The sun is a tremendous source of generating clean and sustainable energy. It produces energy without any trace of CO2 emissions and toxic pollutants. The potential environmental impacts of solar energy vary greatly depending on technology – photovoltaic (PV) cells or concentrating solar thermal plants (CSP). The size and scale of the system are to be considered too in the level of its environmental impacts.
Here are the four types of environmental impacts linked with solar energy:
Land Use
Larger utility-scale locations can have concerns on land degradation and habitat loss. Total land area requirements vary on the technology, topography of the location and intensity of the solar source. The utility scale PV systems require an estimated 3.5 to 10 acres per megawatt while the CSP facilities require around 4 to 16.5 acres per megawatt.
Utility scale system’s land impact can be minimized by locating them at a lower-quality land. For instance, it can be built at brownfields, abandoned mining land, or existing transportation and transmission corridors. Smaller scale PV arrays, such as those installed on homes and commercial buildings, have less impact on land use.
Water Use
Solar PV systems do not use water in generating electricity. Nevertheless, some of its components require water to manufacture solar PV components.
Concentrating solar thermal plants (CSP) require water for thermal cooling just like all other thermal plants. Water usage depends on the plant location, plant design and its type of cooling system.
Wet-circulating technology, often applied in CSP, uses cooling towers and withdraws around 600 to 650 gallons of water per megawatt of electricity produced. Once-through cooling technology has higher water level withdrawal but lower water consumption since the water is not lost as steam. Dry-cooling technology reduces water use at CSP by around 90 per cent yet it is significantly less effective at temperatures above 100 degree Fahrenheit.
Hazardous Materials
Hazardous materials are present in the manufacturing process of PV cells. Most of which are used to clean and purify semiconductor surfaces. These include hydrochloric acid, sulfuric acid, nitric acid, hydrogen fluoride, 1,1,1-trichloroethane, and acetone. Type of cell, amount of cleaning materials needed and the size of the silicon panel are to be considered in identifying the amount and type of chemicals used. Workers in PV cell manufacturing facilities face risks associated with inhalation of silicon dust. This may cause inflammation and scarring of the lung tissues reducing its ability to take in oxygen. Therefore, PV manufacturers must implement rules to follow to ensure that the workers are safe and far from the harmful effects of exposure to these chemicals. It must be ensured that the manufacturing wastes are disposed of properly.
Meanwhile, thin-film PV cells contain more toxic chemicals. It includes gallium arsenide, copper-indium-gallium-diselenide, and cadmium-telluride. These materials pose a serious threat to the environment and health when mishandled and disposed improperly. However, manufacturers strongly ensure that these materials are recycled and not thrown away.
Global Warming Emissions
While it is true that solar energy produces the cleanest energy with 0 emission of harmful gas, emission is associated with solar life-cycle. It includes manufacturing, materials transportation, installation, maintenance and decommissioning and dismantlement.
Photovoltaic system’s life-cycle emissions range between 0.07 and 0.18 pounds of carbon dioxide per kilowatt-hour. Concentrating solar power estimates .08 to 2 pounds of carbon dioxide per kilowatt-hour. In both cases, if compared to natural gas and coal life-cycle emissions, solar life-cycle is cleaner. Natural gas emits 0.6 – 2 pounds of carbon dioxide per kilowatt-hour and coal with 1.4 to 3.6 pounds of carbon dioxide per kilowatt-hour.
