General Studies IIIEnergy

One Nation One Grid One Frequency


Recently, the Power Grid Corp. of India Ltd (PGCIL) celebrated the anniversary of operationalization of One Nation One Grid One Frequency i.e National Grid.

One Nation One Grid One Frequency (National Grid):

Evolution of  National Grid in India

  • In India, Grid management started in sixties on regional basis. Initially, grids were inter-connected to form regional grid. Following this, India was divided into 5 regions on the basis of grid-
  • Northern Grid
  • Eastern Grid
  • Western Grid
  • North Eastern Grid and
  • Southern region.
  • The North Eastern and Eastern Grid were connected in October 1991.
  • Western Grid and North Eastern Grid were interconnected in March 2003.
  • In 2006, North and East grids were interconnected.
  • Thus, 4 regional grids Northern, Eastern, Western and North Eastern grids were inter-connected to form a central grid operating at one frequency.
  • Southern Region was connected to Central Grid in 2013, with the commissioning of 765kV Raichur-Solapur Transmission line.
  • All possible measures are taken to ensure that the grid frequency always remains within the 49.90-50.05 Hz (hertz) band.

About National Grid

  • The National Grid is the high-voltage electricity network in India, connecting power stations and major substations and ensuring that electricity generated anywhere in India can be used to satisfy demand elsewhere.
  • The National Grid is owned, operated, and maintained by state-owned Power Grid Corporation of India.
  • It is one of the largest operational synchronous grids in the world with 334.40 GW of installed power generation capacity as on 31 January 2018.

 Benefits of centralized power grid

  • Synchronization of all regional grids will help in optimal utilization of scarce natural resources by transfer of Power from Resource centric regions to Load centric regions.
  • Further, this shall pave way for establishment of vibrant Electricity market facilitating trading of power across regions.
  • One Nation One Grid shall synchronously connect all the regional grids and there will be one national frequency.

Cross border transmission links

India began cross-border electricity trade in the mid-1980s. India established 33 kV and 132 kV interconnections in radial mode from Bihar and Uttar Pradesh to Bhutan and Nepal respectively. The first interconnection with Bangladesh was commissioned in December 2013, connecting Berhampore with Bheramara. As of April 2017, there are 12 cross-border interconnections between India and Nepal. India became a net exporter of electricity for the first time in the 2016-17 fiscal year.

Presently, India is importing electricity from Bhutan with synchronous transmission links while exporting power to Nepal, Bangladesh and Myanmar with asynchronous transmission links between the National Grid, and the electricity grids of these countries

Capacity of National Grid:

  • Presently, the country has a total inter-regional transmission capacity of about 1,12,250 MW which is expected to be enhanced to about 1,18,740 MW by 2022.

India’s power sector:

  • The power sector has three main segments:
  • Generation: It is the process of producing power using different fuels and is done in generating plants.
  • Transmission utilities carry bulk power from the generation plants to the distribution substations through the grid at high voltages.
  • Distribution: Distribution utilities supply electricity from the substations to the consumers through distribution networks. Distribution is the selling stage and operates at lower voltages.


  • Many different energy sources are used to generate power.
  • These include coal, natural gas, hydro, nuclear and renewables (Solar, wind, small hydro and biomass).
  • In the last two decades, India’s power generation capacity has increased considerably. This is mainly due to the delicensing of power generation in 2003, which enabled unlimited participation of private players.
  • Currently, private utilities generate about 46% of the country’s power, followed by state utilities (30%) and central generating utilities (24%).
  • India is the third-largest producer and consumer of electricity in the world as of July 2019.
  • It is ranked 4th in wind power, 5th in solar power and renewable power capacity as of 2018.
  • Also, it is ranked 6th in the list of countries to make the most investment in clean energy.

Renewable energy generation:

  • In March 2019, the Union Cabinet announced that hydropower projects will also be classified as renewable energy projects along with wind, solar, biomass and small hydropower.
  • Renewable sources could either be connected to a grid or be off-grid systems.
  • As of January 2019, the total grid-interactive renewable power capacity (excluding hydro) is at 45 GW.
  • The government has set a target of installing 175 GW of renewable energy capacity by 2022 (excluding hydro).
  • To achieve this target, the government needs to add an average capacity addition at around 33 GW per year. Currently, it is just around 24 GW per year.
  • It should be noted that wind and solar power have lower plant load factor than thermal power due to intermittent wind speed and sunlight and thus, the renewable capacity addition needs to be higher than for thermal power plants to generate the same amount of electricity.


  • It is carried out mostly by central and state companies.
  • The transmission segment was separated from the central government agency in 1989 and the Power Grid Corporation was established.
  • Power Grid Corporation is in charge of planning, implementation and maintenance of the interstate transmission system and operation of national and regional power grids.
  • Following the implementation of the Electricity Act, 2003, consumers can buy power from any power generating plant through non-discriminatory access to transmission and distribution lines, according to the specifications set by states.
  • India’s transmission lines have grown at an average annual rate of 6.5% between 2007 and 2019.


  • Distribution involves the maintenance of the distribution network and retail supply of electricity to the consumers.
  • It is mainly carried out by state-owned discoms.
  • Currently, the state discoms are faced with poor financial health, leading to the negative effects on their ability to purchase power for supply and the ability to invest in improving the distribution infrastructure.

Source: PIB

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