The Use of Solar Energy - Assignment Example

Solar Energy Faculty One thing had never changed for the last several millions of years and will never change infuture is the Sun light that comes everyday on our planet. This is the energy that is responsible for life on earth. Humankind uses this energy in various forms for the last few centuries, e.g. use of magnifying glass for melt or burn, and now this form of energy is used in space too for the power need of orbiting satellites. Solar energy can be used in two different ways that are for heating (cooking, water heating, etc.) and generation of electricity (Photovoltaics). In present scenarios 83 % of the consumed energy are fossil fuels such as coals, oil and natural gas, which lead to a petroleum crisis and significant increase of the price of the petrol and the natural gas. However, the world economy is decarbonizing and over the past two centuries, carbon rich fuels (coals) have given way to fuels with less carbon (oil and natural gas) or with none (renewable energy such as solar and wind power). These days more and more fuels used are of hydrogen. In addition, renewable energy such as wind power and solar power are doubling every two and three years respectively, worldwide and these will ultimately slow down global warming [Lovins 2005]. In bellows figure the percentage share of renewable energy worldwide is shown for the year 2005. Figure 1: World Renewable Energy in 20051 From above figure it can be seen that the percentage share of solar power towards renewable energy is approximately 6.83%. Lets look some facts about solar energy. The energy the Sun sends toward our planet is about 20,000 times the energy used worldwide and it is about 1,000 W/m2 or in other words the power that shines on Earth from the sun is virtually limitless. The total energy (power) used by humans in entire years is less than the solar energy that comes (strikes) our planet every year [Solar is the Solution]. In addition, solar energy is pollution free, there is no global warming effect and dependence on foreign oil powers, effectively there is an infinite supply and because it is decentralized, therefore it is virtually terrorist proof. Moreover, there is news that solar power could soon be in use by the Pentagon as a low-cost, high-efficiency source of energy for an experimental airship. The U.S. Army is already using photovoltaic panels to harvest solar energy to power portable electronics [Tuttle 2006]. Below are some current developments of solar power worldwide. Developed countries could be generating more electricity from sunlight than from nuclear power within the next 20 years. Germany is capable of increasing its solar-cell power output from less than a Gigawatt at the moment to 12 Gigawatts by 2012. Japan is planning to expand its output from 1.1 Gigawatt in 2004 to 100 Gigawatts by 2030. UK could replace its 12 Gigawatts of nuclear power with solar power by 2023. The US solar contribution meanwhile could expand well beyond 28 Gigawatts by 2020. (Source: Hot claims for solar power, New Scientist) From above facts if we look forward and think of future than solar power is going to be part of that solution. There are some problems also associated with solar power. The electricity produced by solar power is still costly and is 10 times of fossil fuels, despite decades of improvements. But current developments from a new finds shows that nanometer-sized particles can generate electrical charges from sunlight more efficiently than any semiconductor tested before. If the lead-based particles work inside solar cells as well as they do in the lab, they could boost the solar conversion efficiency from a best of about 32% today to perhaps as much as 66%. This will be enough to slash the cost of solar power. [Service 2005] Different types of technologies exists, which uses solar power, and some of them are solar design in architecture, solar heating systems, solar cooking, solar lighting, Photovoltaic, Solar thermal electric power plants, solar pond and power towers. The basic equipments that are used for generation of solar power are solar panels, charge controller, battery and an inverter. Some of the uses of solar power/energy are discussed below: Solar heating systems: These days’ solar water heaters are used for the heating water by using the sunlight. Solar water heaters are used to heat domestic hot water, to heat swimming pools and for space heating. Solar water heater is composed of solar thermal collectors, a storage tank and a circulation loop. Solar water heaters are basically classified in three ways; batch systems, active systems and passive systems. Batch systems consist of a tank that is directly heated by sunlight and these are the oldest and simplest solar water heater designs. Active systems pumps to circulate water or a heat transfer fluid. Passive systems, which are also called as thermosiphon systems, circulate water or a heat transfer fluid by natural circulation. [Wikipedia] Figure 2: Solar Water Heaters for Rooftop2 Solar cooking: The use of solar power for cooking is used now in many places throughout the world. Basically these are useful in cases where other source of energy is not frequently available for cooking. A solar cooker traps the suns energy in an insulated box. These boxes are successfully used for cooking, pasteurization and fruit canning. Solar cooking is helping many developing countries these days by reducing the demands for local firewood and maintaining a cleaner breathing environment for the cooks. [Wikipedia] Figure 3: Solar Cooker3 Photovoltaics: Solar cells, which are also called as photovoltaic cell, are devices (bank of devices) that use the photovoltaic effect of semiconductors to generate electricity directly from sunlight. These are used most frequently in various types of low power devices such as the calculators having LCDs. Their use has been limited, until recently because of high manufacturing costs. Now these days they are used in various types of remote applications such as roadside emergency telephones, remote sensing, road lights, cathodic protection of pipe lines, and home power applications. This is the technology that is used as power source for orbiting satellites around the earth and for spacecrafts. [Wikipedia] Figure 4: Solar Panel4 Figure 5 shows the simple a Photovoltaics System in which solar panels, batteries, and inverter are used for the generation of electricity that can be used for home appliances. Figure 5: Photovoltaics System5 Benefits of Solar Power: The several benefits that solar power provides are: The solar power is free, abundant, inexhaustible and cleanest. Gives independence from utility companies and protect against rising utility rates. Cheaper than utility power and dependable. Improves electricity reliability and addresses peak power demands. Better for the environment as generating electricity from solar energy means less consumption of fossil fuels, reducing pollution and greenhouse gas emission Good return on investment (ROI), long term (25 to 40 years) reliability and low maintenance costs Economic growth and job creation, Diversity of fuel supply and rapid deployment Wind and solar power work particularly well together and when properly combined, wind and solar facilities are more reliable than conventional power stations. In addition, if solar cells are integrated into buildings saves the cost of roofing materials and provide power that can fulfill the need of residents of it. In developed countries, too it is the cheapest ways to get electricity to the people who have no access to power lines. [Lovins 2005] References: Lovins, Amory B. 2005. More Profit with Less Carbon. Article, Scientific American; September 2005, Vol. 293 Issue 3, p74-83. Solar is the Solution. Article, Mother Earth News; Aug/Sep2006 Issue 217, p4-4. Tuttle, Rich 2006. Sun Power. Article, Aviation Week & Space Technology; 5/22/2006, Vol. 164 Issue 21, Special section p12-12 Hot claims for solar power. Article, New Scientist; 3/4/2006, Vol. 189 Issue 2541, p29-29. Service, Robert F. 2005. Savings on the Sun. Article, Science Now; 5/31/2005, p4-5. Solar power, April 21, 2007, retrieved on 21 April 2007 from http://en.wikipedia.org/wiki/Solar_power Renewable energy, April 21, 2007, retrieved on 21 April 2007 from http://en.wikipedia.org/wiki/Renewable_energy Read More