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India’s renewable energy expansion posing threats to its grid stability 

Transmission of Renewable Energy – Learn about the power challenges & guarantees of grid stability in India.

By Rajeev Tyagi
New Update
Renewable energy transition and grid stability in india

Read in Hindi | Do you ever consider how the energy that charges your phone actually reaches your home and where it comes from? It's likely not something we frequently contemplate, but a complex network of towers, substations, wires, cables, and transformers known as the grid ensures that energy is transported from its source to our homes. In India, electricity is the subject of the concurrent list i.e. the grid is jointly operated by both the central and state governments. The grid system can be divided into four main components: Generation, Transmission, Distribution, and Utilization.

In conversations around renewable energy, the majority of attention is typically towards its production, mostly the amount of electricity generated from various renewable sources. However, one crucial aspect that often goes unnoticed is energy transmission i.e. the process of delivering the produced energy to its intended destination(s). 

Schematic Diagram explaining how electricity reaches your home and offices
Schematic Diagram explaining how electricity reaches your home and offices

The electricity produced by various energy sources is transported to the substation through transmission lines. At the substations, the voltage is regulated and then distributed to our homes via distribution lines. This entire energy generation, supply, and demand system must remain in perfect balance at all times. If there is an excess of generated energy with insufficient demand, there is a potential risk of infrastructure damage caused by energy surges. Conversely, if there is an insufficient supply of generated energy, there is a risk of blackouts. The responsibility of grid operators is to ensure a harmonious equilibrium between energy generation and consumption.

RE intermittency, and the threat 

As per government data, India's total installed capacity is 423 GW by July 2023. This capacity comprises 212.52 GW from coal, 25.63 GW from oil and gas, 46.85 GW from hydro, 7.48 GW from nuclear, 71.15 GW from solar, 43.94 GW from wind, and 10.82 GW from bio-power production. And, the share of renewable in the energy mix would need to increase to fulfil India’s aims to achieve its net-zero targets. As per the United Nations, net zero refers to reducing greenhouse gas (GHG) emissions and re-absorbing the remaining atmospheric carbon through sequestration

India's source of energy till September 2023
India's sources of energy till September 2023

However, the rapidly increasing integration of renewable energy, which is variable and intermittent, poses significant challenges for grid operators in performing their duties effectively.

Dr. Somit Dasgupta, former member of the Central Electricity Authority, says that

“The grid system in India is just as robust as those found in developed nations, if not better. However, grid instability, characterized by fluctuations in frequency and voltage, does occur due to the intermittent nature of renewable energy sources and the resulting gap between generation and load. Balancing this gap can be achieved through measures such as load shedding or by increasing the utilisation of alternative energy sources.”

The reason for this is, that our grid system has relied on energy sources such as thermal, and hydropower plants. These sources have allowed us to have control over supplying continuous, uninterrupted power, based on demand. However, the situation is different with solar and wind energy. In these cases, the amount of electricity generated is determined by factors such as the brightness of the sun and the speed of the wind.  This variability poses a challenge in maintaining grid stability. In order to ensure a stable grid, it is crucial to constantly match the load and generation of electricity, as mentioned above.

However, to achieve the net-zero target by the year 2070, India must address the fundamental challenges associated with renewable energy transmission.

Transmission lines in Sanchi Madhya Pradesh
Transmission lines in Sanchi Madhya Pradesh

One Nation One Grid

Explaining India's grid operations, Somit says, 

“One significant advantage we have is that we operate under the One Nation One Grid policy, wherein the grids of all states in India are interconnected and operate on a unified voltage and frequency. Our grid comprises generation units and a mix of load dispatch centres situated at the state, regional, and central levels. These centres effectively manage the electricity demand and supply.”

Diagram of India’s National grid interconnected with load dispatch centres at various levels | Source: CEA India
Diagram of India’s National grid interconnected with load dispatch centres at various levels | Source: CEA India

Due to interconnection, India's National Grid has become the world's largest synchronized grid with a remarkable installed capacity of 423 GW. This interconnected system has greatly facilitated the efficient delivery of power from resource-centric regions to load-centric regions. It is worth mentioning that prior to October 1991, India had five separate regional grids, each operating at different frequencies. However, in December 2013, these grids were integrated into a single grid, ensuring a uniform frequency and voltage across the entire country.

India’s transmission capacity in CKM (Circuit Kilometres)  as of July 2023 | Source: India Climate and Energy Dashboard 
India’s transmission capacity in CKM (Circuit Kilometres)  as of July 2023 | Source: India Climate and Energy Dashboard 

Dr. Somit mentions that India has not experienced any blackout outages post-renewable energy integration in the grid. However, accurate estimation of generation and load forecasting is crucial to ensure the seamless operation of the grid.

Tejal Kanitkar, Associate Professor at the National Institute of Advanced Studies (NIAS), says about  the biggest problem, 

“We operate on a centralized grid system. However, the power dispatch process occurs at the regional level, leading to significant challenges in managing the surplus energy produced from solar and wind sources. This persisting issue not only impedes the growth of renewables in India but also undermines the stability of our grid.”

Furthermore, addressing the question of grid stabilisation, she says

“Promoting energy diversity is vital for ensuring energy security. However, disproportionately prioritizing solar energy undermines this diversity. Consequently, this could lead to imbalances within the grid, particularly when it comes to meeting electricity demands throughout the day and night.”

Non-curtailment policy

What is curtailment? Explaining this, Tejal says that 

“Curtailment refers to the restriction or denial of the off-take (flow) of generated electricity. In India, there exist long-term power purchase agreements between state load despatch centres and DISCOMs (distribution companies). The load dispatch is conducted under a 'cost-based policy' that prioritizes the dispatch of the cheapest power first. However, as per the Indian Electricity Grid Code 2010, there is a non-curtailment policy specifically applied to renewables. This policy mandates State Load Dispatch Centers to prioritize renewables during dispatch, except in the case of grid insecurity, even if the cost of renewable energy is higher than other sources. Regrettably, in reality, SLDCs (State Load Dispatch Centres) frequently curtail renewable sources disguised as grid security measures, influenced by the commercial interests of DISCOMs.”

The DISCOMs are obligated to make fixed payments to thermal plants regardless of whether they utilize their electricity or not due to the two-part tariff mechanism. This situation leads to the curtailment of renewable energy sources in favour of thermal power. Furthermore, older wind and solar plants with higher tariffs are particularly more susceptible to such curtailment.

Smart Grids for stability

Until now, the grid's sole purpose has been to transmit electricity from the generation centre to the consumer. However, with the rise of rooftop solar, consumers are now also producing electricity. In such a scenario, there is a growing need for a smart grid that can accurately assess both generation and load. A smart grid is a two-way communication system that utilizes smart meters to collect real-time energy consumption data and transmit it to energy generation centres. A computerised system is set up between the energy provider, and appliances at home. Then, the system would automatically alert to minimize consumer appliances' energy usage during stress on the grid. 

Additionally, the smart grids monitor transmission lines, safeguard against faults, and can even detect instances of power theft, which currently costs India over $16 billion per year. 

Power distribution substation in Sanchi
Power distribution substation in Sanchi

Considering these, the Government of India initiated the National Smart Grid Mission in 2015 with the objective of establishing smart grids across the country. As of August 2023, progress is being made on 11 smart grid projects in various states. However, Soumit argues that implementing smart grids in India is a financially demanding endeavour, and requires substantial capital.

Energy sufficiency, and decentralisation for grid stability

To mitigate the risk of energy loss during long-distance transmission, the implementation of decentralization in energy distribution has proven to be an effective approach. By adopting a decentralized energy system, energy generation facilities are strategically located in close proximity to the point of energy consumption. Chetan Solanki, the founder of Energy Swaraj and an IIT professor, emphasizes the need for the decentralized nature of solar energy. By establishing solar microgrids, clean energy can be supplied even in challenging geographical terrains. This decentralization process not only reduces the strain on the grid but also eliminates the need for extensive capital investment required for laying long-distance transmission lines.

Chetan further says that, 

"Emphasizing the importance of self-sufficiency in energy, it is crucial to promote Swaraj in the field of energy, wherein individuals generate their own electricity according to their needs. This shift would render large-scale solar parks and storage systems unnecessary. Furthermore, a significant transformation in our behaviour is necessary. Prioritizing energy conservation, we should actively engage in high-energy tasks during daylight hours while adopting energy-saving practices."

Transmission infrastructure, and Green energy corridors

Geographically in India, the western states possess greater solar potential, whereas wind energy potential is higher in the western and southern coastal regions. Consequently, an increased capacity of inter-state and inter-regional transmission is necessary to transport solar and wind energy to areas with limited renewable energy generation potential. This is particularly vital in major Indian cities characterized by high electricity consumption but limited space to install solar park(s).

Somit says that, 

"Efforts are underway in India to establish dedicated green energy corridors, aiming to collect and distribute renewable energy from small units across the country to areas with higher energy demands. Nonetheless, the implementation of such a system necessitates substantial capital investment."

India has decided to invest Rs 2.44 lakh crore in upgrading its transmission grid. This investment aims to boost the inter-regional transmission capacity from 112 GW to 150 GW by the year 2030. Additionally, the National Electricity Plan supports this initiative, 

The Inter-State Transmission System (ISTS) component consisting of 3200 ckm transmission lines and 17,000 MVA substations was completed in March 2020. The Intra-State Transmission System (InSTS) component has been sanctioned to eight RE-rich states of Tamil Nadu, Rajasthan, Karnataka, Andhra Pradesh, Maharashtra, Gujarat, Himachal Pradesh and Madhya Pradesh for evacuation of over 20,000 MW of renewable power.  

Power Transmission lines in Sanchi Madhya Pradesh
Power Transmission lines in Sanchi Madhya Pradesh

Storage for Grid Stability

According to the roadmap of the Central Electricity Authority, India is working towards increasing the flexibility of the grid in view of the increasing penetration of renewable energy in the grid. For this, it has focused on several measures, such as increasing the flexibility of coal-based power plants so that they can meet the dynamic needs of the grid. Readily ramp up and ramp down rapidly, expand geographic and power balancing areas, expand transmission in strategic locations, improve forecasting and scheduling mechanisms, install grid-scale storage systems such as pumped hydro storage, batteries Energy Storage System (BESS) etc. We have talked about the storage technologies available in detail in our previous article.

Somit asserts that India will not retire coal power plants for the next 25 years, as India’s energy demands are likely to double in the next five years. Until we have efficient and economical storage available, coal-based power plants, and hydropower plants will be used to manage the demand-supply gap and grid stability.

This is the second of three articles series on India’s renewable energy expansion, and storage system. This story is produced with the support of the Earth Journalism Network story grants

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