Sunday, April 2, 2017

Energy: Chile Plugs into Superior Sunpower

-The Washington Post

On the solar farms of the Atacama Desert, the workers dress like astronauts. They wear bodysuits and wraparound sunglasses, with thick canvas headscarves to shield them from the radiation.
The sun is so intense and the air so dry that seemingly nothing survives. Across vast, rocky wastes blanched of color, there are no cactuses or other visible signs of life. It’s Mars, with better cellphone reception.

The Atacama is well-suited to solar energy production for the same reasons astronomers put high-powered telescopes in northern Chile for the clearest possible Earth-based views of the cosmos.

In nations such as Japan and Germany, which are some of the world leaders in solar energy production, the sun’s rays are partly diffused by water molecules floating in the air, even on days when it isn’t cloudy.
But in the super-dry Atacama, where it virtually never rains, the photons beam straight down.

Put a solar panel beneath them and its like plugging directly into the sun.

At the Finis Terrae solar plant near the tiny town of Maria Elena, more than 500,000 PV panels blanket the desert. The 160-megawatt plant was the largest solar installation in Latin America when it went online last summer, capable of powering nearly 200,000 homes. Since then, another Chilean plant has surpassed it.

“Compared with the Arabian, Sahara and Australian deserts, the Atacama Desert has the highest levels of direct normal irradiation, the key component of the sun’s rays for energy production,” said Salvatore Bernabei, the head of renewable energies for Latin America at Enel, an Italian multinational that owns the plant.
The radiation is so intense that no one is really sure how long standard-issue PV panels — which are designed to last 25 years — will be able to withstand it. One solar plant here had to replace most of its exposed cables after six months because the radiation fried their insulation.
Another problem solar companies are facing is the desert soil. In the afternoons, writhing dust devils zigzag across the desert floor, sprinkling particles onto the panels and reducing their output. Plant managers try to keep them clean using specially outfitted tractors with long wiper-arms, but there’s little water available.

Chilean energy officials say these challenges are relatively minor. The country derives about 6 percent of its energy from solar, but the potential of the Atacama is so great that Chile could generate all of its electricity with about 4 percent of the desert’s surface area, if there were a way to efficiently store and distribute that energy.

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