Read the following passage and mark the letter A, B, C, D on your answer sheet to indicate the best answer to each of the following questions from 31 to 40.
[I] India’s combination of abundant sunshine and a large, energy-hungry population makes it ideal for developing solar energy. [II] But the main challenge in building a large number of solar farms is finding the right place to do it, considering the shortage of land due to high population. [III] The region of Gujarat, however, has found an answer to this problem: covering its water canals with solar panels. [IV]
Overall, Gujarat has more than 80,000km of canals flowing through the state. According to Gujarat State Electricity Corporation, if 30% of this were converted to solar, 18,000MW of power could be produced, saving 90,000 acres of land. The electricity generated from a “solar canal” can be provided to farmers during the irrigation season when energy demand is usually high, and out of season it can be fed into the state grid, sold to distribution companies so that the state can earn some profit, or used by those in charge of the canals for specific purposes.
Building solar plants atop canals obviously helps produce clean energy and save land, but there are also other benefits. Firstly, these special plants can be built much faster than large coal or gas power stations. In addition, when solar panels cover the canal, they help prevent evaporation, leaving more water for crops and people. Another plus of the panels’ shade is that it can curb algal blooms, which can have negative effects like clogging water pumps and causing toxicity, in the canals. And the panels benefit from the water below as well. The running water helps the panels to remain cool, which increases their efficiency by at least 2.5 to 5%.
There are some drawbacks, however. Canal-top solar plants are more costly to construct than normal solar plants since the panels must be built with protective materials to prevent corrosion caused by water. Finding the right location is also difficult, as the width of the canal has to be suitable. Too wide, and the construction becomes difficult and expensive. Too narrow, and the number of panels constructed are too few to absorb enough sunshine. The twisting nature of the canals also leads to restrictions. To maximise the absorption of energy, the solar panels should face south, but the canal’s direction cannot be dictated by humans.
Nevertheless, eight Indian states have commissioned canal solar projects so far. “These innovative projects can provide cheap and consistent electricity to millions of farmers and improve their profits,” says Manik Jolly, who was involved in the 2015 canal-top solar plant project. And there is also potential to maximise renewable power from India’s canals if solar farms above were combined with hydro-power from below.
With their water-cooled efficiency, and mutual benefits for the canals that run beneath, it looks likely that these innovative solar canals is going to become a much more common sight in India in the near future.
(Adapted from bbc.com)
The word "curb" in paragraph 3 is OPPOSITE in meaning to_______.