Solar Energy Construction Impacts
Construction activities that may cause environmental impacts include ground clearing, grading, excavation, blasting, trenching, vehicular and pedestrian traffic, and drilling.
Typical activities during the solar energy facility construction phase include ground clearing (removal of vegetative cover), grading, excavation, blasting, trenching, drilling, vehicular and pedestrian traffic, and construction and installation of facilities. Activities conducted in locations other than the facility site include excavation/blasting for construction materials (sands, gravels) and access road construction. Potential impacts from these activities are presented below, by the type of affected resource.
The following potential impacts may result from solar energy construction activities.
The primary sources of noise during construction would be equipment (e.g., rollers, bulldozers, diesel engines). Other sources of noise include vehicular traffic and blasting for raw materials. Whether the noise levels exceed U.S. Environmental Protection Agency (EPA) guidelines or local ordinances would depend on the distance to the nearest residence. If near a residential area, noise levels from blasting and some equipment operation could exceed the EPA guideline but would be intermittent and extend for only a limited time.
Air Quality (including Global Climate Change and Carbon Footprint)
Emissions generated during the construction phase include vehicle emissions; diesel emissions from large construction equipment and generators; VOC releases from storage and transfer of vehicle/equipment fuels, small amounts of carbon monoxide, nitrogen oxides, and particulates from blasting activities; and fugitive dust from many sources such as disturbing and moving soils (clearing, grading, excavating, trenching, backfilling, dumping, and truck and equipment traffic), mixing concrete, storage of unvegetated soil piles, and drilling and pile driving.
A permit is needed from the state or local air agency to control or mitigate these emissions; therefore, these emissions would not likely cause an exceedance of air quality standards nor have an impact on climate change.
Direct impacts to cultural resources could occur from construction activities, and indirect impacts might be caused by soil erosion and increased accessibility to possible site locations. Potential impacts include:
Ecological resources that could be affected include vegetation, fish, and wildlife, and their habitats. Vegetation and topsoil would be removed for the development of the solar energy project, including associated access roads, transmission lines, pipelines, and other ancillary facilities. This would lead to a loss of wildlife habitat, reduction in plant diversity, potential for increased erosion, and potential for the introduction of invasive or noxious weeds. The recovery of vegetation following interim and final reclamation would vary by community (e.g., grasslands would recover before sagebrush or forest habitats) or the type of plant community desired (e.g., most of the solar energy project site would be kept devoid of vegetation or allow only low-growth grasses and forbs. Indirect impacts to vegetation would include increased deposition of dust, spread of invasive and noxious weeds, and the increased potential for wildfires. Dust settling on vegetation may alter or limit plants' abilities to photosynthesize and/or reproduce. Although the potential for an increase in the spread of invasive and noxious weeds would occur during the construction phase due to increasing traffic and human activity, the potential impacts could be partially reduced by interim reclamation and implementation of mitigation measures.
Adverse impacts to wildlife could occur during construction from:
Wildlife would be most affected by habitat reduction within the project site, access roads, and gas and water pipeline rights-of-way. Wildlife within surrounding habitats might also be affected if the construction activity (and associated noise) disturbs normal behaviors, such as feeding and reproduction.
Depletion of surface waters from perennial streams could result in a reduction of water flow, which could lead to habitat loss and/or degradation for aquatic species.
If significant impacts occurred in any resource areas, and these impacts disproportionately affected minority or low-income populations, then there could be an environmental justice impact. Issues of potential concern during construction are noise, dust, and visual impacts from the construction site and possible impacts associated with the construction new access roads. Additional impacts include limitations on access to the area for tribal recreation, subsistence, and traditional activities.
Hazardous Materials and Waste Management
Solid and industrial waste would be generated during construction activities. The solid wastes would likely be nonhazardous and consist mostly of containers, packaging materials, and wastes from equipment assembly and construction crews. Industrial wastes would include minor amounts of fuels, spent vehicle and equipment fluids (lubricating oils, hydraulic fluids, battery electrolytes, glycol coolants), and spent solvents. Hazardous materials include compressed gases used for welding, cutting, brazing, etc., dielectric fluids, heat transfer fluids, oils and coolants (for steam turbines), chemicals for treatment of the steam cycle, and compressed gas cylinders of hydrogen (for stirling dish engines only). These materials would be transported off-site for disposal, but impacts could result if the wastes were not properly handled, and were released to the environment.
Human Health and Safety
Potential impacts to worker and public health and safety from solar energy project construction would be similar to those expected for any construction project with earthmoving, large equipment, transportation of oversized materials, and construction and installation of industrial facilities. In addition, health and safety issues include working in potential weather extremes, and possible contact with natural hazards, such as uneven terrain and dangerous plants, animals, or insects.
Impacts to land use could occur during construction if there were conflicts with existing land use plans and community goals; conflicts with existing recreational, educational, religious, scientific, or other use areas; or conversion of the existing commercial land use for the area (e.g., agriculture, grazing, mineral extraction).
Existing land use during construction would be affected by intrusive impacts such as ground clearing, increased traffic, noise, dust, and human activity, as well as by changes in the visual landscape. In particular, these impacts could affect recreationists seeking solitude or recreational opportunities in a relatively pristine landscape. Ranchers or farmers could be affected by loss of available grazing or crop lands, potential for the introduction of invasive and noxious plants that could affect livestock forage availability, and possible increases in livestock/vehicle collisions. An expanded access road system could increase the numbers of off-highway vehicle users, hunters, and other recreationists in the surrounding area.
Impacts to aviation could be possible if the project is located within 20,000 feet (6100 meters) or less of an existing public or military airport, or if proposed construction involves objects greater than 200 feet (61 meters) in height. The Federal Aviation Administration (FAA) must be notified if either of these two conditions occur, and the FAA would be responsible for determining if the project would adversely affect commercial, military, or personal air navigation safety. Similarly, impacts to military operations could occur if a project was located near a military facility, if that facility conducts low-altitude military testing and training activities.
Impacts to paleontological resources could occur directly from the construction activities or indirectly from soil erosion and increased accessibility to fossil locations. Potential impacts include:
Direct impacts would include the creation of new jobs for construction workers and the associated income and taxes generated by the solar project. Indirect impacts would occur as a result of the new economic development, and would include new jobs at businesses that support the expanded workforce or provide project materials, and associated income and taxes. Solar energy development activities could also potentially affect property values, either positively from increased employment effects or negatively from proximity to the solar field and any associated or perceived environmental effects (noise, visual, etc.).
Adverse impacts could occur if a large in-migrant workforce, culturally different from the local indigenous group, is brought in during construction. This influx of migrant workers could strain the existing community infrastructure and social services.
Soils and Geologic Resources (including Seismicity/Geo Hazards)
Sands, gravels, and quarry stone would be excavated for constructing access roads; making concrete for foundations and ancillary structures; and improving ground surface for lay-down areas and crane staging areas.
Possible geological hazards (earthquakes, landslides) could be activated by excavation and blasting for raw materials, increasing slopes during site grading and construction of access roads, altering natural drainage patterns, and toe-cutting bases of slopes. Altering drainage patterns could also accelerate erosion and create slope instability.
Surface disturbance, heavy equipment traffic, and changes to surface runoff patterns could cause soil erosion and impacts to special soils (e.g., cryptobiotic soils). Impacts of soil erosion could include soil nutrient loss and reduced water quality in nearby surface water bodies.
Short-term increases in the use of local roadways would occur during the construction period. Heavy equipment likely would remain at the site. Shipments of materials are unlikely to affect primary or secondary road networks significantly, but this would depend on location of the project site relative to material source. Oversized loads could cause temporary transportation disruptions, and could require some modifications to roads or bridges (such as fortifying bridges to accommodate the size or weight). Shipment weight might also affect the design of access roads for grade determinations and turning clearance requirements.
Possible sources of visual impacts during construction include:
Water Resources (Surface Water and Groundwater)
Water would be used for dust control when clearing vegetation and grading, and for road traffic; for making concrete for foundations and ancillary structures; and for consumptive use by the construction crew. Water is likely to be obtained from nearby surface water bodies or aquifers, depending on availability, but could be trucked in from off-site.
Water quality could be affected by:
Surface and groundwater flow systems could be affected by withdrawals made for water use, wastewater and stormwater discharges, and the diversion of surface water flow for access road construction or stormwater control systems. Excavation activities and the extraction of geological materials could affect surface and groundwater flow. The interaction between surface water and groundwater could also be affected if the surface water and groundwater were hydrologically connected, potentially resulting in unwanted dewatering or recharging of water resources.