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Due to the predicted shortage of fossil fuels and other non-renewable energy sources, research is now looking at alternatives. These alternatives are known as renewable energy. Renewable energy effectively uses natural resources such as sunlight, wind, rain, tides and geothermal heat, which can be naturally replenished. If the use of renewable energy isn’t explored for future use, we may be living without appliances we take for granted today. For example, imagine a winter without a heater and a summer without air-conditioning, and day-to-day life without televisions, cars, washing machines, even lights. The earth could get to a stage where it was so severely scarred from people trying to find more energy sources, that the damage is irreversible. With the current consumption rate of non-renewable energy, this scenario may very well be the state of the planet in future years.
Hence, this paper will explore the use of the alternate energy source, solar power for present and future use. The advantages and disadvantages of the energy source will be discussed, in relation to its technological, economical, viability factors. In doing so, the paper will attempt to prove that not only is solar energy as an alternate energy source better for the environment, but also verify that it is better for our economy in the long run.
Table of Contents
1.0 Introduction 4
1.1 Overview of Solar Energy 4
1.2 Everyday Usage 6
2.0 Technological Viability 6
2.1 Efficiency 8
3.0 Environmental Sustainability 8
4.0 Economical 9
5.0 Conclusion 10
In today’s climate of growing energy needs and increasing environmental concern, alternatives to the use of non-renewable and polluting fossil fuels have to be investigated.
We have only really been looking at the possibility of solar power seriously for the past fifty years, and fossil run machines and power plants have been researched for the past century. In the journal article, “Photovoltaics A Path to Sustainable Futures”, Joshua M. Pierce states that since 1957, electricity demand in the US has increased by over 450% while the US population has increased by only 50%, which illustrates how the demand for electricity has grown.It has been estimated that we only have 50 to 70 years left of all fossil fuels at the current consumption rate. This is a scary figure, considering that as soon as 2050 there could be no more food to feed the industrialized machine. Something will have to change, it’s obvious, and renewable energy is the most logical answer .
Green Peace India defines Renewable Energy “as a sustainable energy source that comes from the natural environment that is perennial. Clean Renewable Energy are those, which do not contribute to any sort of emission harmful to lives such as radiation, carbon, or involve extractive processes, or which would cause large scale displacement of people or destruction of land and forest covers.” (Green Peace India, 2009). In other words, renewable energy can be taken continuously from the natural environment and does not affect the normal activities in the biosphere.
One such renewable energy source being considered for future use is solar energy.
Photovoltaics, “photo” meaning light and “voltaic” meaning electricity, is one of the fastest growing solar energy technologies. Photovoltaic devices, or solar cells, use semiconductor material to directly convert sunlight into electricity.
Overview Solar Energy
Solar cells, primarily made of silicon, absorb sunlight which contains photons, the energy by-products of the nuclear reaction in the sun. The photons release electrons that are captured in the form of an electric current which is used as electricity. This is also known as the photoelectric effect. Solar energy is the oldest type of energy found on earth, as it is as old as the sun. Every second the world receives 95.8 trillion watts of power, (Pearce, 2002). That is well beyond the amount of power used in one day.
It is unknown when humans began using solar energy to improve their lifestyles. As far as we know, people have always used the sun for growth, vision and warmth.
“Some of the first ancient cultures to use solar energy as heating were those from the deserts, and dry areas”. (Goswami, 1997)
It was however recorded that countries such as Egypt, Libya and Algeria would build thick walls of mud to protect them from their harsh climate. For example, during the hot days the wall would absorb the suns energy, leaving the huts cool, and during the night when temperature were much colder, the walls when emit the days heat inside. (Goswami, 1997)
Throughout history people have experimented with the many uses of the sun’s power. In the 17th century, scientists in Europe began rediscovering the sun. When a French scientist proved that the sun’s rays could melt copper and fuse pieces of iron if concentrated and focused through a glass prism, people began to see the usable power of the sun. In the 1690’s an Italian scientist invented a solar furnace that was so hot it could shatter a diamond, one of the hardest substances on earth (Goswami, 1997)
Using the sun to produce energy was explore in greater lengths in the 19th century.
During this time, an engineer named Frank Shuman, made a breakthrough. He built a plant that used black troughs covered in glass with a few inches of water. This was exposed to the sun, the water would become very hot, causing it to circulate and power an electric generator. He was able to find financial backers and built the world’s first solar electric power plant in Egypt. However, the Eastern Sun Power Company went out of business even though it was using free fuel. It didn’t produce enough electricity for the area that it used, 14,000 sq. ft of sun-collecting land. (Pearce, 2002)
In 1954 Bell Laboratories invented the first photovoltaic (or solar) cell, made from the semi-conductor silicon, and other elements. It was the first way to convert sunlight directly into electricity. These solar cells were chosen as the power source for the satellites in the 1960s, because they can be small and light, and don’t need heavy batteries or other types of generating electricity. After NASA and other major researchers backed solar energy, the technology greatly improved. “The first major use of solar cells, other than in satellite, were various emergency units and in remote areas where power lines couldn’t be reached.” (Energy Matters Pty Ltd). In these situations, it was more expensive to run power lines than to purchase the costly solar equipment. For example, in the high mountains of Papua New Guinea, where there is too much jungle for easy access, there are necessary telephone lines run by solar power and only visited for routine check-ups.
1.2 Everyday Usage
Numerous devices for collecting solar energy and converting it into electricity have been developed throughout the years, and solar energy is now being used in a variety of ways. As well as supplying energy to residential homes and companies, they are popularly used in agriculture where they supply the power to pump water, prevent ice from forming on ponds where livestock drink, heating barns to keep animals from freezing, and temporary lighting. They are also used to operate electric dams in areas that cannot be supplied by power lines.
Solar powered objects have started to appear quite commonly in many consumer items such as watches, radios, calculators, rechargeable batteries, flashlights, etc. The main attraction in these items is that you don’t have to replace the batteries, which saves money in the long run. (International Solar Energy, 2006)
2.0 Technological Viability
The time in which solar energy is available, is also the time we least need it least – daytime. One disadvantage of solar power, according to International Solar Energy is its consistency and reliability. Solar-powered devices rely on the steady delivery photon to keep the electricity generating process going, as discussed previously. When the sun falls below the horizon at night, photons stop striking the solar panels and the power drops instantly.
However, the improvement in technological advancement over the last few years, have seen the construction of a solution. As the sun’s energy cannot be stored for use another time, we need to convert the suns energy into an energy that can be stored. Due to this nature of solar energy, two components are required to have a functional solar energy generator. These two components are a collector and a storage unit.
The collector collects the radiation that falls on it and converts a fraction of it to other forms of energy (either electricity and heat or heat alone). Solar collectors use reflective materials such as mirrors or lenses to concentrate the sun’s energy to provide heat energy which is then converted into electricity. This can be done in three ways.
“The first method is a trough systems which use curved mirrors to concentrate the sun’s heat onto a tube which contains a fluid, usually oil. The hot oil then boils water to produce steam which is used to generate electricity.
Alternatively, mirrors in the shape of a dish can be also used to concentrate the sun’s heat onto a receiver. The latter transfers the solar energy to a heat engine, converting the heat into mechanical energy which drives a generator to produce electricity. This method is called the dish/engine system.
A third method of concentrating the sun’s energy is through the use of power towers which provide a centralized power supply with the ability to store energy. These systems use a large array of mirrors, called heliostats. These heliostats concentrate the heat onto a receiver on top of the towers. The receiver contains a fluid that once heated can be used to produce steam which then turns a turbine to produce electricity.”(Markvart & Castañer, 2003)
The storage unit is required because of the non-constant nature of solar energy; at certain times only a very small amount of radiation will be received. At night or during heavy cloud cover, for example, the amount of energy produced by the collector will be quite small. The storage unit can hold the excess energy produced during the periods of maximum productivity, and release it when the productivity drops. One possible method of storing solar energy is by heating water that can be insulated. The water is heated by passing it through hollow panels. Black-coated steel plates are used because dark colours absorb heat more efficiently. However this method only supplies enough energy for activities such as washing and bathing. The solar panels generate “low grade” heat, that is, they generate low temperatures for the amount of heat needed in a day.
Apparently, according to International Solar Energy Pty Ltd, in order to generate “high Grade” heat, intense enough to convert water into high-pressure steam which can then be used to turn electric generators there must be another method. The concentrated beams of sunlight are Collected in a device called a solar furnace, which acts on the same principles as a large magnifying glass. The solar furnace takes the sunlight from a large area and by the use of lenses and mirrors can focus the light into a very small area
It was found that, a backup power supply is usually normally added, too, for the situations when the amount of energy required is greater than both what is being produced and what is stored in the container.
An issue raised by International Solar Energy Pty Ltd, was that only regions with lots of sunlight are suitable for solar power generation. But this concern is currently being worked on as scientists have just recently invented a plastic solar cell that can convert solar energy to electrical energy even on a cloudy day. This plastic device, containing the first solar cells able to harness the sun’s invisible rays. Also, the researchers are holding this futuristic view that plastic solar panels could be laid across deserts to provide the entire planet with enough clean energy.
Another solution to the issue of the inconsistent light is being researched right now by Arthur D. Little Inc. The sun’s rays are not constant on earth due to weather, location, and season. To avoid this scientists have envisioned “huge solar powered space stations that would orbit the earth, capable of sustaining themselves for decades.” (Committee on Aeronautical and Space Science, 2005). They would generate electricity by a vast array of mirrors on solar cells, and then the energy would be converted to micro-waves that could be beamed to earth and then distributed. These stations are estimated to be about 10 miles long, and some 23,000 miles above the earth. As far fetched as this seems, it’s actually theoretically possible, and may one day be our source of power. One flaw in the plan however, is that there is actually quite a lot of space debris floating around at high velocities. If this debris collided with the solar panels, as it invariably would, they would be damaged. How much, and at what price is still to be figured (Goswami, 1997)
Another idea is the “solar farm.” It would be ideally located in desert regions where it is sunny almost every day. The farms would actually harvest sunshine, using flat plate collectors to absorb immense amounts of heat, which would in turn heat water. The heated water would turn giant turbines, and produce electricity.
Solar cells, contain no moving parts, and have a working life of 20 – 30 years. According to “Convincing the Home Builder to Build Solar Homes-Evaluation of the Passive Solar Workshop for Builders” by S. Klein, they are reliable because they operate for a long time with practically no maintenance .
Most of the photovoltaic cells on the market today operate at an efficiency of less than 15% ;that is, of all the radiation that falls upon them, less than 15% of it is converted to electricity. The maximum theoretical efficiency for a photovoltaic cell is only 32.3%, but at this efficiency, solar electricity is very economical. Most of our other forms of electricity generation are at a lower efficiency than this. Unfortunately, reality still lags behind theory and a 15% efficiency is not usually considered economical by most power companies, even if it is fine for toys and pocket calculators. Hope for bulk solar electricity should not be abandoned, however, for recent scientific advances have created a solar cell with an efficiency of 28.2% efficiency in the laboratory. This type of cell has not been field tested. If it maintains its efficiency in the uncontrolled environment of the outside world, and if it does not have a tendency to break down, it will be economical for power companies to build solar power facilities after all.
4.0 Environmental Sustainability
It is estimated that the sunlight that falls on the surface of the earth in the time period of two weeks is equivalent in energy to all the energy stored in all the oil and natural gas and coal and other fuels that exist on, or under the earth (Markvart & Castañer, 2003)
Solar power has two big advantages over fossil fuels. The first is in the fact that it is renewable; it is never going to run out. The second is its effect on the environment. According to Solar Heating Systems: Analysis and Design with the Sun-Pulse Method by Gordon F. Tully, solar cell systems do not harm the environment, as do conventional methods of power generation. The sun is an infinite source of energy and since its use for powering homes causes no damage to the environment. We should use the clean and silent energy source it to its maximum potential.
As the primary element of construction of solar panels, silicon, is the second most common element on the planet. Therefore, there is very little environmental disturbance caused by the creation of solar panels. (Markvart & Castañer, 2003)
While the burning of fossil fuels introduces many harmful pollutants into the atmosphere and contributes to environmental problems like global warming and acid rain, solar energy is completely non-polluting. While many acres of land must be destroyed to feed a fossil fuel energy plant its required fuel, the only land that must be destroyed for a solar energy plant is the land that it stands on.
However, solar energy only causes environmental disruption if it is centralized and produced on a gigantic scale. At this scale, the production of solar energy would have some unpredictable negative environmental effects. If all the solar collectors were placed in one or just a few areas, they would probably have large effects on the local environment, and possibly have large effects on the world environment. Everything from changes in local rain conditions to another ice age has been predicted as a result of producing solar energy on this scale. The problem lies in the change of temperature and humidity near a solar panel; if the energy producing panels are kept non-centralized, they should not create the same local, mass temperature change that could have such bad effects on the environment. (Tully, 1981)
In due course, solar power will reduce the emissions associated with power generation. Consistent with, Solar Heating Systems: Analysis and Design with the Sun-Pulse Method by Gordon F. Tully, with 1 million solar energy roofs are in place, could reduce carbon emissions equal to the annual emission from 850,000 cars.
For many. fossil fuels are too available and cheap for the investment in solar energy to be worthwhile. Ironically, although the sun’s energy is free, the curse of solar power is that the techniques are always too expensive. (Green Peace, 2006)
One major concern with solar power is cost-effectiveness. The silicone used for production , is one of the most readily available elements on earth. Nevertheless, “the kind of grade silicon needed for solar cells is very expensive. It is grown in tall cylinders, and then cut in thin segments. The cutting process is wasteful and expensive” (Pearce, 2002). A new product is polycrystalline silicon, which is grown in thin sheets and cut in squares. In Peter Lorenz, Dickon Pinner, and Thomas Seitz article The economics of solar power it states that “Although polycrystalline is not as efficient as natural silicon, it’s significantly cheaper, and lowering the cost is one of the most important things in making solar energy practical.”
The initial cost of installing a solar power system is preventing current installation for these devices . The Australian Governments, and many others across the world had recognize this and are offering annual rebates and tax incentives to customers who install the systems in their homes.
Consumers with solar power systems in their homes will save about 50-60% on their utility bills, (Energy Matters Pty Ltd). These savings will exceed the original cost of a system in about 10-12 years. After the initial cost is covered, the customer is still saving thousands of dollars in utilities compared to electricity and gas usage.
As we burn more fossil fuels, the costs of electricity and gas would be subject to increase over the years. With solar powered home, monthly bills would stay about the same no matter how expensive electricity and gas become. The financial savings of solar-powered homes is an extra benefit for consumers who know that their homes are helping to preserve our environment.
The great thing about solar power is that once you’ve paid for the system you don’t have to worry about rising utility costs. You’re basically buying all your electricity at once. However, the cost is still a main factor to be considered. Arrays of rooftop solar panels capable of generating one kilowatt of electricity cost at least $7,500 even with the solar panels now costing about one-third of what they did a decade ago. (Lorenz, Pinner, & Seitz, 2008) Still, the average household requires two to four times that much power, meaning that it would take about a $30,000 system to save about $15 per month for each kilowatt of power generated. It would take about 20 years until enough electricity would be generated to make up for the investment. (Energy Matters Pty Ltd).
Despite the great cost of solar energy systems, people are still investing in them because of their obvious benefit to the environment and because once you have it installed, the energy is free. As technology improves, solar energy will become more economically feasible because the price of solar panels will go down.
The number of advantages associated with using solar power for the future, greatly out way the disadvantages. Many of the issues explored throughout this paper are currently being research or have already solved, some of which show great promise for the future. Despite being currently still quite expensive, and showing negative effects to the environment if implemented in a large centralised scale, there is no doubt that solar energy will continue to grow and slowly replace the fossil-fuelled world around it .Besides the upcoming scarcity of fossil fuels, their highly pollutive nature makes solar energy a much healthier and wiser decision.
The fear of exhausting all our resources has also spurred further development of alternative fuels, and created a greater interest in overcoming those disadvantages of solar power that remain. Technology changes rapidly, and the number of disadvantages of solar power that seemed virtually impossible only a few years ago are now relatively minor inconveniences.
Hopefully, with continued this research, we will be in a place one day where we can directly rely on the sun for all our energy needs, and never have to use pollutant non renewable resources again. With an energy source like solar power, that’s environmentally safe, capable of producing the raw power to satisfy the entire planet’s energy needs, we would be incredibly foolish not to use it.
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