Solar energy has been eliciting considerable attention these years because of its beneficial to the environment. While applying and developing solar energy, people also focus on its bad influence of the environment. This Wiki page aims to introduce the solar energy and discuss if it is sustainable. Due to the solar panel is the most representative technology of using solar energy, this Wiki page also indicates the technology of solar panel and its pros and cons for the environment. In addition, the recommendations are suggested at the end of the Wiki page.
This section will briefly introduce the definition of solar energy, some general background information about solar energy, and the comparison between traditional energy and solar energy.
Up to now, the main uses of solar energy is solar photovoltaics and solar thermal energy. Solar photovoltaics is the transform between solar energy and electric energy that rely on the photovoltaic effect. Solar thermal energy is harnessing solar energy to generate thermal energy by storage heat in water. Accordingly, the technologies relevant to solar energy are mostly using transformed heat or electricity. Solar ponds, Solar water heating system, decontaminate of water, and the solar panel is some common technologies that globally used.
Application of solar energy technologies using by general public is common in many counties as well, for instance, in China there are 5200,0000 square meter installed private solar water heaters up to 2003, which helped to save nearly 823,000 tones coal consumption.
Additionally, the new technology on solar energy using is continually developing in order to decrease the utilization cost and increase the efficiency of transform. Researchers in the university of New South Wales (UNSW) in Australia have been able to increase the efficiency of converting solar energy into electricity by more than 40%. A study that subsidized by Europe Union have successfully produced the "solar energy" fuel which makes up by water and carbon dioxide and uses the high-temperature energy provided by the sun that can provide energy for normal cars and planes.
The governments' decisions plays an important role on developing solar energy.
For example, In 2009, the Chinese government decided to support a minimum of 500MW of photovoltaic power generation demonstration projects within two to three years by means of financial subsidies. By the end of 2015, China has become the world's largest photovoltaics installed capacity. In 2017, China's new photovoltaics installed capacity has reached half of the world's new capacity. The impelling actions made by the China government is highly efficient and useful for pushing the development and promotion of solar energy.
In America, there are lots of funding programs provided the U.S. Department of Energy (DOE), U.S. Department of Agriculture (USDA), U.S. Department of Housing and Urban Development (HUD), and the Environmental Protection Agency (EPA) by to support greater solar deployment.
Also, the incentive policy to encourage the public using solar energy instead of traditional energy is helpful as well. Canada has developed many Canadian solar energy programs aim to help the Canadians to integrate solar power systems into their homes, which allow the citizens saving money on their power bills as well as saving natural resources.
The developing of solar energy not only occurs at scholarly community and government policy but also shows an increasing trend on the consumers' using around the world in multiple countries. For example, in Canada, there are more and more home owners using solar panels on their roofs instead of nuclear and coal to save electricity and reduce power bills. They choose to use solar energy from their roof first, which can meet 20%-50% amount of their total annual energy consumption. This inspiring trend is stimulated by the government policy, but also shows the personal altitude of Canadian consumers.
Solar energy, which is abundant and pollution-free, has many benefits for the environment, such as reduce greenhouse gases emission. However, it needs to be discussed whether solar energy is sustainable because some applications of solar energy have limitations and the extra cost of reducing the pollution caused by producing the equipment. The representative applications and their pros and cons will be introduced below.
Solar ponds can collect and store solar energy simultaneously. It is a thermal energy storage system which uses water as a heat storage media and it can be used on space heating, water desalination, and power generation. However, the solar pond has a strict location requirement. It just can be used in regions with readily available land, much sunlight, and access to low-priced salt. In addition, the shade can also influence the performance of it a lot.
Solar water heating system is another application to store the heat from solar energy. There are different fields to use water heating system. Aquaculture, which needs people to adjust the temperature of the water to the fish adaption temperature, is one of the fields. Solar water heating system can reduce the cost of heating. However, this system can only be used in the specific conditions, i.e. only specific conditions can make the system usable (geographic, season, climate, etc.). The individual house is also a field in which the solar water heating system can be used. In this field, the system can reduce the heating cost and reduce the CO2 emission. However, the lack of suitable location limit the use of this system, and the solar water heating system always needs a back-up heating system, which is an economic issue for this technology. Solar energy can also be used to decontaminate the water. The specific spectrum (e.g. ultraviolet radiation) of solar radiation can be used for the decontamination of effluents feasible. The technology can reduce the CO2 emission by saving the electric energy and reduce the emission of mercury because of the replacement of artificial ultraviolet radiation (i.e. mercury lamp). However, the technology is expensive and is limited by the season and climate condition.
The solar cooker is a kind of device which uses solar energy directly to heat, cook or pasteurize drink and other food materials. This technology can directly save electronic power which leads to the CO2 emission reducing, enhance the circular economy for its being made by recycled materials. Nevertheless, it is also limited by the climate condition (cannot be used in the cloudy day) and space (cannot be used in the house)
Solar photovoltaic is the most representative technology of solar energy application. It has many advantages, such as reducing green gas emission, low cost of equipment operation maintenance, and being recharged everywhere. However, the technology pollutes (e.g. waste gas and wastewater) the environment during the process of producing the devices of solar photovoltaic. The sections below provide the complete introduction about the solar photovoltaic and solar panels, and discuss the advantages and disadvantages of them.
In conclusion, the solar energy is environmental friendly, but the application of solar energy is still not sustainable for it's economic and practice limitation as the sustainability requires that the technology should benefit economic, ecology, and society.
This section will generally introduce the solar panels about its composition and its relationship with solar energy. And explore the environmental benefits of solar panels through multiple dimensions.
Solar panels, also known as solar or photovoltaic modules (PV modules), convert solar radiation directly into electrical energy by using the photovoltaic effect of the semiconductor material in the panel. A typical solar-energy system consists of a solar panel, a battery or group of batteries and a solar controller. The key component of the solar panel system is made up of several solar cells in series and the solar cells can change sunlight directly into electricity. Therefore, exploring the environmental benefits of solar energy can also represent the environmental benefits of solar panels to some extent.
Generating electricity from solar energy rather than fossil fuels can greatly reduce greenhouse gas emissions, especially carbon dioxide (CO2). Energy-driven consumption of fossil fuels has led to a rapid increase in CO2 emissions since the industrial revolution, disrupting the global carbon cycle and exacerbating the effects of global warming. Although the manufacture of solar panels produces greenhouse gas emissions, they are far more environmentally friendly than other options. The total amount of greenhouse gas emissions involved in solar energy is still much lower than that of coal or natural gas. A 2011 report showed that solar’s carbon footprint averaged at roughly 85 tonnes of carbon dioxide equivalent (CO2e) per gigawatt-hour (GWh), compared with 499 CO2e/GWh for natural gas and 888 CO2e/GWh for coal. Thus, solar panels can reduce the demand for fossil fuels and limit greenhouse gas emissions.
One home installing a solar system can have a measurable impact on the environment. According to the U.S. Energy Information Administration, the average home with solar panels in Connecticut uses 8,280 kilowatt-hours (kWh) of electricity per year. In this state, switching from fossil fuels to solar energy has the same emission reduction effect as planting about 150 trees a year. Therefore, solar panels have an effective impact on reducing greenhouse gas emissions by providing renewable and clean energy.
Solar PV can be regarded as an inexhaustible and free energy source since it can directly convert sunlight into electricity, and does not need the help of machines or any moving devices. The installation of solar photovoltaic equipment is not subject to regional restriction; it can be installed on roofs, desert areas and remote areas. A study by Vasilis Fthenakis and Hung Chul Kim of Columbia University in 2009 found that the utility-scale PV in the U.S. Southwest requires less land than the average U.S. power plant using surface-mined coal. Moreover, a previous NREL (National Renewable Energy Laboratory) report had estimated that if solar energy was to meet 100% of all electricity demand in the United States, it would account 0.6% of the country’s total area. As a result, less land is needed to install solar panels, and land resources can be used more efficiently for other meaningful projects.
One of the biggest benefits of solar panels is that it produce very little air pollutants. An analysis by the National Renewable Energy Laboratory found that widespread use of solar panels would significantly reduce nitrogen oxides, sulfur dioxide and particulate matter emissions.
Overall, solar panels provide renewable and clean energy without causing land, ecological and environmental problems.
Despite all the advantages of solar panels that mentioned above, they are not entirely environmentally friendly. The production, use and recycling of solar panels all have different degrees of adverse impact on the environment. For example, the production of solar panels requires more energy than other forms of energy production which is due to the manufacturing process required to convert the original mineral into a usable photoelectric material. As for the recycling, although the recycling of solar panels has not yet become a major problem, it will need to be replaced as solar panels in the coming decades.
The following categories include impacts related to the existence and operation of solar facilities rather than the actual construction and decommissioning of solar facilities, and it is especially focus on the impact on animals and environment.
Solar panels are often used on a large scale in remote and sunny places, such as deserts. Recently, the desert was characterized by large blocks of continuous and interconnected habitat. Road and urban development continue to exacerbate the habitat fragmentation of this landscape. Large-scale energy development is likely to exacerbate and exacerbate this situation, creating potential barriers to the migration and gene exchange of wild animal populations, including bighorn sheep, deer, turtles and other species of concern and social significance.
While many people consider that solar production as a "quiet" endeavor, noise is associated with their operations. For example, equipment using a wet cooling system may have noise from fans and pumps. For equipment with a dry cooling system, only fan noise is generated during operation. As the size of the dry cooling system increases, the number of fans will increase to produce more noise. Noise affects wildlife, including changes in habitat use and activity patterns, increased stress, weakened immune systems, reduced reproductive success, changes in foraging behavior, increased predation risk, decreased communication with peers, and impaired hearing.
When the electricity from a solar panel passes through a cable, it creates electric and magnetic fields. From the perspective of human and wildlife health, the Electromagnetic fields (EMFs) generated by the energy transmitted through the system cables is a concern. And some scientists think that electromagnetic radiation may cause harm to many kinds of wild animals and lead to the decrease of some mammal populations.
A dry-cooled solar facility—in particular, one with a concentrating-trough system—could reject heated air from the cooling process with temperatures 25–35 degrees Fahrenheit higher than the ambient temperature. This could affect the microclimate on site or those in adjacent habitats.
USSEDO, especially at wet-cooled solar facilities, there are potentially dangerous chemical leaks at the site, with toxic substances used in cooling systems, antifreeze, rust inhibitors, herbicides and heavy metals.
These emissions may contain chemicals that prevent dirt and scale formation. Potentially contaminated water is usually stored in evaporation ponds, which further concentrate toxic substances .Many species may be adversely affected by the attraction of water to desert wildlife.
In areas where water is scarce, water use is tightly controlled throughout the region. Because of this water limitation, the type of cooling system installed in solar installations is also limited. For example, disposable cooling systems (a form of wet cooling) are often not available in arid environments because there are few permanent bodies of water. Solar equipment also needs water to regularly clean mirrors or panels of dust.
Fires can occur in any power and heating system, and renewable energy facilities are no exception. In most concentrated solar systems with temperatures above 300 c, coolant system leaks and leaks increase the risk of fire.. While all vegetation on the site is usually removed during construction, reducing the risk of fires spreading both inside and outside the site, increased human activity increases the likelihood of fires, especially in desert areas.
Solar energy facilities can produce two types of light pollution: ecological light pollution (ELP)and polarized light pollution (PLP).The latter, known as PLP, can be mass-produced in facilities that use photovoltaic solar panels because dark surfaces polarize light. ELP can also be produced in the form of reflected light in solar installations. ELP may have adverse effects on the physiology, behavior and ecology of wild animals, including changes in predation, competition and reproduction . Many man-made products, often dark (e.g., oil spills, glass Windows, cars, plastics, paint, asphalt), can unnaturally polarize light, which can adversely affect wildlife.. For example, many animal species use polarized light to locate and navigate. Therefore, PLP has the potential to disrupt the orientation and migration of desert wildlife, including sensitive species. So this has a profound but unquantifiable impact on the ecological communities around solar installations
Research into solar-panel recycling is not yet sufficient, most of these researches have focused on the extraction of silicon and the recycling of rare metal elements. Currently, there are three approaches of processing waste solar panels: component repair, module separation, and the removal of silicon and other rare metal elements from components.
The policy of managing used solar panels around the world is not mature enough. Basically, countries outside the EU market rarely take any measures to regulate waste solar panels. Strengthening producers’ responsibility through the life cycle of photovoltaic panels can be an effective way to manage sustainable materials. Relevant measures can be implemented from the following aspects:
The present invention generally relates to photovoltaic technology, and more specifically to thin-film photovoltaic modules with a transparent front and rear electrode arrangement. Traditional photovoltaic cells are usually opaque. They have a first light incident and a second back covered by a metal electrode film. Although they are both conductive and reflective, they are inadequately used because of the angle of illumination.
Therefore, Cuevas et al. disclosed "double-sided" arrays capable of receiving solar energy on their relative surfaces, "50% increase in output power of flat plates collected using the albedo of double-sided solar cells", solar energy, 29-5, PP. 419-420 (1982). The disclosed array comprises a plurality of p-type crystal substrates with diffusion regions on the relative main surface. Each substrate forms a pair of independent solar cells capable of receiving light from the opposite direction. These batteries are manufactured using expensive crystalline silicon technology, including grid contacts, and absorb all radiation from any direction to the semiconductor material. Making the effective utilization rate increase greatly. Since the components of the present invention are transparent to light in part of the solar spectrum, they can be used instead of traditional glass, thus making the transmitted light have a separate non-photovoltaic use. Examples of such USES include Windows, skylights, and car skylights.
A rationalized and comparative evaluation of options from technical, social, cultural, economic, financial, political, legal points of view (not all of these categories will be relevant to all situations)
Solar energy and its relevant technology are well noticed by worldwide researchers and governments since its clean, inexpensive, renewable, and inexhaustible characteristics. As a result of summarizing the current applications of solar energy, it's relatively not much sustainable due to the economic and practice limitation. Among the various using of solar energy, solar panels have been paid most attention and discussed. Due to its fast growth perspective and high levels of investment involved, the photovoltaic market is now being more disputed around the world, especially in Europe, China and in the United States. Solar panels contain lots of environmental benefits that performs better than traditional energy. For example, reducing greenhouse gas emissions, less land use occupied, and little air pollution production are all highly environmentally friendly. However, solar panels also remain various negative influences on the environment. Habitat fragmentation, noise effects, electromagnetic field generation, microclimate effects, pollutants from spills, water consumption, fire risk, and light pollution are the main downsides that listed and discussed in this Wiki page.
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