Ambitious emission reduction programmes are driving unprecedented amounts of renewable energy into the grid as the world strives to embrace a zero-carbon energy future. Integrating renewable energy resources while also improving the reliability of India’s electric grid is a significant challenge and will require the use of energy storage systems and other modernised grid enhancements to accelerate a successful energy transition.
In 2021, India, an economy traditionally dependent on fossil fuels, pledged at the COP26 conference in Glasgow to increase its non-fossil energy capacity to 500 GW and meet 50 per cent of its energy requirements from renewable energy by 2030, and achieve net zero emissions by 2070. The pledge recognises the deep integration of fossil fuel resources in India’s energy mix and the recurring climate challenges that are stressing the grid assets. These two factors will require significant investment in new generation, transmission and distribution resources.
Wind power is viewed as an increasingly significant element of India’s new energy future. In June 2022, the country announced that it will auction 4 GW of offshore wind per year for a period of three years starting 2022-23 for development off the coast of Tamil Nadu and Gujarat. Solar PV generation at scale will also play an important role in shifting India’s economy from its historic reliance on coal power.
Over the years, India has committed to developing close to 500 renewable energy projects, with a value of about $196 billion, including wind and solar resources.
Enter energy storage
Supportive government policies such as the offshore wind plan and the production-linked incentive (PLI) scheme for high efficiency solar PV modules are encouraging India’s private and public power sectors to aggressively pursue the implementation of large-scale renewable energy generation projects.
While wind and solar power help resolve the climate crisis by replacing fossil fuel energy with zero-emission electricity, their variability creates challenges for power system operators seeking to increase access to reliable power across the country.
Hybrid renewable energy projects pair renewable energy from solar and wind facilities with energy storage systems, including battery energy storage systems (BESSs) and eventually green hydrogen storage. Such combinations improve grid operators’ ability to meet customers’ round-the-clock (RTC) power supply requirement. These systems reduce the risk of curtailment by effectively smoothening electricity prices through arbitrage, management of evening energy ramps and backup power.
So far, several large hybrid projects utilising solar and wind technologies paired with storage solutions have been awarded in India. More public tenders for hybrid projects are expected, mirroring state-owned utility Gujarat Urja Vikas Nigam Limited’s (GUVNL) plans to enter into power purchase agreements for up to 500 MW of renewable energy projects along with energy storage systems for the rural electrification of off-grid villages in Gujarat.
Different energy storage technologies will be required to balance the demands of a population seeking to boost electrification across the residential, commercial and industrial sectors.
How much storage do we need?
Lithium-ion (Li-ion) batteries, which can support up to eight hours of storage, are currently among the most mature and economical BESS technologies available. Li-ion batteries are the lightest in weight and smallest in size of any commercially available battery chemistry, which makes them a suitable option available today.
Lithium-iron phosphate is also the least prone to thermal runaway, in which a battery’s short circuits heat up and catch fire. Unlike other Li-ion batteries, when lithium-iron phosphate is forced to short-circuit, it remains cool and composed.
BESS is favoured for its flexibility and capability to perform multiple functions in a single facility. For example, in a frequency regulation role, BESS can help balance electricity supply and demand, making the grid stable and reliable. In an arbitrage role, BESS can assist in saving electricity when it is not needed to be used later when it is needed. That said, Li-ion batteries may face potential future supply chain challenges as they are extremely mineral-intensive.
Other storage options include thermal storage, in which heat is stored in the form of steam, molten salts or other mediums for use at a later date; and emerging battery technologies such as flow batteries or alternative chemistry batteries.
India also has the opportunity to deploy pumped storage hydropower (PSH). PSH plants are storage systems based on hydropower operations between two or more reservoirs (upper and lower) with an elevation difference. PSH plants are geography and weather dependent, have long gestation periods and lack modularity. However, PSH plants are a highly effective and viable form of storage when conditions permit.
Hydrogen energy storage
In addition to short-duration energy storage, Asia requires cost-effective, utility-scale, long-duration energy storage to unlock the full potential of renewable energy to cut carbon emissions. One such emerging longer-duration technology is hydrogen.
Hydrogen, as a form of chemical energy storage, is ideal to both complement and serve as a reliable alternative to batteries, particularly when hydrogen prices will become more competitive going forward. Green hydrogen, produced through the electrolysis of water powered by renewable energy, offers a carbon-free solution.
To be economical, traditional batteries need to be charged and discharged on a daily basis. Hydrogen, on the other hand, can be produced continuously and stored, providing seasonal storage that can be used for backup power, limited only by storage volume capacity. As an example, excess solar power captured during summer could be stored as hydrogen for use as an energy source in months when solar power generation is more constrained.
Along with batteries, hydrogen can be procured from generation facilities and deployed when it is needed with fast ramp-up times, much like the natural gas or diesel backups in use today. This flexibility and its feature as a carbon-free, mineral-free electricity generator provides premium benefits that offset the conversion losses as hydrogen is extracted from water, stored, then used in backup turbines or engines that are the conventional power equipment sources that produce electricity.
Another capability hydrogen offers that is unique to other storage technologies is its potential for direct use. For example, as a feedstock in the hard-to-carbon-abate cement, steel, chemical and petrochemical industries; as a zero-carbon fuel in fuel-cell vehicles; for creation of synthetic fuels ranging from methanol to gasoline to sustainable aviation fuel; and as “green ammonia”, an energy storage medium which can be more readily transported compared to liquid hydrogen. Multiple revenue streams make hydrogen even more valuable. As cost remains an issue for hydrogen today, it is critical for developers to consider its full potential as an energy source.
To advance hydrogen energy storage technologies, these projects will first need to be demonstrated and scaled up so as to lower cost. Further, regulation changes and government incentives will be required to speed up the transition.
In 2021, India launched its National Hydrogen Mission to aid the government in meeting its climate targets and making the country a green hydrogen hub. The efforts of the mission have led to the development of the Green Hydrogen Policy. The policy aims to scale up green hydrogen production and its utilisation in India by identifying manufacturing zones for green hydrogen, and providing concessions to developers to set up renewable energy-based green hydrogen and green ammonia projects.
Where to start?
In India, a combination of electrochemical storage and hydrogen will ultimately be required to meet the country’s RTC power requirements. This journey is far from straightforward. Factors such as the evolving geopolitical landscape, technology maturity and costs, contingent infrastructure modifications, time-to-deploy, development of ancillary markets to monetise storage deployments as well as global supply chain issues will all impact the optimal mix of these systems and challenge the timeline for cost effectively integrating storage with variable renewable energy resources and creating stable and reliable decarbonised electric grids in India.
What is critical is that both the public and private sectors remain focused on their commitments and vision for a decarbonised future and work together to achieve their targets while maintaining reliable energy systems that continue to support the country’s growth and prosperity.