We're huge fans of NASA's Earth Observatory website here at ReWire, so it pains us to report that the site got something badly wrong on Sunday. It put a controversial solar power plant in the wrong place, despite clear evidence in the post's photo, reprinted above: a Landsat 8 photo of the Ivanpah Valley taken in December 2013.
The post, written to describe the image of the day, makes the error in the second paragraph: "The new solar power plant sits within Ivanpah Dry Lake on 3,500 acres of public land that sees 330 to 350 sunny days per year." The error even extends to the post's title: Harvesting Sunlight on the Playa. (Update: NASA changed the second paragraph after this post was published; the headline remains unchanged.)
What's the problem? The Ivanpah Solar Electric Generating System (ISEGS), which officially went online last month, was not built "within Ivanpah Dry Lake," a.k.a "the playa." The project is actually several miles uphill from the dry lake, on an alluvial fan once teeming with wildlife. A half-trained eye could look at the Landsat image and see that's so. And here's why that distinction is important.
Dry lakes, often called playas after the Spanish word for "beach," fill many valley floors in the American deserts. Dry lakes are where all the dissolved salts and tiny soil particles accumulate after they're washed out of the surrounding hills. Salts are often toxic to plant roots, and the tiny soil particles in playas aren't the best environment for those roots even without the salt accumulation. And because playas fill the bottoms of valleys with those flood-borne soils, they tend to be very flat.
That means that playas are often visually barren, devoid of vegetation, rocks, and relief. They aren't lifeless: many playas have thriving ecosystems hiding in them, fairy shrimp and spadefoot toads waiting for the next flood to fill the dry lake for a time.
But they look barren, and that's the important thing here.
Dry lakes are also about the last place any competent solar developer would want to site a solar facility. Dry lakes are usually dusty and often alkaline, and it doesn't take much wind to pick that dust up into the air and send it hurtling somewhere else. Wind-driven sand isn't good for mirrors or PV panels: scratches interfere with their efficiency in converting sunlight into power. Wind-driven alkali can play hell with electronics and high-tech finishes. And even if the dust doesn't do damage, it does get things dusty, which means solar companies have to spend more time and money and scarce desert water cleaning things.
You don't even need a windstorm to blow into a valley for a dry lake to get sandblasted: the dry lake is fuly capable of generating its own storms. In summer the superheated playa surface generates updrafts, which spawn little mini-tornados familiarly called "dust devils" that can reach reasonably high wind speeds, with the biggest devils capable of pitting windshields and stripping paint jobs. I spent 2008 living about five miles from Ivanpah Dry Lake, and I watched more dust devils each day than I could count.
And as the NASA photo clearly shows, Ivanpah's builders were not so foolish as to site their project on Ivanpah Dry Lake. Instead, they built the thing about three miles uphill, on an alluvial fan running down off the east face of Clark Mountain. The NASA photo shows this clearly. Here's that photo with a pink overlay showing where the playa actually is, in relation to the project:
As you can see, the sprawling ISEGS isn't even close to being "within the dry lake." At its closest point, it's about 1.6 miles from the playa, and about 4.5 miles at its farthest point.
Even if you don't recognize the characteristic bleached white sediments of the playa at first glance, there's another hint in the Landsat photo indicating that ISEGS isn't on the playa: the plant has drainage channels running through it that carry ephemeral flows of water from the highlands of Clark Mountain in the Mojave National Preserve to lower elevations. Those channels are partly engineered in the grounds of ISEGS itself, but they were there before the plant was built, and you can see them in the image if you know what you're looking for. Here's a slice of the original Landsat photo in which we've tweaked the contrast and sharpened to make those drainages pop a bit more. To the right of ISEGS, they appear as roughly horizontal stripes that are a bit darker than their surroundings.
Why are these drainage channels -- "washes", in Mojave desert parlance -- important? Because playas occupy the lowest point in their valleys. If the washes flow into the plant on one side and out the other, that means the floods that carved the washes still had more downhill to go on the other side, hence the playa has to be on beyond that right-hand side of the plant somewhere.
Why does this matter? Because unlike the playa, where the ecological diversity is well-hidden and admittedly rather simple, the alluvial fans of the Mojave Desert can hold a remarkable amount of wildlife of the plant and animal varieties.
Which means that when someone says ISEGS was built on the nearby dry lake, people imagine the plant replacing a landscape like this:
... while what ISEGS actually displaced once looked like this:
There are people in the U.S. who resent industrial solar plants like ISEGS being held to any environmental standard whatsoever. They include tech industry cheerleaders, some mainstream pundits, and people who worry about climate change but who don't want their lifestyles to be affected by any workable solution.
Though state and federal agencies are taking increasing interest in ISEGS' effect on the desert's wildlife, there are many who still seek to downplay those effects. They do so by dismissing the plant's effects compared to a similarly sized coal plant, despite the fact that ISEGS is more likely to displace rooftop solar than coal -- and that the plant may burn a significant amount of natural gas to keep its turbines going.
They do so by referring to the hundreds of Threatened desert tortoises displaced from the Valley's prime old growth desert habitat as "a handful."
And they often do so by insinuating that the plant's site, with its formerly remarkable plant and animal diversity, was essentially the same as the barren dry lake familiar to millions of L.A.-to-Vegas drivers.
NASA may not have intended to downplay the site's ecological significance, but it reinforced the spin of those who do so intend. And in the process, NASA may have made the chances of an honest, spin-free discussion of the plant's effects that much harder.