As India edges towards its ambitious renewable energy target, the next challenge will be effective energy storage solutions that can be made in the country. India has embarked on an ambitious programme of accelerating renewable energy deployment in the country. The target for renewable energy has been expanded multi-fold to 175 GW by 2022. A major part of the target is going to be from solar PV (100 GW) and wind energy (60 GW) and the rest from small hydro and biomass plants (5 and 10 GW respectively). India's current installed capacity for solar PV is around 9 GW and wind being a more mature technology is at 29 GW. India's current power generation capacity is around 315 GW. These renewable energy goals are directly translated from India's commitment at the Paris COP21, where the country committed to achieve 40 per cent of renewable energy in its energy mix by the year 2030. In particular, India's solar energy generation programme seems to be at the forefront of rapid cost de-escalation. Earlier in February 2017, India witnessed yet another record low solar tariff of Rs 3.29/kWh (Levelised over 25 years). This tariff is already lower than tariffs for thermal power plants discovered under reverse bidding. 'Bridge to India' reported: “Recent bids for new thermal power capacity in Andhra Pradesh saw tariffs at Rs 4.27/kWh to Rs 4.98/kWh. In 2013, in Rajasthan and Tamil Nadu, thermal power prices were even higher at Rs 5.41/kWh and Rs 5.66/kWh.” These costs do not take into account variability in fuel costs over the lifetime of the thermal power plant, environmental externalities and other social costs that might accrue from these enormous power plants. Simultaneously, solar PV module prices are scheduled to decline. The International Renewable Energy Agency (IRENA) predicts a 59 per cent decline in global PV prices by 2025. Meanwhile, the efficiency of solar panels is also steadily increasing for both mono and poly crystalline configurations. SunPower - a leader in PV module technology recently announced an efficiency of 24.1 per cent at the module level last year. Increased module efficiencies directly translate to a lower land requirement. This is a boon for India - a country that struggles to acquire large tracts of land for any infrastructure project. In this backdrop, it is clear that solar PV technology will become the mainstay energy source of India in the years to come. Challenges The main challenges of renewable energy are three-fold - predictability (inability to predict the power output in a future point of time), variability (non-constancy of power output) and dispatchability (inability to deliver required amount of power). These challenges, while important, were somehow muted given the low quantum of renewable energy on India's grid. However, with the rapid growth in renewable energy and the non-growth in load demand, the penetration of renewable energy on the national grid as well as localised regions of the grid is increasing sharply.

The rapid increase in renewable energy capacity has not resulted in a similar growth in transmission infrastructure in most cases. This has resulted in evacuation bottlenecks in the grid. The states of Tamil Nadu and Rajasthan have been particularly affected. A petition filed by the Indian Wind Power Association (IWPA) estimates that wind energy generators in the state of Tamil Nadu have had to back down to an extent of 50 per cent. Another petition before the Central Electricity Regulatory Commission (CERC) states that for the year 2013-14, wind energy generators lost 33 per cent of the total energy possible. Solar energy developers too have not been spared. The state of Rajasthan also curtailed solar power for the first time in 2016. These instances point to a need for better infrastructure, better forecasting and scheduling regulations and technology and energy storage possibilities. With the price of renewable energy now cost competitive with thermal power, effective grid management is the next technology focus area. This would mean stronger transmission and distribution infrastructure with low down time, advanced communication capabilities that would help the Load Dispatch Centres (LDC) to control and monitor generation and energy storage technologies. One of the severe challenges faced by most LDCs in India today is to manage instant ramping up (or down) of traditional thermal power plants. Figure 1 below shows that ramp rates of 211 MW/min are not uncommon in India. With an increased penetration of renewable energy, especially solar PV, the evening ramp is likely to be exacerbated. Solar PV starts to ramp down in the evening hours and this coincides with an increase in the load. To compound the problem, solar PV's inherent uncertainty could shift tremendous stress on gas and coal power plants to deliver uncertain ramp rates in a relatively short time. Managing this through solar and wind coupled storage for a few hours in the evening is one opportunity for storage solutions. Recent Initiatives The Government of India recognises these challenges and has announced India's first storage tender through the Solar Energy Corporation of India (SECI). SECI has invited solar project developers to install storage solutions along with new solar energy project. The tender is a 100 MW solar tender in the state of Andhra Pradesh and mandates that 50MW of solar projects shall be connected to a storage capacity of 2.5 MWh. SECI has also announced a similar tender for energy storage project in Karnataka, for 200 MW (of 50 MW/2.5 MWh). Although nascent, these steps indicate the direction that India wants to take in terms of creating a vibrant energy storage market in the country. Several international storage players such as NGK Insulators, AES Energy Storage, Sumitomo Electric, LG Chem, Samsung SDI, NEC Energy, BYD, Toshiba, GE and Saft are already in discussion with local partners and are keen to enter the Indian market. Meanwhile the Central Regulator, CERC has recently issued a staff paper on Introduction of energy storage in India. The document highlights various energy storage technologies employed globally, installed capacity in India and potential value chains. These initiatives show that the Indian government is determined about the role that energy storage would play in better managing the grid. Ultimately, any storage solution for India will need to be cost competitive with retail power tariffs. The current rates of energy storage are far too high to justify any large scale application. Chemical battery based technologies average between $/MWh 300 to 500. India should attempt at creating a vast market across its various states to ensure a scale effect, which would in turn bring down prices. India can do well to learn from its experience in bringing down solar PV tariffs through transparent reverse auctions. Once the price for storage comes down as a result of scale, the size of the storage solutions can be proportionally increased. In doing this, India must ensure that it does not make the same mistake that it did with regards to manufacturing solar PV modules in India. India must ensure that it facilitates an ecosystem for energy storage solutions in India to ensure that they are Made in India.

Akhilesh Magal is Head Advisor, Solar Energy, and Souvnik Roy is a Project Officer at the Gujarat Energy Research and Management Institute (GERMI), an institute dedicated to research in the fields of solar energy, energy efficiency, environment and petroleum research.