Integrating renewable energy: An enabling technology framework is essential

One of the challenges confronting India’s efforts to expand renewable energy (RE) is the suboptimal absorption of RE power in the national grid. Although RE — principally solar, wind, and hydroelectric — stands at over 40 per cent of installed generation capacity, coal-based fossil fuels continue to account for 78 per cent of generation. This gap reflects the difficulties the national grid faces in absorbing RE power. As a recent report in this paper pointed out, the principal challenge in grid management lies in handling “too much RE power”. Addressing this unique problem of smoothly integrating RE within grid systems in a sustained manner is vital if India is to achieve its target of 500 Gw from renewable sources by 2030.

 

RE is intermittent in nature, peaking during daylight hours, creating oversupply, whereas peak demand typically occurs in the evening. During this peak time, reliance on RE drops sharply, requiring immediate backups from chiefly coal-based thermal power. But sudden spikes, surges, and drops in RE generation can cause massive grid disruption, including outages. Spain’s power blackout last month, for instance, has been attributed to the sudden and steep drop in solar-power generation. Last year, solar-rich states in India also faced local outages during peak summer demand. As of now, executives of Grid India, the country’s grid operator, are exploring options to manage this demand-supply mismatch, including running thermal power in two shifts — during the morning and after sunset — and taking it offline during the solar hours. The other option is to run thermal-power plants at a heat rate of 40-55 per cent and ramp up whenever RE falls short (the heat rate refers to the ratio of thermal-energy input to electrical-energy output). The Central Electricity Regulatory Commission is exploring regulations to compensate thermal-power generators for reducing the heat rate.

 

All these approaches, though important, cannot be sustainable substitutes for creating a robust infrastructure of battery-energy storage. According to the Central Electricity Authority (CEA), the government’s advisory body on power-policy planning, India will need 74 Gw of energy-storage capacity to support plans to integrate higher levels of solar and wind capacity into the grid. Indeed, the CEA recently issued an advisory mandating the colocation of energy-storage systems with solar-power projects. The CEA has also mandated that all RE-operating agencies incorporate two hours of colocated energy storage in future tenders. Battery Energy Storage Systems (BESS) are found to be the most efficient technology in balancing power supply from RE sources. But India has installed a BESS capacity of 219 MwH and an additional 4.7 Gw of operational pumped hydro-storage capacity. China, by contrast, has a well-established BESS value chain and storage capacity is likely to exceed 70 Gw this year. In India, the adoption of BESS technology remains mired in policy uncertainties linked to cost (owing to its heavy reliance on relatively expensive and import-dependent lithium-ion technology), lack of pricing guarantees and capital offset rules, and an absence of guidelines for waste management. If RE is to become an integral part of India’s rapidly expanding energy demand, working through the basic policy hurdles to BESS technology adoption would be a good beginning.