Solar-powered islands? The story of Diu and T’au


Diu, India’s first solar city, is one of the three districts of the union territory of Dadra and Nagar Haveli and Daman and Diu of India. It is made up of Diu Island and two small enclaves on the Indian mainland. 

With a population of 50,000, Diu is one of the top 10 least populated districts in India. A very low population density and large barren land make it perfectly suitable for solar power generation. 

The union territory was completely dependent on the Gujarat government to provide its citizens with basic amenities like electricity. However, in 2016, Diu became the first city in India to completely run on solar energy. The island has good exposure to the Sun and has installed two solar parks and rooftop solar on almost 112 government establishments, which operate for 12 hours, from 6 am to 6 pm. 

The solar parks have a cumulative power generation capacity of more than 10 MW, against the city’s demand of around 5 to 7 MW. The plants supply power to residential, industrial, and even establishments like hospitals. The projects were done by BHEL and a private company in unison.

The parks were sanctioned in 2013 and became operational in 2015. To ensure the efficiency of production does not drop, regular cleaning is required. The excess power generated is transferred back to the grid. 

This solar success couldn’t be replicated in Daman, the neighboring city of Diu, as the city has been completely industrialized and has hardly any free space. As there is no barren land, the most deployed type of solar is rooftop solar.

T’AU is a small island in American Samoa, situated more than 4,000 miles away from the West Coast of the USA. It has a population of 600 only.  

For its power requirements, the island was completely dependent on diesel generators, which consumed more than 100,000 gallons of diesel a year. The diesel was shipped from the main island of Tutuila. The transport of fuel from Tutuila was prone to disruption because of bad weather and rough seas. 

The island switched almost entirely to solar power with the installation of a microgrid featuring 1.4 MW solar and 6 MWh of battery storage. Neighboring islands of T’au are planning to replicate this success. 

The solar and energy storage solution is not only a cleaner alternative but also offers cost savings. The batteries store the excess solar energy for use at night, and there is no longer a need for power rationing.

The project was funded by the United States Environmental Protection Agency.

It is quite astonishing to see the whole population, on a considerable landmass, thriving only on solar energy. With these model cases to look up to, the real test now is to replicate 100% solar adoption in bigger land masses where high population density, crippling bureaucracy, and lack of space are the likely challenges.


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