|Fig. 1: Rooftop Solar Panels on the Convention Centre in Kolkata, India. (Source: Wikimedia Commons)|
A major limitation of electricity is that when it is generated, regardless of the source, it needs to be consumed instantly.  This factor has led a push for energy storage capabilities across the globe. India is no exception as the second most populous country in world looks to provide for energy consumption that has nearly doubled since 2000.  Historical advancements in energy storage capabilities have come in the way of batteries and accumulators. India currently utilizes lead-acid batteries as their primary means of energy storage. 
Recent advancements in potential applications of energy storage as well as a global push toward more sustainable energy production and use has created demand to replace conventional storage solutions and create larger scale solutions in order to keep up. India has also set an ambitious target to reach a renewable energy capacity of 175 GW by 2022, furthering the necessity to develop storage capabilities to maintain and further the grid's flexibility and reliability.  Furthermore, in most simulations, pumped hydro storage is the main form of storage considered, but India only has 6 GW of pumped hydro storage identified, and after a nationwide power outage in July of 2012 there are strict, low limits on movement of power between states that has not been scheduled.  These challenges make for a large, necessary market to fulfill demand with both known and unforeseen difficulties.
The necessity of advancements in energy storage prompted the Central Electricity Regulatory Commission in India to announce in August of 2015 that it would be mandatory to have generation reserves in place, allowing storage providers to participate in the bidding.  Unfortunately the lack of technical expertise, questions in pricing, and high entry costs have made the market slow to emerge, but recent advancement on a 28-megawatt-hour battery plant in the Andaman and Nicobar Islands hope to kick-start the utility-scale market.  The project was tendered by state- owned coal mining company NLC India and won by Indian EPC provider Mahindra Susten. They were one of ten companies who pitched in on the bidding, showing indications that demand is there for solar-plus-storage projects fueled by desirable economic and environmental perspectives. This demand is additionally backed by the Government of India targeting 40 GW of solar-power to be achieved through roof-top installations by the year 2022 and the implications and applications of corresponding battery and energy storage technologies.  An example of such roof-top installations is shown in Fig. 1.
While the Indian government has set ambitious goals in an attempt to drive demand and production of emerging energy storage technologies, the time and cost to create such energy storage is what ultimately deters progress. The scale of which the Indian Government has proposed a transition to renewable energy simply does not seem to be financially supported within the outlined time frame. According to the BP Statistical Review of World Energy 2017, India used over
|1400 TWh||=||1400 × 1012 Wh||=||1.4 × 1015 Wh||=||1.5 × 106 GWh|
|=||5.04 × 1018 joules|
in 2016.  Breaking this massive amount of energy down to daily use, we find that India used about 3835 GWH per day in 2016. Dividing further (by 24hrs) we find that India's average power consumption in 2016 was 160 GW. The vast majority of this came from non-renewable resources.
With battery storage costs around $3 per watt for the necessary ~10 hours of storage, we find a total cost of $3 Watt-1 × 160 × 109 Watts = $480 billion, not including maintenance costs, to stabilize renewable energy in India. Furthermore, while India's target of 175 GW by 2022 accounts for the rising demand of electric power and looks to provide for their energy demand, it fails to identify a means for achieving it. The goal of 40 GW of rooftop solar cells by 2022 is great in theory, but with a mere 800 MW from current installations as of 2016 it seems like a great stretch financially with troubling further questions of whether this is even constructible within the given time frame. 
The intermittent nature of solar and wind energy combined with large variations of energy demand throughout the day require that in order to make renewable resources sustainable, a daily storage capacity of at least 1/3 of the total daily usage is necessary. And while India makes progress toward this with the Andaman and Nicobar Islands storage facility, it only accounts for a miniscule fraction of this need. Dividing India's total energy use in 1 day by 3, we obtain 3835 GWh / 3 = 1278 GWh. The 28 MWh capability of the facility only amounts to 0.0000219 of this. (28 MWh/1278 GWh = 2.8 × 107 Wh / 1.278 × 1012 Wh = 2.19 × 10-5 = 0.0000219) These pressing questions of feasibility and capability reveal major gaps in India's policy targets and action with regards to achieving large scale and sustainable renewable energy.
Fueled by recent advancements in energy storage applications for renewable energy, demand for a utility-scale market is present. Currently dominated by lead-acid battery storage, drawbacks such as limited depth of discharge, cycle life, and other technical challenges, demand is shifting towards advanced battery chemistries with longer cycle life and higher depth of discharge.  Lack of technical expertise and questions revolving around the economics of such systems have forced the marked to be slow to emerge, but recent advancements in large-scale battery plants suggest demand is continuing to increase, backed by sustainability perspectives. Although the Indian Government has set very ambitious goals for obtaining large scale renewable energy, major questions and limitations revolving around the feasibility and capability of establishing necessary systems are what keep such goals from becoming reality.
© Boomer Fleming. The author warrants that the work is the author's own and that Stanford University provided no input other than typesetting and referencing guidelines. The author grants permission to copy, distribute and display this work in unaltered form, with attribution to the author, for noncommercial purposes only. All other rights, including commercial rights, are reserved to the author.
 N. Kuldeep et al., "Energy Storage In India," Council On Energy, Environment, and Water, November 2016.
 "India Energy Outlook," International Energy Agency, 2015.
 J. Deign, "India Takes the First Steps Toward a Utility-Scale Energy Storage Market," Greentech Media, 29 Oct 17.
 "BP Statistical Review of World Energy 2017," British Petroleum, June 2017.