PBS高端访谈:加州太阳能项目对栖息地的影响

 　　JUDY WOODRUFF:Now the challenges of combating climate change.

　　This week, the European Union announced it was loosening its strict environmental regulations in the face of economic setbacks. In the U.S., renewable sources of energy like wind and solar have struggled to take hold on a large scale.
　　As Andrea Kissack of KQED-San Francisco reports, one major effort to harness the power of the desert sun shows promise, but has had its own effect on the land.
　　JOSEPH DESMOND,BrightSource Energy: What's that sort of shiny object off in the distance there over a sea of mirrors? That's the first thing you see are the towers from over the mountains, and, as you get a little closer, you begin to see a sense of the scale of how it is designed.
　　ANDREA KISSACK, KQED:Three giant towers and three 300,000 mirrors have gone up in California's Mojave Desert one hour south of Las Vegas.
　　The $2.2 billion Ivanpah solar project is the largest of its kind in the world. It will be able to produce as much electricity as a medium-sized natural gas plant, but without the carbon emissions 1.
　　JOSEPH DESMOND:We selected the Ivanpah site because this good sun. The better the sun, the more cost-effective the energy is delivered because you can produce more.
　　CARL ZICHELLA,Natural Resources Defense 2 Council: Within 200 miles or less of Los Angeles, we have one of the very finest solar resources on the planet. You know, we need to take the carbon out of the world's largest economy and do it in a very short time frame. Large-scale solar in the best locations like the desert are going to be important parts of that.
　　ANDREA KISSACK:Ivanpah is one of seven new big solar plants in the state that will be finished by 2014. And solar energy from plants and rooftops will continue to grow.
　　California utilities are rushing to fulfill 3 a state law that requires them to produce one-third of their electricity from renewable energy by 2020.
　　CARL ZICHELLA:California was among the very first states to adopt a policy that required utilities to buy a certain percentage of their electricity from renewable energy sources. Now 34 states have adopted similar policies.
　　ANDREA KISSACK:Unlike the photovoltaic solar panels you find on rooftops and in some solar plants, Ivanpah uses a technology called concentrating solar thermal 4. Mirrors reflect sunlight and concentrate it on to boilers 6 filled with water on top of three towers, each as tall as a 45-story building.
　　The taller the towers, the more mirrors fit on the field. The boiler 5 produces high-pressure steam that powers a turbine at the base of the tower. Just as at any traditional power plant, the turbine produces electricity.
　　JOSEPH DESMOND:The project itself will on an annual basis serve the equivalent of about 140,000 homes.
　　ANDREA KISSACK:One of the shortcomings of solar energy is that it's only available when the sun is shining. But systems in place at some solar plants similar to Ivanpah get around this by storing heat in molten salt for later use.
　　JOSEPH DESMOND:When you add storage you're essentially 7 making this a power plant just like a natural gas plant, meaning it has the ability to be flexible, controllable and deliver power when it's most valued and most needed on to the grid 8.
　　ANDREA KISSACK: Ivanpah doesn't include storage, but the first U.S. solar plant with storage started delivering electricity in 2013 in Arizona.
　　Despite the advantages of these large solar plants in the desert, Ivanpah ran into challenges.
　　ILEENE ANDERSON,Center for Biological Diversity:From the get-go, we knew that the Ivanpah project was located in an area that had fairly high density 9 of desert tortoise in it.
　　ANDREA KISSACK:Worried about habitat disruption, the Center for Biological Diversity out of Los Angeles testified against the project. But construction began in 2010.
　　Desert tortoises are protected under the Endangered Species Act, so the project's developer, BrightSource, based in Oakland, California, asked for a permit to move any tortoises it found on the federal land where it was building the plant.
　　JOSEPH DESMOND:The initial surveys did not show that there were a lot of desert tortoises.
　　ANDREA KISSACK: Surveys conducted during dry years led BrightSource to believe they would find close to 30 tortoises. But the rains came, and 173 tortoises showed up instead.
　　JOSEPH DESMOND:We stopped construction in one area of the project. What they did is have us take a pause in the area in which they had located the additional tortoises.
　　ANDREA KISSACK:The company transferred the tortoises to pens and later moved them back on to wildland; 53 additional tortoises have been born in captivity 10.
　　JOSEPH DESMOND: If you take into account the care and monitoring of all the tortoises involved in the program, it works out to be about $55,000 per tortoise.
　　ILEENE ANDERSON:I think, early on, it was a big rush to get projects on the ground. There hadn't been any planning. There hadn't been any large-scale evaluation 11 of the landscape.
　　ANDREA KISSACK:In response, more research is taking place and new policies are being adopted.
　　Biologists like Ken 12 Nussear from the U.S. Geological Survey are trying to better understand how development might impact animals like desert tortoises.
　　KEN NUSSEAR, U.S. Geological Survey:Each tortoise has its own channel, and we plug that channel in.
　　We got tortoises up in this hillside somewhere.
　　ANDREA KISSACK:The U.S. Interior Department has identified solar energy zones on public land in six Southwestern states. These 300,000 acres are close to transmission lines and have fewer threatened species.
　　In California, government agencies and environmental groups are working to identify large tracks in the Mojave Desert suitable for wind and solar plants. This plan would also set aside land for desert species.
　　ILEENE ANDERSON:We're engaged in that process and very much looking forward to help crafting a good plan that allows for renewable energy development, as well as allowing for good, strong conservation to occur.
　　KEN NUSSEAR:So this one here is a new burrow 13. And we just put an address here so we can see not only how many times does he use this same exact place, but which other tortoises are using this place.
　　I got a position. Here we go, 665-672.
　　ANDREA KISSACK:Around the country, developers, policy-makers and environmentalists are faced with the delicate task of balancing the need for clean energy with the need to protect well-loved landscapes.