Solar Panels Over Canals May Help India Combat Climate Change

Though solar panels over canals are expensive, they have benefits over regular ground-mounted ones.

India’s first solar power plant project near Kadi. (Photo: Hitesh Vip/Wikimedia)

As far as the eye can see, line after line of solar panels stretch out in the midday sun beating down on the village of Chandrasan here in the eastern Gujarat district of Mehsana, which squeezes in 80 more people per sq km than India’s already crowded average of 441 people per sq km.

But there is no land conflict involved with the Chandrasan installation because the solar panels unfurl over a 750 m length of irrigation canal.

The canal-top solar panels were installed in India’s sunniest state in 2012 and now offer hope for a country three times as densely populated as China, at a time when India aims for almost a nine-fold increase in solar capacity between between 2017 and 2022 to fulfil global climate-change commitments and reduce its dependence on coal-fired power plants.

The 10 MW solar canal-top plant at Vadodara in Gujarat, built atop the Sardar Sarovar Canal. As costs reduce, solar installations atop or beside thousands of kilometres of canals might allow India to double its renewable-energy capacity, while saving land. (Image courtesy: IndiaSpend/Mukta Patil)

The canal-top idea was first tabled at a 2011 Vibrant Gujarat Summit by the then Chief Minister of Gujarat, Narendra Modi, said Bela Jani, a spokesperson at state-owned Gujarat State Electricity Corporation Limited (GSECL). The aim was to utilise the area above the canals, saving the government the cost, time and inconvenience associated with land acquisition.

Gujarat alone has a canal network of 80,000 km. Using even 30 percent of this network for canal-top solar projects, according to GSECL estimates, 18,000 MW of power could be produced in just Gujarat – almost equal to the current coal-based installed capacity of Delhi, Rajasthan and Telangana – and 90,000 acres of land, or twice the size of Kolkata, could be saved.

In other words, installing solar-panels over 30 percent of Gujarat’s canals could be used to meet nearly a fifth of India’s solar power targets by 2022.

Currently, about 100 MW of solar installations atop and besides canals are either approved or under construction in eight Indian states. Government subsidies are limited to public-sector companies that own canals or canal banks, but, if successful, private-sector involvement is inevitable.

As the midday sun beats down relentlessly, solar panels fixed at an angle atop a 750 m long length of canal in Chandrasan village, Mehsana district, work quietly to produce power while saving evaporation of water that runs beneath. (Image courtesy: IndiaSpend/Mukta Patil)

India’s Solar Future

Coal generates over 75 percent of India’s electricity and is among the cheapest energy sources available, IndiaSpend reported in May 2015.

With over 300 million Indians without reliable energy, and industrial demand growing, the need for coal-fired electricity is estimated to increase three times by 2030, with consequent environmental impacts.

The real potential in a sunny country to replace fossil fuels is solar: India has a renewable-energy potential of about 895 GW, of which 750 GW is solar, as IndiaSpend reported in February 2015.

By 2022, solar energy could achieve grid-parity in India, meaning it would cost the same as other sources of electricity – although some reports suggest this might happen by 2018. That is the year, as another IndiaSpend report said, renewable-energy sector, primarily solar, could generate 1 million jobs – over 4,00,000 already exist, according to a 2016 status report by Renewable Energy Policy Network for the 21st Century, a global, multi-stakeholder network based out of Paris.

Solar power plants can be built faster than either coal, gas or nuclear power plants.

The panels placed at optimum angle over canal water. When they are cooled from below, their efficiency increases and enhances output by 2.5-5 percent. (Image Courtesy: IndiaSpend/Mukta Patil)

Water Saving

The power output of ground-mounted solar panels decreases at a rate of 1 percent every year for the first 10 years. However, panels mounted on Chandrasan’s canal showed no degradation and the power generated stayed stable over the past three years, according to research conducted by the Gujarat Energy Research and Management Institute (GERMI), a research institution promoted by the Gujarat State Petroleum Corporation Ltd, which is a Govt of India undertaking.

Apart from this, since the panels are placed on top of water, they are cooled from below, which also increases their efficiency and enhances output by 2.5-5 percent.

Essentially, this means the panels will last longer than 25 years, which is the average lifespan of a ground-mounted solar panel, while producing more power due to increased efficiency.

The average solar panel lasts 25 years before it needs to be replaced. (Photo: iStock)

Why Solar is Important For India’s Climate-Change Commitments

By 2030, global greenhouse-gas emissions are expected to reach 54-56 giga-tonnes of CO2 equivalent (GtCO2eq) – far exceeding the level of 42 required to limit global warming to 2℃ by the year 2100, according to data from the Emissions Gap Report 2016, compiled by the United Nations Environment Programme every year.

As part of its Intended Nationally Determined Contribution, India has committed to source 40 percent of its electricity from non-fossil fuel sources by 2030. By October 2016, renewable installations amounted to nearly 15 percent of the installed energy capacity, according to the Central Electricity Authority.

India now faces the challenge of adding close to 91 GW of solar-power capacity over the next six years to reach its target of 100 GW of solar energy by 2022.

A board outside the 10 MW canal-top solar plant in Vadodara shows the daily export of power from the plant as well reduction in emissions. (Image courtesy: IndiaSpend/Mukta Patil)

As Land Availability Falls, Canal-Top Solar Prospects Look Bright

In 2012, when the first canal-top project was commissioned, the land required for a 1 MW solar installation was about 5 acres. By 2015, with advances in technology, this was down to 4 acres, Jani said.

Given that the population density of India during the same period (2015) was over 3 times that of China at 441 people per sq km, and over 7.5 times the world average of 56.6 people per sq km, land availability will inhibit solar-energy expansions.

Space-saving designs, such as Gujarat’s canal-top installations and floating solar panels (in Kolkata), could ensure future renewables growth.

However, capital costs of canal-top installations are, currently, higher than their ground- mounted counterparts. The 1-MW solar plant at Chandrasan (in 2012) cost Rs. 17.73 crore, 77.3 percent higher than the benchmark cost issued by Central Electricity Regulatory Commission.

“We should be looking at this (canal-top projects) as research, and not expect it to be commercially viable immediately,” Kuldeep said.

The canal-top panels next to their ground-mounted counter parts, used to check effect of cooling and enhanced efficiency of the panels atop the canal. (Image courtesy: IndiaSpend/Mukta Patil)

The canals over which the solar panels are installed have already gone through environmental impact assessments. Therefore, according to officials, the new constructions over the canal or on the sides are exempt from further assessments.

The construction of the project at Chandrasan was done in under six months. Permissions and approvals were received quickly and work was fast-tracked because there was no land to acquire or environmental impacts to consider, Jani said.

However, these solar projects require levelling of the canal banks and shadow-free areas above panels. If canals are tree-lined, this would involve cutting trees. Construction could also contaminate the water in the canal, said Kuldeep. “Environmental clearances are important because this is a separate construction that is being undertaken,” he said.

(This piece originally appeared in IndiaSpend, and has been edited for length. You can read the full piece here.)