India’s electricity sector has grown multi-fold since Independence, from a total installed generation capacity of just 1.7 GW in 1950, it has now reached around 500 GW. During the first 65 years after Independence, major generation sources were hydro, thermal and nuclear. It is only since 2012 that Variable Renewable Energy (VRE) has become a large contributor in the country’s total power generation capacity. Conventional generation plants were initially developed under state sector. However, since 1975, Centre has added the lion’s share to the total power generation capacity addition.
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The introduction of Electricity Act, 2003 brought about major changes and, thereafter, majority of generation plants were developed by the private sector. Conventional generation (thermal, gas, hydro, nuclear) plants are, in general, distributed across all major states of the country, and transmission systems for them were developed for evacuation of generation capacities to load centre and almost evenly distributed across India. Initially, every state had its independent transmission system, which was first integrated as regional transmission system (five regions) and finally as national transmission system (one nation one grid).
For the faster development of variable renewable generation (solar and wind) sources, the government has brought in various incentives. One of them was waiver of ISTS charges, wherein developers were asked to install their renewable plants based on solar or wind potential, anywhere in India, with assured transmission system and zero Inter-State transmission charges for 25 years. This provision led to unprecedented development of renewable plants, initially, in Rajasthan and Gujarat at ISTS level, and thereafter in Karnataka and Andhra Pradesh, as well.
Rajasthan and Gujarat already have more than 35 GW RE generation projects commissioned each. As per the state governments’ plan, by 2030, Rajasthan shall have RE generation capacity of more than 100 GW at ISTS level, while Gujarat and Andhra Pradesh would have around 60 GW each at ISTS level. As one can see, generation capacities through VRE (solar and wind) sources are getting concentrated in a few states. As per expected power demand and generation capacity addition plan by 2030, India may be meeting power demand of 335 GW, with around 100 GW (mainly solar) of generation during peak solar hours supplied by solar plants in Rajasthan. In that scenario, maintaining standard grid operation, during any major reduction of generation in Rajasthan, due to extended wet days or transmission faults, shall be a nightmare for grid operators.
Solar and wind generation are mainly dependent on natural resources. Solar radiations are available across India with some variations, while wind speed required for power generation is mainly available in eight states. Due to policy of waiver of ISTS charges on VRE and assurance of building high-capacity transmission lines, every developer rushed towards slightly higher solar radiation areas such as Rajasthan, Gujarat and Andhra Pradesh. Easy availability of land is another criterion for faster development of such plants.
As no restriction for minimum utilisation of transmission lines was kept while granting connectivity to VRE plants, 765/400 KV transmission systems are not being utilised to its full potential and even high capacity HVDC systems are being created to transfer power from standalone solar or wind plants. As renewable energy is intermittent in nature, a number of STATCOMS projects is installed to control reactive MVAR, especially during line faults.
In the future, many synchronous condensers and Battery Energy Storage System (BESS) will be needed for providing inertia and active energy support during transmission system faults, in concentrated RE generation zones. These arrangements will further add to the cost of underutilised transmission system. If we calculate in actual terms, considering transmission charges, solar energy delivered with such arrangements is much more costly than if it were being produced locally in areas where it is needed, despite lesser insolation level. Transmitting solar power from these three-four states with transmission lines is like transmitting solar radiation from one part to another, although the same is available at both places.
A vital lesson that one can learn is that a country should not concentrate their power/energy generation plants in some specific area in such a manner that an outage affects the entire country
In fact, power system planning, continued in similar ways, as was done earlier, to transfer power from remote generation centres to the load centre. However, in case of renewable energy, especially solar, balanced approach was needed as solar resources are available across every part of India, with some generation variation/square meter.
The concentration of generation resources has another angle in reference to secured grid operation. If we critically analyse geopolitical situation with special focus on the Russia-Ukraine war, one can understand that the most preferred attack by warring parties are on power/energy installations, to disturb the economic activities of the opposite party. A vital lesson that one can learn is that a country should not concentrate their power/energy generation plants in some specific area in such a manner that an outage affects the entire country. Rather, it should be as distributed as possible to avoid any major failure of power in case of an attack. Large power generation resources in our country, prior to the addition of RE power, were better distributed across the nation. But the disproportionate addition of renewable energy capacity in two border states alters the advantage India previously had from a more evenly distributed expansion of conventional power.
India, being a developing country, is poised to see an increase in power demand, which cannot be met without developing generation plants in every part of the country, including in border states. However, calibration is needed in planning criterion to ensure minimum cost of delivered energy per unit, including transmission charges.
Any major concentration of power generation resources in one area in comparison to the total installed capacity of the country needs to be assessed in terms of vulnerability of the future grid operation due to any unexpected major generation loss by reasons attributable to defence, climate changes and active/reactive power management during fault of transmission lines.
1. Present power consumption pattern of country is distributed as: Industrial 42 percent, Domestic 24 percent, Agricultural 18 percent, Commercial 8 percent. There are some variations in consumption pattern across states. Power demand of 335 GW by 2030 needs to be bifurcated at the district level. All increment of district demand in every state in agricultural, domestic and commercial consumption needs to be met from district-level solar or wind and BESS projects, and other tied-up thermal/hydro/gas/nuclear plants. Suitable land needs to be identified for installing RE plants in states. If land is not available in one district, planning with combination of districts may be made. This will reduce the requirement of both Inter and Intra-transmission lines and attached inertia enhancement systems. It will also provide evenly distributed employment opportunities across all districts and GST revenue to each state during the installation of plants. An exception to any state may be allowed in view of any geographical constraints.
2. The incremental demand of industrial load and additional demand due to requirement of change from conventional energy to RE energy can be met both locally (VRE and tied-up conventional plants) and through remote RE generation plants with the development of transmission systems. Such remote capacities may be developed for meeting bulk demand of industries such as data centres, green H2/NH3 production and other bulk power consumption industries needing RE power, as required under renewable consumption obligations (RCO).
3. Connectivity with EHV system may be granted only if connected generation system, supply energy at single connected point with minimum CUF of more than 50 percent (can be further fine-tuned), this will ensure connection of only hybrid, either solar+wind or solar+wind+BESS or solar+BESS or wind+BESS plants, and allow better utilisation of the transmission system.
4. The utilisation of all existing, built transmission systems for VRE power evacuation needs to be enhanced to minimum 40 percent by introducing various opportunities to connect in the same transmission system during less or zero utilisation period.
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5. Overall, the development of power system of the country shall have criterion that in case of major outage of one state generation due to any reasons as specified earlier, power of other parts of the country will not be affected. It may be noted that the country needs to utilise all resources available, including in the border states, but guarded development with above criterion will ensure development in a phased manner. This will avoid crowding of all developments in two-three states and reduce increasing Right of Way (ROW) issues and increased expenditure against it due to the simultaneous construction of transmission lines in the same corridor.
