Environmental Impact of Renewable Energy Sources: Wind and Solar (original) (raw)

Environmental Impact of Renewable Energy Sources: Wind and Solar

Erinle, Tunji John 1{ }^{1}; Oladebeye, Dayo Hephzibah 1{ }^{1}; Adesusi, Olanrewaju Moses 2{ }^{2}; Oni, Peter Bamidele 3{ }^{3}
1{ }^{1} Mechanical Engineering Department, Federal Polytechnic, Ado- Ekiti, Ekiti State, Nigeria.
2{ }^{2} Mechanical Engineering Department, Federal University of Agriculture, Abeokuta, Ogun State, Nigeria.
3{ }^{3} Ekiti State College of Education, Ikere- Ekiti, Ekiti State, Nigeria.

Correspondence: +234-08069635034
E-mail address: authenticfaithful@gmail.com; dayobeye@yahoo.com; adesusiolanrewajumoses@gmail.com; onilead03@gmail.com

Abstract

There are several sources of renewable energy such as tidal, wave, wind, hydro-electric, geothermal, ocean thermal conversion (OTEC), solar and biofuels. All the renewable energy sources have received increasing attention in such a way that they do not have a fuel cycle in which they are regarded as environmentally more favourable. Renewable energy sources introduce environmental impacts of their own in many ways. The wind and solar energies have the potential to reduce grievous environmental impacts caused by conventional energy sources. This study considered positive and negative environmental impacts of wind and solar energies. Wind and solar energies do not generate atmospheric contaminants. The study provides ways to understand which one of these renewable energy sources have the highest adverse environmental effects due to their facilities. Conclusively, wind energy facilities have adverse environmental impacts which include aesthetic and other impacts on humans and effects on ecosystems; solar energy does not have such adverse environmental impacts.

Keywords: Energy; Environment; Renewable; Solar; Wind.

1. Introduction

Alternative Energy is a form of energy that is not based on fossil fuels but is either renewable or sustainable without depleting a finite resource. Replenishable sources of energy are biomass (biofuel), hot springs (geothermal), sun (solar), tides (tidal), ocean thermal conversion (OTEC), wave, rivers (hydro-electric) and wind (Encarta Encyclopaedia, 2009 and Encyclopaedia Britannica, 2013). Solar and wind energy are often looked at uncritically by environmental proponents. Harnessing power from the wind is one of the cleanest and most sustainable ways to generate electricity as it produces no toxic pollution or global warming emissions. Solar and wind power only benefit the environment so much (Fitzner, 2019).

Sunlight, wind and other renewable resources are increasingly converted into useful forms of energy with ever-greater efficiency. The new technologies still provide 14 percent of the total world’s energy supply, but they appear to be advancing rapidly. Many experts believe a transition toward renewable, carbon-free energy technologies would go a long way toward addressing the problems of dwindling oil

reserves and the potentially ruinous environmental impacts linked to the burning of fossil fuels. Such a transition could make the 21st century the age of renewable energy (Flavin and Dunn, 2009; UNDP, 2000; Flavin and Lenssen, 1994). Figure 1 depicts the significant energy resources that power human activities. This study provides help to understand positive and negative environmental impacts of wind and solar energy facilities. The work aims at considering beneficial and adverse effects which include impacts on landscapes, view-sheds, wildlife, habitats, water resources, air pollution, greenhouse gases and others.

Figure 1: Significant Energy Resources that Power Human Activities (Encyclopaedia Britannica, 2006 and 2008)
Fossil fuel combustion has a number of negative environmental consequences. Fossil-fuelled power plants emit air pollutants, particulate matter and toxic chemicals including fossil-fuelled vehicles emit air pollutants and particulate matter. Exposure to these pollutants can cause heart disease, asthma and other human health problems. In addition, emissions from fossil fuel combustion are responsible for acid rain, which has led to the acidification of many lakes and consequent damage to aquatic life, leaf damage in many forests, and the production of smog in or near many urban areas. The burning of fossil fuels releases carbon dioxide (CO2)\left(\mathrm{CO}_{2}\right), one of the main greenhouse gases that cause global warming (Encyclopaedia Britannica, 2013; Whitney, 2009). Growth in wind power exceeded 30 percent and production of solar energy through photovoltaics grew at 25 to 30 percent annually and renewable energy technologies continue to expand (EWEA, 2009, Gipe, 2009; Mukund, 2006; Department of Energy, 2019).

2. Solar Energy

The Sun is an extremely powerful energy source and the sunlight is by far the largest source of energy received by the Earth. “Solar energy is free, but it’s not cheap”. Solar energy refers to the energy generated from solar power, whether electrical or as heat. Solar radiation is the most important natural energy resource because it drives all environmental processes acting at the surface of the Earth. Knowledge of the quantity and quality of solar energy available at a specific location is of prime importance for the design of any solar energy system (Anonymous, 2013; Ashok, 2013; Michael, 2012).

2nd International Conference, Center for Research, Innovation and Development (CRID) FPA, August 2019

Figure 2: Interior and the hot core of the Sun (Encyclopaedia Britannica, 2013; Encarta Encyclopaedia, 2009)
The relative motion of the sun with respect to the earth will allow surfaces with different orientations to intercept different amounts of solar energy. The amount and intensity of solar radiation reaching the Earth’s surface depend on the geometric relationship of the Earth with respect to the Sun. The Sun provides the Earth with an enormous amount of energy and also provides almost all the heat and light Earth receives and therefore sustains every living being as shown in figure 2. The energy stored by the oceans helps maintain the temperature of the Earth at an equilibrium level that allows for stability for a broad diversity of life (Holladay, 2009). Solar energy is the radiation from the Sun capable of producing heat, causing chemical reactions, or generating electricity. The total amount of solar energy incident on Earth is vastly in excess of the world’s current and anticipated energy requirements. If suitably harnessed, this highly diffused source has the potential to satisfy all future energy needs (Ashok, 2013). Figure 3 shows the percentages of incident solar radiation and how energy from the sun could be converted into thermal and electrical energy.

Figure 3: Percentages of Incident Solar Radiation and Solar Power Plant (Encyclopaedia Britannica, 2008; Age Super Stock, 2013)

This radiation can be converted either into thermal energy (heat) or into electrical energy, though the former is easier to accomplish. Two main types of devices are used to capture solar energy and convert

it to thermal energy: flat-plate collectors and concentrating collectors (Encyclopaedia Britannica, 2013). Also, the main device to capture solar energy and convert it directly into electricity: solar or photovoltaic cells (Richard, 2001; Alan and Richard, 1983).

2.1. Solar Thermal Energy Application

Sunlight can be used to heat water or air in buildings. Solar heating refers to generating hot water or warm air using solar heating panels or ground-source heat pumps (Michael, 2012). There are two types of solar heating: passive and active.

2.1.1. Passive Solar Heating

Passive heating relies on architectural design to heat buildings. The building’s site, structure and materials can all be utilized to maximize the heating effect of the sunlight falling on it. The entering sunlight warms the air and the solid surfaces in those rooms exposed to it. This warmth is carried to other rooms in the building by natural convection. The air is circulated past the solar collector, over the storage system and into the rooms as shown in figure 4.

Figure 4: Passive Solar Heating (Encyclopaedia Britannica, 2013)

2.1.2. Active Solar Heating

Active heating uses mechanical means to store, collect, and distribute solar energy in buildings in order to provide hot water. The sunlight falling on a building’s collector array is converted to heat, which is transferred to a carrier fluid usually water. The water is pumped through tubes that are in contact with a flat-plate collector in the process absorbs some of the sun’s energy. The carrier fluid moves to the heat exchange, where the carrier fluid warms water that is used by the household. Finally, a pump moves the carrier fluid back to the solar collector to repeat the cycle as shown in figure 5.

Figure 5: Active Solar Heating (Encarta Encyclopaedia, 2009)

2.1.3. Solar or Photovoltaic Cell Application

Solar electricity refers to generating electrical power using photovoltaic solar panels. The photovoltaic cell is a relatively new form of solar power that converts sunlight directly into electricity. The photovoltaic cell is a semiconductor device (contain semiconducting materials), closely related to a computer chip that relies on the photoelectric effect that describes how sunlight can create an electric current by generating electrically charged particles (Fonash, 2013, Ashok, 2013; Fonash, 2013; Michael, 2012). The solar panels collect energy from sunlight and convert it directly into electricity. When light strikes the material, electrons move from one layer of the material to another, forming an electric current (Corbis, 2009). The applications of photovoltaic for power generation, either on the rooftops of houses or in large fields connected to the utility grid are promising as well to provide clean, safe and strategically sound alternatives to current methods of electricity generation as shown in figure 6 (Anonymous, 1981; Zweibel, 1990).

Figure 6: Connected Solar Cell System (Encyclopaedia Britannica, 2013)

3. Wind Energy

Wind is also abundant, inexhaustible, and affordable, which makes it a viable and large-scale alternative to fossil fuels (Fitzner, 2019). The wind is the movement of rushing air in motion usually as the natural

horizontal motion of the atmosphere and created when air that has been warmed over sun-heated land rises, leaving a vacuum in the space it once occupied. Cooler surrounding air then rushes in to fill the vacuum (Gipe, 2009). Figure 7 depicts the movement of wind in action. The wind is produced by differences in atmospheric pressure, which are primarily attributable to differences in temperature together with differences in the thermal properties of land and ocean surfaces (Blackadar, 2009). Wind Energy is the energy contained in the force of the winds blowing across the earth’s surface. When harnessed, this energy can be converted into mechanical energy for performing work (pumping water, grinding grain and milling lumber.) and into electrical energy for generating electricity (Gipe, 1995). Generation of electricity by wind energy has the potential to reduce environmental impacts caused by the use of fossil fuels to generate electricity. The wind power industry estimates that the world could feasibly generate 12 percent of its total electricity from wind power by 2020. Wind energy is a promising source of electrical power because it is a clean and renewable resource. This energy does not generate atmospheric contaminants or thermal pollution, thus being attractive to many governments, organizations and individuals (Hills, 1996).

Figure 7: Winds (Encarta Encyclopaedia, 2009)

3. 1. Wind Energy System

Wind energy systems consist of three basic components as shown in figure 8, a tower on which the wind turbine is mounted; a rotor that is turned by the wind; and the nacelle, which houses the equipment, including the generator, that converts the mechanical energy in the spinning rotor into electricity.

Figure 8: Components of Wind System (Encyclopaedia Britannica, 2013)

4. Environmental Impact

The environmental impact may amount to both positive and negative effects of these two renewable energy sources as a case study in which the comparison is qualitative. The consideration involves beneficial and adverse effects of the two alternative sources of energy which include impacts on humans, and ecosystems with social, psychological and ecological impacts. Wind power plants have relatively little impact on the environment compared to fossil fuel power plants (Wind Energy Development Environmental Concerns, 2019). The environmental benefits of wind and solar energy accrue through their displacement of electricity generation that uses conventional energy sources, thereby displacing the adverse environmental effects of those non-renewable energy generators.
The electricity generation through wind and solar energy have the potential to reduce environmental impacts caused by the use of fossil fuels to generate electricity. Wind and solar power have their pluses and minuses as regards environmental impact. The wind and solar energy do not generate atmospheric contaminants or thermal pollution. They reduce atmospheric emissions, which include greenhouse gases, mainly carbon dioxide (CO2)\left(\mathrm{CO}_{2}\right), oxides of nitrogen (NOx), sulphur dioxide (SO2)\left(\mathrm{SO}_{2}\right) and particulate matter (Watt Committee on Energy, 2003).

Environmental Impact of Solar Energy

During the operation of solar energy generation, there are no gaseous or liquid emissions and also the photovoltaic array acted as an environmental heat shield in protecting the building on which it is mounted. Solar energy affects the environment negatively that Solar panels contain toxic metals like lead, which can damage the nervous system, as well as chromium and cadmium, known carcinogens as pollutants. All three metals are known to leach out of existing e-waste dumps into drinking water supplies. The washed out of the fragments of solar panel modules over a period of several months by

rainwater could pose threat to human health (Environmental Progress, 2017; Solar Energy and the Environment, 2018; Fitzner, 2019). The solar panel disposal is another problem which can cause adverse environmental effect in future. Solar panels can take up large chunks of desert previously used by a host of wildlife from pronghorns and tortoises to coyotes and rattlesnakes (Fitzner, 2019). The production of photovoltaic systems can cause very similar health and safety problems to those found in the semiconductor industry. The quantities of pollutants generated from photovoltaic production plants are relatively small.

Environmental Impact of Wind Energy

There are a variety of negative environmental impacts associated with wind power generation despite its vast potential that should be recognized and mitigated (Fitzner, 2019). The aesthetic impacts are specific to wind energy facilities plus other impacts on humans and ecosystems, including the killing of wildlife, especially birds and bats through the turbine blades; visual intrusion; noise (mechanical noise from the transmission and aerodynamic noise from the blades or from the blades passing the tower); Interference to television and radio signals. (National Research Council, 2007).

5. Conclusion

The use of wind and solar energies have some beneficial and adverse impacts while concluding that the facilities of considered energies have net environmental benefits. Nonetheless, the adverse effects of renewable energy sources are far less than that obtainable from conventional energy sources. This work provided a guide needed to conduct a more comprehensive analysis. Conclusively, wind energy facilities have adverse environmental impacts which include aesthetics plus other effects on humans and ecosystems while solar energy does not have such adverse environmental impacts.

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