outcome

The pilot will demonstrate the techno-economic benefits of AGC and aid in the development of a scalable roadmap for the policy makers and regulators for countrywide adoption of AGC.

The GTG-RISE Initiative, in collaboration with Karnataka Power Corporation Limited (KPCL), Karnataka Power Transmission Corporation Limited (KPTCL) and NTPC Limited, is implementing this pilot to enhance the ancillary reserves in Karnataka and Andhra Pradesh. The GTG-RISE pilot will assess AGC’s ability to provide a secondary response in southern India. The pilot will cover both hydel and renewable power plants and identify technical requirements and compensation mechanisms for those generation units that participate in the AGC secondary reserve market. The key activities under this pilot are enhancement of existing control facilities at two hydro units at Varahi and Sharavathi, one solar power plant at NP-Kunta, and one wind farm in Karnataka.

The pilot will demonstrate the techno-economic benefits of AGC and aid in the development of a scalable roadmap for the policy makers and regulators for adoption of AGC. This pilot is part of a significant national level initiative to test AGC before implementing CERC’s mandatory roll out of AGC across all inter-state stations as contained in its Order dated 13 October 2015.

Stage 1: Conceptualization & Pilot Implementation

  • Technical due diligence and pre feasibility assessment of AGC
  • Selection of Implementing Agencies
  • Demonstration of AGC pilot on Hydro and RE Plants in Southern India

Stage 2: Compensation framework for AGC support

  • Develop compensation framework for enabling AGC support from Hydro and Solar generation.
  • Design, Modeling and implementation of economic evaluation

Stage 3: Scale Up

  • Pre-feasibility studies for scaling roll-out across all regional and national power plants
  • Recommendation on regulation, policy and market framework

Pilot Progress

Supporting 1765 MW Hydel and 250 MW Solar power generation plants on deployment of Automatic Generation Control (AGC) that shall provide the experience and pathway for a national rollout covering 67 inter-state stations. The AGC pilot shall provide insights to regulatory market-based framework for harnessing flexibility from various energy sources in the grid to meet short-term imbalances in the system.

Key activities in this pilot includes upgrade of software and communication infrastructure to enable AGC support from hydro, solar and wind units for a period of 3-6 months with recording of system parameters and generator response. Software updates will be required at both the generation and system operator ends and adequate supervisory control and data acquisition (SCADA) and communication links are required to be established.

Following in-principle approval of KPCL and KPTCL in Karnataka, a joint team of GTG-RISE, KPTCL-SLDC and KPCL undertook field visits to Varahi and Sharavati Power Plants in October 2017 and 10 MW Solar Power Plant at Shivanasamudra in December 2017. Specific enhancements at these power plants as well as at the SLDC have been identified for enabling and testing AGC.

Towards this, Grantee(s) for carrying out enhancements of existing Energy Management Systems and communication network at the select pilot generation sites (Varahi and Sharavati Power Plants) has been appointed in December 2018.

In addition, based on suggestion from POSOCO, a 250 MW solar plant at NP Kunta (commissioned by NPTC) is selected for the AGC pilot and the selection process for the grantees has been commenced.

Part A of this pilot shall also document the key learnings from AGC enablement for hydro, wind and solar units and carry out an assessment of the balancing support which AGC can provide at regional / national level with increasing RE penetration.

Next Steps

  • GTG-RISE is currently evaluating potential partners for demonstration of AGC from renewables (solar and wind) in southern India and have initiated discussion with private developer and is looking forward to have a partnership for demonstrating AGC for solar and wind generating units.
  • Implementation of AGC (Hydro) are expected to be completed by April 2019 and testing proposed over June-September 2019
  • Inputs to CERC for developing regulations for AGC’s phased implementation with accompanying compensation mechanisms.
  • Demonstrate benefits of AGC to grid operators and assist SERC in setting appropriate levels of incentives in retail tariffs

After the successful demonstration of AGC pilot, RISE will focus on analysis and development of a proposed compensation framework for enabling AGC support from various types of generating units in the country, which shall inform CERC in framing necessary regulations in this regard.
Inferences shall be drawn from international experiences on pricing and compensation for generators operating on AGC mode for secondary response ancillary services. The scope of the study also includes assessment of comparative benefits of AGC as secondary reserves over other options such as storage, thermal flexibility etc.
NREL, which has conducted grid modelling studies at the national and regional level for the Indian power system shall be a key partner in providing inputs on commercial aspects of enabling AGC through production cost modelling simulation snapshots and defining the framework for the analysis and in peer reviewing the outputs of the international firm, which shall undertake the detailed modelling exercise.
Additionally, the pilot intends to outline pathways for devising suitable compensation mechanisms for secondary control through AGC which shall be inputs for CERC to specify necessary regulations in this regard.

Events & Activities

To share knowledge with and train stakeholders, various workshops, bootcamps and executive exchange programs have been organized, under the USAID’s GTG program, on AGC so far.

Pilot Review Board (PRB)

The central component of GTG, RISE initiative, aims to design, implement and scale-up series of prioritized innovation pilots that support the integration of RE into the grid. Each pilot has its own implementation roadmap, stakeholder commitments, coordination and collaborations and periodic reviews by appropriate Government and regulatory counterparts. Towards this, a ‘Pilot Review Board’ (PRB) has been established for each pilot with an aim to promote transparency, ownership and accountability with the key GOI counterpart and other key stakeholders. PRB envisages to guide to address challenges, support stakeholder participation, help promote pilot awareness and lessons learned, and contribute to the sustainability of the individual pilots. PRBs is also there to review the ongoing performance of pilot activities and to recommend corrective action to maximize sustainability and minimize risk if any. Likewise PRBs will also review the challenges met or overcome in the scaling of pilot activities and make recommendations to support scaling.

PRB Structure and Members

Each innovative pilot requires different skill sets of technical expertise and respectively necessitates separate PRB for the pilot. The nominated PRB members represent policy makers, state and central regulatory bodies, grid operators, relevant utilities and even representatives from Original Equipment Manufacturers (OEMs)/Associations. Supported by GTG-RISE team, USAID’s Contracting Officer Representative (COR) for GTG-RISE initiative is the convener of the PRB. The PRB Members details for pilot on flexible operation of coal power plants are provided below:

Member Name Member Designation Member Organization
N Nallarasan Sr. General Manager POSOCO
Phanisankar Chilukuri Dy. Manager POSOCO
Ravindra Kadam Advisor-RE CERC
V Ponnuraj Managing Director KPCL
Dr. S. Selvakumar Managing Director KPTCL
Sri Shambhu Dayal Meena Chairman Karnataka Electricity Regulatory Commission (KERC)
K Balaraman Founder and Executive Director National Institute of Wind Energy (NIWE)
Monali Zeya Hazra Contracting Officer Representation (COR) USAID/India GTG-RISE
Shubhranshu Patnaik Chief of Party (COP) USAID GTG-RISE Initiative