Solar renewable energy - Research Paper Example

 Solar Renewable Energy Introduction The energy that comes from sources which are continually replenished such as geothermal heat, sunlight, tides, wind, water and waves is widely known as renewable energy. We can also define renewable energy to be the energy that comes from the natural and persistent flow of energy found in the immediate environment. This energy source contributes to about 16% of the world’s final energy consumed, with 10% from traditional biomass, is used mainly for heating and 3.4% is mainly from hydroelectricity. Another 3% is accounted for by new renewable which are rapidly growing including modern biomass, wind, solar, geothermal, bio-fuels and small hydroelectricity[Joh10]. Electricity generation contributes around 19% of the share of renewable out of which hydroelectricity contributes 16% and the remaining 3% comes from new renewable. Solar energy is the energy that comes from the sun in the solar radiation form which is used in heating or generation of electricity. To generate electricity using solar powered electricity generation system, one requires using photovoltaic or heat engines known as concentrated solar power. Some of the most common solar applications include solar cooling using solar architecture, lighting, heating of the space, solar cooking, high temperature industrial process heating and solar water heating application among others. There exists a broader solar technology classification into active and passive solar which depends on how they are captured. The practice that uses photovoltaic panels and thermal collectors to harness the solar energy is referred to as active technique while the technique that orientates the building to the sun, selects materials that possess good thermal mass or favorable light dispersing properties and design light pathways that circulates air naturally, is known as a passive technique. By the year 2100, the world population will be in excess of twelve billion people. This will push subsequently push the world’s energy requirement to be five times the current demand if the technological progress and innovation keep up with its current trend. If the current rate with which we utilize coal, gas and oil continues, the global temperature will increase by two degrees Celsius by 2020. This will cause adverse effects such as increased flooding in the lowland areas, desertification and climate change all over the world. While it is known for a fact that renewable energy contributes to only 11% of our primary energy consumption in the world today, and we really want to do something to save our planet, then this renewable energy must form part of our daily energy consumption. We are highly expecting that by 2070, 60% of our energy will come from renewable energy. We need to employ the attitude that today is better than tomorrow and the sooner we do that, the better to raise this figure by 20% so as to reach 80% by2070. According to one of the World Renewable Energy Network (WREN) journals, several bodies including the World Solar Summit, the World Bank and the World Solar Decade have come up in support of the projects dealing with the renewable energy and the environment conservation which can be seen by their recent over four billion dollar allocations towards the same. This can clearly show how important renewable energy is viewed from the face of the world as the new source of power for the future. This research therefore tries to discover the merits and demerits of the renewable energy and especially solar energy, the fundamental principles of renewable energy, how we try to apply science and technology in our efforts to conserve the environment as well as how we can carry out solar water heating in our efforts to go to renewable energy. Solar renewable energy (Fundamental principles of renewable energy) From the definitions of renewable and non-renewable energies, the fundamental differences can be pinpointed. Consequently, there must be a correct application of certain principles for efficient use of renewable energy. Such principles are as discussed below: a) Energy currents: Sufficient renewable current is said to be already present in the local environment as this is essential. Attempt to create this energy current for a particular system is not a good practice. It should be obvious for example that solar energy production should only be contemplated on already existing solar radiations and not the creation of the solar radiation. Likewise, for a solar energy production station, the sunlight radiations should exist locally in order to avoid the large inefficiencies which could be brought about by unpredictability or inadequacy of the sunlight radiation. Therefore, from this principle, we can derive a practical implication that we need to highly monitor and analyze the local environment over a long period of time in order to precisely establish the energy flows present. b) Dynamic characteristics End- use for non-renewable energy requirement most of the time tend to vary with time. For example, demand for electricity often reaches its peak in the mornings and evenings and its minimum in the night when most of the activities are dormant. Consider a finite power supply source such as oil, its input will require to be adjusted to meet the demand. However, in the case of renewable energy systems, their end use varies uncontrollably with time just as their natural environmental supply also varies. The precise dynamic behavior may be greatly affected by certain irregularities. Solar energy in this principle becomes more predictable in certain regions such as Khartoum and very unpredictable in others such as Glasgow. c) Quality of supply The proportion of an energy source that is capable of being converted into mechanical work is what we refer to as quality. For example, when electricity is consumed in an electric motor, more than 95% is converted into mechanical work to perform functions, may be to lift a weight and only small proportions like less than 5% to heat losses hence electricity has a high quality. For solar energy, the photon process includes photosynthesis and photochemistry and photovoltaic conversion. For instance, a single photon solar frequency, through the electricity with high frequency using a matched solar cell, can be transformed into mechanical work. Since matching is made difficult by the broad band of frequencies in the solar spectrum, photon conversion efficiencies of 20-30% when achieved are considered good. d) Dispersed versus centralized energy There tends to exist a pronounced difference between renewable and non-renewable energy supplies in the energy flux density which is evident in the initial transformation. Solar beam irradiance, for instance arrives at 1kWm-2 while finite centralized energy sources arrive at energy flux densities which are orders of magnitude greater. In a nutshell, renewable energy proves to be the most easily produced in dispersed locations but is expensive to concentrate. Thus, the use of renewable sources may favor rural development as compared to urbanization. e) Complex systems There is a great link of the renewable energy to the natural environment such that it is not only academic discipline such as physics or engineering that must be applied to produce this energy. For instance, solar energy makes the use of the naturally occurring earth's surface and other surfaces provided to convert the radiation into mechanical energy. Again, through photosynthesis, a process that utilizes solar energy, plants reproduce and the old waste drop which are again used to make compost manure which is good nutrient cycling and better agriculture yields. f) Situation dependence Since there is a great variation in the ability of the local environment to supply energy and sustainability of the society to accept this energy, it is hard to find any renewable energy source universally applicable. It is necessary to conduct energy surveys for domestic, agriculture and industrial use before one embarks on exploiting this energy system. This will enable one to match particular end use and the renewable energy supply in the locality. This situation makes it practically impossible to make international or national energy plan. You wind that solar energy systems in Southern Italy should be quite different from those in Belgium and for that matter, Northern Italy. Contributions of science and technology to major environmental issues Solar energy as a source of renewable energy technology took off in the 1980’s[Wil10]. There has been a drastic increase in its use and reduction in cost. In operation, photovoltaic has proved to be environmentally friendly where no emissions and noise to the environment have been experienced. However, some noxious chemicals are involved in their manufacture and there is a great use of energy. The time for a photovoltaic to generate electricity which is equal in energy to the energy used in its manufacture depends on the method of manufacture used and the site insolation. A photovoltaic module will take approximately 3-4 years as payback time for this energy depending on the technology whether it is thin-film or sunnier location[Bla03]. The average life span of a photovoltaic is about 20 years while some will take a little longer than this. Solar water heating Heating of air and water is an obvious use of solar energy. Solar water heaters, which are sometimes referred to as domestic water heaters, utilize the sun's energy to heat either water or a heat transfer-fluid. The already heated water is then stored in a tank similar to the conventional hot water storage tank. In certain systems, there is the use of electric pumps to supply the fluid to the collectors[Mug01]. This is a technology that can be operated in any climatic type though its performance varies partly depending on the amount of sunlight or solar energy available at the site and also on the coldness of the water coming into the particular heating system. In all the climates, it is recommended that one should have a conventional heating system for backup purposes. This goes in order with many building codes which recommend that one has a conventional water heating system as a backup. The solar water heating system consists of collectors, storage tank, and depending on which system one employs, an electric pump. Most of the solar heating systems are equipped with either flat-plate, evacuated or concentrating collectors. The storage tank should be well insulated to minimize or avoid heat loss. Some of the heaters use electric pumps to re-circulate warm water from the storage tanks via the collectors to the exposed tanks to avoid freezing of the exposed tanks when the temperatures of the external environment drop. Active solar water heaters are those that use an electric pump to circulate the heat transfer fluid while the passive solar heating system has no electric pump. Several factors determine the amount of hot water that can be produced by a solar water heater and they include: the amount of sun available at the site, the type and size of the system, the tilt angle and orientation of the collectors and proper installation of the system. On the benefits of the solar water heater, it is economical since it compares favorably with the electric water heaters. On the other hand, economically it does not compare well with the gas water heater. This system offers the largest potential saving of up to 50-85% savings by households annually on utility bills over electric water heating costs[Kar97]. The project payback period varies widely but one would expect a payback of between 3-5 years when the system is well installed and properly designed. After the payback, one can continue to accrue savings from the system for about 15-30 years depending on the system and method of manufacture. This technology has been used widely to cut down on the actual demand. Depending on the circumstances, a country may undergo delayed investment for power generation as well as reduction in import bills for countries that import power. This technology can also mean long-term benefits from it can cushion a country from future fuel shortages and price increases, reducing overdependence on importing petroleum which also emits CO2 which is not environmentally friendly, meaning that you will also be saving on the environment by reducing the causes of global warming. According to Muguti, when one replaces an electric water heater with solar water heater just for 20 years, it represents 50 tons of avoiding carbon dioxide emissions[Mug01]. However, the disadvantages of the system may include high cost of solar water heaters compared to electric geysers, poor past performance and lack of standards, low cost of electricity in certain countries which make solar water heater seem expensive to other users. By use of solar water heater, one avoids the use of fossil fuels which are not environmentally friendly since they involve emission of the ozone gasses which are involved in the degradation as well as causing the greenhouse effect that leads to global warming. How the solar water heater works This system begins with the installation of a module of solar tubes on the roof in a sun-exposed area. Cold water is made to pass through the tubes which are heated by the sun. Once the water is heated, it flows to an insulated cylinder[Gre12]. Alternate systems use glycol which is easier to heat than the glycol heats the water as it passes through the tubes. Most of the solar heating systems are always fitted with an electric powered backup known as a booster, whose function is to kick in and further heat the water, killing any bacteria. The booster also heats the water on cloudy nights when the system does not receive enough sunlight. In certain systems, the storage tanks are fitted inside the room while in others, the tank is fitted outside the room. The main advantage of fitting the tank inside is that there is maximum insulation while the one fitted to the outside enjoys cheaper and easy installation for retro-fitting. How the water gets to the cylinder also differs with the conventional solar water heating system using the conventional principle. In this system, hot water rises to transfer the hot water into the cylinder. It stores the hot water above the module and this does not require mechanics or electricity. We also have pump based systems which use pumps fitted with electricity to transfer the water to the cylinders. Conclusion In summary, it is so evident that renewable energy, also known as green energy has more benefits compared to the drawbacks that may come up. Solar energy, which is readily available in other countries - like the countries close to the Equator experiencing 12 hours of sunshine every day, but which just goes to waste, can be harnessed and be used as a source of energy to replace the use of fossil fuels. Such countries can then do away with many unnecessary spending in importing petroleum and other fossil fuels. They can also reduce dependence on other countries to import fuel. By going green and using solar energy which is relatively cheaper and economical than electrical water heaters, countries can save up to 50-85% of the utility bill annually which can then be transferred to develop other sectors of the economy. Before installing on embarking on installing a solar renewable energy technology, one must carry a survey to find out the sunlight availability at the site and consider the amount available with the purpose for which it is to be used, whether domestic, agricultural or industrial purpose. Solar water heater is another technology which comes like a savior to replace electrical water heaters which emit carbon dioxide and expensive as well. The solar water heater when employed can make us save our environment by avoiding emissions of 50 tons of carbon dioxide in 20 years. The technology can be employed in any climate as long but is more efficient in areas with more daylight hours. Many households and commercial firms are on the high rise in the installation of solar water heater since they have found out that it is cheap and economical and this is the way to go even for institutions that need to warm a lot of water for many people to shower with such as schools and hotels. Ina nutshell, for us to maintain a healthy and friendly environment, avoiding harsh climatic conditions and global warming, we need to encourage the use of renewable energy which is generated using readily available and sometimes not much competitive resources we have like sunshine, tides, waves, wind, livestock byproducts and water for us to work together in saving our mother environment. Let’s go green. References Joh10: , (John & Weir, 2010), Wil10: , (Wiley, 2010), Bla03: , (Blakers, et al., 2003), Mug01: , (Muguti, 2001), Kar97: , (Karekezi & Ranja, 1997), Gre12: , (Greg, 2012), Read More