Solar energy is considered a sustainable energy supply technology however, the production technology for solar modules (which are used to convert energy into power) requires relatively high energy outputs. The predominant negative environmental impacts of solar energy come from producing the solar panels. Production of these panels consumes substantial amounts of energy and produces waste water and hazardous by-products which are released to the air during the manufacturing process.
A solar panel system typically consists of concrete, aluminium and steel. During the manufacturing process of solar panels, pollutant and heavy metal emissions such as sulphur dioxide, nitrogen oxide and lead are produced. Recycling technologies for reusing silicon from the solar cells are still not commercially in place but it has been proven that making a solar panel from recycled components requires 1/3 of the energy than producing panels from scratch. Research and development initiatives are taking place to recover key materials such as silicon glass, EVA foil and aluminium from existing panels which can then be recycled and used to make new panels.
To combat the environmental effects of producing the panels, hazardous by-products and air pollutants are passed through pollution control equipment and waste water is treated before being discharged into drains (and of course, the benefits of solar energy to the environment when compared with energy produced from coal or natural gas somewhat displace the negative impacts of the solar panel production phase).
Over the course of their lifetime, crystalline silicon solar panels generate 9-17 times the energy required to produce standard panels. Depending on the type of photovoltaic (PV) technology, the clean energy payback of a PV system ranges from one to four years. Replacing electrical power from the national grid mix with electricity generated by solar panels results in an 89 percent reduction in greenhouse gas emissions. (Goodcompany, 2008).
The point of concern in the manufacture of solar panels is that the silver content used in the module is leftover and is considered a dangerous waste. Producing these panels in high quantities could also lead to the depletion of silver resources. According to scientist G.J.M. Phylipsen's book Environmental Life-cycle Assessment of Multicrystalline Silicon Solar Cell Modules, a PV contribution of five percent of the current world electricity production would require about 50 percent of current silver production.
Extra care should also be taken to prevent accidental emissions of Tetrafluoromethane (CF4) as well as solvents and other volatile organic compounds during the various manufacturing steps of panel i.e. fluoride nitrate, (sulphur dioxide) SO2 which is toxic to humans,CO2 which effects global warming and isopropanol and solvents which support photochemical ozone formation and are also toxic to humans.
The construction and operation of solar farms also has an impact on the environment. The major drawbacks of constructing a solar farm are that it affects existing land uses, such as grazing, agriculture and minerals production and also affects areas of critical environmental concern or special recreation management areas.
The direct environmental impact of installing a solar farm has to do with the clearing large areas of land which in turn affects native vegetation and wildlife in numerous ways and has an adverse ecological impact and can affect the rainfall and the drainage of a region. Reflected light beams coming from the concentrated solar power system can, if misdirected, interfere with aircraft operating pathways. CSP system operations involves high temperature emissions in surroundings which may pose an environmental risk. These facilities also produce electric and magnetic fields which can hamper the natural surrounding.
Parabolic troughs and central tower systems use steam plants to generate electricity, which generally use water for cooling. Increase in water demand can strain available water resources while the use of chemicals at solar facilities i.e. dust suppressants, dielectric fluids, herbicides could result in contamination of surface or groundwater and also impact soil, water and air resources.
Construction and decommissioning of utility-scale solar energy facilities would involve a variety of possible impacts normally encountered in construction/ decommissioning of large-scale industrial facilities. If new electric transmission lines or related facilities were needed to service a new solar energy development, construction, operation and decommissioning of the transmission facilities could also cause a variety of environmental impacts.
Solar power is beneficial to the environment in contrast to other power producing sources as it does not produce CO2 air emissions. Using a renewable resource medium like concentrated solar power decreases the need for fossil fuels, provides an alternative to the steadily increasing fossil fuel market while also helping us keep tabs on our carbon footprint. Good maintenance practices and proper planning can certainly help minimise the negative impacts of producing solar panels using hazardous material. Innovative production technologies for PV modules would help to lower the environmental impacts by efficiently utilising silicon in modules and recycling it. Reducing the use of silver content in the modules would also be a significant step.
Implementing other technological improvements such as monitoring of energy and materials input in cell and module production and attention for efficiency of the overhead energy consumption in production plants; avoidance of CFC’s and PFC’s in production processes; use of secondary (recycled) materials in BOS components; increase of cell conversion efficiency and longer life time of modules and inverters would contribute to reduction of environmental impacts.
Author: Ajay Pal Singh Chabba/ RESET editorial