The Ivanpah Solar Electric Generating System

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(Fig. 01)
Map of Ivanpah Solar Plant
(Fig. 02)
04/29/2015 Trip Notes: Whenever you make a visit to Nipton California these day's you can’t help but miss the bright light beams generated by the Ivanpah Solar Electric Generating plant when looking off to the west (Fig. 01). As it always invokes questions as to how it operates, I decided to put this little information page together to describe its history and operation. In a nutshell, Ivanpah produces electricity the same way that most of the world’s electricity is produced – by creating high-temperature steam to turn a conventional turbine. However, instead of burning fossil fuels to create the steam, we use the clean and infinite sun as fuel. As you can see from the map in (Fig. 02), it is located near Nipton, California,  about 40 miles southwest of Las Vegas, near the Nevada-California boarder.
Areial View of Ivanpah plant
(Fig. 03)
Description: The Ivanpah solar power plant is currently the largest solar thermal power plant in the world. Few power plants can be called “small,” but nearly everything about Ivanpah is mammoth. the three-unit site sprawls over 3,500 acres of the Mojave Desert – nearly 5 miles from end to end (Fig. 03). The facility is large enough to be visible from orbit, and the glow of the three power towers is visible from many miles away when the units are online. The station uses 173,500 heliostats (each with two mirrors) to concentrate sunlight onto its three 459-foot towers. Its more than 300,000 mirrors, each the size of a garage door (Fig. 04), reflect solar rays onto three boiler towers, each as high as a 40 story building. Each heliostat field is more than a mile across, making the furthest heliostats more than half a mile away from their tower. Four types of heliostats were used depending on the distance. Capable of withstanding 85-mph winds, each one was precisely placed using GPS to ensure accurate alignment.
Solar Mirrors
(Fig. 04)
How it works: Its more than 300,000 software-controlled mirrors track the sun in three dimensions and reflect the sunlight to boilers that sit atop the three 459 foot tall towers. When the concentrated sunlight strikes the boilers' tubes, it heats the water to more than 500 degrees, creating superheated steam, which is then piped from the boiler to a standard turbine where electricity is generated. Each tower holds a 2,100-ton Riley Power boiler that directs steam into a Siemens turbine generator at ground level. The boilers retain enough heat from the previous day to start up on sunlight alone, though an auxiliary boiler is used during cold start conditions or when it is desirable to start up the plant earlier in the morning. A 110-ton tuned mass damper is located at the top of each tower to keep it stable in high-wind conditions. The facility relies on air-cooled condensers supplied by SPX Cooling Technologies to condense the turbine exhaust. This design was selected in order to help Ivanpah use about 95% less water than a wet-cooled thermal plant. In practice, the plant has been even more water-thrifty than expected: Through the first hundred days of operation, it used only 6% of its allotted water, just under 20,000 gallons per day. The plant’s only water needs are boiler makeup and mirror cleaning. Water is sourced from two wells on the site and purified for use. In full operation, the plants turbines have a power production between 377-392 Mega Watts, capable of providing power to more than 140,000 homes. The view below (Fig. 05) was shot from the head of a basin on the west slope of the Lucy Grey Range, west of the McCullough Range, about 7 miles northwest of Nipton.
(Fig. 05)
Environmental Concerns: During construction, a major concern was the protection of the Desert Tortoise. Ultimately, more than 170 were found and relocated. Over the seven year period, more than $30 million has been spent on tortoise protection measures, including the building of a temporary tortoise habitat. Since it opened for operation, there has been much concern over the killing of birds that end up flying in the paths of the directed sunlight. Workers at the site have given a name to the birds that fly through the plant’s concentrated sun rays - “streamers,” for the smoke plume that comes from birds that ignite in midair.