Canal Top Solar PV Plant in Gujarat: A Unique Nexus of Energy, Land, and Water

India, a country with an everincreasing population (over 1.2 billion as per Census 2015) and need for energy is faced with the enormous challenge to produce energy with efficient utilization of available resources. In this context, the state of Gujarat came up with an innovative and cost-effective solution to utilize the existing irrigation canals to mount and produce solar energy. According to the Central Electricity Authority of India, the average requirement of energy per capita in India is 1,010 kWh. Despite the fact that the per capita energy demand is the lowest in the world, there is a substantial need to increase the energy generation as India is emerging as one of the leading manufacturing nations in the world. India recognizes the need for producing clean energy and for this reason, several policies have been enforced. Currently, over 70 per cent of the country’s electricity is generated from fossil fuels, but as per the draft National Renewable Energy Act, the government has a target 175 GW through renewable resources by 2022. The proposed act also takes into account the provisions of the Electricity Act, 2003, Land Acquisition and Rehabilitation and Resettlement Act, 2013, and Environment Protection Act, 1986, to address the issues of environment protection and rehabilitation due to renewable energy installations.

It is for this reason that renewable energy utilization, particularly solar energy, is being enthusiastically enforced in India. However, land is a precious commodity for India. Justifying the use of land to set up solar plants, which can be used for habitation, cultivation, and manufacturing, is a tough proposition. India has aggressive target to achieve 100 GW of installed capacity of solar PV plant by the year 2022. If all the plants are installed at one place, the land occupied shall be 1.5 times more than that of the state of Delhi. A key challenge under Smart City Programme is to generate solar energy from barren landmass or through rooftops, a requirement which is difficult to accommodate in metropolitan and other large cities. Taking into account the country’s large irrigation canal network, the Government of Gujarat put forth the concept of construction of solar PV plant on canal top and created the first pilot demonstration project near Sanand, Gujarat, in 2012 (Picture 1).

A key challenge under smart city programme is to generate solar energy from barren landmass or through rooftops, a requirement which is difficult to accommodate in metropolitan and other large cities.Taking into account the country’s large irrigation canal network, the government of Gujarat put forth the concept of construction of solar PV plant on canal top and created the first pilot demonstration project near Sanand, Gujarat, in 2012.

Engineering Marvel

Constructing large structures without damaging the canal and its function became a challenging task. The width of the canal bed was about 4 m and the canal bank was over 6 m wide. However, to provide an exemplary structure design, which could be easily replicated in the future, a structure of 16 m width was designed so as to fit on any large canal. The manufacturing of the structure also posed several problems. Construction of a structure in the middle of the flow path of the canal would have obstructed the flow of water significantly. Thus, the structure was designed with only end supports. Although this design increased the cost of the project, it resulted in a design which could be replicated in the future for canals facing water flow problems. Galvanization of the large structures was also a major practical concern for manufacturing. The mounting structure also created a region of high air flow below it, similar to a wind tunnel. To reduce the chances of damage to the structure owing to high wind speeds, the concept of a wind breaker was introduced. This significantly reduces the wind speed, thus preventing damage to the structure.

Superior Performance

Solar cells give out a lower voltage output when they are subjected to heating. Typically, this results in solar PV plants losing 10–15 per cent of the available energy on an annual average basis. These losses result in the loss of final power of up to 8 per cent annually. It was observed that the solar cells mounted on the canal top were cooler than their land-based counterparts. This resulted in the cells with an average temperature which was cooler by 10 per cent. Due to this, the energy generated by the plant was significantly higher than a groundmounted solar PV plant. The plant has offered capacity utilization factor (CUF) of around 17.71 per cent which is almost constant since its inception. In addition, the canal mounted solar plant also had lower panel degradation as compared to a traditional ground mounted solar panel system. Typically for ground mounted PV panels, the power output decreases by 1 per cent on a flat basis for the first 10 years. Contrary to this, a recent study conducted by Gujarat Energy Research and Management Institute (GERMI) establishes stable generation even after three and a half years of sunlight exposure and continuous operation. This is a significant feat which would allow the canal mounted solar panels to have a life expectancy beyond 25 years. It, thus, becomes evidently clear that with the use of a canal mounted solar PV plant—long-term financial benefits are possible. This, in turn, would allow allocation of more resources for setting up similar projects.

Saving of Resources

With the increasing population also comes the need to address the problem of water security. For a country relying primarily on monsoon to deliver the annual water supply, it becomes an issue of pivotal importance. The solar panels mounted on the canal top block the radiation of the sun, thus helping to keep the water in shade. This reduces the evaporation of the water in the canal. According to conservative estimates, a 1 MW plant can save 9 million litres of water per year. As the area covered by the solar panels increases, a large quantity of water is saved. The water in the canals gives rise to algae growth due to abundant sunlight and moisture. Algae block and clog the irrigation and water pumps and spoil the quality of water. Thus, due to the fitment of solar PV panels and absence of sunlight, algae growth is drastically minimized. This helps in lowering the cost of maintenance and extends the life of irrigation equipment. Furthermore, the solar panels can provide electricity to the irrigation pumps. Since the pumps are often located at remote locations, this would also solve the issue of transmission of electricity as well as strengthen the grid. This way, the canal top becomes the best administrative model for communityscale solar powered water pumping/ village electrification programme. Solar pumps no longer need to be installed in isolation since they are susceptible to theft, mishandling, poor maintenance, etc. Canal top offers better administrative model. The authors believe that canal top solar PV project has a very big role to play in the Smart City Programme, National Solar Mission, and greater use of irrigation pumps. Another advantage of the canal top solar power plant is that the energy generation is closer to the point of consumption. This results in the minimization of the transmission and distribution losses of electricity, thus enabling urban and rural settlements to generate their own power. The generation at remote consumption centres would also enable the strengthening of the grid which in turn would improve the reliability of the power being supplied.

Typically for ground mounted PV panels, the power output decreases by 1 per cent on a flat basis for the first 10 years. Contrary to this, a recent study conducted by Gujarat Energy Research and Management Institute (GERMI) establishes stable generation even after three and a half years of sunlight exposure and continuous operation. This is a significant feat which would allow the canal mounted solar panels to have a life expectancy beyond 25 years.

In addition, a lot of intangible gains are also possible with the implementation of the project. Furthermore, there has been no disturbance to the ecology and habitation of the area near the canal as well as the flora and fauna. The project has offered employment opportunities to rural and urban workers, working in both skilled and unskilled jobs on the site. Working on the operation and maintenance of the plant would also help in generating interest and in turn, earning more projects in the future.

Replication

The canal top power plant presents an amazing potential for replication. The project is easy to begin as very few approvals/clearances are required. Further, it offers a faster implementation period as no land acquisition/development is required. Since irrigation canals exist throughout India, it provides a fairly simple and economically viable model for replication. In Gujarat alone, where the pilot project is successfully implemented, there exists a canal network of 80,000 km. As per the estimation of the Gujarat State Electricity Corporation Limited (GSECL), even if 30 per cent of this canal network is used for solar PV plant installation, it can generate up to 18,000 MW of power and a saving of 90,000 acres of land. Similar large canal networks exist across the entire country, ensuring a cost effective and smart model for generating energy. Many other canal top plants have been set up in India itself—a 10 MW plant has been replicated in the city of Vadodara in Gujarat (Picture 2), a 1 MW plant has been set up in Karnataka, and a canal top plant has also been added in Andhra Pradesh.

Since the pumps are often located at remote locations, this would also solve the issue of transmission of electricity as well as strengthen the grid. This way, the canal top becomes the best administrative model for community-scale solar powered water pumping/ village electrification programme. Solar pumps no longer need to be installed in isolation since they are susceptible to theft, mishandling, poor maintenance, etc. Canal top offers better administrative model. The authors believe that canal top solar PV project has a very big role to play in the smart city programme, national solar mission, and greater use of irrigation pumps.

It is pertinent to note at this juncture that similar canal networks exist throughout the world. Also, the possibilities to further implement this idea are endless. Recognizing its importance, the Government of India has prepared the policy for absorbing 100 MW of capacity addition through canal top solar projects. The first pilot project demonstrated by the GSECL received the prestigious Prime Minister’s Award for Best Project in Public Administration for the year 2015.

Conclusion

The canal top solar power plant is an innovative idea that efficiently utilizes land and conserves water. It provides a better administrative model for smart village, smart city, and irrigation projects. Further, it can be developed under the public private partnership (PPP) mode. With declining cost trends, canal top projects are expected to acquire a larger share of national solar targets. Large capacity canal top solar parks may offer faster and more economical deployment of solar power projects in India.

Mr Om Shukla, Dr Sagarkumar M Agravat (Email: sagar.a@germi.res.in), and Ms Narayani Srivastava are at the Gujarat Energy Research & Management Institute (GERMI), Gandhinagar, Gujarat. Ms Bela B Jani and Mr Gurdeep Singh are at the Gujarat State Electricity Corporation Limited, Vadodara, Gujarat, India.