Solar energy is promoted as a green alternative for the environment that harnesses the free and abundant energy of the sun. This promises cheaper energy to consumers and is also a source of energy free of greenhouse gases and other pollutants. But as critics are quick to point out, this optimistic picture is not entirely true.
Solar energy has its own environmental challenges related to land use, water consumption, emissions and the use of hazardous materials. Let’s “light up” these environmental impacts and determine whether good outweighs bad in solar energy and the environment.
The implications of land use for solar energy projects depend on their scale. Small networks on the roof are not a major problem. However, larger projects can take up a lot of space.
Depending on the topography, the intensity of the solar radiation, and the type of solar technology, large systems can cover 3.5 to 16.5 acres per megawatt of production. (One MWh can serve around 650 homes, more or less.)
As the Union of Concerned Scientists (UCS) notes, large solar installations could “raise concerns about land degradation and habitat loss.”
Unlike wind power In energy projects that can coexist with agricultural land, there is little room for a sharing model with large solar installations that could disrupt local flora and fauna. This problem can be solved by using low cost locations such as brown fields, abandoned mining sites, or along transportation and transportation corridors.
Use of water
When it comes to water use, it is important to note that there are two main types of solar technology:
- photovoltaic (PV) solar cells
- Concentrated solar thermal power plants (CSP)
Solar PV systems do not use water to generate electricity, while CSP projects consume water. Actual water consumption depends on variables such as plant design, location and type of cooling system used.
CSP units using wet recirculation technology with cooling towers recycle between 600 and 650 gallons of water per megawatt hour of electricity, according to UCS. Dry cooling technology can reduce water consumption by up to 90%, but can lead to higher costs and reduced efficiency.
One potential problem is that some of the best solar power spots have the driest climates and poor water availability. Therefore, water supply is an important factor when it comes to solar projects.
Several hazardous materials are used in the manufacturing process of solar cells. Chemicals are mainly used to clean and clean semiconductor surfaces, including substances such as hydrochloric acid, sulfuric acid, nitric acid, hydrogen fluoride, 1,1,1 -trichloroethane and acetone.
Manufacturers must comply with legal requirements to ensure that workers are not exposed to hazardous chemicals and that these substances are disposed of appropriately.
Thin film solar cells include toxic substances such as gallium arsenide, copper-indium-gallium diselenide, and cadmium HM-tellurium. While improper handling or disposal can lead to serious environmental problems, manufacturers have a strong incentive to recycle these high-value materials rather than sending them to landfill.
To be sure, toxic materials are associated with every type of power generation: coal needs to be cleaned with chemicals and burned, nuclear power needs highly radioactive materials, and wind turbines use metal that needs to be mined. and processed. Neither type of energy is ideal, but it is clear that some are better than others, as shown by the comparative lifecycle emissions discussed in the next section.
Life cycle emissions
Solar energy is earning its stellar reputation as an energy source because it does not generate greenhouse gases while in operation. However, emissions linked to global warming are generated at other stages of the solar energy life cycle. These stages include resource extraction, production, transportation, installation, maintenance, decommissioning and dismantling.
However, this initial investment in energy will pay off in 30 years of clean energy production. In contrast, electricity produced from fossil fuels continues to generate greenhouse gas emissions steadily.
“Yes, solar PV does require a lot of energy just before materials are extracted and produced,” one article explains, “but when these emissions are dispersed over a 30-year production profile, the emissions / kWh are much more favorable. “
Most estimates show that solar energy, over its entire lifecycle, produces much less carbon dioxide equivalent than natural gas and significantly less than coal. Photovoltaic systems are in the range of 0.07 to 0.18 pounds of carbon dioxide equivalent per kilowatt hour, while CSP solar systems generate a CO2 equivalent in the range of 0.08 to 0.2 pounds , according to UCS. These numbers are significantly lower than the life cycle emissions of natural gas (0.6 to 2 pounds CO2E / kWh) and coal (1.4 to 3.6 pounds CO2E / kWh).
So, while solar power is not an ideal solution, it is much more environmentally friendly than generating electricity from non-renewable sources, especially coal. Ultimately, whether solar power is a good idea in your community depends on variables such as solar radiation from other renewable energy sources.