Introduction 

Grid Flexibility is defined as the power system’s capability and its resources to respond swiftly and reliably to maintain generation-demand balance. A truly flexible system ramps generation up or down, shifts or curtails demand when needed, stores surplus energy for later use, and uses transmission and distribution networks efficiently to move power across regions. Together, these elements enable the system to maintain frequency stability, balance supply and demand across multiple time horizons, and integrate large shares of renewable energy without compromising reliability. 

Flexibility requirements emerge across different time-horizons: 

• Seconds to minutes: Frequency containment, inertia response. 

• Minutes to hours: Balancing net load variations. 

• Hours to days: Handling daily solar ramps, low-wind conditions. 

• Weeks to seasons: Coping with seasonal RE and hydro variations. 

Why Flexibility Matters 

Electricity is unlike any other commodity. For a power system to function reliably, supply and demand must be matched continuously and instantaneously. Even small imbalances, whether excess generation or shortages can destabilize the grid and potentially trigger a blackout, recovery from which may take hours or even days. Unlike oil or gas, electricity cannot yet be stored in a cost-effective manner, meaning generation and consumption must be balanced at every moment. 

The variability in solar and wind output, combined with traditional fluctuations in demand, has made grid operations more complex. In addition, renewable generation is increasingly decentralized, with thousands of small units connected at the distribution level. Most distribution systems were designed for one-way power flows from large central plants to consumers, so the rise of distributed energy resources has created new congestion and visibility issues. 

Flexibility, therefore, has become a cornerstone of modern power systems. A flexibility assessment evaluates whether the existing and planned system can handle these challenges of variability and uncertainty. Without such assessments, a grid may appear adequate in terms of installed megawatts but still fail during critical ramping events. Assessments help identify gaps in the system’s ability to respond dynamically and, guide regulators and operators in designing procurement mechanisms, market products, and infrastructure investments to remove these gaps. In India, which has committed to achieving 500 GW of non-fossil capacity by 2030, flexibility assessments are essential to integrate renewable energy at least cost, minimize curtailment, and reduce reliance on emergency measures such as load shedding. 

Need for Flexibility Assessment 

Why Regulation is Needed 

Reliability and grid security are classic public goods once provided, all consumers benefit, and no single actor can be excluded. Flexibility, in turn, is the key capability that enables reliability in a modern power system marked by variable renewable generation, demand fluctuations, and unexpected contingencies. However, individual utilities or generators often have little incentive to provide flexibility, since the costs are borne privately while the benefits follow system wide. For example, operating a thermal plant at a lower technical minimum or maintaining spinning reserves increases costs for operators without direct compensation. Without a regulatory framework, such services are unlikely to be delivered consistently. 

Regulation makes flexibility assessment a mandatory, system-wide exercise. It requires distribution companies, transmission operators, and system operators to collectively evaluate whether the grid can withstand variability, uncertainty, and contingency events. Regulation also establishes standardized methodologies for measuring flexibility such as ramping requirements, reserve margins, and the effective load-carrying capability of renewables and storage. This prevents fragmented, state-level approaches and ensures national consistency. 

Equally important, regulation ensures that flexibility is properly valued and compensated. Without clear market signals or cost-recovery mechanisms, resources such as demand response, battery storage, or fast-ramping generation remain underutilized. By embedding flexibility into the Grid Code and ancillary service frameworks, regulators make it visible, measurable, and enforceable turning it from an optional attribute into a core reliability requirement. 

Regulatory Roles in Flexibility Assessment 

Regulators perform several critical roles in ensuring effective flexibility assessment. They can mandate system operators, POSOCO, RLDCs, SLDCs and planning bodies like the CEA to carry out regular studies. These studies should feed into national and state resource adequacy plans as well as long-term network development. Regulators also standardize the metrics used to measure flexibility, such as ramp rates, load-following ranges, flexibility envelopes, and the system’s ability to absorb renewable forecast errors. 

Another regulatory function is requiring scenario-based studies. Assessments should test not only average conditions but also stress cases with high renewable penetration, extreme weather, or low-inertia systems. This approach ensures the system is resilient under challenging conditions. Furthermore, regulators should require assessments to be comprehensive, recognizing flexibility from both supply and demand-side resources. Gas, hydro, and batteries are important, but demand response, load shifting, and distributed storage must also be integrated into assessments. Finally, regulators can enable procurement mechanisms to value flexibility, such as ancillary service markets, tariff-based incentives, and cost-recovery mechanisms for flexibility-enabling investments like storage or digital grid infrastructure. 

Flexibility in the Indian Grid Code 

The Indian Electricity Grid Code (IEGC) 2023 introduced by CERC embeds flexibility across planning, operations, and dispatch. In the Resource Planning Code, distribution licensees are required to ensure resource adequacy, explicitly including the ability to manage peak demand, renewable variability, and contingency events. The Code highlights that planning must consider not just installed capacity but also flexibility in terms of ramp rates, start-up times, and technical minimums. Non-compliance with adequacy and flexibility requirements can attract regulatory action. 

In the Operating Code, flexibility underpins system security. Frequency must be maintained within a tight band of 49.90–50.05 Hz, which in practice requires ramping and reserves. The Code introduces Secondary and Tertiary Reserves Ancillary Services as formal procurement mechanisms, and recognizes the importance of reserves, black-start capabilities, and islanding schemes as tools of resilience. 

The Scheduling and Dispatch Code further operationalizes flexibility through Security Constrained Unit Commitment and real-time scheduling. These tools allow system operators to optimize dispatch across all generators and storage resources in response to renewable fluctuations. The role of Qualified Coordinating Agencies in aggregating renewable generation and improving scheduling accuracy is also emphasized, reducing system uncertainty. Overall, the IEGC integrates flexibility not as a separate concept but as a cross-cutting requirement embedded in planning, operations, and compliance. 

Flexibility Assessment Challenges 

Despite progress, regulatory and institutional challenges remain. Responsibilities for flexibility are fragmented across multiple actors such as generators, DISCOMs, transmission licensees, system operators, and regulators with no single institution accountable for ensuring sufficient flexibility at the system level. This leads to coordination gaps between central and state institutions. 

Flexibility is also not fully recognized as a distinct service. While reserves and ramping are addressed in the Grid Code and Ancillary Services Regulations, flexibility is not traded as an explicit product with its own price and settlement rules. As a result, resources such as battery storage and demand response remain undervalued. 

Data limitations further constrain flexibility planning. There is no comprehensive registry of flexible assets such as pumped hydro, fast-ramping gas plants, or demand response potential. Distribution companies and state operators often lack accurate data on behind-the-meter resources like rooftop solar or captive plants. 

Incentives for flexible operation are also limited. Thermal plants, which currently provide much of India’s ramping capability, incur higher costs and technical wear when operated flexibly. Without adequate compensation for these costs, operators have little incentive to lower technical minimums or provide rapid ramping. Implementation across states is inconsistent as well. While the Grid Code provides a national framework, state-level application by SERCs and SLDCs varies widely, with some enforcing renewable scheduling and demand-side measures effectively and others lagging. 

Finally, regulatory frameworks have yet to fully adapt to emerging technologies. Storage, electric vehicles, and distributed energy resources can provide significant flexibility, but their participation in markets and adequacy planning remains limited. Likewise, cybersecurity and digitalization, essential for flexible, data-driven grids are not yet fully integrated into regulatory practice. 

To sum up/Highlight 

Flexibility is no longer a secondary consideration; it is central to the reliability, affordability, and sustainability of modern power systems. Flexibility assessments ensure systems remain resilient, not just adequate in installed capacity. Regulation provides the framework to make this assessment systematic, transparent, and enforceable. 

References 

1. Status of Power System Transformation 2019: Power system flexibility – Analysis – IEA 
2. Press Release:Press Information Bureau, 2024 
3. Indian Grid Code 2023 
4. G. Shrimali,  Managing power system flexibility in India via coal plants, Energy Policy, 2021. 
5. IEA, Niti Ayog, Renewables Integration in India 2021