The Mojave Desert is not only a paradise when it comes to filming movies, setting video games and name operating systems: It is also home to thousands of plant species that are accustomed to an extremely hostile climate. It is estimated that there are about 2,000 species and a very specific one is in danger of extinction. Until they decided to build one of the largest photovoltaic plants in the United States on top of it.
The Gemini Solar Project.
In short. The journal Frontiers in Ecology and Evolution revealed a few weeks ago the results of a curious study. The ‘threecorner milkvetch’ plant (which has a name for everything except a plant) went from 12 specimens in the Mojave Desert to 93. This plant was being evaluated for inclusion in the Endangered Species Act in the United States and not only has its number multiplied: the new plants are larger and produce more flowers.
And they have “only” had to build one of the largest photovoltaic plants in America on top of it, next to Guanchoi in Chileto achieve it.
Threecorner milkvetch. It is a creeping plant that has curious needs: it only grows in sandy soils of the Mojave Desert. However, it is dependent on rainfall because its seed remains dormant in the soil and only germinates and reproduces with favorable rainfall. In dry years, it remains completely unnoticed, waiting for a little rain.
And it is so rare that the species remains under evaluation for status as threatened or endangered under U.S. Fish and Wildlife Service regulations. In the same desert there is another threatened species: the desert tortoise Gopherus agassizii. The habitat of the two species should be the last one on which it would be decided to build a photovoltaic plant, but there is the Gemini Solar Project.
The plant
Megaplant. When such an installation is to be carried out in the desert, a technique known as clearing and leveling is used. In essence, all vegetation is removed, the land is leveled and prepared for install the pillars of the solar panels. Not only is a lunar landscape created, but any type of latent seed beneath the surface, such as that of the threecorner milkvetch, is destroyed. However, the Gemini Solar Project’s approach was different.
The company wanted the land because it is especially ‘fertile’ within the US to harvest sunlight, but concessions had to be made. One was to minimize the alteration of the habitat of both species to conserve the desert surface with all its biological resources, preserve the topsoil and adapt the facility to the natural relief. On the US Geological Survey website we can see photos of little turtles between the panels.
Works. This is part of what we know as ‘ecovoltaics’, with a branch called ‘agrovoltaics’ that we have also talked about and that, although it can be used by companies as a facelift, it serves to unite energy activities with agricultural activities. In the study on the impact of the Gemini Solar Project and the evolution of the plant, researcher Tiffany Pereira discovered what we have mentioned: there were more plants and they were healthier.
This showed that the energy company had done its part by not destroying the soil because the seeds had been able to germinate, but they found something else. The plants inside the installation evolved earlier than those outside it and grew not under the panels, but in the strips between the rows. This implies that they still need intense sunlight to mature.
The yellow zone is where the Sun shines the most hours. The blue one is the stripe that varies depending on the position of the Sun. The red one is where direct light never shines.
Okay, but then… what is the role of the panels in the improved evolution of these plants? The hypothesis used by the researchers is that the panels provide partial shade on the groundslowing down evaporation. We have already said that seeds are dormant until they have the necessary humidity conditions to germinate, and in this context, a more humid microclimate has allowed plants to grow more and produce more seeds.
Not all the field is oregano. Now, like almost every scientific study, we look at the other side of the coin. The rainfall in recent years has been favorable and we will have to see what happens with periods of prolonged drought. In a few years we could talk about long-term effects. But, in addition, this absence of plants under the panels could indicate a possible loss of potential habitat in very humid years.
In any case, Pereira’s study is not isolated. Other studies point to improvements in both the number of flowering plant species and pollinators in agrovoltaic installations in a state like Minnesota. AND in China there are also indicators that those photovoltaic plants in deserts is contributing to the moisture pocket construction in which plants can thrive more easily.
As we said, it remains to be seen the impact of the panels on the creation of a “new” biodiversity in the long term, but for now, what is evident is that it is not necessary to raze land to build a photovoltaic plant.
Images | DRI, Tiffany PereiraGemini Solar Project
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