LONDON, March 29 (Reuters) - India’s electricity transmission system is coming under increasing strain as booming power demand outstrips growth in despatchable generation.
Mild temperatures in February and March have masked the struggle to meet fast-growing loads from industry as well as for refrigeration and air-conditioning.
But periods of more severe temperatures between April and September are likely to reveal the increasingly thin margin of spare generation.
Total electricity consumption increased by 8% in February 2023 compared with the same month a year earlier and by 13% compared with February 2021, according to the Grid Controller of India.
Peak demand met was up by 8% compared with a year ago and 11% compared with 2021 (“Monthly report”, Grid India, March 23, 2023).
But generation capacity has increased by only 4% since 2022 and 9% since 2021, ensuring generation units must be used more intensively.
Like other countries before it, India is experiencing classic pressure on its transmission system associated with rapid industrialisation and electrification of the economy.
Pressure on the network is evident from the amount of time frequency on the transmission system is below the minimum target level.
Frequency is related to the balance between generation and load - excess generation causes frequency to accelerate, excess load causes frequency to drop.
Grid controllers are therefore instructed to keep frequency within tight limits to ensure the network remains stable and avert the risk of a cascading failure.
India’s grid is synchronised at 50.00 cycles per second (Hertz) with a maximum acceptable operating limit of 50.05 and a minimum of 49.90.
But frequency fell below the minimum acceptable target of 49.9 Hz almost 11% of the time in February 2022 up from 6% in 2022 and 7% in 2021.
The increasing incidence of under-frequency shows controllers struggled to schedule enough firm generation to meet increasing demand on the system.
So far, periods of under-frequency have been modest, in contrast to March and April 2022 and October 2021, when severe under-frequency was the forerunner of widespread blackouts.
But strain on the system will increase as temperatures rise towards their summer peak in June and again in September-October after the monsoon fades.
The system is already running hard. Peak electricity demand in January (210,618 megawatts) and February (209,665 megawatts) was only slightly lower than at the height of last summer in June 2022 (211,856 megawatts).
India needs to maximise generation from all sources, fossil fuels (coal, gas and diesel) as well as renewables (hydro, solar and wind) this summer to keep the lights on.
Government policy aims to maximise the availability of firm generation by prioritising coal movements on the rail network, mandating coal imports, and building up inventories in the yards of coal-fired power stations.
Policymakers have ordered privately owned and captive coal-fired and gas-fired generators to ensure their units are ready to run in the event of an instruction from the grid.