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A recent grid oscillation recorded in Rajasthan was reportedly felt as far as Kudankulam, Tamil Nadu, highlighting the growing stress within India’s national electricity grid. The incident has drawn attention to structural challenges in managing the rapid expansion of renewable energy while ensuring grid stability.

What are Grid Oscillations?

Grid oscillations refer to rapid fluctuations in voltage and frequency within the power transmission network. These fluctuations typically arise when there is a sudden mismatch between electricity generation and demand.

With increasing penetration of solar and wind energy, which are inherently variable and weather-dependent, the grid faces intermittent supply conditions. When not balanced properly, such variations can:

• Destabilise transmission voltage and frequency
• Damage equipment
• Trigger cascading failures
• Lead to large-scale blackouts

The recent oscillation event underscores the sensitivity of interconnected grids across long distances in India’s unified national grid.

Key Reasons for Grid Instability

• Limited Grid Flexibility and Automation: India’s grid is not yet sufficiently “smart” to seamlessly switch between conventional (coal-based) and renewable sources. Inadequate automation, limited real-time balancing mechanisms, and weak forecasting systems restrict efficient load management.
• Coal Plant Inflexibility: Coal-fired power plants are designed primarily for baseload supply, operating at steady output levels. They cannot ramp up or down rapidly to compensate for sudden drops or surges in renewable generation. This structural rigidity makes balancing intermittent sources difficult.
• Inadequate Energy Storage Infrastructure: Large-scale battery storage and pumped hydro facilities remain limited. Without sufficient storage:
  • Surplus renewable energy cannot be stored for later use.
  • Sudden drops in renewable output create supply gaps.
  • Grid stability becomes vulnerable during peak fluctuations.

India’s Renewable Energy Expansion

India has made significant strides in renewable energy capacity:

• 48 GW of renewable capacity was added in 2025, the highest-ever annual addition.
• Non-fossil sources now account for approximately 52% of installed capacity (around 264 GW).

However, a critical structural gap remains:

• Despite the large installed renewable capacity, nearly 75% of actual electricity generation still comes from coal because it provides reliable, on-demand power.

This highlights the distinction between installed capacity and actual generation share, an important concept for energy policy analysis.

Structural and Policy Implications

• Need for Smart Grid Modernisation: Deployment of advanced forecasting tools, AI-based load management, and automated switching systems is essential to manage renewable variability.
• Flexible Thermal Operations: Retrofitting coal plants for flexible operations can improve ramping capability and support renewable balancing.
• Energy Storage Expansion: Investment in:
  • Grid-scale battery storage
  • Pumped hydro storage
  • Green hydrogen-based storage is critical for long-term stability.
• Grid Infrastructure Strengthening: Transmission upgrades under initiatives like the Green Energy Corridors must be accelerated to integrate renewable-rich regions with demand centres.