Renewable Energy Sources - Report Example

Name: Instructor: Course: Date: Renewable Energy Sources Energy is vital for almost every human activity, but it presents one of the greatest challenges as individuals seek more sustainable methods of delivering goods and services to the society. For the energy to be sustainable, it has to be environmental friendly, safe to use, meet all the energy demands today and in the future. Renewable energy (RE) source has all these attributes; hence, it is a sustainable source of energy. Renewable or nonconventional energy sources are derived from natural sources, and they are replenished over a short period. They include sun, wind, moving water, geothermal, biomass or waste material, and organic plant. They are used to generate electricity among other applications. For instance, solar energy can be used to heat water or passive heating biomass as boiler fuel to generate heat and landfill methane gas for heating (Tiwari and Mishra 7). Renewable energy sources have enormous potential because they can satisfy the energy demand of the entire world. Biomass, wind, hydropower, and geothermal can offer workable energy services, established on the use of consistently available, indigenous resources. Today, many nations are shifting towards renewables because their costs are declining whereas the price of oil and gas continue to increase. For the past four decades, the sales of wind power systems rapidly increased thereby reducing capital costs and costs of generating electricity and hence enhancing their performance attribute. In reality, non-renewable and renewable energy prices, and social and environmental costs are heading in parallel directions. Furthermore, the economic and policy mechanisms required to backup the extensive awareness and sustainable markets for renewable energy systems are growing rapidly (Herzog, Lipman and Kammen 8). Today, scientists are encouraging the use of renewable sources of energy with greater zeal than earlier decades in order to prevent global warming. This presupposes that renewable energy sources are clean and benign, unlike the conventional energy sources. They offer a number of social, environmental, and economic benefits (Abbasi 243). Globally, more than eighty-five percent of all energy use is currently from fossil-based fuels. Hydropower is the leading renewable energy resource, and in the U.S, in several decades, it has been fully advanced. On the other hand, others renewable sources are experiencing fast development, but from a minute base and with upper limits on capabilities near that of hydropower. Although fossil resources are abundantly available, and will continue to be the most treasured and convenient energy resources, they have depleting effects hence the future development of net energy supply is progressively questionable (Kreith and Krumdiek 81). On the other hand, with the growing trend of renewable energy today, it is apparent that the future growth of the energy sector will be chiefly on the new regime of renewable energy and to some extent, on the natural-gas-based systems, which do not depend on in fossil oil and coal sources. The developments have given rise to new market opportunities to allow innovation and gaining in a bid to encourage renewable energy technologies, with the additional support of governmental and media sentiment. The advancement and use of renewable energy sources can improve diversity in energy supply markets. In addition, it contributes to safeguarding long-term justifiable energy supplies, assist in minimizing local and global environmental emissions, and offer commercially pretty choices to meet particular energy service needs, particularly in developing nations and rural areas where it helps in creating job opportunities (Herzog, Lipman and Kammen 8). This paper explores different renewable energy sources, their challenges, and advantages. Additionally, an analysis is given on whether one can control the future market. Wind Energy Wind energy is the most promising renewable source of energy. It is highly anticipated to take a larger share in power generation in the coming years. It has shown remarkable growth all over the globe for the past few decades. It has been one of the primary sources of energy for transporting goods, pumping, and milling grain for several eras. The key technical parameter shaping the economical outcome of a wind turbine system is its annual energy output, which is determined by the parameters like average wind speed, statistical wind speed distribution, distribution of occurring wind directions, turbulence intensities, and roughness of the surrounding environment (Herzog, Lipman and Kammen 28). Wind energy is derived from moving air through the help of atmospheric pressure wherein wind flows from higher pressure to lower pressure regions (fig.). The larger the gradient of atmospheric pressure, the higher the wind speed. Consequently, the wind turbines capture larger wind energy. Recently, wind turbines have been installed at an amazing rate. For instance, 2009 broke the record because annual installation globally was 37GW bringing the global wind capacity to 158GW. Challenges From the control point of view, wind energy conversion systems are very challenging. Wind turbines present non-linear and non-minimum phase subtleties and are visible to large cyclical movements that may stimulate the poorly damped atmospheres modes of drive trains and towers. Moreover, the mathematical models used to define their dynamic behavior accurately are hard to access because of the specific operating conditions. They absence of models that are accurate must be counteracted by vigorous control strategies that have the capacity to secure steadiness and some features in spite model uncertainties. The control challenges are even more complex when the turbines operate at variable speed and pitch; however, the best use can be achieved using multivariable controllers (Bianchi, Battista, and Mantz 1). The other challenge of wind power involves sitting turbines because in heavily populated nations where the best sites on land are occupied, the public increasingly resist, making it difficult to realize the projects at suitable costs. For instance, in countries like Denmark and Netherlands, the turbines are concentrated on offshore projects; notwithstanding the fact that technically and economically they are anticipated to be less promising than land sites that are good. Nevertheless, in nations such as the United Kingdom and Sweden, offshore projects are strategic, not because they lack good land sites, but they are conserving the landscape for national value. In addition, the best wind site locations are not close; people with the large energy demands, for instance the U.S make such sites unrealistic because of high transmission costs due to long distances. Although wind energy is regarded as environmentally sound, it has some negative aspects, which include emission of acoustic noise, visual impact on the landscape, affecting bird’s life, rotor causing shadows, and electromagnetic meddling affecting the response of radio, TV, and radar signals. On the other hand, wind energy has some benefits, which include environment friendly and cost competitive, easily expandable, the failure of one turbine does not affect distribution, can repay it installation cost in few months, and does not produce carbon dioxide during normal operations. In addition, small environmental friendly and economic turbines are being developed in rural areas due to new technology (Herzog, Lipman, and Kammen 28). Geothermal Energy Geothermal energy is another plentiful energy resource that has been used magnificently over the past few years in different parts of the world to cater for both commercial and domestic energy needs. Geothermal energy utilizes earth’s internal heat. It is generated from beneath the earth, clean, and renewable. The magma contained in the earth produce heat continuously. The temperatures hikes about three degrees centigrade for every one hundred meters; hence, it is dug below the ground. If the earth is dug below (fig.) ten thousand meters, that heat is used to boil water since the temperatures are too high. Water finds it way, deep inside the rock, where it is boiled by the hot rock. Then, the geothermal heat pumps capture the steam produced by the boiling water. The steam turns the turbines, thereby starting generators (Gupta and Roy 9-10). In reality, in thousand years, many have profited from hot springs and steam vents, by using them for bathing, cooking, and heating. Currently, technological development have made it possible and commercial to locate and drill into hydrothermal reservoirs, pipe the steam or hot water to the surface, and the heat is used directly or converted into electricity (Herzog, Lipman, and Kammen 42). Geothermal energy is available in enormous amounts, although it is unevenly distributed, seldom concentrated, and regularly at the depth too great to be exploited for commercial and industrial use. Geothermal energy harnessing involves five phases, which are surface exploration, first phase exploration drilling, second phase surface exploration, second phase exploration drilling and appraisal and operational phase. Geothermal energy harnessing is different from other renewable sources because the resource is not directly available for measurements or assessment (Arrson 5). Challenges Geothermal energy has various environmental effects, and EIA is only probable after drilling a number of wells, but even then, the level of uncertainties regarding some of the items that require to be addressed in the EIS is large. The geothermal fluids enclose variable concentration of gases, such as nitrogen and carbon dioxide with some hydrogen sulphide and minor portions of ammonia, mercury, radon, and boron. Most of these chemicals are concentrated, hence difficulty in the discarding water, which is typically reinserted back into the drill holes so that there is little release into the environment. Nevertheless, present technologies can manage the environmental effect of geothermal energy development; it is regarded a relatively clean source of energy. Another challenge is that, the process of harnessing geothermal power is more complex than other renewable sources. Nevertheless, it gives an opportunity and a requirement for streamlining (Herzog, Lipman, and Kammen 42). On the other hand, geothermal fields are used for other purposes such as tourism attractions and reducing the reliance on fossil fuel. Moreover, it is cost effective because no fuel is required to harvest the energy. Hydropower Hydropower is the leading source of renewable energy in the electricity sector. In 2008, it contributed to 16 percent of global electricity supply. It continues to be the most effective method of generating electricity because today, modern hydro turbines can convert 90 percent of the obtainable energy into electricity, whereas the best fossil fuel plants are just 50 percent efficient. For instance, in the U.S., hydropower is generated for a 41average of 0.7 cents/kWh, which is the third of the cost of using fossil fuel (Herzog, Lipman and Kammen 40). Hydro energy is produced from moving water through solar radiation in the hydrological cycle. Solar radiation is absorbed at the land or sea surface heating the earth and creating evaporation in water areas. A greater percentage of about fifty percent of all the solar radiation reaching the earth surface is utilized in water evaporation and driving the hydrological cycle. In order to harness energy, moving water must be regulated. A huge reservoir is constructed, normally by damming a river to construct a man-made lake or reservoir. Water is controlled via tunnels inside the dam. The turbines are forced to turn by the water flowing through the tunnels of the dam, thereby making the generators move. The engineer controls the amount of water passing through the dam. The process of controlling flow of water is called the intake system. In case high energy is required, most of the tunnels to the turbines are opened, and when less energy is required, engineers close some of the tunnels. During floods, a spillway is created to assist the intake system. A spillway is a structure that gives water an outlet below the dam, bypassing all tunnels, turbines, and generators. It prevents damage to both the dam and community. The main types of hydropower projects are run-of-river, pumped storage, reservoir based, and in-stream technologies (Kumar and Schei 441). Challenges Even though hydroelectricity is usually regarded as a renewable and clean energy source, it emits some greenhouse gases (GHG). It regularly has noteworthy hostile socio-economic effects. Large-scale dams do not minimize the overall GHG emissions while equated to fossil fuel power plants. Moreover, constructing a dam requires regular flooding of a vast land. Therefore, in densely populated rural areas, most poor and indigenous people are displaced. Mitigating such social effects signifies a noteworthy cost to the project, which if considered prior the project, hinders the project from being economically and socially viable. Other environmental issues include decline in biodiversity and fish populations, sedimentation that can widely minimize dam productivity and harm the river habitat, poor water quality, and the spread of water-related illnesses. For instance, in the U.S., a number of large power production dams are being withdrawn because of their negative impacts on the atmosphere. Addressing all these concerns properly would result in the increase of the overall cost of generating electricity, thereby making it less competitive than it is normally stated. The continuation of large hydro industry requires reconciliation with its poor record of both cost approximation and project execution (Herzog, Lipman and Kammen 41). On the other hand, hydropower energy is clean, renewable, endless, predictable, and manageable. Biomass Energy Biomass energy is produced through the conversion of biological materials and wastes into power that can be used for heating, power generation, and transportation. Biomass refers organic materials, which originate from plant, trees, and crops. It involves gathering and storing sun's energy through photosynthesis. Biomass energy is used for heating, electricity, and liquid fuels. The energy comes from the land as dedicated energy crops or from remains produced in the processing of crops for food or other products like pulp and paper from the furniture industry. In addition, other significant contribution is from post-consumer remains streams like construction and demolition wood (fig. below), municipal solid but clean waste (MSW), and pallets used in transportation. Bioenergy systems can be regarded as the control of flow of solar produced materials, food, and fiber. Nevertheless, not all biomass is directly used to generate energy; it can be converted into intermediary energy transporters called biofuels such as charcoal, ethanol or producer gas, which are produced from biomass gasification (Herzog, Lipman and Kammen 8). Biomass is the oldest form of energy because wood has been the main source of energy. Today, out of 450 EJ of total energy per year, biomass gives 40 to 55 exajoules (EJ = 10,18joules) or equivalent to 10-14 percent of total energy per year. It is the fourth largest source of energy behind oil, which is 33 percent, coal 21 percent, and natural gas 19 percent (Herzog, Lipman, and Kammen 10). Biomass is not mostly considered as a modern energy because of the role that it has played and continues to play, especially in developing countries and poor nations. More than two billion people use biomass to cook through direct combustion; for instance, the use of firewood. In the developed nation, biomass is converted to electricity and process heat in industries. Today, biomass is modernized and converted efficiently and in cost-effective forms such as gas, liquid, and electricity. Modernization has advanced variety of technologies that convert solid biomass into clean, suitable energy carriers, which can be used by households and large industries. Many biomass technologies are available commercially, although others are in their developmental stages. If such technologies are widely supported and implemented, they could enable biomass energy to play a much more vital role in the future than it does today, particularly in developing nations (Herzog, Lipman and Kammen 11). Although biomass is a renewable source, it as well shares many attributes with fossil fuel both positive and negative, but if managed properly, it is not hazardous to the environment. Many technologies of bioenergy conversion give flexibility in choice of feedstock and the way in which it is generated. Challenges Biomass generation is encountering a number of challenges. When used extensively for energy purposes, the extra land for biomass generation becomes scarce by day and as well, water for other uses declines. The high moisture content of fresh biomass makes collection and transport costly. In addition, the extensive use of biomass results in an increase in food price where the biomass was derived (Capareda 2). On the other hand, the information on the requirements and use of biomass energy are lacking. Informational is not accurate all the times. Additionally, there are no standardized methods and accounting methods for biomass. Therefore, it is complex to make comparisons of the existing data (Calle xxi). On the other hand, biomass is easily available and does not create greenhouse gases. It helps in reducing landfills. Biomass crops have environmental benefits, which include carbon sequestration, biodiversity, landscape, and soil balance (Herzog, Lipman and Kammen 21). Can One Resource Control The Future Market Against Others Or It Is A Collective Utilization Of All? Today, the promise of renewable energy has now become a reality. For instance, wind energy and biomass have grown rapidly. Nevertheless, since the security of energy supply is still a major challenge facing both developing and developed nation, it is unlikely that one resource will control the market in the future, but it will be a collective utilization of all. Moreover, each renewable resource has been experiencing its own challenge and others are unevenly distributed, for instance, geothermal and wind. Therefore, it is unlikely that one will dominate the market globally, but the growing trend shows a promise for biomass since it is evenly distributed and has low environmental impacts compared to hydropower. In reality, biomass resources are possibly the largest renewable global energy sources, with an annual principal generation of about 4500 EJ with a 2900 EJ bioenergy, which is about 270 EJ. It is considered obtainable on a workable basis (Herzog, Lipman and Kammen 10). The problem is not in the availability per se, but in a sustainable organization and conversion and distributing to the consumer in the form of latest and cost-effective energy services. Mainly, the biomass used today is either a remain in a bioprocessing factories or firewood’s used in households for daily cooking and heating. If we argue that biomass will become a leading energy supply in the world, then remains will not serve and energy crops may require stocking up to 80 percent of the future feedstock, which is not the case today. In order to mitigate energy security challenges such as the inability of electricity infrastructure systems to satisfy the demand of the locals, instabilities of energy market, technical system failure, and threat of attack on centralized energy generation structures by terrorist and extreme weather conditions, all the resources must be considered. This is because of the increased technological development in the resources, innovation to expand them all and collective utilization. These can improve diversity in energy supply markets, add to securing long-term sustainable energy supplies, and create an impact on the decrease of local and global environmental emission. Although fossil fuels will continue in the fuel mix in the foreseeable future, escalating high petroleum costs, fleeting or not, demonstrates the level of social and political ill that might be generated by renewable energy. Therefore, integration of renewable energy supplies together with technologies can aid in reducing the cyclical nature of fossil fuel markets, and give all renewables a foothold where they can continue to develop and compete. There exist opportunities for innovative integration of renewables into energy generation systems such as integration of intermittent renewable systems and base load conventional systems with matching capacity profiles. Such integrations will deliver continued sales growth for all renewable resources in the near future (Herzog, Lipman, and Kammen 56). Through the utilization of all renewable energy technologies into energy generation systems, together with the support from the government and public sector where necessary, it is possible to offer a path to future reliance on renewable energy systems. The future will be sustainable both in the context of environmental and social than it is today, because today individuals follow more conservative paths based on the dependence on fossil fuel. Works Cited Abbasi, Tanseem, and S A. Abbasi. Renewable Energy Sources: Their Impact on Global Warming and Pollution. New Delhi: PHI, 2011. Print. Bianchi, Fernando D, Battista H. De, and Ricardo J. Mantz. Wind Turbine Control Systems: Principles, Modelling and Gain Scheduling Design. London: Springer, 2007. Print. Capareda, Sergio C. Introduction to Biomass Energy Conversions. 2013. Print. Gupta, Harsh K, Sukanta Roy, and Harsh K. Gupta.Geothermal Energy: An Alternative Resource for the 21st Century. Amsterdam: Elsevier, 2007. Print. Herzog, Antonia V., Timothy E. Lipman, Jennifer L. Edwards, and Daniel M. Kammen. "Renewable Energy: A Viable Choice." Environment (2001): 63. Print. Ingimarsson, J. "Challenges for geothermal energy - experience from Iceland." (2011): 5. Print. 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