Solar Panels

Social Impacts of Photovoltaic Technology: A Preliminary Desk-Based Research

Abstract:

Photovoltaic (PV) technology has distinct environmental advantages for generating electricity over conventional technologies. PV technology does not produce any noise, toxic-gas emissions, or greenhouse gases. It is a zero-emissions process.

However, from a sustainable approach, social impacts should also be analyzed in order to better understand the whole impact of the technology. After explaining the main components of a photovoltaic structure (solar panel and inverter) the article presents potential social impacts related with photovoltaic technology as the outcome of a preliminary desk-based research that is part of a social impact assessment of the technology.

Photovoltaic technology is close related with the electronic industry where we can find severe social impacts throughout the supply chain from raw material extraction to disposal. In the PV case, the manufacture of solar cells involves several toxic, flammable and explosive chemicals. Many of those components supposes a health hazard to workers involved in manufacturing of solar cells who must be protected from exposure to materials used even if they are relatively inert like silicon. Also, solar farm locations must be carefully selected to reduce competition with agriculture and soil erosion. Finally, because solar PV semiconductor manufacturing processes have roots in the electronics industry, many of the chemicals found in e-waste are also found in solar PV, including lead, brominated flame retardants, cadmium, and chromium. The disposal of electronic products is becoming and escalating environmental and health problem in countries in West Africa, Asia and Latin America.

Key:

Photovoltaic, Social Impact, Life Cycle Assessment

Introduction

Photovoltaic (PV) technology has distinct environmental advantages for generating electricity over conventional technologies: PV material requirement are extremely low (V. M. Fthenakis and Moskowitz 2000); PV technology does not produce any noise, toxic-gas emissions, or greenhouse gases (Vasilis M. Fthenakis 2003) so PV contributes to climate change mitigation; photovoltaic operation phase is a zero-emissions process and does not require water; has low maintenance requirements; PV can be used off-grid to supply energy to isolated devices, houses or business, characteristic that is widely used in development projects; solar contribute to the security of energy supply in every country; each module lasts around 25 years; systems can be recycled at the end of their life; thousands of jobs can be created (Greenpeace and European Photovoltaic Industry Association 2011).

The International Energy Agency details the high growth of grid-connected and off-grid PV power (Table 1) but, although most of the authors accept that the current high costs will fall substantially, energy policymakers still prefer to leave its evolution mainly in the hands of the market (Jackson and Oliver 2000).

|Year |Off-grid |Grid-connected |Total |

|Cumulative (MW) |Increase (%) |Cumulative (MW) |Increase (%) |Cumulative (MW) |Increase (%) | |2005 |485 |8 |3758 |55 |4243 |48 | |2006 |535 |10 |5347 |42 |5882 |39 | |2007 |663 |24 |7684 |44 |8347 |42 | |2008 |741 |12 |13752 |79 |14493 |74 | |2009 |883 |19 |19875 |45 |20758 |43 | |2010 |980 |11 |33973 |71 |34953 |68 | |Table 1: Cumulative installed PV power and annual percentage increase (IEA International Energy Agency 2011)

Nevertheless, from a sustainable point of view, social impacts should also be analyzed in order to better understand the overall impact of the technology. After explaining the main components of a photovoltaic structure, the article presents potential negative social impacts related with the solar module and the inverter of a photovoltaic system as the outcome of a preliminary desk-based research that is part of a social impact assessment of the technology.

Methodology

The methodology considered for the social impact assessment of a planned action that involves the use of photovoltaic cells includes the following steps: scoping, formulation of alternatives, profiling, projection, assessment, evaluation, mitigation, monitoring, ex-post evaluation or audit (Barrow 2001).

This paper does not consider any planned action. The outcome of the desk-research will become information to be used in the first steps of the methodology of whatever social impact assessment of planned actions that involves photovoltaic cells. So, it will be useful to determinate affected stakeholders of the planned action from a complete life cycle approach (scoping), possible alternatives to be considered about what materials and devices should be used (formulation of alternatives) and possible impacts to consider (profiling).

Sheikh and Kocaoglu (2011) made a literature review of solar photovoltaic technologies assessment considering five perspectives: social, technological, economic, environmental and political (STEEP). Technical and economic were the most frequent perspectives examined (these are typical in an engineering project), whereas social and political were the least considered ones. Few papers reflect the social and political perspective and only in a conceptual level. The authors recommend the inclusion of the five perspectives along with a hierarchical decision model in the analysis of the photovoltaic technologies.

After making a literature review (ISI Web of Knowledge, Internet, NGOs and administration reports), tree main sources were used to discuss the potential negative impacts of the PV technology: Fthenakis (Vasilis M. Fthenakis 2003; V. M. Fthenakis and Moskowitz 2000) one of the most cited author in the literature about photovoltaic cells hazards and safety issues; Silicon Valley Toxics Coalition (2009) a NGO working on health and environmental issues of high-tech industry with an emphasis in PV technology and EPRI and California Energy Commission (2003).

It should be taken into account that PV technology is not mature for many of the technologies being implemented (mainly thin-film). Research and development is on stage to increase the efficiency of the cells. It means that the components used to manufacture PV cells will change in the near to middle future and the recount of hazardous materials will change accordingly. On the other hand, hazardous components phase out or substitution is something social impact assessment looks for, task easier to realize during the first stages of the particular technology system development.

Solar Photovoltaic Technology

There are four primary applications for photovoltaic systems: off-grid domestic provide electricity to household and villages that are not connected to the utility electricity network; off-grid non-domestic provide electricity for applications such as telecommunications, water pumping, vaccine refrigeration, etc; grid-connected distributed provide power to a customer or to the grid; and grid-connected centralized works like centralized power station (IEA International Energy Agency 2011).

Although different configurations derived from the type of connection (off-grid, grid-connected) exist, a solar photovoltaic system generally consists of (Thornycroft and Markvart 2003): solar cell panels, inverter, DC isolator, AC switched disconnector, batteries (off-grid), wires and the mechanical structure to support the different devices of the system. The devices considered in the desk-research are the solar cell panels and inverter.

There are three generations of solar cell panels: first generation is the basic crystalline silicon (c-Si); second generation corresponds to thin-film technologies that include amorphous silicon (a-Si), Cadmium Telluride (CdTe), Copper Indium Selenide (CIS) and Copper Indium Gallium Selenide (CIGS); and third generation includes concentrator photovoltaic, organic and other technologies not yet enough commercialized (Greenpeace and European Photovoltaic Industry Association 2011). Finally, Gallium Arsenide (GaAs) and Multijuntions Cells are used mainly in communications and military satellite applications. In this desk-research only the first and second generations are analyzed.

The inverter converts DC electric energy produced by the PV system to AC electric energy that is compatible with the electric distribution network and devices connected to it. There are inverters for different power needs. They range in power from hundreds watts to kilowatts or even thousands of kilowatts for large scale solar power plants. Inverters, among other components, incorporate: printed circuit boards, resistor, transistors, capacitors, integrated circuits (ICs), transformer, and the container. Severe social impacts of electronic equipment have been found throughout the supply chain of the electronic industry from raw material extraction to disposal (Pellow and Park 2002; Hightower et al. 2006). The disposal of electronic products is becoming and escalating environmental and health problem in countries in West Africa, Asia and Latin America (Silicon Valley Toxics Coalition 2009).

Impacts

The main concerns about occupational and health risks from a life cycle perspective of a PV system are related with the emission of toxic or risky substances used to manufacture PV cells. The potential risk can occur during the manufacturing process, from the leaching of substances or from the combustion of modules. The list of chemicals in the final PV cell is different from the chemicals used to manufacture them, as solvents and acids for cleaning the semiconductors parts or gases for depositing the thin-film layers are not present in the final product (EPRI and California Energy Commission 2003).

Among the most dangerous substances related with PV systems from a life cycle approach, we can find (not all the substances are present in all the PV technologies):

• Silica (SiO2). The mining of metallurgical grade silica can produce silica dust that has been associated with silicosis, a severe lung disease.

• Cadmium (Cd). Known carcinogenic. Extremely toxic (EPA and OHSA). Potential to cause kidney, liver, bone, and blood damage from ingestion. Lung cancer from inhalation. Workers may be exposed to cadmium compounds during manufacturing. It is restricted by RoHS directive.

• Silane (SiH4). Most significant hazard. It is extremely explosive. Dangerous for workers and communities. The semiconductor industry reports several silane incidents every year, although some companies use an alternative that in turn could be used in the PV industry.

• Chlorosilane (HSiCl3). Very toxic and highly flammable

• Silicon Tetrachloride (SiCl4) (waste). Extremely toxic substance. Causes skin burns, and is a respiratory, skin and eye irritants.

• Hydrogen selenide (H2Se). Highly toxic and dangerous at concentrations as low as 1 part per million in the air. Will present occupational health and safety issues.

• Sulfur hexafluoride (SF6). Extremely potent greenhouse gas. Accidental or fugitive emissions will greatly undermine reductions gained by using solar power.

• Selenium dioxide (SeO2). Potential formation at high temperatures. It is a tissue poison like arsenic. The recovery of selenium is very high but not 100 percent.

• Sodium hydroxide (NaOH), hydrochloric acid (HCL), sulfuric acid (H2SO4), nitric acid (HNO3), hydrogen fluoride (HF), phosphine (PH3) or arsine (AsH3), Isopropyl alcohol (C3H8O). These components require special handling and disposal procedures because of possible chemical burns and risks from inhalation of fumes.

• Kerf (waste silicon dust from sawing c-Si wafers). May generate silicon particulate matter that will pose inhalation problems for production workers and those who clean and maintain equipment.

• Lead (Pb). Highly toxic to the central nervous system, endocrine system, cardiovascular system, and kidneys.

• Brominated flame retardants (BFRs), Polybrominated biphenyls (PBBs) and Polybrominated dephenylethers (PBDEs). Hexavalent chromium (Cr(VI)). They are considered carcinogenic.

The hazard to health depends on: toxicological properties of materials, some of which are toxic, carcinogenic or flammable; intensity or concentration; frequency and duration of human exposures or doses; and the existence of a complete pathway from the compound to the receptor. These, also, depends on the availability and efficiency of safety and pollution control systems (V. M. Fthenakis and Moskowitz 2000). It is also important to note that not-known interactions paths between components (for instance while operation of the PV system) exist and not all the interactions have been tested in the laboratory. Many of the occupational and health problems can be resolved if proper actions are taken, but in some places like developing countries it is not the case (Cha 2008). From a life cycle approach, the impacts can occur in the following cases:

Manufacturing An accidental release (low probability) may present risks to workers and communities in the nearby as a number of gases (silane, phosphine, arsine, hydrogen sulfide…) are involved. The toxicity and explosive nature of these gases can cause both physical (explosions) and biological (inhalation) damages (EPRI and California Energy Commission 2003). Also, exposures to low levels of toxic materials over long periods of time could affect both workers and the general public.

Use/Operation Although the risk is low, potential human damage could occur from the leaching of materials from broken PV modules with heavy metals with cadmium or selenium being of special concern. Accidental fires could release fumes into the atmosphere and the nearby community are the main concern. The risk is higher in commercial buildings than in residential buildings (EPRI and California Energy Commission 2003).

Decommissioning Disposal of large quantities of modules to a single landfill presents potential risks for humans, communities and the environment as the leaching of chemicals can contaminate local ground and surface water. Fthenakis (2003) indicates that the main concern during this life cycle phase will be associated with the presence of Cadmium (Cd) in CdTe and CdS solar films cells and Pb in x-Si panels if they contain Pb-based solder. Nevertheless, he specifies that proper disposal will result in a tiny fraction (0.5%) remaining in the ash, which should be disposed properly in controlled landfills. The long life of PV cells and the fact that it is a young industry makes data from landfills not yet available. Many of the chemicals found in electronic waste (e-waste) are also found in solar PV, including lead, brominated flame retardants, cadmium, and chromium. The disposal of e-waste is becoming and escalating environmental and health problem in countries in West Africa, Asia and Latin America. This should be prevented in the case of PV systems.

A different type of impacts comes from the land uses of large PV installations. PV farm locations must be carefully selected to reduce competition with agriculture and soil erosion; visual impacts affecting visitor experience; or creation of isolated public land parcels.

Conclusions

The manufacture of PV modules uses some hazardous materials which can present health and safety hazards, if adequate precautions are not taken. Hazardous materials could adversely affect occupational and public health during accidents or improper handling and treatment in all the lifecycle stages because of lacking the appropriate technology as is the case in some developing countries.

Silicon Valley Toxic Coalition (2009) has made the following recommendations for the PV industry:

• Implementing design for environment and green chemistry strategies.

• PV manufacturers should be held responsible for the lifecycle impacts of the PV systems.

• Promote high quality “green jobs” preventing occupational and health damages.

• Protect communities throughout the supply chain of PV industry and recycling operations.

References

Barrow, C. J. 2001. Social Impact Assessment: An Introduction. A Hodder Arnold Publication.

Cha, Ariana Eunjung. 2008. “Solar Energy Firms Leave Waste Behind in China.” The Washington Post, March 9, sec. Business. http://www.washingtonpost.com/wp-dyn/content/article/2008/03/08/AR2008030802595.html.

EPRI, and California Energy Commission. 2003. Potential Health and Environmental Impacts Associated with the Manufacture and Use of Photovoltaic Cells. EPRI, Palo Alto, CA and California Energy Commission, Sacramento, CA.

Fthenakis, V. M., and P. D. Moskowitz. 2000. “Photovoltaics: environmental, health and safety issues and perspectives.” Progress in Photovoltaics: Research and Applications 8 (1) (January): 27–38.

Fthenakis, Vasilis M. 2003. “Overview of Potential Hazards.” In Practical Handbook of Photovoltaics: Fundamentals and Applications, ed. Tom Markvart and Luis Castañer, 998. 1st ed. Oxford, UK: Elsevier Science.

Greenpeace, and European Photovoltaic Industry Association. 2011. Solar Generation 6. Solar Photovoltaic Electricity Empowering The World. Solar Generation. http://www.greenpeace.org/international/Global/international/publications/climate/2011/Final%20SolarGeneration%20VI%20full%20report%20lr.pdf.

Hightower, Jim, Ted Smith, David A. Sonnenfeld, and David Naguib Pellow. 2006. Challenging the Chip: Labor Rights and Environmental Justice in the Global Electronics Industry. Temple University Press.

IEA International Energy Agency. 2011. Trends in Photovoltaic Applications. Survey report of selected IEA countries between 1992 and 2010.

Jackson, Tim, and Mark Oliver. 2000. “The viability of solar photovoltaics.” Energy Policy 28 (14) (November): 983–988.

Pellow, David, and Lisa Park. 2002. The Silicon Valley of Dreams: Environmental Injustice, Immigrant Workers, and the High-Tech Global Economy. NYU Press.

Sheikh, N., and D. F Kocaoglu. 2011. “A Comprehensive Assessment of Solar Photovoltaic Technologies: Literature Review.” In Technology Management in the Energy Smart World (PICMET), 2011 Proceedings of PICMET ’11:, 1–11. IEEE.

Silicon Valley Toxics Coalition. 2009. “Toward a Just and Sustainable Solar Energy Industry.” http://svtc.org/wp-content/uploads/Silicon_Valley_Toxics_Coalition_-_Toward_a_Just_and_Sust.pdf.

Thornycroft, Jim, and Tom Markvart. 2003. “Grid Connection of PV Generators: Technical and Regulatory Issues.” In Practical Handbook of Photovoltaics: Fundamentals and Applications, ed. Tom Markvart and Luis Castañer, 998. 1st ed. Oxford, UK: Elsevier Science.

References: Barrow, C. J. 2001. Social Impact Assessment: An Introduction. A Hodder Arnold Publication. Cha, Ariana Eunjung. 2008. “Solar Energy Firms Leave Waste Behind in China.” The Washington Post, March 9, sec. Business. http://www.washingtonpost.com/wp-dyn/content/article/2008/03/08/AR2008030802595.html. EPRI, and California Energy Commission. 2003. Potential Health and Environmental Impacts Associated with the Manufacture and Use of Photovoltaic Cells. EPRI, Palo Alto, CA and California Energy Commission, Sacramento, CA. Fthenakis, V. M., and P. D. Moskowitz. 2000. “Photovoltaics: environmental, health and safety issues and perspectives.” Progress in Photovoltaics: Research and Applications 8 (1) (January): 27–38. Fthenakis, Vasilis M. 2003. “Overview of Potential Hazards.” In Practical Handbook of Photovoltaics: Fundamentals and Applications, ed. Tom Markvart and Luis Castañer, 998. 1st ed. Oxford, UK: Elsevier Science. Hightower, Jim, Ted Smith, David A. Sonnenfeld, and David Naguib Pellow. 2006. Challenging the Chip: Labor Rights and Environmental Justice in the Global Electronics Industry. Temple University Press. IEA International Energy Agency. 2011. Trends in Photovoltaic Applications. Survey report of selected IEA countries between 1992 and 2010. Jackson, Tim, and Mark Oliver. 2000. “The viability of solar photovoltaics.” Energy Policy 28 (14) (November): 983–988. Pellow, David, and Lisa Park. 2002. The Silicon Valley of Dreams: Environmental Injustice, Immigrant Workers, and the High-Tech Global Economy. NYU Press. Sheikh, N., and D. F Kocaoglu. 2011. “A Comprehensive Assessment of Solar Photovoltaic Technologies: Literature Review.” In Technology Management in the Energy Smart World (PICMET), 2011 Proceedings of PICMET ’11:, 1–11. IEEE. Silicon Valley Toxics Coalition. 2009. “Toward a Just and Sustainable Solar Energy Industry.” http://svtc.org/wp-content/uploads/Silicon_Valley_Toxics_Coalition_-_Toward_a_Just_and_Sust.pdf.