Land is the one commodity Bihar cannot manufacture. With a population density of 1,106 persons per square km—four times the national average—every acre is either under paddy, occupied by a homestead, or tangled in litigation that dates back to the Zamindari Abolition Act. Yet the state needs to add 4,000 megawatts of renewable capacity by 2030 to meet its committed contribution to the national solar mission. The solution, elegantly borrowed from Japan and Singapore, is to colonise the surface of its vast network of rivers and reservoirs. On 7 September 2025 the cabinet gave the go-ahead for a 1.5-gigawatt floating-solar park spread across three reservoirs—Gandak, Kosi and Barh—at an estimated cost of ₹5,500 crore, making it the largest such installation outside China and the first in India to be entirely funded by domestic green bonds.
Floating photovoltaic (FPV) panels are not merely a space-saving hack; they are technically superior to ground-mounted systems. Water cools the silicon cells, improving efficiency by 8-10 %, while the panels reduce evaporation by 70 %, a critical benefit for a state that loses 1.2 billion cubic metres of water every year to the atmosphere. The environmental-impact assessment carried out by The Energy and Resources Institute (TERI) predicts that the 1.5-GW project will save 2.1 million litres of water daily—enough to meet the annual drinking needs of half a million people—and will cut carbon-dioxide emissions by 2.1 million tonnes a year, the equivalent of taking 450,000 cars off the road. Because the anchoring is temporary, no land acquisition is required, eliminating the single biggest source of delay and litigation that has bedevilled ground-mounted parks in Rajasthan and Andhra Pradesh.
The financial engineering is equally novel. The state-owned Bihar Renewable Energy Development Agency (BREDA) will create a special-purpose vehicle that will issue green bonds with a tenure of 15 years and a coupon of 7.4 %, 40 basis points lower than the state’s normal borrowing cost because the paper carries a greenium—an investor discount for climate-positive assets. The Securities and Exchange Board of India has cleared the bond structure under its new “solar-only” category, and the first tranche of ₹1,200 crore was subscribed 2.3 times within three hours of listing on the Bombay Stock Exchange. Power Finance Corporation will provide a back-stop guarantee, while the state government will offer a viability-gap funding of ₹750 crore, spread over the construction period of 30 months. The levelised cost of electricity works out to ₹2.95 per kilowatt-hour, 70 paise cheaper than the current average pooled-cost of power purchased by Bihar’s distribution companies, ensuring that consumers will not have to cross-subsidise the green premium.
Technology selection has been conservative by design. The pontoon platform will use high-density polyethylene (HDPE) pipes manufactured by Reliance Industries, each module rated to withstand wind speeds of 180 km per hour—higher than the maximum gust ever recorded in the Kosi belt. The inverters and transformers will be housed on shore to minimise corrosion risk, and the entire array will be fitted with a remote monitoring system that can detect hotspots or cable damage within 30 seconds. Unlike land-based parks, floating systems do not require herbicides to control weed growth, eliminating a potential source of chemical runoff into the river. The anchoring grid has been aligned with the irrigation department’s draw-down schedule so that the panels rise and fall with the seasonal water level without ever grounding on the reservoir bed.
The tender, floated on a build-own-operate basis for 25 years, attracted nine bidders, with the lowest tariff discovered at ₹2.89 per kWh. The winner is a consortium of Tata Power Solar and Norway’s Ocean Sun, which brings a patented flexible membrane that allows the panels to ride waves rather than resist them, extending the life of the mooring cables by an estimated 15 %. Construction will begin in March 2026, and the first 250 MW is scheduled to be grid-connected by December, in time to meet the winter peak when river flow—and therefore hydropower output—is at its lowest. The power-purchase agreement has been signed with the state distribution company for 100 % off-take, and the tariff will escalate at 3 % per year for the first ten years, after which it remains flat, giving investors an inflation-protected return without burdening consumers.
The socio-economic spill-overs are already visible. Because the project requires no land, the only local negotiation is with fisher-cooperatives that traditionally use the reservoirs. The agreement grants them exclusive rights to harvest fish between the panel rows, while the shade provided by the modules is expected to reduce water temperature and increase dissolved oxygen, boosting fish yield by 12-15 %. Each cooperative will receive an annual royalty of ₹40,000 per MW, creating a passive income stream that could total ₹60 crore over the project life. In addition, 800 local youth will be trained as float-park technicians—skills ranging from underwater drone inspection to SCADA software—through a partnership with the National Institute of Solar Energy. The first batch, enrolled at the government polytechnic in Khagaria, includes 250 women who will form India’s first all-female solar-on-water maintenance crew.
Critics warn that floating solar is still an emerging technology and long-term data on weather resilience are sparse. A freak hailstorm in Vietnam last year damaged 40 % of an FPV installation, and the anchoring cost—15 % higher than ground-mounted systems—can balloon if reservoir siltation is faster than projected. The state’s counter is a comprehensive insurance policy that covers not only equipment damage but also business-interruption losses for up to six months, underwritten by New India Assurance at a premium of 0.8 % of project cost, half the standard rate because the risk is spread across three geographically separated sites. If the pilot succeeds, BREDA has already identified an additional 4 GW of floating potential on the Gandak canal network, enough to power every household in the state during daylight hours and to export surplus green power to Bengal and Jharkhand. In a region where land is mythically sacred, the idea of harvesting sunlight from water may sound like alchemy, but the first megawatt will hit the grid before the next Rashtriya Janata Dal rally hits the road.