Solar Power Tower Developers Attempt to Dismiss Shortfalls

Solar power tower developers have chided critical press coverage of their massive facilities as letting perfect be the enemy of good.  But we have learned enough about this technology to know that power tower projects do not even qualify as "good" clean energy projects.  Far superior alternatives exist in terms of life-cycle carbon emissions and sustainable siting.

Solar power towers have earned a bad reputation, and their developers are desperate to restore the green halo that they enjoyed a few years ago.  NRG - the current owner of the Ivanpah Solar project in California - and Solar Reserve - owner of the Crescent Dunes project in Nevada - have long been on the defensive with inaccurate and misleading public relations efforts.  But they have stepped up their PR efforts after new reports on their natural gas use and impacts on wildlife. Although developers promise to eventually deliver energy storage benefits, other technologies allow us to do so without burning birds in mid-air or natural gas.

The Ivanpah Solar project destroyed 5.6 square miles of intact desert habitat, displaced or killed over 150 desert tortoises, burns birds in mid-air, and burns natural gas at night to keep its boilers warm.  But the project's owner, NRG, would like you to believe that it is a good "clean" energy project.

Dissecting the PR Campaign
You'll hear that the power tower projects' natural gas use is trivial, or that the projects have found a way to avoid all bird deaths.  Or that they have only been built on already-disturbed lands. These claims are misleading and dismiss significant deficiencies in sustainability that do not deserve to be part of our renewable energy portfolio.

Natural Gas
The latest fact to irk the solar power tower industry is that the Ivanpah Solar project uses natural gas to keep its giant boilers warm at night, and emitting nearly 50,000 metric tons of carbon dioxide each year.  A Las Vegas Sun editorial favorable to NRG - a corporate behemoth that also operates coal and oil burning power plants - suggested that concerns over Ivanpah's natural gas usage is tantamount to criticizing the fuel usage of a hybrid Toyota Prius.  This is an erroneous comparison.  It would be more accurate to say that Ivanpah Solar is a Tesla electric vehicle that secretly burns fossil fuels when it is sitting in the garage at night and not even being used.  Or, at best, Ivanpah is like a Volkswagen Jetta that we thought had a certain level of efficiency, but later found out to guzzle a lot more fossil fuels.

We were told that Ivanpah is a solar power project that generates energy from the sun, but apparently it cannot do so without burning natural gas.  And the Ivanpah project's developers increased the amount of natural gas usage after the public environmental review process.  Are we making perfect the enemy of good?  No, because "good" clean energy projects don't actively burn fossil fuels to generate said "clean" energy.   Other renewable energy technologies have matured beyond the need for fossil fuel training wheels.  We're not going to applaud NRG for taking us back to the fossil fuel era.

Crescent Dunes does not use natural gas like its cousin in Ivanpah, but from a life-cycle perspective its power tower is still a monument to fossil fuels.  The project's tower is composed of approximately 130,000 cubic yards of concrete, according to the Las Vegas Review-Journal.  Every cubic yard of concrete is responsible for nearly 400lbs of carbon emissions (low estimate). So the Crescent Dunes project alone is responsible for at least 23,000 metric tons of carbon emissions.  Other solar technologies (and especially rooftop solar) do not require as much carbon-intensive material as power tower construction.

Bird Deaths
The industry has deployed two opposite, but misleading responses to the problem of bird mortality at power tower projects - that they have solved the bird mortality problem (not true), and that other human activities kill more birds than power towers so therefore we should not be concerned with mortality at power towers (a classic red herring).

Wildlife biologists have attempted to study bird deaths at the Ivanpah and Crescent Dunes projects, but the sheer size of the projects pose many challenge.  Finding dead birds among fields of mirrors that can span several square miles is not easy, and scavengers can pick up the dead birds before biologists have a chance to find them.

In the case of the Crescent Dunes project, the solar flux generated by the field of mirrors in stand-by mode may be so intense that the birds are incinerated in mid-air, leaving little for biologists to find on the ground.  Solar Reserve erroneously claims that simply putting the mirrors in a different stand-by position will reduce bird deaths at the project to zero. This is a nonsensical claim because bird deaths at power tower projects are not only caused when mirrors are in a stand-by position.  Focusing the mirrors in many different positions may reduce the intensity of the solar flux during stand-by, but birds can still sustain life-threatening heat stress in the elevated heat above the mirror field.  And when the mirrors are focused on the power tower, the intense heat closest to the power tower still burns birds' feathers. 

Solar Reserve counters that the brightly-lit tower will "deter" birds.  This is another absurd claim because we know that the brightly-lit tower at Ivanpah still kills birds.  If anything, the intense light may attract swarms of insects that attract the birds.  A video (see below) recently obtained by Basin & Range Watch also shows what are likely horned larks flying into the solar flux zones immediately adjacent to the brightly-lit tower at Crescent Dunes.  All evidence indicates that solar power towers kill birds, whether they are in operation or in stand-by mode.  Industry cannot simply wish away a problem and expect us to accept their unscientific claims.


Studies based on early mortality reports estimate that the Ivanpah Solar project may kill as many as 28,000 birds each year.  NRG executives have told the press that those numbers are "inflated," and then deploy the "cat" excuse - cats kill millions of birds each year, so it's not worth worrying about power tower impacts on birds.   ReWire excellently tackles this faulty comparison in-depth.  Simply put, two wrongs do not make a right.  We need to reduce all sources of avian mortality, and especially avoid introducing new sources of mortality in the heart of our desert wildlands.

Definition of "Disturbed" Lands
Utility-scale energy developers that bulldoze wildlands will find any reason to label wildlands as worthy of destruction.  An NRG executive wrote an op-ed chiding coverage of the Ivanpah plant's use of natural gas, but also claims that:

"[I]t is important to note that the plant was not built on undisturbed land, as stated in the article. The land had been previously used for cattle grazing and off-road vehicle use, and was littered with abandoned vehicles and crisscrossed with transmission lines and is within walking distance of a 36-hole golf course, an Interstate, a casino and a shopping mall." -David Knox, NRG.

This is a ridiculous statement and shows NRG's ignorance of geographic scale and conservation biology.  For starters, NRG doesn't know where it's own project is located.  NRG's website depicts the location of Ivanpah as being located north of Tecopa, over 50 miles away from the actual location.  In the Ivanpah Valley, where the project is actually located, the company mowed down nearly 5.6 square miles of intact desert wildlands.  For comparison, you could fit 12  Disneyland & California Adventure theme parks within the perimeter of the Ivanpah Solar project.

A screenshot taken from NRG's website on November 8, 2015.  NRG depicts the Ivanpah Solar project location as north of Tecopa, California.  It is actually located southwest of Primm Nevada, over 50 miles away.

It is true that a highway splits the Ivanpah Valley, and the relatively small outpost of Primm has some hotels, gas stations, and a golf course.  But Ivanpah Solar is still more than three times larger than all of that development combined.  And the habitat that Ivanpah destroyed was not in an abused state as NRG claims - it was vibrant enough to host rare plant species and over 150 threatened desert tortoises.  Once again, NRG would like us to believe that previous human impacts are an excuse for the company to do more damage.

A construction marker on intact desert habitat before crews mowed down 5.6 square miles of creosote and yucca scrub habitat.  The video below shows crews mowing vegetation to make way for the Ivanpah Solar project.