What Happened
- The Idukki Hydroelectric Project (IHEP) completed 50 years of operation in February 2026, having been commissioned on February 12, 1976, by Prime Minister Indira Gandhi.
- The golden jubilee has prompted reflection on both the project's transformative contribution to Kerala's energy landscape and emerging challenges: climate change-driven rainfall unpredictability, ecological sensitivity of the Western Ghats, and questions about future hydropower expansion in the state.
- Kerala State Electricity Board (KSEB), which operates the project, is considering an Idukki Extension Project (800 MW) but faces environmental and regulatory hurdles.
- With most major river basins in Kerala already dammed, experts suggest the future lies in optimising existing infrastructure rather than building new large reservoirs.
What the Project Is
The Idukki Hydroelectric Project is built across the Periyar River in Idukki district, Kerala. It comprises three dams — the iconic Idukki arch dam (168.91 metres tall), the Cheruthoni gravity dam, and the Kulamavu dam — creating a 60-square-kilometre reservoir holding approximately 2,000 million cubic metres of water. Power is generated at the underground Moolamattom powerhouse through six Pelton turbines, with total installed capacity of 780 MW (6 × 130 MW units). Construction began in 1969 with Canadian technical assistance. The Idukki arch dam is one of the highest arch dams in Asia.
Static Topic Bridges
Western Ghats — Ecological Sensitivity and Infrastructure Conflict
The Western Ghats is one of the world's eight "hottest hotspots" of biological diversity, recognised as a UNESCO World Heritage Site. It spans approximately 1,600 km along India's western coast across six states (Gujarat, Maharashtra, Goa, Karnataka, Kerala, Tamil Nadu) and is the source of major rivers including the Periyar, Kaveri, Krishna, and Godavari.
- Gadgil Committee (2011) and Kasturirangan Committee (2013) both assessed Western Ghats ecology — Gadgil recommended ~64% of Ghats as Ecologically Sensitive Area (ESA); Kasturirangan recommended ~37%.
- The Idukki reservoir is located adjacent to the Periyar Tiger Reserve, one of India's most important protected areas for tigers and elephants.
- Dam construction in Western Ghats leads to reservoir-induced habitat fragmentation, disruption of fish migration routes (particularly in Periyar), and changes in downstream river morphology.
- The 2018 Kerala floods were exacerbated partly by emergency spillway releases from multiple dams (including Idukki/Cheruthoni) during extreme rainfall — highlighting the operational challenges of multi-dam systems.
Connection to this news: The Idukki project's location in the ecologically sensitive Western Ghats means that any expansion — including the proposed 800 MW extension — faces intense regulatory scrutiny under the Environment Protection Act, 1986, the Wildlife Protection Act, 1972, and the Forest Conservation Act, 1980.
Hydropower in India — Renewable Classification and Policy Status
Hydropower is India's largest source of renewable electricity. As of 2025, India has an installed hydropower capacity of approximately 47,000 MW (large hydro) — the world's fifth largest. The Ministry of New and Renewable Energy (MNRE) classifies small hydro (up to 25 MW) as renewable; large hydro was also reclassified as renewable in 2019 for the purpose of Renewable Purchase Obligations (RPOs).
- India's National Hydroelectric Power Corporation (NHPC) and state utilities (like KSEB) are the primary operators of large hydro.
- Hydropower's key advantage: dispatchability — it can respond rapidly to grid demand fluctuations, making it an essential complement to intermittent solar and wind power.
- India's hydropower potential is estimated at 1,45,320 MW at 60% load factor — but only about 32% has been developed.
- Hydropower projects require environmental clearance under the Environment Impact Assessment (EIA) Notification, 2006, along with wildlife clearance if located near protected areas.
- The 2019 RPO amendment including large hydro was aimed at accelerating hydropower development, particularly in the Northeast (states like Arunachal Pradesh, Sikkim).
Connection to this news: Despite its renewable classification, large hydropower projects face significant opposition on environmental and social grounds. Idukki's 50-year track record shows hydropower's contribution to energy security, but climate change is now altering the rainfall patterns on which reservoir-based generation depends.
Climate Change and River Basin Management in India
Climate change is fundamentally altering the hydrology of Indian rivers. The Western Ghats and Himalayan river systems — both critical for hydropower — are experiencing more erratic monsoons, intense precipitation events interspersed with extended dry spells, and changing snow/glacier melt patterns. India's dams, designed on historical hydrological data, may not be calibrated for the new climate reality.
- India's 2018 and 2019 Kerala floods were among the worst in a century — extreme rainfall events overwhelmed reservoir capacity and forced emergency releases, damaging downstream communities.
- The Central Water Commission (CWC) is responsible for hydrological data collection and dam safety oversight under the Dam Safety Act, 2021.
- The Dam Safety Act, 2021 (passed after Machchu dam disaster, 1979, and Tiware dam failure, 2019) mandates regular safety inspections, Emergency Action Plans (EAPs), and sets up a National Dam Safety Authority.
- Kerala has over 60 major dams — managing their coordinated operations during extreme rainfall events is a serious water governance challenge.
- Pumped Storage Hydropower (PSH) is emerging as a solution — instead of building new reservoirs, it recirculates water between upper and lower reservoirs to store solar/wind energy.
Connection to this news: The Idukki project's 50-year anniversary occurs as climate-altered rainfall patterns are challenging the assumptions on which it was designed. The future of Kerala's hydropower may lie in adaptive management of existing systems and pumped storage, rather than new large dams.
Key Facts & Data
- Idukki Hydroelectric Project commissioned: February 12, 1976 (by PM Indira Gandhi)
- Installed capacity: 780 MW (6 Pelton turbines × 130 MW each)
- Construction start: 1969 (with Canadian technical assistance)
- Idukki arch dam height: 168.91 metres — one of Asia's highest arch dams
- Reservoir area: ~60 square kilometres; water storage: ~2,000 million cubic metres
- Location: Periyar River, adjacent to Periyar Tiger Reserve, Idukki district, Kerala
- Proposed Idukki Extension Project: 800 MW (awaiting statutory clearances)
- Kerala's total major dams: over 60
- India's total installed large hydropower capacity (2025): ~47,000 MW
- India's estimated hydropower potential: 1,45,320 MW at 60% load factor
- Large hydro reclassified as renewable energy: 2019 (for RPO purposes)
- Dam Safety Act: passed 2021, sets up National Dam Safety Authority