Canal-Top Solar Could Add 131 GW Without New Land, but Has Not Scaled Since 2012

The news

Gujarat, Punjab and India’s wider irrigation network. In an analysis in The Hindu on Wednesday, Shantanu Roy, Sector Coordinator for Renewables and Energy Conservation at the Center for Study of Science, Technology and Policy (CSTEP), argues that India’s canal network, one of the largest in the world, is an under-used site for solar power. In canal-top photovoltaics (CTPV), solar panels are mounted on elevated structures built over canal stretches, or along canal banks, designed so that water flows unobstructed; floating solar, by contrast, puts panels on platforms that float on reservoirs. The occasion is the recently approved PM Surya Sarovar Yojana (PM-SSY), which aims to develop 5,000 MW of floating solar capacity on reservoirs and other inland water bodies; the author says this interest in “land-neutral” solar could extend to CTPV. The biggest advantage is that CTPV needs virtually no additional land: in Punjab, 20 MW of canal-top systems is estimated to have saved nearly 100 acres. Shade over the canal cuts evaporation, and the water beneath cools the panels and improves their output in hot weather. India was an early adopter. A 1-MW system over the Narmada Canal in Mehsana, Gujarat, commissioned in 2012, reportedly saves close to 9 million litres of water a year while generating 1.6 million units of electricity annually. Two 10-MW systems were commissioned in Vadodara between 2014 and 2017, and 20 MW in Punjab in 2017-18. In 2014 the Ministry of New and Renewable Energy (MNRE) launched a pilot-cum-demonstration scheme targeting 50 MW each of canal-top and canal-bank projects, with assistance of ₹3 crore and ₹1.5 crore per MW respectively, or 30% of project cost, whichever was lower. In September 2025 the Punjab Energy Development Agency invited expressions of interest for 40 MW across a canal network of over 10,000 km, and Haryana is exploring six irrigation canals. A 2024 assessment co-authored by CSTEP put canal-top and canal-bank potential at around 131 GW, with vertical bifacial panels (which capture light on both faces) for canals wider than 30 m; Uttar Pradesh, Bihar, Karnataka, Andhra Pradesh and Punjab lead. Yet deployment has stayed limited for over a decade because of high structural cost, difficult maintenance over running water, and linear layouts far from substations. The author seeks site prioritisation, viability gap funding, low-cost debt and standard specifications. The syllabus link is GS3 on energy infrastructure and on land as a factor of production.

Static syllabus linkage

1. India’s solar programme sits inside a national climate mission and an international pledge. The Jawaharlal Nehru National Solar Mission was launched in 2010 as one of the eight missions of the National Action Plan on Climate Change (2008), and its target was raised in 2015 to 100 GW of solar capacity by 2022. At COP26 in Glasgow in 2021, India announced a target of 500 GW of non-fossil electricity capacity by 2030. India’s updated Nationally Determined Contribution, submitted in August 2022, commits to about 50% of cumulative installed electric power capacity from non-fossil sources by 2030. The Ministry of New and Renewable Energy is the nodal ministry for all of these.
2. Land, not technology, has become the binding constraint on ground-mounted solar. Utility-scale solar needs roughly four to five acres per MW; the Punjab example in the article, 100 acres for 20 MW, works out to about five acres per MW. The Centre’s scheme for the Development of Solar Parks and Ultra Mega Solar Power Projects (2014) tried to pre-assemble land for developers, but solar parks have repeatedly run into disputes over common grazing land and livelihoods. In M.K. Ranjitsinh v. Union of India, the Supreme Court in 2021 ordered power lines in Great Indian Bustard habitat in Rajasthan and Gujarat to be placed underground where feasible, and in 2024 a three-judge bench modified that order while recognising a right against the adverse effects of climate change under Articles 14 and 21. The case shows that even clean energy has a land and biodiversity cost.
3. Floating, canal-top and agrivoltaic systems form the family of land-neutral solar. Floating solar places panels on pontoons on reservoirs and lakes; NTPC’s 100 MW floating plant on the Ramagundam reservoir in Telangana, commissioned in 2022, is an early large example. Canal-top systems span the canal on steel structures, while canal-bank systems use the embankment strip. Agrivoltaics raises panels high enough for crops to be grown underneath. All three reduce competition with agriculture, and the water-based ones reduce evaporation, which links them to the water-energy nexus: the idea that decisions about water and power must be planned together because each consumes the other.
4. Viability gap funding exists for projects that are socially useful but commercially thin. The Viability Gap Funding scheme was introduced in 2006 by the Department of Economic Affairs, Ministry of Finance, to support public-private partnership infrastructure projects that are economically justified but not financially viable on their own. Under it, the Centre can provide a capital grant of up to 20% of total project cost, and the sponsoring ministry or State may add up to a further 20%. The same idea of a one-time capital grant to bridge the cost gap has since been used for newer energy technologies such as battery storage and offshore wind. PM-KUSUM (2019) is the related farm-solar scheme: its Component A supports small grid-connected plants of up to 2 MW on barren or fallow land, and Component C supports solarisation of grid-connected agricultural pumps.

Why UPSC loves this

1. GS3 asks about infrastructure: energy, and about the costs of growth. The syllabus lists “Infrastructure: Energy” and “Conservation” side by side, and UPSC has asked in GS3 about the status and targets of renewable energy in India and about access to affordable and clean energy under the SDGs. An answer that moves beyond capacity numbers to the land and water constraints on renewables, with CTPV and floating solar as examples, stands out.
2. Prelims tests scheme architecture and technology definitions. Questions on the National Solar Mission, the International Solar Alliance, PM-KUSUM’s components and terms such as bifacial panels or floating solar are standard. The first canal-top plant on the Narmada Canal in Gujarat is exactly the kind of ‘first in India’ fact the paper favours.
3. The land question links energy to the economy paper. Land is one of the four factors of production, and its scarcity drives up the cost of every megawatt. Examiners increasingly ask about trade-offs within green growth, for example renewable energy versus grasslands or bustard habitat, so this story supplies a solution-side example for such answers.

Analysis

1. The 131 GW figure is a technical ceiling; the grid map will set the real number. The CSTEP estimate already screens for irradiation, canal geometry, protected areas and distance from substations, but technical potential is not economic potential. Canals run through farmland, far from load centres, and a linear plant strung along several kilometres needs more cabling and more connection points than a compact solar park. The article itself notes that costs rise where substations or transformers are not strategically located. A realistic target would therefore start with canal stretches that pass near existing agricultural feeders and substations. Even a small fraction of 131 GW, however, is significant for States like Uttar Pradesh and Bihar, which top the list and where farmland is too valuable to cover with panels.
2. The 2014 pilot failed for institutional reasons that money alone cannot fix. The 2014 scheme offered generous support of ₹3 crore per MW for canal-top projects and still did not produce a pipeline, which the author concedes shows financial support alone may not suffice. The deeper problem is ownership: canals belong to irrigation departments, whose priority is water delivery, desilting and embankment repair, while power belongs to State nodal agencies and distribution companies. A structure over a canal complicates the irrigation engineer’s job, and nobody in the irrigation department is rewarded for generating electricity. Unless revenue-sharing or lease payments give irrigation departments a stake, they will treat CTPV as a nuisance. The counter-view is that the economics have changed since 2014 because module prices have fallen steeply, so the structural premium is now a smaller share of total cost.
3. Water saving is a bonus, not the business case. The Mehsana plant’s 9 million litres a year is useful, but in most Indian canals seepage through unlined beds loses far more water than evaporation from the surface. Selling CTPV mainly as a water-saving measure invites the obvious question of whether the same money would save more water if spent on canal lining. The stronger argument is land: 100 acres saved for every 20 MW in Punjab is farmland that stays under crops, and land acquisition disputes are what delay solar parks. Policy should therefore price the avoided land cost when comparing CTPV with ground-mounted solar, rather than comparing only per-MW capital costs.
4. Canal-top solar fits naturally with decentralised farm power. Canal commands are exactly where agricultural pumping load sits, so power generated over the canal can be fed into nearby agricultural feeders with low transmission losses. This matches the logic of feeder-level solarisation under PM-KUSUM, which aims to supply daytime power to farmers from local plants. A combined programme could let a State solarise feeders using canal stretches instead of acquiring fallow land. The risk is that distribution companies, already burdened by subsidised farm tariffs, may resist buying more daytime power at a higher tariff, which is why viability gap funding and standard power purchase terms matter.
5. Standard designs are the cheapest reform on the list. Every early project was a bespoke engineering exercise, designed to a particular canal’s width, orientation and flow. Standard specifications for spans, foundations, wind loads and maintenance access would cut design time, give lenders confidence and let manufacturers build to volume. The author’s call for standardised guidelines and streamlined process flows is therefore more than administrative tidiness: it is how costs fell for rooftop and ground-mounted solar. A national design code, prepared with irrigation engineers rather than only power engineers, would also address the maintenance problem at the design stage.

Administrator's brainstorm