A Disregarded Consequence of Solar Photovoltaic Construction
by Pat Flanagan
Several other articles in this issue have described the damage done when undisturbed desert lands are utilized for energy generation at large scale photovoltaic installations. Damage to the biotic community when the surface is scraped clean is obvious. A less obvious consequence is the release of carbon which has been sequestered in the soil for centuries. Still another consequence that is visible, but which is seldom acknowledged, is the release of dust into the air that results from the construction itself and from the changes in land cover in the succeeding years. It is this fugitive dust that is the subject of the article here. I will begin with a story.
In 1907 John Muir, the co-founder of the Sierra Club, traveled south with his daughter Helen from their home in northern California. Helen, a survivor of tuberculosis but still unwell, was advised to live in a dry desert environment. Having earlier checked out Palm Springs, the father and daughter arrived in Daggett, a small railroad town east of Barstow on the edge of the Mojave River. Helen stayed and did well in Daggett – the air was clean as well as dry. She was fortunate.
Since the 1960s there has been a noticeable transition in the Mojave River Valley as the stable vegetated dunes transformed into dunes on the move. The death of the vegetation stabilizing the dunes was caused principally by agriculture and groundwater pumping resulting in the lowering of the ground water table. These human activities began the sand and dust movement problems experienced today. More recently, the damage has come from another human source.
In 1982 Daggett became the home of the experimental Solar One, the first sun driven thermal power plant. On 130 acres, it was designed to produce 10MW of energy to be fed into Edison’s commercial grid. I worked at the Solar One site in 1982. My job was to find any birds that had crashed into the surface of a heliostat, mistaking the clear view mirrored behind them for the path ahead - a story for another time.
Daggett Solar site with alfalfa field on the left and healthy desert on the right showing creosote rings.
Source: Google Earth
While walking the completely graded field, I remember noticing the amount of dust raised by tractors plowing the agricultural fields near the Barstow-Daggett Airport and wondering how the pilots could land safely. A 1983 Sandia Report on the construction of Solar One gives us more background, ”. . . during plant construction the existing ecosystem within the plant site was completely removed, an estimated 160 metric tons of sand have been blown from the heliostat field to adjacent downwind areas, and some of the annual plant growth has decreased where the most sand has been deposited.”1 The dunes on the move were part of the Sand Transport Path releasing their fugitive dust, but I didn’t know this back then.
Fugitive dust is any solid particulate matter (PM) that becomes airborne without passing through a stack or duct, directly or indirectly as a result of anthropogenic (human) activities. Particulate Matter PM10 and PM2.5 are official criteria air pollutants, meaning that acceptable limits have been determined for health and to avoid property damage under the federal Clean Air Act and California air pollution law. The smaller particles, 2.5 microns in diameter, pose the greatest risk to health since these fine particles can get deep into your lungs and some may even get into your bloodstream.2
Today, the Solar One project has been dismantled, but in its place, Clearway Energy Group is constructing Daggett Solar Power + Battery Energy Storage System (BESS). When completed, this Daggett Solar project will produce 482 MW of solar power with 394 MW of energy storage on 3,636 acres, making it the largest solar + battery storage project currently built in California.
The Mojave Desert Air Quality Management District (MDAQMD), charged with monitoring the air in compliance with federal and state laws, requires an approved Dust Control Management Plan before construction begins. District monitoring for particulate matter (PM) east of Barstow where Utility Scale Solar (USS) projects are developed, is carried out with Purple Air monitors,3 not recognized by the EPA for regulating but very good for letting you know what is happening in real time.
Dust is made of fine particles of solid matter, generally consisting of particles in the atmosphere that come from various sources such as soil lifted by wind (an aeolian process), volcanic eruptions, and pollution. Sand grains are heavy and don’t move much above 6 feet. Dust is very light and can travel thousands of feet into the air and go for many miles. Sand and dust move in high winds. The MDAQMD Plan 403 for Fugitive Dust Control clarifies high winds - when the wind speed instantaneously exceeds 25 miles per hour, or when the average wind speed is greater than 15 miles per hour. The average wind speed determination shall be on a 15-minute average at the nearest District-approved meteorological station. Unfortunately, when winds raise dust at Daggett Solar, the approved MDAQMD monitoring station in Barstow is 15 miles upwind from the source and is unable to provide useful information.
Clearway Energy, owner of Daggett Solar, is an energy provider to at least five different utilities across the western United States.4 Energy from the Mojave Desert will be transmitted hundreds to thousands of miles to satisfy these regional companies’ commitments to provide green energy to their customers. Newberry Springs and Daggett, both disadvantaged communities with Environmental Justice scores on CalEnviroScreen4.0 of 75, get none of the energy or even a credit on their electric bill.
Soitec Solar Project on 22 acres in Newberry Springs. The sand originates from the acreage only and is burying the house across the street. Picture taken on May 26, 2018, looking west with Black Butte in the background. Photo by Pat Flanagan
As you will see, this green energy has repercussions for the downwind community of Newberry Springs. Already fugitive dust is a hazard in the local communities. This is documented thoroughly in the Newberry Springs Community Alliance blog at <bit.ly/3HOg3vr>. It is well known that airborne dust can trigger asthma attacks, and visual consequences of blowing dust are best shown graphically.
It wasn’t until 2013, with the construction of the first two solar projects in the Joshua Tree area that I personally began experiencing dust outs during wind events where I live three miles east (downwind) from the facilities. I reported on this in the March 2017 Desert Report. Sand Transport Paths (STP) are wind-driven, low-relief accumulations of eolian sand deposits found in the basins between mountain ranges. Source areas for the sand are dry lakes, or in the case of Daggett/Newberry Springs area, the Mojave River. The STPs found throughout the Mojave Desert Basin and Range Province, began forming at the end of the ice ages as the desert climate warmed and the lakes dried. Today undisturbed STPs are stabilized by plant roots, commonly creosote bush and galleta grass, and covered by intact desert soil crust.5 The two solar facilities near my home were built on a scraped STP on private land. At the same time Lucerne Valley to the north of me was caught off guard by dust blows from two other projects, one on 80 acres and the other on 152. The soil unit descriptions noted only a slight hazard of eolian dust, but the contractor found 70-acre feet of water was needed to suppress the dust and not very successfully. In an already depleted aquifer this is serious. Newberry Springs was blessed with the 22-acre Soitec Solar that from its construction onward buried the house across the street. All three projects are on soil units that the Natural Resource Conservation District has analyzed with high potential for blowing dust when disturbed.
The examples that have been given here highlight one of the general problems that accompany the construction of many of the large photovoltaic projects in the desert. There is an argument that the state needs both utility scale solar projects as well as distributed solar to meet California’s goal of 100 percent renewable and zero-carbon electricity by 2045. However, unless utility scale solar sites are thoughtfully chosen and carefully constructed, human health and possibly lives will be impacted by the release of sand and dust during construction, operation, and decommissioning. Revegetation to the original condition has little history of success. On paper the San Bernardino County encourages development on already disturbed land such as fallowed agricultural fields, parking lots, warehouse roofs, and industrial brownfields but they continue to approve projects on intact desert. We know that fallowed agricultural fields, when scraped, can also emit dangerous levels of dust.
Chuck Bell, president of the Mojave Desert Resource Conservation District advises, based on years of experience, that construction be halted during the months with high winds – January to June. Further only small areas should be graded, mulched, and stabilized before moving on. If mulch doesn’t work then gravel is the answer. The Owen’s Dry Lake strategy, based on years of research to restore what had the dustiest air in California, applies 4 inches of ½ inch gravel.6 Requiring water application has never been shown to work beyond a few minutes. Clearway maintains they are watering as directed and using the dust suppressant product FSB-1000 at triple strength, and you see in the blog how well that is working. There are no actions that do not have consequences. Far better that we should plan in advance than learn after the fact.
Pat Flanagan has been resident in the Mojave Desert since 2002. She represented her Desert Heights community on the Morongo Basin Municipal Advisory Council, is a board member of the Morongo Basin Conservation Association, and is on the Technical Advisory Committee for the Mojave Desert Resource Conservation District.
1) https://www.osti.gov/servlets/purl/6124299 Page 26.
2) https://ww2.arb.ca.gov/resources/documents/maps-state-and-federal-area-designations .
3) https://www.mdaqmd.ca.gov/air-quality/purple-air-community-monitor-map .
4) https://www.clearwayenergygroup.com/press-releases/clearway-begins-full-construction-on-massive-solar-energy-storage-project-in-southern-california/ .
5) Zimbelman, SH Williams, VP Tchakerian. Sand transport paths in the Mojave Desert, southwestern United States. Desert aeolian processes, 1995 https://scholar.google.com/scholar?hl=en&as_sdt=0%2C5&q=Zembelman+Sand+Transport+paths+in+the+Mojave+Desert&btnG=
6) Great Basin Unified Air Pollution Control District (GBUAPCD) Rule 433 https://gbuapcd.org/Docs/District/AirQualityPlans/OwensValley/Rule433.pdf