MC EXCLUSIVE Govt plans battery storage for thermal power plants amid renewable energy fluctuations

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The government is considering battery storage systems for thermal power plants as well to reduce rising operational costs amid frequent renewable energy fluctuations, two power ministry officials have told Moneycontrol.

Until now, the focus has been on storage systems for renewable energy projects, as the electricity produced through them is intermittent. Battery energy storage systems (BESS) help make renewable energy available round-the-clock, especially during evening hours when there is no sunlight for solar power.

“The concept of having BESS for thermal power plants is new since globally, everyone is grappling with the issues arising from higher renewable energy penetration in the electricity grid,” one of the officials cited above said.

The Central Electricity Authority (CEA) is working on how BESS can help thermal power plants improve efficiency, which is being affected due to the frequent need to ramp down during the day when there is “high injection of renewable energy”, especially solar power, into the national grid, the official said.

The CEA is a statutory body that advises the Union government on electricity policy and planning. In a thermal power plant, "ramp down" refers to the controlled reduction of the electricity output or power generation.

The government has already begun including energy storage for renewable projects in its tenders.

Moneycontrol was the first to report on the Centre’s plan to make battery storage mandatory for upcoming renewable energy projects.

The need for energy storage systems in thermal power plants arose after power producers such as state-run NTPC Ltd flagged operational concerns over increased flexibility demanded of their plants.

Why the need?

Thermal power plants now need to be flexible to accommodate the intermittent nature of renewable energy sources such as solar and wind.

Energy storage allows them to absorb excess energy when renewables are overproducing and discharge it when renewables are underperforming, thus maintaining a stable supply.

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Operating thermal power plants at low capacity to allow supply of renewable energy during the day is expensive. This is because low plant load factor (PLF), which is the ratio of actual energy generated to the maximum possible energy that could have been generated, results in fixed costs being spread over a smaller number of units of electricity, driving up the per-unit cost.

Cost of solar power now ranges from Rs 2.5 to Rs 2.9 a unit, while that of thermal power is between Rs 3.5 and Rs 5.

Thermal power plants are designed to operate most efficiently at or near their full capacity. When they run at lower loads, their efficiency decreases, which means power producers spend more on fuel but get less return through energy charges, leading to financial losses.