HOW DIU BECAME INDIA’S FIRST SOLAR CITY BY DAY

Mahesh Solanki used to pay about ₹1.8 lakh a month for power. Last year, it dropped by about ₹15,000; last month by ₹15,000 again. “With electricity costs rising everywhere, this was a pleasant surprise,” says Solanki, who owns a 36-room beach resort in Diu.

In September 2016, the scenic beach town became the first city in India to run completely on solar energy during the day. The power comes from its two solar parks spread over 0.2 sq km, and the rooftop panels on 112 government establishments.

In all, the two parks have a capacity of 10.27 MW, and operate for about 12 hours a day. Demand in this 42-sq-km city of 52,074 residents ranges from 5 MW to 7 MW.

Which means that through the day, the sun is powering all homes, the resorts with central air-conditioning, Diu’s 60-bed hospital, office buildings, and the ice factories and fish warehouses that are its main power-consuming industries.

“Until the first park, Diu did not generate any power and bought power from the Gujarat grid,” says Diu collector Hemant Kumar. “Now, we actually contribute to the grid during the day.” can lower capacity,” says Paresh Patel, a junior engineer with the Daman & Diu electricity department.

The parks are managed by two companies, the public sector Bharat Heavy Electricals Limited and the private renewable power company Ujaas Energy. At the control centres at each park, employees can track power production through the day. At 6 am, the panels start to hum; they peak around noon, and begin to ebb at 6 pm.

Through the day, excess power goes to the grid; after dark, Diu draws from the grid. There are plans to plug this gap too, switching from solar to wind at sundown.

“We hope to have four windmills sanctioned by the end of the year, with a capacity of about 6 MW,” says Kumar. In Fudam village, thousands of solar panels are laid out on a rocky hilltop overlooking the sea. They have essentially eliminated raw material and production costs, allowing the electricity department to slash power tariffs, says executive engineer Milind Ingle.

At the two year-old Diu government hospital, panels covering the roof have a capacity of 120 KW, with the power going to the grid. “Since it’s a government building, the net metering system doesn’t apply, but hospitals are usually huge spaces with major electricity consumption. Using open terraces for solar panels can cut this expenditure,” says senior surgeon and hospital head Sanjay Verma.

Can Diu’s success be emulated in a bigger city? The administration is finding it tricky to replicate even in Daman.

“They are twin territories, but the same policy cannot be applied because Daman is heavily industrialised with very little free space,” says Ingle. Instead, there would need to be centralised generation models as there are for thermal energy production. Mumbai, for instance, gets most of its power from coal-fired plants in Chhattisgarh; Delhi, from plants in Uttar Pradesh.

“Since solar energy needs a lot of space, it would make sense to use barren land in non-prime rural areas,” says Ingle. It would also make sense to start with the smaller territories.

As Ingle puts it, “A village can be lit with just 5-6 acre of land and at a cost of about ₹3 crore.”