Power System Operation Corporation Limited (POSOCO) has grown from strength to strength in managing the rapidly expanding and increasingly complex national grid. With greater integration of renewables, POSOCO is moving to the next level forecasting and scheduling, as well as calling for greater flexibilisation. In an exclusive interview with Power Line, K.V.S Baba, chairman and managing director, POSOCO, shares his views on grid management, challenges as well as the way forward for the national grid operator…
What is your perspective on the current state of the power sector?
The importance of a reliable and secure power system has never been more evident than during such an uncertain time. Through the challenges of the pandemic, POSOCO has fulfilled the mission of maintaining grid reliability and efficient administering of the wholesale electricity market just as we have across more than a decade in history. With the lifting of the lockdowns, normalisation to historical behavioural demand patterns is being observed. Given the reduced electricity demand during the lockdown, the relative share from renewables increased in the generation mix. The spot prices of power, compared to those in the previous year, are on a lower side, mainly reflecting adequacy in the system. The challenges and uncertainties associated with the Covid-19 pandemic still lie before us.
What have been the trends observed in power generation and demand?
On the renewables front, the average wind generation recorded in August 2020 stood at 291 GWh per day, which was 4.8 per cent higher than that in the previous year. Further, the average solar generation in August 2020 was 133 GWh per day, which was 27.2 per cent higher than that in the previous year. The maximum all-India demand recorded in August 2020 was around 167 GW, which was about 6 per cent lower than the 177 GW observed in August 2019. The daily average energy consumption recorded in August 2019 and 2020 hovered around 3.5-3.6 TWh. The average cross-border exchange with neighbouring countries in August 2020 was around 15 per cent higher than that in August 2019. In the past few months, many states such as Rajasthan (280.2 MUs), Haryana (241 MUs), Punjab (302 MUs), Bihar (121.6 MUs), Assam (38.1 MUs) and the northern region (1,520 MUs), had a record energy consumption in a day. Also, the state of Uttar Pradesh (22,110 MW) and the northern region (68,605 MW) met the all-time highest peak demand. One of the best all-day grid frequency was observed on July 22, 2020, when frequency remained within the Indian Electricity Grid Code (IEGC) band for 87.84 per cent of the time, with a frequency variation index of 0.018.
How have grid operations evolved over the years and how are they expected to change?
The increase in system size over the years and the rise in interregional power transfers have certainly required ramping of efforts by POSOCO. The system operator has to be proactive for maintaining reliability, which is a priority. The commissioning of power electronics devices in the grid such as high voltage direct current (HVDC), (static synchronous compensator), STATCOM inverters, etc., requires an in-depth analysis of their behaviours and POSOCO is following the developments very closely. Given that the integration of a large amount of renewables is the key agenda of the country for a sustainable future, improving the flexibility of all resources is essential. The ramping capability of generators is one of the key areas for renewable integration.
How did the grid perform in the past year?
The reliable operation of the Indian grid has led to an improved frequency profile, with minimal grid incidents, meeting a record demand of 182 GW. Growth in electricity demand also saw a temporary halt due to the Covid-19 outbreak, similar to other sectors in the country and across the world. It is pertinent to bring out here that despite the reduction in electricity demand over the past months, POSOCO has continued to contribute in the formulation and implementation of the regulatory framework and initiatives in areas such as secondary control through automatic generation control (AGC), security constrained economic despatch, introduction of gate closure and real-time market (RTM), and national open access registry, among others.
We are very happy to share that POSOCO very successfully handled the annular solar eclipse phenomenon that occurred on December 26, 2019 and June 21, 2020, wherein more than 6.5 GW and 11 GW of reduction in solar generation, respectively, was observed. Further, POSOCO, as the nodal agency for disaster management in the power sector, coordinated for preventive measures and quick restoration of power systems of the affected regions during natural calamities such as Cyclone Fani in the eastern coast in May 2019, and Cyclone Vayu and Cyclone Maha on the western coast in June 2019 and November 2019 respectively.
What are your views on the growing flexibility requirements of the grid?
The maximum penetration of wind and solar in daily energy met has touched 15.1 per cent, with the maximum instantaneous percentage of wind and solar in all-India demand met being 19.4 per cent. However, some states are observing a much higher penetration of renewables with the instantaneous penetration crossing 90 per cent. With increasing penetration of renewable energy sources in the Indian power system, real-time system operation is facing the challenge of balancing variable renewable energy. In order to manage the variability associated with renewable energy-based generation as well as the increasing ramp in all-India demand, the flexibility attributes of conventional power plants need to be effectively harnessed.
Although the technical minimum level (minimum operational level) for coal-fired plants under the jurisdiction of the CERC has been brought down to 55 per cent, plants under the jurisdiction of the state commissions are yet to implement the same. In order to avoid network congestion or renewable energy curtailment in the future, it is imperative that a comprehensive review of the operation of conventional power plants (including gas and future nuclear) at the minimum possible level be carried out and necessary provisions in this regard be incorporated in the existing state regulations. Similarly, the flexibility in transmission is being achieved using flexible AC transmission systems (FACTS) and HVDC links.
In June 2020, a pan-India RTM in electricity was implemented, allowing consumers including discoms to buy or sell power just one hour ahead of delivery. The introduction of the RTM has brought the required flexibility in the market to provide real-time balance, while ensuring optimal utilisation of the available surplus capacity in the system.
What are POSOCO’s plans to move to the next level of demand forecasting?
An artificial neural network-based algorithm has been developed in-house by POSOCO for forecasting the all-India demand. Day-ahead forecasting with real-time correction on an hourly basis has been implemented. Load forecasting will become complex day by day with the growing penetration of behind-the-meter technologies, such as solar, electric vehicles (EVs), batteries, etc. There is a need to obtain further information on behind-the-meter resource characteristics. There is a need for optimal use of multiple forecast providers and methodologies such as renewable forecast, weather forecast and load forecast. POSOCO is working with the academic and research community to enhance numerical weather prediction models; specifically, ensemble forecasting. In addition to our in-house efforts, we are in continuous dialogue with other stakeholders, such as states, to adopt scientific methodology for demand forecasting. Further, we are collaborating with the Indian Space Research Organisation and the Indian Meteorological Department for geospatial information and weather parameters.
What are the key challenges faced in grid operations?
Today’s electrical grid is experiencing many challenges, including a changing generation landscape with increasing renewable and remote generation, an ageing AC transmission infrastructure and an increasing global demand for electricity. Another interesting challenge is the changing demand pattern. These challenges are overstressing the existing infrastructure, resulting in operation closer to grid stability limits. The future of the power system would be to have more integration of clean energy sources. The application of HVDC and FACTS would provide performance solutions for network control. It would also include applications of EVs. The development of distributed energy resources and demand response, and future changes in the distribution system would lead to bidirectional power flows.
Operational challenges include fast ramping, variability, potential grid instabilities resulting from loss of inertia, loss of visibility and controllability of behind-the-meter resources, load stagnation/ oversupply, inadequate communication interfaces and operator training.
What is your outlook for the power sector?
POSOCO has a significant and critical role in the energy value chain and hence, needs to be quick in adapting while also mitigating new risks. One of the key priorities of POSOCO is to implement the framework for reserves along with primary and secondary frequency controls. The deployment of AGC in thermal and hydro interstate generating stations as per the CERC’s order is being done on a priority basis. Load and generation forecasting (including renewables) is another thrust area to manage uncertainties on account of load and renewable variations.
Looking ahead, we recognise a paradigm shift from the common denominator of reliability, at least cost, to a more complex algorithm-based optimisation, also incorporating a diverse generation and demand mix. POSOCO is focused on improving grid resilience and making the grid self-healing to adapt to natural calamities and climate change phenomena. In view of cross-border interconnections, POSOCO’s role would be pivotal beyond the countries’ boundaries. Further, POSOCO would hand-hold the emerging economies to have reliable and secure grid operation along with a robust electricity market.