The state of California, USA has set high goals to shift its energy system towards a more sustainable one based on renewable energy (RE) resources. In 2015, it harvested more solar electricity than all other 49 U.S.A. states combined. Before 2009, no solar projects were permitted on public land in California. By 2015, there were already 29 solar project permissions in the South-West of the USA. Developing large-scale solar projects in the state of California has become increasingly challenging as new federal regulations seek to decrease the environmental footprint and impact of especially large-scale projects. On the other hand, the Obama administration gave the development of renewable energy (RE) sources priority by pledging to generate 20 gigawatts of power by 2020, which equals powering six million homes. 
The project The Ivanpah Solar Electric Generating System (ISEGS) is located in California’s Mojave Desert and was at the time of construction (2012) the largest concentrating solar power (CSP) plant in the USA. The power plant is based just below California’s Clark Mountain, close to the state line of Primm, Nevada.  The ISEGS plant occupies approximately 3,500 acres (ca. 1,416 ha) of federal land administered by the US Bureau of Land Management (BML). Upon completion, the project aimed to double the total solar electricity output generated in the US. In 2012, the Ivanpah SEGS project was therefore awarded the ‘CSP Project of the year’ by the organization Solar Power Generation USA.  The project is meant to be an “environmentally responsible project” , as it aims to contribute to the reduction of CO2 emission of around 400,000 tons on an annual basis. The technological system of CSP employed by the developing company BrightSource Energy (BSE) is considered to be one of the most land-efficient RE technologies. The heliostat layout is flexible and can thus be built around natural contours avoiding sensible vegetation and areas.  Due to water scarcity the Ivanpah SEGS uses a closed-loop air-cooling system allowing the plant to use 90% less water than equivalent power plants utilizing wet-cooling.  The director and vice president of BSE stated the Ivanpah Solar power plant will be an important step to get California closer to its goal of generating 33% of its electricity by RE resources by 2020. 
In 2006, the developer BSE applied for a pre-qualification with the Department of Energy (DOE) Loan Guarantee program.  After that, BSE submitted the first application for certification (AFC) to build a solar power plant in 2007. However, since then, environmental groups in California objected the project over possible disturbances of the tortoise habitat in the Ivanpah valley (see below impacts). Nevertheless, the construction of the Ivanpah SEGS had its break ground date in October 2010 and was expected to deliver electricity to the two utility companies PG&E and Southern California Edison by 2013.  This goal was missed and electricity generation started in 2014. 
Environmental impacts and related conflicts
Several concerns over the project's potential impacts have been expressed by environmental groups. The first concern was about the impacts on wildlife – more specifically on birds, insects and the desert tortoise. Other conflicts emerged also about endangered plant species and water usage. Further, there has been a controversy on the unions involved in the project.
1. Impact on birds and flying insects: According to an article published on the platform Renewable Energy World, there are some measurable and quantifiable impacts from the solar power plant on insects and birds. Birds physically strike all kinds of human-made infrastructure such as transmission lines, buildings or wind turbines. In general, most of these strikes have the nature of a physical collision causing birds’ deaths, or (mortal) injuries. In the case of the ISEGS project, there are collisions between birds and the power tower’s heliostats, but also damages caused by “elevated concentrations of solar flux” , which are a new form of human-made environmental impact. Solar flux is the reflected, concentrated sunlight close to the towers. Birds are suffering ‘feather singeing’ which impairs their flying ability and can thus lead to their death.  According to the conservation group ‘Center for Biological Diversity’, the ISEGS project could kill up to 28,380 birds annually. This number is an extrapolation from a study conducted by an environmental organization, which is opposing the project.  Among the affected species are hummingbirds, warblers, doves, swallows, and sparrows.  Another study published in IEEE Spectrum, mentioning monitoring data from October 2013 to October 2014, reports a range of 693 to 3,504 affected birds from 83 different species and an additional 32 dead bats.  Some regional birds (nighthawks, yellow warblers ) are feasting on insects (e.g. caterpillars, grasshoppers, dragonflies, beetles, bees and wasps ). These small insects are turned immediately into ash when entering a solar flux concentrated light beam. In general, the closer the birds get to the solar towers, the higher their risk is of singeing respectively dying. One possible technological mitigation strategy is using the birds’ fear of predation. Other mitigation strategies are ‘bio-acoustic deterrence’, the use of ‘nonlethal avian respiratory irritant’ and equipping towers with ‘anti-perching spikes’ .
2. Desert tortoise: The environmental organization ‘Basin and Range Watch’ states on their webpage, that the Ivanpah valley is of excellent quality as a desert tortoise habitat. In 1994, the so-called 'Desert Tortoise (Mojave Desert) Recovery Plan' was published. When the recovery plan was conducted the Ivanpah valley showed to have the highest known tortoise density with 200 to 250 animals per square kilometer. In 2011 the recovery plan was revised showing that large areas of the Ivanpah area do show “high potential” to support the desert tortoises. Scientists’ findings demonstrated that conservation measures are required in order to ensure the survival viability of the population.  In surveys, environmentalists have found 25 desert tortoises around the project’s land, as stated in a news blog . BSE’s first reaction in reducing the total electricity producing capacity of the ISEGS power plant was, according to environmental groups, a step into the right direction. Anyhow, it did not dissolve their concerns. “This reconfiguration is pretty minimal from what we’ve seen, and it hasn’t really addressed the core issues on the impact on desert tortoise and rare plants”  said the Californian representative for Defenders of Wildlife. However, the company stated that significant changes were already made to the project, alluding to a decrease in the overall output from 440 to 392 MW. The company also hired an environmental consultant to review the new design.  Later, fences around the plant’s territory were installed in order to protect the desert tortoises. However, the fences cause roadrunners (a type of non-flying bird) to get trapped and becoming easy prey for coyotes. In a further step, Ivanpah’s environmental manager installed ‘road runner exits’ into the fence.
3. Rare plant species: According to the environmental organization ‘Basin and Range Watch’, the Ivanpah valley in which the ISEGS is to be located is of “unparalleled pristine quality among deserts” and also to be one of the “world’s last functional ecosystems”.  In total, twelve rare plant species were documented on the ISEGS’s project site such as the “Mojave Milkweed, White-margined Penstom, and Desert Pincushion” . The California Energy Commission considered five of these plant species to be significant for the California Environmental Quality Act and concluded that a substantial portion of their habitat would be threatened. The California Native Plant Society argued that a simple translocation of the plants would not be sufficient and that there is no known mitigation method compensating for the loss of rare plant habitat. Consequently, the only suitable mitigation strategy is not constructing in sensible plant’s habitat. 
4. Water controversy: The increasing need for scarce freshwater is a key issue and concern for the development of California’s renewable energy sector . The Ivanpah project would use an estimated 25 million gallons of water per year mainly in order to wash its mirrors. Utilizing a wet-cooled solar through system would imply drawing 705 million gallons of water in the Mojave desert – an area of very scant rainfall. There is a general legal fight taking place in California where a legal bill was being prepared that should allow the usage of drinking water when harvesting RE power. However, as the California Energy Commission deputy director stated: “By allowing projects to use fresh water, the bill would remove any incentives that developers have to use technologies that minimize water use,”.  Ivanpah’s developer consequently did swap to the solar tower technology in order to rid the problem of water scarcity in the Mojave desert, since solar towers can be cooled with an air-cooling system needing to a great extent less water. In general, the downside from a business-perspective of using dry-cooling systems is that costs are added and the overall efficiency is reduced, which leads to less profit. However, BSE claims that deploying dry-cooling system in the Ivanpah project does not lead to a “prohibitive decline in power output”. 
5. Indigenous concerns: Phillip Smith, a Chemehuevi and elder of the Colorado River Indian Tribe and Ron Van Fleet (Fort Mohave Indian Tribe), reminded about the cultural relevance of the plant’s site to their tribes. They tell that their ancestors have come to the “altars” (stones on the site of the Ivanpah plant) to “worship the divine and admire the Mojave Desert.”  In September 2010, about 20 protesters came to the sacred site to protect the 5.6-square-mile stretch. P. Smith stated that animals such as “desert tortoises, bighorn sheep, mountain lions, haws, snakes, and many sensitive medical plants” are “getting squeezed out” of the area and further that they – the local tribes are “their protectors”.  He further told that the company BSE would destroy their home to profit from the cheap electricity of the sun stating that the project is about “fast money. It’s all fast money.” And that this goes against the living space of the indigenous tribes and the animals that have been living in the same area of the project’s site. The reply of a BSE’s spokesman was that they had not heard of the American Indians’ concerns until then, adding that they (BSE) “share their passion for the desert” and that they are confident that the approach they are taking “is the right approach from an environmental perspective”. 
6. Labor union Controversy (California wide and applies specifically to the Ivanpah case): The Union group California Unions for Reliable Energy raised no complaint when they were informed of BSE’s intention to build a bigger power plant than the competing companies. To give an example: another company called ‘Ausra’ was before deluged by a union group on environmental issues. The Californian union group ‘California Union for Reliable Energy’ even urged regulators to speed up the approval process in case of the BSE project. The difference between BSE and Ausra is that BSE had before pledged to hire labor-friendly contractors. The Ausra company even accused labor unions to make abuse of environmental laws in order to gain a labor agreement. Some developers contend that they are forced to sign agreements pledging to utilize union labor, if they refuse “they can count on the union group to demand costly environmental studies and deliver hostile testimony at public hearings” . Instead if they commit to make use of union labor, they would not let the environmental objections materialize. The Californian energy commissioner commented that “this does stress the limits of credibility [of the union’s environmental concerns] to some extent” . Californian unionist lawyers negotiate both labor agreements and also participate in the environmental reviews of the projects. The main question that arises from this fused conflict of interests is if the future green sustainable energy system will be based on a service economy with low-paid employees installing solar technology or higher paid union labor. Some environmental groups being worried about that these labor union tactics could cause a backlash in transitioning to a renewable energy system. Others again, confirm that California’s unions show a effectiveness at receiving extracting concessions that finally aid the environment. Anyhow, it seems that the “blue[union]-green[environmentalists] alliances” are showing some strains. 
Outcome and Status Quo:
The project was constructed and has been producing electricity since 2014. In 2010, there was an amendment in the size of the project. It was scaled down from 440 MW to 392 MW gross energy generation , mainly because of disturbing the habitat of the imperiled desert tortoise that must be relocated and further avoiding the disturbance of the area of rare plants. Initially, the project was intended to take up 4,000 acres of land (1,619 ha). This number was shrunk by 12%, according to a news article . However, the same article states that BSE managed to sidestep the water and labor controversies by utilizing a water-saving air-cooling system, respectively contracting union labor (see above). The construction of the project was temporarily halted on April 15th 2011 by the US Bureau of Land Management (BML) due to endangering desert tortoises.  Thereafter, the organization US Fish and Wildlife Service found on 10th June 2010 that the project did not jeopardize the endangered desert tortoise anymore and the BML lifted the construction hold/ban.  In response to the concerns over the project’s impacts on wildlife animals and their habitat, the developer BSE installed fences in order to keep wildlife (especially desert tortoises) out of the project’s area. In order to mitigate the impacts on birds, the above mentioned two measures were taken: ‘bio-acoustic deterrence systems’, and ‘anti-perching spikes’. The use of an ‘nonlethal avian respiratory irritant’ was discussed but not being installed. Whatsoever, one can say that the Ivanpah project is taking a leading role when it comes to testing the effectiveness of bird deterrents in large scale solar energy projects. The deputy chief of the environmental organization Fish and Wildlife Service’s migratory bird program states that they would like to transport the learnings on deterrents to other solar energy projects around the world.