Que: What does ‘flexibility’ truly mean for India’s power ecosystem today?

Ans: Flexibility means the power system can respond fast when variable renewable energy output changes, demand rises or drops sharply, or grid conditions shift. As renewable capacity grows, the challenge has moved beyond just adding megawatts. It is making sure the system can absorb and use that green power reliably and affordably.

Today in India, curtailment and grid stress are already visible. In Rajasthan, roughly 3-4 GW of solar and wind have been curtailed since March 2025, with estimated losses of INR 250 crore. In Tamil Nadu, up to 70 million units of renewable power were wasted in a single week in May 2025. These are signs that India's energy transition has entered a more complex phase. Building solar and wind capacity was the first challenge. Absorbing that green power to the maximum extent and delivering it reliably is the next one, and flexibility is what makes it possible. To do this, India needs fast-ramping balancing power through energy storage, gas-based internal combustion engine plants, and stronger transmission, working together to absorb renewable fluctuations and keep the grid stable. This is what flexibility means for India, and it will determine whether India's renewable ambition translates into reliable, affordable power for everyone.

Que: What is the ideal mix of storage, flexible generation, and renewables for a resilient and cost-effective grid?

Ans: India needs a balanced system where renewables, storage, and flexible generation each play the role they are genuinely suited for. Renewables will soon emerge as the backbone of the grid because they are the cleanest and lowest-cost source of new power. Batteries are essential for fast response, frequency support, and short-duration energy shifting, and their momentum is real: India's battery energy storage capacity is expected to surge nearly tenfold to around 5 GWh in 2026, up from 507 MWh in 2025.

But batteries cover only part of the balancing need. India's peak demand arrives during evening hours, once solar generation drops. Those non-solar peaks last 5 to 6 hours in the evening and 2-3 hours in the morning, well beyond what battery storage can practically and economically cover. It calls for flexible generation that can dispatch on demand and sustain output across those hours. A joint study by Wärtsilä and KPMG found that by 2030, India will need at least 9 GW of flexible gas-based engine power plants alongside 38 GW of battery storage for balancing and ancillary services.

These technologies are complementary. Deploying them together creates a more resilient and more affordable system than either can deliver alone.

Que: How does advanced system modelling help utilities and large energy users optimise their power systems? Can you share examples?

Ans: Advanced system modelling helps decision-makers see the full picture. Instead of evaluating one technology in isolation, it shows how generation, storage, fuel, demand, transmission, and emissions interact across the whole system, hour by hour. That matters because the cheapest plant on paper is not always the lowest-cost answer for the grid. In systems with high renewable penetration, total system cost, including balancing, transmission utilisation, and reliability under peak conditions, is a far more meaningful measure than per-unit generation cost alone.

At Wärtsilä, we use PLEXOS modelling to identify the least-cost, lowest-emission pathway while maintaining reliability. We have completed more than 200 power system analyses globally. In Finland, our modelling showed that, with the current power system, electricity prices will be 30 percent higher by 2027 compared to 2023. Adding 2 GW of firm and flexible balancing power could reduce electricity costs by 10 percent, equivalent to EUR 1.3 billion. In Chile, combining renewables, storage, and balancing power could save USD 17 billion by 2045. Globally, our crossroads to net zero report found that a balanced pathway, incorporating flexible generation alongside renewables and storage, is 42 percent less costly than a renewables-and-storage-only approach, translating to a saving of over EUR 65 trillion from 2025 to 2050.

These cases point to the same conclusion. Without sufficient flexibility, power systems tend to compensate by oversizing renewable and storage capacity, which drives up costs even when individual technology tariffs are low. Modelling is what makes that visible before investment decisions are locked in.

Que: What innovations is Wärtsilä bringing in to enhance the efficiency and responsiveness of gas-based power plants?

Ans: Wärtsilä's engine power plants are well-suited to the demands of a renewable-heavy grid. They have no minimum up or downtime, meaning they can start or stop rapidly as needed, and ramp from zero to full load in around two minutes. Unlike coal plants or combined-cycle gas turbines, engines maintain high efficiency at different outputs, which is critical when operating as a balancing asset.

Beyond core performance, two innovations are extending what these plants can do in high-renewable systems. The first is our synchronous condenser feature, deployed for the first time in a 120 MW plant in Kalgoorlie, Western Australia. It allows generators to provide reactive power support and inertia independently of the engines, strengthening grid voltage and frequency stability precisely when renewable input is at its highest.

The second is the WISE (Wide and Intelligent Sustainable Energy) initiative, a Wärtsilä-led EUR 200 million collaboration ecosystem of over 200 Finnish organisations, working toward autonomous balancing power plants designed to run on 100 percent e-fuels such as green hydrogen. It represents our long-term commitment to making flexible generation fully compatible with a zero-emission energy system.

Today, our engines can already operate on up to 100 percent natural gas, and 100 percent hydrogen-capable power plant solutions are also available. The assets supporting grid stability now are the same assets that will support deeper decarbonisation over time, protecting investments made today from becoming stranded.

Que: How can India strike the right balance between sustainability, reliability, and affordability?

Ans: These three goals are often presented as competing priorities, but they are deeply connected. The key is system-level planning rather than asset-level planning. When policymakers and planners focus only on the lowest per-unit generation cost, they miss the full picture. Renewable energy tariffs may be low, but without adequate flexibility, systems compensate by overbuilding capacity, cycling coal plants inefficiently, and curtailing clean generation. All of these add cost and undermine both reliability and sustainability.

The consequences are already measurable in India. Baseload plants cycling to balance renewables operate at 55 to 65 percent plant load factor (PLF) against a norm of 85 percent, well below the level at which they are designed to run efficiently. The system is already paying a growing cost to manage renewable variability through assets that were never built for that role. Without sufficient flexibility, that cost will only increase as renewable penetration rises.

India has the foundation to get this right. According to IRENA, the country is now the world's third-largest renewable energy market, with total renewable energy capacity reaching approximately 250 GW as of 2025, and has raised its ambition to 60 percent of installed power capacity from non-fossil sources by 2035. The challenge now is ensuring that capacity translates into reliable, cost-effective power.

That requires an energy mix where coal and renewables do the heavy lifting (flat baseload), while storage and flexible balancing power keep the system stable and efficient. The next phase of the transition will be defined not only by how much clean energy India adds, but by how intelligently that system is designed and operated.

Que: What policy or regulatory interventions are needed to accelerate the adoption of flexible power solutions?

Ans: India is on a transformative journey, and the policy framework is being amended to adapt to the new normal in the power sector. The Draft National Electricity Policy 2026 explicitly emphasises resource adequacy planning and grid reliability alongside renewable integration, which is a welcome signal that system-level thinking is entering mainstream policy. Strategic planning for future power systems and capacity additions must be guided by data to achieve a rapid transition and a cost-optimal technology mix for affordable electricity.

The first priority is enabling an accelerated expansion of renewables and balancing technologies together. This means upgrading transmission systems, streamlining permitting processes, and investing in storage and flexible generation technologies. Financing must be mobilised to support this at the necessary scale and speed to reduce reliance on inflexible assets and accelerate emissions reductions.

The second is redesigning electricity markets to incentivise flexibility. Markets should move toward five-minute dispatch granularity, with new ancillary services covering clearly defined primary, secondary, and tertiary reserves, alongside ramping, voltage, and inertia products introduced as renewable penetration rises. Bankable revenue models for low-running-hour balancing power plants, including flexibility-linked capacity payments and scarcity pricing, are essential to attract the right investment. A Wärtsilä-KPMG power system study underscored this need, particularly in renewable-rich states like Gujarat, Tamil Nadu, Maharashtra, and Rajasthan.

The third is choosing future-proof technologies and preparing for sustainable fuels. Balancing technologies deployed today should be ready for green hydrogen and other e-fuels from the mid-2030s onward. Natural gas bridges the transition. Green hydrogen completes it.

India has the ambition and the renewable momentum. Now it needs the right policy framework to support flexibility infrastructure, as well as the market design and the right technology selection to match.