Sustainable energy development is the process of obtaining energy from renewable energy resources such as solar and wind to minimize the harmful impact of traditional energy resources such as fossil fuels, coal, and natural gases. These traditional energy resources are a major concern for our ecosystem as they have a high carbon footprint and they also contribute harmful greenhouse gases, which are the key factor behind the unwanted climate change around the globe. According to reports by the Environmental Protection Agency, the burning of fossil fuels contributed up to 73% of the total global GHGS emissions and accounted for 92% of the total U.S. CO2 emissions. They are also facing a shortage in their supply because of their uncontrolled and unchecked use.

Solar and wind energies are leading renewable energy resources, finding their applications on a large scale in different industries to meet the surging energy demands all over the world. These resources are clean, sound, and environment-friendly sources of energy as they do not include the burning of fossil fuels, and their contribution to greenhouse gas and other toxic pollutants emissions is much lower as compared to non-renewable energy resources. Solar systems such as photovoltaic cells and mirrors are used to concentrate the solar radiation and convert it into other energy forms, such as electric energy, to power communities or electric car stations. On the other hand, wind energy harnesses the moving wind energy through wind turbines to produce useful forms of energy, specifically electricity. These energy means are efficient substitutes to reduce the greenhouse gas load on the eco-system and to rapidly reduce non-renewable energy resources.

The objective of this blog post is to highlight the importance of harnessing renewable energy resources (solar and wind energy) and their impact on the environment. We will find out about the background, technological, and economic aspects, the role of policies and regulations supporting these innovations, and the challenges and opportunities in the adoption and growth of renewable energy systems. We will also try to find out how solar and wind energies can be a possible eco-friendly solution to meet the surging energy demands in the future.

When radiations from the sun fall on the solar panels, they get absorbed by the photovoltaic cells present there, resulting in the production of electrical charges accelerated by the electric field of the cells to generate electricity. Photovoltaic cells absorb photons from the sunlight to generate free electrons under the photovoltaic effect. The use of sunlight dates back to the 7^th century B.C., when it was used to light the fire by concentrating it with the help of a magnifying glass. The revolution of the solar energy era started with the invention of solar panels in 1883 by Charles Fritter; later on, photovoltaic cells using silicon (efficiency up to 6%) were developed by Bell Laboratory researchers and scientists in the 1950s. With time, different innovations were made in the solar energy sector; for example, thin-film solar cells made from cadmium telluride and copper indium gallium selenide were introduced as a cheap and lightweight substitute for conventional silicon cells. The current technologies involve solar tracking technology, which directs the solar panels according to the sun's movements to provide better efficiency. Bifacial solar panels are the result of the latest advancements in this era, which implement the use of photovoltaic cells on both sides of panels to utilize direct sunlight and reflected sunlight off the ground, increasing the power production efficiency by up to 20%.

Wind turbines harness the moving air to rotate their propeller-shaped blades around a rotor connected to a shaft that operates the generator for electricity generation. The kinetic energy of the air is converted into mechanical energy, which is then converted into electricity with the help of a generator. The use of wind energy dates back to 5,000 B.C., when it was used by people to propel boats in the Nile River. The first wind turbine for electricity generation was developed by Josef Friedlander in 1883, and later on, another wind generator was developed by Prof. James Blyth in Scotland. In the 20^th century, different wind turbines were developed, implementing the use of better technologies for efficient performance. For example, a wind-driven generator named “Freelite” was used in Australia, having the capacity to produce electrical power of around 100 watts from the slow-moving wind (at a speed of about 10 miles per hour). With modern innovations, different new technologies have been introduced to improve renewable energy production using wind; for example, floating wind turbine technology introduced in the early 2000s and the latest airborne turbines supported by aerodynamic lift are the improved forms of wind energy production systems.

The efficiency of a renewable energy system can be defined as the rate of conversion of the available energy source by the energy production system, such as solar panels or wind turbines. The efficiency of such systems is dependent on different factors, such as location, the type of technology used for the production system, and altitude in the case of wind turbines. The energy conversion efficiency of solar panels ranges from 15 to 20%; on the other hand, the energy conversion efficiency of wind turbines differs from 20 to 40%, as reported by the United States Environmental Protection Agency.

New technologies are improving solar panel efficiency by implementing the use of a semiconductor (perovskite cells) layer over the silicon layer. They help in capturing more light, usually blue light, from the visible spectrum to increase the absorption and conversion of more sunlight. This innovation has the potential to increase energy conversion efficiency by up to 30%. Solar tracking technology to move the panels according to the sun's movements can increase the efficiency by 25%. Similarly, technological advancements are improving the efficiency of wind turbines in terms of energy conversion. For example, the use of longer blades with segmentation can efficiently drive more energy from the wind, and the increased height of the wind turbines (generally up to 17 m) helps in more efficient energy conversions even at low airspeed. Floating turbines, automated control strategies, offshore wind farms, and integrated data analytics are key advancements in improving the wind energy production process.

According to the International Energy Agency, solar technology contributes almost 4.5% of the total electricity generation all over the world, making it the third-largest renewable energy source. The adoption of solar energy as a renewable energy source is increasing at a staggering rate due to its affordability and eco-friendly features. Rooftop panels are being installed to meet the energy needs of the small households. Concentrated solar power plants can meet commercial energy as well as utility-scale needs as they implement the use of lenses and mirrors for the concentration of sunlight in a small area, and this concentrated light is effectively utilized by photovoltaic cells for electricity generation on a large scale. Solar farms are installed on a large scale in the form of solar power plants that can function just like traditional electricity grids to supply electricity to residential, commercial, and other utility needs.

Wind energy contributed almost 7.33% of the total global electricity production in 2022, making it one of the major renewable energy sources. Small and medium-sized wind turbines can be installed to meet the energy needs of residential areas, while large communities of wind turbines, such as offshore wind turbines, can meet the needs of commercial areas. Organized and integrated wind turbines on a large scale with modern wind turbine innovations can fulfill the energy demands on a large scale.

There are geographical and environmental constraints that limit the wide-scale application of these renewable energy systems. The proper functioning of a solar panel system is dependent on the sunlight, and factors like weather patterns can lower its efficiency. There are some areas with limited sunlight and frequent clouds, which limit solar energy production. Moreover, solar farms require large areas of land for their installation, which can raise concerns about the use of productive land and the loss of biodiversity. Similarly, the successful functioning of wind energy systems depends on areas with consistent speed, land area, and also on weather patterns. The location of wind turbines is another limiting factor, as they are usually in far-off places from human communities, increasing maintenance and energy transmission costs.

Solar panels contain photovoltaic cells made from the incorporation of large quantities of silicon. The silicon manufacturing process is highly intensive and contributes almost 6 kg CO2e/kg as per the silicon metal prepared for use in these cells. The other metals and harmful chemicals used in the manufacturing of solar panels, such as copper, tellurium, and indium, and acids such as hydrochloric, sulfuric, and nitric acids, also contribute to CO2 emissions during their mining and PV manufacturing processes, respectively. The lifecycle GHGS emissions of solar panels differ from 98.3 to 149.3g CO2eq/KWh, including their manufacturing, installation, maintenance, and decommissioning operations.

Wind turbine manufacturing, installation, and maintenance processes also contribute to harmful emissions such as CO2 and other harmful pollutants. For example, during the construction of a wind energy farm, fossil fuels are used to operate heavy machinery, transmit electricity to distant places, manufacture wind turbine materials, and dispose of them. All these processes contribute harmful GHGS and other toxicants to the earth’s atmosphere. The lifecycle carbon emission from on-shore wind is about 15 g CO2 eq/KWh and 12 g CO2 eq/KWh for off-shore wind energy, according to research conducted by the University of Edinburgh. However, the carbon footprint of wind energy is 75% less than that of solar energy, thus providing more clean energy.

Large solar farms require a large land area for the installation of solar panels and concentrated solar systems; most of the time, agricultural and forest areas are being cleared and leveled for effective installation of these farms, resulting in natural habitat loss. The construction of these farms is resulting in habitat loss through clearance and displacement of native species and increased land conversion. For example, in North America, solar power plant development utilized almost 0.60 to 19.9 million ha of the ecosystem, as reported by the IUCN. The other impacts include the migration of birds and their high mortality rate due to affected water availability and electrocution through distribution lines.

The offshore and onshore wind energy farms have a great impact on the biodiversity of the areas where they are installed. For example, in the United States, the median fatality rate of wind energy farms is about 1.8 birds per MW per year. The sharp blades of the wind turbines and transmission lines for electricity increase the bird’s injuries and mortality rates.  The clearance of the lands for the installation of wind turbines can affect the nearby agricultural lands and other natural resources or cultural and religious sites, resulting in productive land and heritage loss.

The manufacturing process of solar panels utilizes different natural sources, such as metals like copper, silver, indium, aluminum, etc., and minerals such as silicon, which are widely used, resulting in the rapid depletion of these resources. Large water quantities are also required for the manufacturing and washing processes of solar panels. Fossil fuels are widely used by heavy types of equipment and machinery used for manufacturing, installing, and maintaining solar panels, resulting in the widescale use of non-renewable energy resources. Similarly, wind turbines are manufactured using steel, fiberglass, iron, aluminum, etc. obtained by extraction, mining, and heavy energy-intensive processes powered by fossil fuels, which are non-renewable energy resources. The wind turbine's basic building materials are sometimes hazardous when they are left unintended for natural resources such as water and land.

The early solar panel systems were costly due to the expensive manufacturing materials; in 1975, the cost of solar panels was about $115.3 per watt. According to Berkely Lab’s Tracking The Sun reports that the price of residential solar panel systems was 5.7 $/W in 2013, and this price has dropped to 4.2 $/W, almost by 26% in 2022. It is estimated that these prices will decline more in the future. There has been a 90% decrease in the overall price of solar panel installations due to improved technologies and government policies. Governments all over the world are introducing policies and subsidies to promote the green energy revolution in the form of solar panels and minimize their installation costs. For example, the United States enacted the Solar Investment Tax Credit (ITC) policy in 2006, which provides a 30% tax credit on the installation of solar panels on residential properties. Similarly, the governments of Japan, China, and Germany provide feed-in tariffs to promote the solar industry.

The cost of wind turbines for the production of electricity has faced ups and downs throughout history, but there has been a decline in the prices of wind turbines compared to the past. For example, in 2008, the cost of wind turbines was about $1800/KW; there was a sharp decline to about $850/KW by the year 2021, and prices will decline in the coming years. The government's policies and subsidies are helping to promote wind energy as a renewable energy source. For example, the United States introduced the Production Tax Credit (PTC), which gives a per-kilowatt tax credit to wind energy producers. Similarly, the Ministry of New and Renewable Energy enacted a generation-based incentive to support wind and solar electricity producers.

The solar power sector has great potential for job creation and to support the economy around the globe; this sector can provide jobs in the manufacturing, installation, and maintenance eras of solar systems. The International Renewable Energy Agency reported that the solar industry provided almost 346,000 jobs, only for the installation of solar panels in 2020. The manufacturing department of the solar industry hired about 3 million employees around the world to maintain the supply chain of solar systems to meet surging demands. This industry is helping to improve economies; for example, China contributed up to 30% of the total solar photovoltaic production, resulting in increased exports to generate revenue.

The wind energy sector is also a potential industry in terms of job creation and supporting the economies of the related countries. This industry can generate revenues for local communities by renting lands for offshore wind energy farm installations. The manufacturing, installation, and maintenance of wind turbines require a large workforce, hence creating jobs. According to a report by the Global Energy Wind Council, wind energy can provide 130,000 jobs, US$12.5 billion in revenue, and 3.5 GW of energy capacity to countries like Argentina, Colombia, Egypt, Indonesia, and Morocco in only five years.

The solar and wind energy industries have achieved wide-scale adoption and acceptance due to their eco-friendly nature. Consumers are well aware of the damaging impacts of traditional non-renewable energy resources such as fossil fuels and natural gas. These energy resources have a huge carbon footprint on the environment, and they also add up harmful toxicants and greenhouse gases that lead to undesired consequences such as global warming and climate change. On the other hand, solar and wind energies are sound and clean sources of energy that do not utilize fossil fuels for energy production, and they have a very low carbon footprint. These features are helping the wind and solar power sectors meet energy demands at residential, commercial, and utility levels.

However, some drawbacks can raise concern, affecting the perception of customers about these renewable energy sources. For example, the manufacturing process of solar panels and wind turbines requires metals, minerals, and other resources, such as water, in large quantities, resulting in the depletion of natural resources. The installation of these systems requires large areas of land, i.e., wind farms and solar farms, which can affect the lands neighboring these farms. Loss of natural habitat and biodiversity are other consequences that can be improved by adopting modern technologies and environment-friendly practices.

The accessibility of the solar system is highly dependent on weather conditions and geographical areas. Solar panels are highly accessible in areas with regular and high sunlight intensity, but they can’t perform well in cloudy and low-sunlight areas. The high initial investment can limit the adoption of solar systems, but modern innovations are helping to lower the price of solar systems. The solar PV ownership models can also drive the accessibility of solar energy; the directly owned model isn’t widespread because of high investment; third-party owned and community-owned models can promote accessibility as consumers can easily pay for the installations for using these energy sources.

On the other hand, as wind turbines require a high initial investment for their installation and maintenance, this factor can limit their accessibility for general consumers. Moreover, the efficiency of wind turbines is dependent on the constant and regular wind speed, thus limiting their installation in specific areas. The ownership models affecting the accessibility of solar systems are independent wind farms, community-owned wind farms, and corporate wind farms. Community-owned and corporate wind farms can increase the accessibility of wind energy, as they include multinational organizations and large corporations.

Different policies and regulations were introduced by different countries, regions, and multinational organizations to promote the use of environment-friendly renewable energy resources. The Paris Agreement is one of the international treaties that was adopted by 196 countries in Paris on December 12, 2015. This agreement aims at the use of renewable energy resources such as solar and wind energies to limit the increase of global average temperature below 2 degrees. The International Renewable Energy Agency is an intergovernmental organization that helps countries adopt renewable energy sources to bring sustainability to the environment. Some regional policies are a driving factor behind the large adoption of renewables; for example, the Federal Investment Tax Credit and Production Tax Credit policies are introduced by the United States to give tax credits to individuals or companies that implement the installation of solar panels and provide wind energies to consumers, respectively. The Jawaharlal Nehru National Solar Mission was introduced by the Indian government in 2010. The objective of this initiative was to make India a leading country in solar energy production. Similarly, countries like China, Japan, and the EU 27 are providing subsidies and feed-in tariffs to increase the adoption and acceptance of these renewables on a large scale.

The major challenge that influences the growth of solar and wind energy is the variable nature of these energy sources. The efficient functioning of the solar energy system is dependent on the adequate availability of intense sunlight, while the wind turbines demand regular wind patterns at a speed that can rotate the blades of these turbines, and the seasonal changes can have a great impact as well. The other challenges include the integration of these renewables into the already-existing grids because of a lack of standards, the storage of these energies, which can challenge safety standards, and other regulatory problems.

However, some opportunities can increase the turn towards sustainability by adopting these power systems; for example, government subsidies and incentive policies can encourage businesses and organizations to invest in the renewable energy industry. Modern advancements like smart grid policies can help the integration of solar and wind energies into the energy grids to meet energy demands. Strict environmental standards to lower the use of conventional, non-renewable energy resources and GHGS emission policies can also help in steering the use of renewable energy sources.

Innovations in solar technologies have revolutionized the performance of solar panels and concentrated solar systems. The use of perovskite cells and tandem solar cells in the solar panels is helping to lower the manufacturing cost of these panels; they are easy to manufacture, and they do not demand that many natural resources as compared to the conventional panels made from silicon, copper, and other metals. Innovations in energy storage batteries, such as solid-state batteries and lithium-ion batteries, can easily store a large quantity of solar and wind energies to operate EVs or other appliances. Innovations in the design of wind turbines with improved aerodynamic features can generate more electricity, even from slow-moving wind. A modern wind turbine known as the Makani Airborne Wind Turbine can operate at high altitudes up to 1000 feet to utilize wind speed with more efficiency.

The integration of solar and wind energy into the energy grids is a challenging task because of the variable nature of these renewables. There can be fluctuations in the electricity generation by solar panel systems due to the change in sunlight intensity; on the other hand, variations in wind speed can change the energy production by wind turbines. When such systems are integrated into energy grids, they could lead to voltage fluctuations, resulting in short circuits or other serious problems. Another challenge in the shift towards integration is the distant transmission and distribution of energy from the production places to the human communities, as most solar and wind farms are installed in far-off places.

Integration solutions include the development of efficient energy storage systems, such as modern battery technologies to store excess energy; the implementation of smart grid technologies to monitor and control fluctuations; and predictive techniques to forecast the variations, which can also improve this process. Moreover, hybrid energy systems such as solar and wind energy systems can be intermixed to provide consistent power supplies. The use of interconnected grids to maintain and overcome the variations across a specific region can be a possible solution for the integration of renewable energies into the energy grids.

1- Conventional, non-renewable energy resources are disturbing our eco-system and they are the leading cause behind climate change and global warming

2-The Renewable energy resources such as wind and solar energies are the key energy resources to lower the carbon footprint and GHGS emissions and to bring sustainability

3- The advancements in solar and wind technologies are helping to lower the cost and efficiency of these energy systems.

4- Government policies and subsidies are the driving factor behind the widespread adoption of solar and wind energy systems

5- The integration of solar and wind power into the energy grid can mitigate energy needs in the future.

Solar and wind energies are contributing a lot to meet the energy needs as a sustainable energy source overall. Both energy systems have different requirements, such as location, installation, maintenance, storage, and transmission strategies. However, these energy sources can become an impactful source of renewable energy to meet future needs if these systems are intermixed and installed according to the specifications of the different regions to get their maximum potential.

The traditional energy resources are not only disturbing our nature and ecosystem but are also depleting at a rapid rate; thus, they are unable to meet the surging energy needs in the future. They are also a key factor in unwanted global problems like climate change and global warming resulting from the greenhouse gases contributed by these energy resources. On the other hand, solar and wind energies are clean and sound sources of renewable energies that are helping to minimize the carbon footprint and greenhouse gas emissions. They are one of the main contributors to bringing sustainability and a green revolution to our planet. As these systems have wide-scale acceptability, it is time for businesses and multinational companies to make a shift toward renewables to make our planet an inhabitable place once again.  

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