International Experience Sharing on AGC for Large-Scale Solar Power Plants

International Experience Sharing on AGC for Large-Scale Solar Power Plants

Ensuring reliability of the power system is of central significance to power system operators. This imperative becomes even more critical in the face of increasing penetration of variable renewable energy (RE) into the power grid. As India works to generate and integrate an unprecedented amount of RE, its large and complex grid must be equipped with rapid response capabilities for real-time maintenance of load–generation balance to ensure the grid remains reliable and resilient. Automatic generation control (AGC) is a major control function that can enable grid operators to easily adjust the power output of generators in response to changes in load.

A webinar on March 17, 2021, explored the international experience of AGC operation and dynamic reactive power control (DRPC) in large-scale solar power plants. The webinar was conducted by USAID’s Greening the Grid-Renewable Integration of Sustainable Energy (GTG-RISE) initiative, the central component of a five-year bilateral program between USAID and the Ministry of Power, Government of India. The program is a key Asia EDGE (Enhancing Development and Growth through Energy) initiative and is implemented by Deloitte Consulting.

The webinar provided a platform for disseminating lessons and best practices from international AGC solar implementations. It also provided an opportunity for sharing the key aims and outcomes of an AGC pilot that GTG-RISE is conducting, supported by National Renewable Energy Laboratory (NREL), at National Thermal Power Corporation’s (NTPC) NP Kunta solar plant. Highlighting the importance of the GTG-RISE pilot, Rajiv Porwal, Chief General Manager, Power System Operation Corporation Limited (POSOCO), stated: “We have experiences on AGC at thermal, hydro, and, recently, on gas. USAID’s GTG-RISE is collaborating with NTPC for a landmark pilot on AGC at a solar plant. The learning from this pilot will be of tremendous significance for India’s grid operators to meet the challenge of balancing requirement and ensuring frequency stability. It’ll prove to be of great importance for power producers and system operators in meeting regulatory requirements and defining their future course of action”.

IInternational experts from NREL shared its experience from similar AGC solar pilots in the United States and other countries. Vahan Gevorgian, Chief Engineer, NREL, began by providing the webinar attendees an insight into the energy crisis Texas had faced the previous month (February 2021) and the critical lesson it held with regards grid reliability. Emphasizing on this point in the context of the webinar theme, Gevorgian said: “New reliability challenges are emerging as RE penetration increases and grid operations and system operators need to be ready to manage a more complex grid. A gap exists among various stakeholders on role of PV for provision of essential reliability services to the grid…..accurate data points on high sustainable limits (HSL), maintaining awarded capacity, tolerance bands are must… Having such capability is strategic to enable PV participation in ancillary services markets…”. He went on to discuss in detail the AGC demonstrations NREL had conducted at solar plants in Puerto Rico and Texas, and subsequently in California. Gevorgian also provided information on a new method for estimation of available reserves and on hybrid solar and energy storage plants.

The webinar succeeded in its aim of sharing lessons on AGC solar and stimulating a discussion, as was evident from the numerous questions that were posed to speakers by the attendees. GTG-RISE has been conducting such webinars regularly to build knowledge and support dialogue and advocacy on innovative energy system initiatives and approaches.