On Solar Energy Essay Example

played a crucial role in developing dish/Stirling system technology that harnesses thermal energy from concentrated sunlight for generating electric power. French physicist Alexandre-Edmond Becquerel discovered the photovoltaic effect in 1839 while creating a device that measures light intensity through observing changes in electric current between two metal plates. Solar cells generate electricity within its material as electrons are knocked loose from their atoms due to sunlight absorption.

The photovoltaic (PV) effect refers to the process of converting photons into voltage. However, Becquerel's process only managed to convert 1% of submerged electrode sunlight into electricity, making it only 1% efficient. Despite this low efficiency, scientists continued experimenting with different materials in search of practical PV system applications. It wasn't until the late nineteenth century that scientists discovered selenium's sensitivity to sunlight. In the 1880s, Charles Fritts created the first selenium solar cell, which unfortunately had an inefficiency rate of less than 1% in converting absorbed light into usable electricity.

John Ericsson, a Swedish inventor who worked in the United States, created the world's first solar-energy engine/dish in Pasadena, Calif. He revealed a concept design for the solar machine in 1876 at the centennial celebration in Philadelphia. The Sun Motor of John Ericsson was printed in New York in 1872. Another significant contribution to solar-cell technology was made by the Fritts selenium solar cell. Although it was largely forgotten until the 1950s, efforts to develop an efficient solar cell reignited. Scientists knew that a semiconductor that released electrons when exposed to radiation within the visible spectrum was crucial to photovoltaic cells. In 1901, Pasadena saw the development of the World's First Solar Energy Dish.

During their research at Bell Telephone

Laboratories, scientists were creating semiconductors for communication systems. Calvin Fuller and Daryl Chapin discovered the ideal semiconductor - a doped cell made of phosphorous and boron. This accidental discovery led to the development of the first solar cells in 1954, which had a conversion efficiency of almost six percent. Improvements to the design later increased the efficiency to nearly 15 percent. Bell Telephone utilized a silicon solar cell in 1957 to power a telephone repeater station in Georgia.

Although the process was not efficient in reaching the general market, it was considered a success. The initial application of silicon solar cells took place in 1958 when it powered the radio transmitter of Vanguard 1, which was the second satellite made by the US that orbited Earth. After this milestone, solar cells were incorporated into almost every satellite launched. Solar cell production worldwide increased from less than 10 MWp/yr in 1980 to about 1,200 MWp/yr in 2004. Currently, PV installation capacity globally has surpassed three Gigawatts per year. Photovoltaic cells were already used for powering US operations during the '60s.

Solar-energy systems started powering small calculators and wrist watches commercially in the 1980s. Nowadays, advanced systems provide electricity to power communication equipment, pump water, and generate electricity on a commercial scale using S. space satellites. The market for solar-based electricity production is dominated by two technologies. Concentrating solar power systems increase heat energy by focusing sunlight through a magnifying lens to drive a generator and produce electricity.

There are two ways to utilize solar energy: photovoltaic systems (PV) and solar heating. PV systems use semiconductors to transform sunlight into electricity, while solar heating employs collectors to absorb the sun's

energy and produce low-grade heat for tasks like water heating, space heating in buildings, and pool heaters. Originally designed for satellite power and other space applications during the 1950s-1970s, PV technology research shifted towards large-scale development of solar collectors by the Energy Research and Development Administration in the mid-1970s in the United States. The Department of Energy continued this effort after 1976.

After the 1973 oil embargo, there was growing anxiety about energy supply. This sparked a surge in solar cell research and development, prompting the U.S. Department of Energy to create the Photovoltaics Program in 1976. Several global organizations, including DOE, contributed significant funds towards PV R;D which helped establish a terrestrial solar cell industry.

[4] The cost of solar energy technology has decreased significantly, making it more affordable on a larger scale and promoting its use as the primary source of energy for the future. Solar energy costs decreased by 50 percent in the 1990s, which contributed to its popularity surpassing niche sources of electricity. By the late 1990s, over 10,000 homes in the United States were exclusively powered by photovoltaic systems. Another 200,000 homes supplemented their electricity consumption with some form of solar energy during this time period according to the Solar Energy Industries Association.

Although the global solar power industry was valued at $5 billion in 2003, it only represented one percent of US electricity production due to high costs and easily accessible traditional energy sources. However, recent years have seen significant reductions in these obstacles, leading to a small revolution in daily life. The International Energy Agency reported that solar energy contributed 0.039 percent to the world's total primary energy supply of 11,059

million metric tons of oil equivalent in 2004, which is equal to approximately 4 terawatt-hours out of an estimated total production of 17,450 terawatt-hours (1 terawatt = 1 trillion watts).

The quantity of solar energy accessible at a particular spot on Earth is influenced by its latitude, time of day, and date. The solar spectrum consists of photons with varying energy levels across distinct wavelengths. Photovoltaic cells react to these photons in three ways: reflection, penetration, or absorption. Only the absorbed photons can generate electrical power.

During manufacturing, the material is treated to enhance its absorption of sunlight and release electrons from its atoms. This treatment also promotes electron movement toward the surface, leaving holes behind. As several negatively charged electrons migrate towards the cell's front surface, a voltage potential develops due to an imbalance of charge between the front and back surfaces, similar to a battery's terminals.

When two surfaces are joined while under a load, an electric current is generated. To boost the power output, multiple cells can be connected to create weather-resistant modules that can then be combined to form a full power plant array. The number of necessary modules needed to achieve the desired power output ranges from one to several thousand when they are linked together.

There are different ways to utilize solar energy, including concentrated solar-power systems, passive solar heating and daylighting, photovoltaic cells, thin-film solar cells, solar hot water, and solar process heat for space heating and cooling. All of these methods depend on photovoltaics technology which converts sunlight into electrical power using either crystalline silicon or thin-film cells.

Thin-film solar cells feature a substrate composed of glass, metal, or polymer and contain

small amounts of semiconductor materials such as gallium. On the other hand, crystalline silicon solar cells utilize silicon or polysilicon as their substrate and come in various sizes ranging from 1/2 inch to 4 inches across. Additionally, crystalline silicon solar cells possess extra layers that enhance light absorption. Though thin-film solar cells offer benefits, they are generally less effective than crystalline ones.

When PV solar panels are exposed to sunlight, they release electrons and generate electricity, resulting in the production of Solar energy. The use of multiple solar cells arranged in arrays generates a significant amount of electrical power. In the early 2000s, there were solar cells available with conversion efficiencies approximately at 20%, although some experimental cells achieved twice as high or more efficiency levels. Analysts predict that the market for solar energy will continue to grow significantly in the coming years. To calculate energy conversion efficiency, it is necessary to compare how much available energy is converted into what a device can generate. Despite producing an enormous amount of energy across different light spectrums, only small portions can be captured and turned into electricity through photovoltaics.

The efficiency of commercial PV systems is usually around 20%, but exposure to prolonged sunlight can lead to degradation and a yearly reduction in efficiency. In comparison, the typical fossil fuel generator has an efficiency of approximately 28%. Modules holding about 40 solar cells are often combined, with up to 10 modules mounted in photovoltaic (PV) arrays measuring several meters on a side. These flat-plate PV arrays can be fixed facing south at a specific angle or mounted on a tracking device that follows the sun for optimal sunlight

capture throughout the day. A household may need about 10 to 20 PV arrays for sufficient power, while industrial or large electric utility applications may require hundreds of interconnected arrays in a single, large PV system.

The efficiency of a photovoltaic array's energy output is determined by solar radiation but can be affected by environmental and weather conditions. In August 2008, the National Renewable Energy Laboratory achieved the most efficient solar-cell conversion rate at 40.8 percent. Photovoltaic cells produce DC power similar to batteries and are suitable for low-energy-demand electronic devices.

When converting photovoltaic-generated DC electricity for commercial or utility sale, inverters are necessary to transform it into AC. These solid-state devices are essential in the process. Concentrating Solar Power and Solar Thermal technology use lenses to concentrate sunlight onto solar cells, optimizing light exposure while reducing the need for costly semiconducting PV material. However, these focusing collectors have limitations; they require positioning towards the sun and have restricted utilization in the sunniest parts of the country. Advanced tracking systems are typically needed for most concentrating collectors, which limit their employment to businesses, industries and large structures.

Concentrating solar power (CSP) systems use optical lenses to increase the intensity and heat of sunlight. There are three main types of CSP systems: trough, dish/engine, and power towers. CSP plants incorporate these systems with numerous mirror arrangements to convert sunlight into high-temperature heat, which is then used to generate electricity by producing steam that powers a turbine.

The advantages of CSP over photovoltaic cells in large-scale power generation include more consistent power production and the ability to store energy for several hours after sunset, which can meet evening spikes in

demand. Hybridization with other generating stations that use steam turbines allows plants to burn natural gas or other fuels during nighttime hours, ensuring constant output and maximizing turbine use. According to a report from Emerging Energy Research in December 2007, CSP is currently the second fastest-growing utility-scale renewable energy alternative after wind power and has received most of the federal research funding for solar energy.

The method discussed in the research has the potential to effectively compete with other technologies for generating electricity, as indicated by solar thermal power projects receiving an investment of approximately $20 billion between 2008 and 2013 worldwide. This technique utilizes concentrating collectors that reflect solar energy over a large area and focus it on a small receiving region, resulting in increased intensity of solar energy up to temperatures exceeding 1,000 degrees Celsius. Heliostats track the sun for concentrators to perform optimally. Concentrating solar power systems are available in three primary types: parabolic-trough, dish/engine, and power tower.

One type of solar energy system is the parabolic-trough system. These systems use curved mirrors in a long rectangular shape, tilted towards the sun to concentrate its energy. The mirrors focus sunlight onto a pipe down the center of the trough, heating oil inside. The hot oil flows through the pipe and boils water in a steam generator to produce electricity. The Solar Energy Generating Systems (SEGS) group in California's Mojave Desert includes two of the world's largest parabolic-trough power plants, SEGS VIII and IX at Harper Lake. As of 2007, these plants each had a capacity of 80 MW and were made up of roughly 400,000 mirrors in total.

Typically, around 5 to 10 acres of

land per megawatt of electric capacity is required for a parabolic trough power plant, depending on whether thermal energy storage is incorporated into the design of the solar field. Ideal solar regions with flat terrain are needed for the construction of solar plants. While numerous large parabolic trough facilities have been erected lately, many others are currently in the works. Abengoa, a Spanish industrial group, is constructing a 280Mw parabolic trough station in close proximity to Phoenix and multiple others in Spain. Meanwhile, Martifer Renewables, owned 80% by Portugal's Martifer Group, is bringing to life a 107Mw parabolic trough facility near Fresno, Calif.

In 2011, a new concentrated solar power facility is set to operate in California, as applied for by FPL Group in March. The facility will cost $1 billion and generate up to 250Mw of electricity. There are three types of concentrator designs used for solar energy; one of which is called the "dish system". These types of concentrators look like large satellite TV dishes, and they focus the sun's rays on a focal point directly in front of them. A Stirling Engine or photovoltaic panel is mounted on the dish's focal point to convert heat to mechanical energy and generate electricity.

The solar dish-engine system utilizes sunshine as a source of energy for generating electricity, in place of gas or coal. The main solar component of this system is the dish, which functions as a concentrator. It collects radiant energy from the sun and concentrates it on a small receiver. The receiver receives the heat and passes it on to fluid within the engine. The liquid then expands against a piston or turbine, which

in turn produces mechanical power. This mechanical power drives either a generator or an alternator that creates electricity.

Located in New Mexico, the Solar Energy Dish utilizes a dish-shaped mirror to track and reflect sunlight onto a receiver, which powers a high-efficiency heat engine. The working fluid, typically hydrogen, expands to drive a piston or turbine that generates electricity. At Sandia National Laboratories, an experimental installation achieved a conversion efficiency of over 30% in early 2008. The "power tower" is another type of concentrated solar power (CSP) technology.

Power tower systems involve employing an extensive array of mirrors that focus sunlight onto a tower's top, housing a receiver, which warms molten salt passing through it. The heated salt is utilized to create electricity via a conventional steam generator. This approach facilitates reaching substantially higher temperatures as compared to parabolic troughs, yet the latter convert thermal energy into electricity more efficiently while storage costs less. Abengoa constructed the first power tower, a 10Mw plant located close to Seville, Spain, which was inaugurated in 2007.

Plans for constructing a significant Power Tower facility in the Mojave Desert are underway by BrightSource Energy in the U. S. The first unit of the facility is likely to commence operations in 2011, with a capacity of 100Mw.

ESolar, located in Pasadena, California, has agreed to sell energy from its forthcoming 248MW tower system in the Mojave Desert, USA. This PowerTower will use molten salt to store heat for days, allowing for electricity generation on overcast days or following sunset. Additionally, concentrators will create high temperatures, facilitating the construction of solar furnaces.

Daylighting or passive solar refers to the use of sunlight for illumination in buildings,

which can be accomplished through various techniques and technologies. These include efficient window placement, special coatings that reduce reflection or modify window transmittance, and the utilization of solar collectors and fiber optics. Moreover, researchers are presently investigating hybrid solar lighting that integrates electric lighting with daylight conveyed by optical fiber pipes. The largest facility worldwide for generating high temperatures reaching 5400°F is situated in Odeillo within the Pyrenees Mountains of France. It employs 63 reflectors with a combined area of around 30,515 square feet.

By utilizing this method, a durable source of light can be obtained for less money than standard electric lighting. At the end of the 1800s, solar water heating mechanisms were prevalent in America and exhibited superior efficacy compared to wood or coal-burning stoves. Although synthetic gas derived from coal was an alternative for water heating, it cost ten times more than contemporary natural gas does. As a result, numerous households relied on solar-powered water heaters.

Starting in 1897, solar water heaters were implemented in 30% of homes in Pasadena's eastern region near Los Angeles. As mechanical technology progressed, these systems became popular in sunny areas throughout the United States such as Arizona and Florida. Sales for solar water heaters soared into the tens of thousands by 1920.

However, during this time, vast amounts of oil and natural gas were discovered in western regions, making them readily available and causing fossil fuel-burning heaters to replace solar water heaters on a large scale.

The integration of solar water heaters into mainstream use is on the rise, with Hawaii passing a law in June requiring all new homes to have them installed. This energy-efficient move is anticipated

to result in significant annual energy savings for the state.