Ivanpah Launches as the World’s Largest CSP Plant

The Ivanpah Solar Electric Generating Station, the world’s largest concentrating solar power (CSP) facility, was dedicated Thursday afternoon at a ceremony keynoted by U.S. Secretary of Energy Ernest Moniz.

In his remarks, Moniz hailed the Obama administration’s leadership on supporting renewable energy projects.

“President Obama and the Department of Energy [DOE] are committed to ensuring that all sources of energy are competitive in a carbon-constrained economy,” he said. “This is why we have already invested more than $6 billion in carbon capture and sequestration technologies and recently announced up to $8 billion in available loan guarantees for advanced fossil energy projects that lower emissions.”

Making that happen is an imperative, Moniz noted.

“Investing in clean energy isn’t a decision that limits our economic potential—it’s an opportunity to lead the global clean technology markets that are forming right now,” he said. “We simply can’t afford to be at the back of the train—we have to be at the front, leading the world in these industries.”

Moniz stressed that the DOE is looking to support more projects like Ivanpah. “We have over $40 billion to spend on clean energy projects,” he said. “Bring them on!”

He cautioned, though, that the DOE was not looking to dictate to the market, “but to help provide the options that all of you in your various roles play in determining what the private solutions are,” he said. “There’s no one solution. The ‘all of the above’ approach is working.”

The inauguration was fairly elaborate for a power plant opening, and featured an appearance by Grammy-nominated band The Fray, which filmed a music video for its forthcoming album at the site last year.

Big Output, Big Footprint

Comprising three units with a total capacity of 392 MW (377 MW net), Ivanpah is a joint effort between NRG Energy (through its subsidiary NRG Solar), Google, Bechtel, and BrightSource Energy. The station uses 173,500 heliostats (each with two mirrors) to concentrate sunlight on three 459-foot towers (Figure 1). Four types of heliostats are used depending on the distance from the tower; the furthest out are more than half a mile away. All of them were precisely placed using GPS to ensure accurate alignment. The heliostats are capable of withstanding 85-mph winds.


figure 1
1. Almost 180,000 heliostats, each mounting a pair of mirrors, are used to focus sunlight on the towers. Source: Tom Overton/POWER


Each tower holds a 2,100-ton boiler that directs steam into a turbine generator at ground level (Figure 2). Natural gas is used to bring the boiler up from a cold start, but in normal use, it retains enough heat from the previous day to start up on sunlight alone. A 110-ton counterweight is continually repositioned to keep the tower stable.


figure 2
2. The concentrated sunlight generates steam in the tower-top boilers. When the units are operating, the glow at the top is visible for miles. Source: Tom Overton/POWER


The facility relies on air-cooled condensers to condense the turbine exhaust, allowing it to use as much as 95% less water than a wet-cooled thermal plant. The plant’s only water needs are boiler makeup and cleaning. Water is sourced from two wells on the site.

Moniz dryly noted that the facility uses about the same amount of water as two holes at the Primm Casino golf course next door to the plant. “The energy-water nexus is going to be of increasing importance” in the future, he said.

The 3,500 acre facility—large enough to be visible from orbit—is located in Ivanpah Dry Lake, Calif., about 40 miles southwest of Las Vegas. BrightSource began development in 2006, and construction, led by engineering, procurement, and construction partner Bechtel—which has also invested in the facility—began in Oct. 2010. Shortly after construction commenced, NRG agreed to come on board, committing  about $300 million. In April 2011, Google—which had previously invested $10 million in BrightSource—announced that it would also join the project, investing another $168 million of its own. Google’s investment is part of its intention to source 100% of its considerable electricity demands from renewable energy.

Rick Needham, Google’s director of energy and sustainability said, “At Google we invest in innovative renewable energy projects that have the potential to transform the energy landscape and help provide more clean power to businesses and homes around the world. Ivanpah is a shining example of such a project and we’re delighted to be a part of it.”

NRG Solar will operate the plant going forward.

“We see Ivanpah changing the energy landscape by proving that utility-scale solar is not only possible, but incredibly beneficial to both the economy and in how we produce and consume energy,” said Tom Doyle, president of NRG Solar.

“We’ve demonstrated that this technology works at commercial scale,” said David Ramm, CEO of BrightSource.

The station was first synced to the grid last September and went into commercial operation at the end of 2013. It is selling its power to Pacific Gas & Electric (from Units 1 and 3) and Southern California Edison (Unit 2) under long-term power purchase agreements.

“It was a privilege to be a part of an iconic project, ” said Toby Seay, president of Bechtel’s power global business unit. “Consistent teamwork with a focus on safety and quality is key to executing a project of this size and complexity.”

Environmental Roadblocks

Ironically for a project that is intended to boost California’s production of renewable energy, Ivanpah has faced some opposition from environmental groups concerned about the impact on the sensitive desert ecosystem, in particular the effect on desert tortoises native to the area, which are federally listed as threatened under the Endangered Species Act. Opponents initially requested a move to a more disturbed location rather than the pristine Ivanpah Dry Lake site, but BrightSource declined.

In 2011, the Western Watersheds Project sued the Department of Interior, the Bureau of Land Management (which owns the land under the site), and the U.S. Fish and Wildlife Service (USFWS) over a determination that it claimed underestimated the impact on the tortoises.

Construction was halted after the discovery of more tortoises at the site than there were originally believed to be. In June 2011, the USFWS issued a revised opinion stipulating new protective measures that would reduce impact on the tortoises. BrightSource also implemented a program to locate and protect tortoise eggs and hatchlings and relocate tortoises to outside the construction zone.

One notable element of the Ivanpah site is that the heliostats were mounted in place with little or no grading or even concrete foundations. Instead, the heliostat supports were simply placed into the desert soil as is (Figure 3). This greatly reduced the impact on the existing ecosystem.


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3. To minimize impact on the sensitive desert ecosystem, the heliostats were mounted directly into ground without grading or otherwise modifying the site. Source: Tom Overton/POWER


The heliostats are also oriented slightly out of alignment when their unit is not operating. The reason is that if the mirrors are aligned horizontally, they resemble a lake from the air closely enough to confuse birds, which might attempt to land on them. (This has not prevented a few birds from being killed by the concentrated solar radiation after flying too close to the towers.)

Big Price Tag

Ivanpah’s $2.2 billion cost was supported by $1.6 billion in loan guarantees from the DOE’s Loan Programs Office (LPO). The plant is just a portion of the 2.8 GW of LPO-financed large-scale solar (CSP and photovoltaic [PV]) that is currently operating or under construction.

Though the LPO program has seen a handful of high-profile busts—most notably solar PV manufacturer Solyndra—it has on the whole been successful in nurturing renewable energy projects. The LPO currently oversees a portfolio of more than $30 billion that supports more than 30 closed and committed projects. LPO-supported facilities include one of the world’s largest wind farms as well as several of the world’s largest solar generation and thermal energy storage systems. These include the Solana project in Arizona, which came online in October, and the Mojave Solar Project in San Bernardino, which is projected to start up later this year.

“This project was made possible by the successful public-private partnership between the Department of Energy and the project sponsors,” Peter Davidson, LPO executive director, said in a statement. “Through partnerships like this, we can continue to build an innovative clean energy economy in the U.S.”

The Ivanpah opening comes a few days after the Solar Foundation released a report showing record-breaking job growth in the solar industry last year, particularly in California. Though the industry employed about 143,000 people as of November 2013, that state’s share was the largest by far, with more than 47,000 solar-related jobs—a total that is expected to grow by 22% this year. Employment at Ivanpah peaked at just under 2,700 during construction, which was completed with only a single lost-time accident. It will employ about 90 people full-time.

Thomas W. Overton, associate editor (@thomas_overton, @POWERmagazine)

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