The idea of building a solar power generation farm that floats on a reservoir was first mooted in Kerala. Now Maharashtra is moving fast with a related idea – placing solar panels on a dam wall to generate electricity
Designers of an innovative project under construction are erecting solar photovoltaic panels on the slope of a dam across a river in Maharashtra. They claim that this will be the first time in the country that these panels are being placed at such a location.
The panels will be erected on the downstream slope of the Morbe gravity dam across the Dhavari river, Sunil Kharb, a senior manager of Rays Power Experts Pvt Ltd told indiaclimatedialogue.net.
The municipal corporation of Navi Mumbai – Mumbai’s twin city on the mainland across the harbour – has commissioned Rays Power to execute the Rs 162 crore ($26 million) project, which will generate 20 MW of power.
The panels have to be installed carefully, considering that the slope of the dam is earthen. “It extends for 3 km and we are erecting the panels on the slope,” Rahul Gupta, the 27-year-old founder of Rays Power told indiaclimatedialogue.net.
“It is unique and we have to be extremely conscious of the safety and stability of the dam,” he said. “The topography of the dam is its main feature. The 32 million units of power generated from the site will be fed into the grid.”
Such installation is quite different from erecting solar panels over rooftops or on land. The mounting structures cannot be heavy or else they will compromise the structural integrity of the dam itself. Still, finding innovative places to erect solar panels is crucial in a land-starved country like India.
While there are panels being erected on the surface of dam reservoirs and canals, this is the first time – possibly in the world – that engineers are using the slope of a dam.
“Land is the biggest constraint,” said Gupta, “so there is a huge potential in erecting panels over dams. The central government is proposing to help develop such technology.”
Rays Power was established in 2011 and has a target of installing 150 MW of solar power in all forms by the end of this financial year. It achieved 60 MW in 2013. By this September, the company had orders worth Rs 500 crores ($81 million) and hopes to double this by next March.
Gupta, who is an IIT graduate, believes there is a huge potential of solar power in India as it lies in a sunny region of the world, receiving 4-7 kWh of solar radiation per square metre per day, with 300-325 sunny days in the year. “India has abundant solar resources, as it receives about 3,000 hours of sunshine every year, equivalent to over 5,000 trillion kWh. We felt the need to explore this huge opportunity and hence have set ourselves an achievable target for this financial year,” he said.
Solar panels on canals
In 2012, the Sardar Sarovar Narmada Nigam Ltd commissioned the Gujarat State Electricity Corporation to construct a “highly successful” Rs 17-crore ($3 million) 1 MW solar power installation on top of a canal in Mehsana district, according to former state energy (now finance) minister Saurabh Patel. The pilot project spanned 750 metres.
The project generates 1.6 million units of clean power and by covering the surface of the water, prevents 9 million litres from evaporating every year.
Since the Narmada dam authorities are presently building 19,000 km of canals to carry water to drought-stricken Saurashtra and Kutch, the scope for using these for solar power is immense. With declining costs of solar photovoltaic panels, the cost of such power has dropped from Rs 17 crores ($3 million) to Rs 11-12 crores ($1.8-1.9 million) per MW. Eventually, the canal network will extend for around 85,000 km.
The dam authorities are now investing around Rs 120 crores ($19 million) on a 10 MW project, which will be fed into the grid. The panels will cover 10 km of canals and do away with the need to acquire land for setting these up, which is a protracted and expensive exercise.
The Gujarat government estimates that by using one-tenth of the existing network of 19,000 km for solar panels, it can save 11,000 acres of land and 2,000 million litres of water.
Emulating Gujarat, the Punjab government is planning to generate 1,000 MW with solar panels over canals, of which it has an extensive network as the prime agricultural state in the country. It has announced a target of covering 5,000 km over the next three years, meeting 15% of the state’s electricity demand.
It has entered into an agreement with Lockheed Martin, the US aerospace company, for using nanotechnology to provide lightweight structures to support the panels over canals.
In 2011, Punjab planned to launch a 1 MW pilot canal-top plant using technology from P4P (Power for People) Energy Pvt Ltd from the US. It envisaged using lightweight triple galvanised cables, such as those used in San Francisco’s Golden Gate bridge, which can last for a century.
Since the state has 14,000 km of canals, the promoters claimed that such solar panels would ultimately meet the entire demand for power from the state. This was proclaimed a “sunshine story”, marrying 21st century technology to 19th century canals.
Steven Conger, the founder of P4P, claimed the project would save 5 million gallons of water per megawatt from evaporation and also reduce salinity. He said that by covering canals, fish would be shielded from the fierce summer sun and this could act as a catalyst for farming fish. However, even slight evaporation could affect the performance of solar panels.
The pilot project would have covered a width of 36 metres and length of 200 metres. Although it had the support of the Punjab Energy Development Agency (PEDA), it failed to get off the ground.
Meanwhile, Kerala is planning to set up another 1 MW pilot project where the panels would float over the reservoir of the Meenkara dam in Palakkad district. Irrigation secretary V.J. Kurian, however, warned that conditions in the state had to be studied before going in for such technology.
If the pilot scheme is successful, the government will launch the first phase, with funding from the Cochin International Airport Limited and the central Ministry of Non-Renewable Energy.
The National Hydroelectric Power Corporation is also planning to set up a 50 MW floating solar panel project in Kerala with technical assistance from the Renewable Energy College in Kolkata.
While conventional solar projects require 4 acres of land to generate 1 MW of power, with an investment of Rs 7 crore ($1.1 million), a floating alternative will call for 10-20% less surface area and cost Rs 6.5 crore ($1 million) per MW. This will generate power costing Rs 7 (11 cents) a unit, a rupee less than the conventional solar power system.
The Damodar Valley Corporation – which straddles Jharkhand and West Bengal – also plans to install 1,000 MW worth of solar power by covering 2,500 km of irrigation canals. The company hopes to rope in the World Bank for funds.