The Science of Sustainability

Largest Solar Plant in the World Goes Through Last Test Before Opening

  • share this article
  • Facebook
  • Email


In the last major step before the world’s largest solar plant opens in California’s Mojave Desert, engineers at the Ivanpah solar farm, 40 miles south of Las Vegas, are testing the huge water boilers on top of the plant’s three 459-foot towers.

The $2.2 billion project is scheduled to start delivering electricity to the power grid by the end of the year, said Joseph Desmond, vice-president of marketing for Oakland’s BrightSource Energy, the plant’s developer. Ivanpah is owned by BrightSource, NRG Energy and Google, and is being built by Bechtel. The plant’s electricity will be purchased by Pacific Gas and Electric, in Northern California, and by Southern California Edison.

It will deliver 377 megawatts of power, enough electricity for 140,000 houses, said Desmond, and about the same output as a medium-sized natural gas-fired plant.

Power tower surrounded by mirrors

At Ivanpah, 100,000 to 120,000 mirrors are arranged around three towers like this one. Photo: Gilles Mingasson / Getty Images for Bechtel.

“This is a major milestone for renewable energy development in North America,” said Carl Zichella, senior policy analyst at the Natural Resources Defense Council, an environmental group in San Francisco. “A plant like this creates economies of scale that will reduce the costs in the future.”

Ivanpah, which received a $1.6 billion loan guarantee by the federal Department of Energy in 2011, is one of seven massive solar plants scheduled to open in California by 2014. In the works for years, together they’re part of the coming of age of big solar in the United States.

The boom is fueled in part by state laws designed to promote renewable energy. In California, under a measure signed by Gov. Jerry Brown two years ago, utilities are required to produce 33 percent of their electricity from solar, wind and other renewable sources by 2020.

“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,” said Zichella.

Roughly 30 states now have similar laws, which are known as renewable portfolio standards.

On Thursday, U.S. Sen. Edward Markey, D-Mass., introduced a bill to require every utility in America to produce 25 percent of its electricity from renewable sources by 2025. Environmentalists cheered the news, although similar bills in Congress have failed in recent years due to opposition from Republican leaders and from lawmakers who represent regions that do not have as much wind or sunshine as other areas and worry that such rules would increase monthly utility bills for consumers.

Mirrors and boiler at Ivanpah solar farm

Mirrors concentrate the sun's heat onto a 120-foot boiler atop a 459-foot tower. Photo: Gilles Mingasson / Getty Images for Bechtel.

For the next two to three weeks, engineers at Ivanpah will painstakingly point tens of thousands of mirrors onto a boiler full of water on Unit 1. Their goal: to heat the steam inside to a searing 1,400 degrees Fahrenheit, said Tim Fisk, Ivanpah project director. That’s six times hotter than boiling water. The high-pressure steam powers a turbine, which in turn generates electricity. The “loading of the boiler,” as this step is known, is the last major step before Unit 1 can start delivering electricity to the grid. Afterward boilers on the plant’s other two units will undergo similar tests.

At each of the plant’s three units, 100,000 to 120,000 mirrors are arranged in a circular pattern around a tower as tall as a 45-story building, on top of which sits the boiler. The mirrors are controlled by computers, which move them during the day, sunflower-like, so that they’re always picking up the sun’s rays and sending them to the boiler, a 120-foot high black rectangle of steel tubes.

Concentrating solar power v. photovoltaic

Click to enlarge.

 

The technology is called concentrating solar thermal, and is different than the photovoltaic solar panels commonly used on rooftop installations, which transform the sun into electricity through a chemical reaction. Similar plants exist in Abu Dhabi and Spain.

Concentrating solar thermal technology offers the promise of getting around one of solar energy’s shortcomings. Because the sun only shines during the day, plants stop producing electricity at dusk. Concentrating solar thermal plants can be built to store heat in large vats full of molten salt, and can draw that heat to continue producing electricity for a few hours after sundown.

One of Ivanpah's three towers and turbines

The boiler atop a 459-foot tower delivers high-pressure steam to the turbine at the bottom, which uses it to generate electricity. Photo: Gilles Mingasson / Getty Images for Bechtel.

“When you add storage, you’re essentially 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 onto the grid,” said Desmond.

Ivanpah doesn’t include storage, but the first U.S. plant with storage, the Solana solar farm, opened 70 miles southwest of Phoenix, in Gila Bend, Arizona, in September.

Despite the advantages of large solar plants in the desert, Ivanpah, which is located on about 3,500 acres of federal land owned by the Bureau of Land Management, ran into challenges. While the Mojave Desert is one of the best solar resources in the world and is located relatively near dense population centers like Los Angeles that need the electricity, parts of the desert are also home to endangered species.

Desert tortoise

Desert tortoises in the Mojave Desert are protected under the Endangered Species Act. Photo: Joshua Cassidy / QUEST Northern California.

“From the get-go, we knew that the Ivanpah project was located in an area that had fairly high density of desert tortoise in it,” said Ileene Anderson, a biologist with the Center for Biological Diversity, an environmental group in Los Angeles.

Worried that habitat disruption would impact desert tortoises, which are classified as “threatened” under the Endangered Species Act, the group testified against the project. After it was reduced in size, it obtained federal and state permits, and construction began in 2010.

Initial surveys had led BrightSource officials to believe that they’d find 30 tortoises on the site where they were building the plant. But rains created favorable conditions for tortoises, and resulted in the company finding 173 instead. The company transferred the tortoises to pens and later moved them back onto wild land. More than 50 additional tortoises have been born in captivity.

“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,” said Desmond.

Desert tortoise hatchling

The care of each desert tortoise found on the Ivanpah site, or born in captivity, costs the project some $55,000, said the project's developers. Photo: Kristina Drake, USGS.

The tension between protecting threatened species and pushing for large-scale solar plants in the desert put environmental groups at odds with each other during Ivanpah’s construction.

“There have been genuine local concerns about the location of some of the earlier projects that have led people to feel not so committed to some of the renewable energy options,” said Zichella. “There’s no such thing as an impact-free energy source. If we’re going to deal with climate change, we have to understand that. And if we can choose the locations for these facilities very carefully, we can avoid a lot of the biggest problems.”

Efforts are underway to find the best places for large renewable energy projects. The 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 than other locations.

In California, government agencies and environmental groups are working to identify large tracts in the Mojave Desert suitable for both wind and solar plants. The plan would also set aside land for desert species. A full draft of the plan’s environmental review is expected this fall.

“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,” said Anderson.

Largest Solar Farms in the World

When it opens in the next few months, the Ivanpah solar farm will be the largest in the world, providing 370 megawatts – enough electricity for 140,000 homes. The largest now:

Name Country State/Province Capacity (megawatts) Developer
Agua Caliente USA AZ 278 First Solar
California Valley Solar Ranch USA CA 250 SunPower
Charanka Solar Park India Gujarat 214 Several
CPI Golmud Power Station China Quinghai 200 CPI Huanghe Hydropower Co.
Mesquite Solar 1 USA AZ 150 Sempra Generation

Source: SEIA

Additional reporting contributed by KQED Science radio reporter Lauren Sommer. Tortoise footage: Stephen M. Wessells, USGS.

Additional Links

As World’s Largest Solar Thermal Plant Opens, California Looks to End Solar Wars

Related

Explore: , , , , , , , , ,

Category: Climate, Energy, Engineering, News, Television, Video

  • share this article
  • Facebook
  • Email
Gabriela Quirós

About the Author ()

Gabriela Quirós is a TV Producer for KQED Science & Environment. She started her journalism career in 1993 as a newspaper reporter in Costa Rica, where she grew up. She won two national reporting awards there for series on C-sections and organic agriculture, and developed a life-long interest in health reporting. She moved to the Bay Area in 1996 to study documentary filmmaking at the University of California-Berkeley, where she received master’s degrees in journalism and Latin American studies. She joined KQED as a TV producer when QUEST started in 2006 and has covered everything from Alzheimer’s to bee die-offs to dark energy. She has shared two regional Emmys, and four of her stories have been nominated for the award as well. Independent from her work on QUEST, she produced and directed the hour-long documentary Beautiful Sin for PBS, about the surprising story of how Costa Rica became the only country in the world to outlaw in-vitro fertilization.
  • Bryan Cockel

    As usual Gabi, your work is thorough, impartial and inspirational. Fine work….and BALANCED…..superior work. Keep it up!
    Cheers,
    Bryan Cockel

  • Lylliam Posadas

    Thank you for your article. In the future, it would be nice to read about the impact this project has had on the state's cultural resources. There was considerable debate and many (still unsettled) anxieties among desert communities and those who work in the historical and cultural resources sectors regarding such impacts.

  • trevor

    Parking lots and roof tops make a lot more sense for solar energy and they do not require the habitat damage, mitigation costs, or long, expensive, and fire prone transmission lines.

    • David Gravereaux

      I don't share your conclusion. Large, essentially, means cost effective. PV cell area has got to be 10 times more expensive than a simple mirror even with the control actuators. In the future, please do your homework first before posting. My rough guess for 270MW in PV cell area is 2,079,000 M^2 or 513.7 acres.

  • lee

    http://www.kcet.org/news/rewire/solar/concentrating-solar/ivanpah-solar-has-a-bad-burned-bird-problem.html

    Ivanpah Solar Project Has a Bad Burned Bird Problem
    A solar energy project in the California desert seems to have injured and killed a surprising number of birds in the first two and a half weeks of September, according to data furnished to a state agency that went public Monday. And more than half of those injuries have been linked by project biologists to the facility's concentrated solar energy.

  • Steven Wohlwender

    You're science is wrong, Lauren. The LAST thing we need is more fencing in San Mateo. Just more manmade, ugly, prison fencing to cut off people from trees and natural resources. We have WAY too much rusted metal and poured concrete around here, Lauren. You want to save wildlife? Stop building stuff. While you think you are 'saving animals' you are destroying one of man's core elements — living (and suffering) WITH wildlife. I live in San Mateo, and I'll tell you, this is NOT about saving some deer, is it all about Joe Porsche Driver not wanting a deer to total his car.

  • Pingback: 5 Unthinkable Places Solar Panels Are Being Put Up. #3 Will Even Transmit Power Wirelessly To Your Home. | Viral Futures