From VOA Learning English, this is the Technology Report.

The world's largest solar thermal plant is set to begin producing power in the United States by the end of the year. Wind and energy from the sun are generally considered clean, unlike energy from coal-burning power stations. However, environmentalists now worry that to much solar power development could harm the local environment.

A California company -- BrightSource Energy is building a huge solar power plant in the Mojave desert, about 60 kilometers southwest of Las Vegas, Nevada. The plant is known as the Ivanpah Solar Electric Generating System. Joe Desmond works for the company.

"This is actually one of the highest concentrations of sunlight in the world, out here in Ivanpah," explained Desmond.

BrightSource Energy will deploy 170,000 specially designed mirrors to direct solar energy towards boilers on top of three power towers. The steam produced in the boilers will drive turbines to make electricity.
 
Joe Desmond says the steam can reach temperatures of more than 260 degrees Celsius.

"We can store the sun's thermal energy in the form of molten salt, so we can produce electricity even when the sun goes down. There is a lot of interest in concentrating solar power around the globe in environments where you have lots of sun, such as China, South Africa, the Middle East, North Africa," explained Desmond.

Environmentalists generally support the idea of solar power, however, many are concerned about the effect of power plants on sensitive environment.

Lisa Belenky is a lawyer with the Center for Biological Diversity, a private group. She says environmentalists are specifically worried about the effect of the Ivanpah Solar Project on the sensitive plant and animal life in that part of Mojave desert.

"Even though the desert seems big, when you start cutting it up, it can really affect how the species and the animals and the plants are able to survive in the long run," said Lisa Belenky.

BrightSource Energy has already spent more than $50 million to move endangered desert tortoises away from the power plant, but Lisa Belenky says this is not the answer.
 
"We should be reusing areas that have already been disturbed, [like] old mining sites, for example... either on homes, on businesses, parking lots," said Belenky.

There have also been reports of birds dying at the Ivanpah Plant and others like it. Some birds die after colliding with solar equipment which the animals mistake for water. Other birds were killed or suffered burns after flying through the intense heat at the solar thermal plant. As solar projects increase, environmentalists and developers are considering what to do to reduce bird death.