Batteries are common in individual household systems. Inverters could help, though their technology is not standardized. Automated demand response using smart meters with microclimate forecasting research is well funded (St. John). Building dedicated (express) feeders for larger PV systems with bidirectional voltage regulators is one response. Avoiding fixed capacitator banks and having the PV system absorb volt-ampere reactives are two other possible solutions (Katiraei and Romero Aguero 69-70). On the other hand, PV can be useful to a utility by improving the voltage profile and reducing electrical line losses (Srisaen and Sangswang 855), as well as "relieved transmission and distribution congestion, environmental impact reduction, peak shaving, and enhanced utility system reliability" (Ramakumar and Chiradeja 722-723).
PV has environmental issues. Making solar cells is an energy-intensive process, using significant amounts of water and toxic chemicals. Most good monocrystalline silicon is produced by the highly inefficient (80% waste) trichlorosilane (SiHCl3) distillation and reduction method, which involves highly toxic chemicals like hydrogen chloride in burning quartzite with coal in an electric arc furnace -- not to mention, the process itself is quite expensive. Sheer availability is an issue, when 25%-50% of semiconductor-grade monocrystalline silicon is lost to kerf. If that could be recycled, it would supply the solar cell industry twice over. In addition, wafer slicing requires immense quantities of stainless steel wire and a toxic abrasive slurry composed of silicon carbide (SiC) and a mineral-oil-based or glycol-based liquid -- which then must be cleaned off by toxic organic solvents or detergents. For etching the surface, most use hydrofluoric-nitric-acetic acid, which again is highly toxic. Most cleaning is done with hydrofluoric (HF) acid, which then creates most of the PV industry's toxic waste. Most of these processes also require high-purity deionized water -- about 30 gallons per square inch of silicon wafer (Tsuo, Gee and Menna).
Creating solar cells from the silicon wafer requires other manufacturing processes. Junction diffusion uses more energy in the form of a furnace, either tube or belt. Tube furnaces use POCl3 as a dopant, "which generates toxic P2O5 and Cl2 effluents and requires frequent cleaning of diffusion tubes using HF solutions" (Tsuo, Gee and Menna). Etching uses a chlorofluorocarbon, which contributes to global warming. Antireflection coatings use silane, which is highly flammable. Silver-tin-lead solder baths place metal electrodes, which is highly toxic. Last, but not least, chlorofluorocarbon compounds clean flux (Tsuo, Gee and Menna). All of these pose environmental problems.
Unsurprisingly, workers who manufacture these solar cells are exposed to all of these toxic chemicals, as "process engineering controls….are designed more for the protection of the product than for the protection of the worker or the environment" (Edelman 295). Higher rates of spontaneous abortions, chronic illness, cancers of the respiratory tract and skin, systemic poisoning, cataracts, renal failure are all known issues (Chen 6).
After manufacturing, other environmental issues come up. Utility-scale PV systems require some large amounts of land (Ramakumar and Chiradeja 717), and installation could interfere with sunlight and water run-off. Animals may be impacted by creating bird perches and interfering with grazing. Other issues include transmission line routes and habitats of endangered species. Of course, building a facility would affect archeological sites. Many people find the facilities ugly. If an accident occurs, hazardous materials may contaminate the area. None of these differs from conventional coal-fired power plants, however (Office of Energy Efficiency and Renewable Energy (EERE), Department of Energy (DOE); and the Bureau of Land Management (BLM), Department of the Interior (DOI)).
Many federal incentives are available for building PV systems. Corporations can take advantage of tax deductions for energy efficient buildings, accelerated depreciation schedules, energy conservation subsidies, and tax credits for investment, new home building, and renewable electricity production. Grants are available for Native American tribes, for corporate renewable energy equipment, and for rural communities for renewable energy generation. Agricultural producers and rural small businesses have loans and grants available for renewable energy systems and development assistance. Loans are available for homeowners to finance renewable energy technology. State and local government may issue bonds with federal tax credits to finance renewable energy production, research, demonstration, education, and development. Loans are available to corporations, industry organizations, nonprofit organizations, schools, state and local governments, agricultural producers, institutions, and manufacturers for large renewable energy projects. The renewable energy production incentive payments are only partially funded. Individuals may be eligible for energy conservation subsidies in the form of tax credits, as well as unlimited tax credits for PV system purchases (Database of State Incentives for Renewables & Efficiency (DSIRE)). All these loans, grants, tax credits, tax deductions, subsidies, and incentive payments add up to considerable enticements for PV systems.
PV systems have come a long way since the discovery that light produces electricity. Now, not only do watches and calculators use solar cells, but new thin film and amorphous solar cell technologies allow entire buildings to be shingled in electricity production. During the day, when demand is highest, buildings can produce their own electricity, and at night, they can use grid-based electricity, though widespread use of intertie systems may lead to poor grid performance. Environmental issues are not inconsiderable, but development of environmentally sensitive clean technologies is proceeding, as well as multiuse land methods. Federal financial incentives for PV systems add up to hundreds of millions of dollars. Grid connected PV systems will become more widespread in the future.
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