Innovation in Concentrated Solar Power - Case Study Example

Concentrated Solar Power Introduction The sun is the original source of almost all the energy used on earth. The earth receives staggering amounts of energy from the sun. As much energy falls on the planet each hour as the total human population uses in a whole year. The energy from the sun is in limitless supply, unlike oil or gas. Solar power is a reliable source of energy and prices never fluctuate [1]. The following report will explore the importance of this concentrated solar energy for human use. Covering its initial discovery and development to its practical application in human societies, the report will offer compelling reason why this renewable energy should become more widely adopted throughout the world. The study also focuses on concentrating solar power generation since it is the supreme renewable energy source globally. According to [2], Solar energy technologies are classified into: i) Passive and active; ii) Thermal and photo voltaic; and iii) Concentrating and non-concentrating. Passive solar energy technology simply gathers the energy without changing the light or heat into other forms. It entails maximizing the daylight use or heat through the designs of building. Active solar energy technology on the other hand refers to the collecting of solar energy for storage or conversion for other applications. This can be classified as solar thermal and photovoltaic (PV). The PV technology changes radiant energy in light quanta to electrical energy when light rays falls on a semiconductor material. This then causes electron excitation and powerfully enhancing conductivity [2]. 2. Background In 1767, a Swiss scientist named Horace Benedict created the first solar collector. It was an insulated box covered with three layers of glass to absorb heat energy. His box became widely known as the first solar oven [3]. The next innovation was in 1883. At this time, the first solar cells were introduced. The cells were wrapped with selenium wafers. Then in 1958, solar power was used to power space equipment such as satellites and space station. This was the first commercial use of solar energy [2, 3]. Solar energy technologies have an extensive history. From 1860 to First World War, a series of technologies were invented to produce steam, by capturing heat from the sun to run irrigation pumps and engines [4]. Solar PV cells were developed at Bell Labs in the US in 1954, and they have been useful in space satellites for electricity production as from the late 1950s. The years following the oil shock in the 1970s saw a lot of interest in the improvement as well as commercialization of solar energy technologies. Jumping to 1970, there was major discussion about the efficiency of solar cells and the reduction of costs. Up to that time, the efficiency of solar cells was only about 14 percent and was not comparable to the high cost of producing those cells [5]. In addition, [5] establishes that in 1970, Exxon Corporation designed an efficient solar panel which was less costly to manufacture. This was a major milestone in the history of solar energy. In 1977, the United States government embraced the use of solar energy by launching the Solar Energy Research Institute. Other governments across the world soon followed [5]. Nevertheless, this developing solar energy industry collapsed because of the sharp decrease in oil costs and a lack of constant strategy support. Solar energy markets have recover momentum from early 2000, showing unique growth lately. The entire inaugurated capacity of solar based electricity generation has risen to approximately 40GW by 2010 by nearly insignificant capacity in the 1990s as seen earlier in [1]. Now most recently in 2012, the world has seen enormous investment in utility scale solar power plants with records for the largest plants being frequently broken. As of 2012, the largest solar energy plant was one located in China, with an installed capacity of 200 megawatts [7]. This; however, was recently surpassed by India’s Gujarat Solar Park. A collection of solar farms scattered around the Gujarat region, boasting a combined installed capacity of 650 megawatts. The CSP market initially came up in the early 1980s but declined due to lack of government support in the US. Nevertheless, a current strong revitalization of this market is apparent with 14.5 GW in diverse stages of development in 20 countries as well as 740 MW of additional CSP capacity from 2007 to 2010 as established earlier by [4, 5 and 6]. Whereas most regions globally, for instance, Spain, South Africa, Southwestern United States, Morocco and China, offer appropriate setting for the operation of CSP, market activity is mostly concerted in Spain and South-western United States [8]. This is because they are supported by constructive investment tax credits, policies as well as feed-in tariffs. Presently, a number of projects worldwide are either being constructed, in the planning phases or going through feasibility studies. Thus, the market is anticipated to continue growing at a considerable pace . Solar energy has undergone a remarkable technological shift. Whereas early solar technologies as made up of small-scale photovoltaic (PV) cells, current expertise are represented by solar concentrated power (CSP) as well as large-scale PV systems feeding into electricity networks see [5]. The expenditures of solar energy technologies have decreased considerably over the past 30 years. For instance, the price of high power band solar section has dropped from about $27,000/kW in 1982 to approximately $4,000/kW in 2006. The mounted cost of a PV system fell from $16,000/kW in 1992 to about $6,000/kW in 2008. Hypothetically, solar energy has a resource possibility that by far exceeds the whole world energy demand. In spite of this technological potential and the current expansion of the market, the input of solar energy to the worldwide energy supply mix is slight [8]. 3. Technical Description Solar panels are made of photo-voltaic cells, simply broken down, photo means light and voltaic means the production of electricity. Photo-voltaic technology enables the creation of electricity using light [9].PV cells have at least two layers of semi-conductors, one that is positively charged and one that is negatively charged. When the light shines on the semi-conductor, the electric field across the junction between these two layers causes electricity to flow. According to [9], the greater the intensity of light, the greater the flow of energy. Despite this marvellous feat of engineering, the efficiency of PV cells is not stellar. In 2006 for example, most solar panels only reached efficiency levels of about 12-18 percent as seen in earlier researches [2, 4]. Since the light that hits a solar cell has photons with a wide range of energy, it turns out that some of them will not have enough energy to produce current. They will simply pass through a cell as if they were transparent. Only a certain amount of energy measured in electron volts is required to knock an electron lose [8, 9]. If a photon has more than the required amount of energy, then the extra energy is lost. This accounts for roughly 70 percent of the radiation energy that illustrates the inefficiency in this technology [9]. Traditional PV panels based on crystalline silicon structures such as mono-crystalline and polycrystalline silicone have gradually improved in efficiency over time, reaching efficiencies of about 27 percent. Multi-junction solar cells are solar cells that contain several layers where each layer is tuned to a different wavelength of light, reducing one of the largest inherent sources of losses and thereby increasing efficiency. Currently, the best traditional solar silicones have efficiencies of around 25 percent while lab examples of multi-junction cells demonstrate a performance of 44 percent [7 - 9]. However, this efficiency is gained at the cost of increased complexity and manufacturing price. PV systems are normally used for secluded power networks with or without association to the utility grid. Their aptitude varies from only some Watt to numerous MW. Batteries are applied in minor decentralized supply networks to store the solar energy throughout the night. There are also cases for very big PV systems of up to 1.5 GW each to be constructed in desert regions until 2050. Both large and small scale options have been incorporated in the MED-CSP case, but only grid linked PV has been considered as renewable electricity mix. PV cannot provide any tenable capacity. Backup capacity should be offered by other technologies within the gridiron. Energy from extremely big PV could be kept in pump storage networks [10]. 4. Recent status of solar energy markets and technologies Technologies and resources Solar energy entails energy sources that can be straightforwardly ascribed to the light from the sun or the heat that sunlight produces as established by [1]. There are four types of CSP technologies available on the market currently: Fresnel Mirror, Parabolic Trough, Solar Dish Collector and Power Tower. These technologies focus the light to an explicitly coated absorber pipe. Solar energy heats a liquid that is later used in a heat exchange. Solar radiation is as well concentrated to a central heat absorber by several reflectors on the ground. The concentrating tools, the sun angle and the reflectors positions themselves mechanically. The heat generated inside the collector is later used to produce electricity [9, 10]. 5. Environmental Impact of the Technology According to climate scientist Barry Brook, a major challenge facing humanity is energy. The human population is skyrocketing and by 2050, the United Nations estimates there will be 9 billion people on the planet [8, 9, 10]. Moreover, the energy demands by then would have more than doubled. Therefore, renewable and cheap energy is crucial to meet this growing demand. Solar energy is renewable and clear, unlike coal, oil and gas. It is also sustainable and will allow homeowners to reduce their environment footprint. Moreover, solar energy does not contribute to global warming as it does not contaminate the atmosphere by releasing carbon dioxide or other known harmful pollutants like mercury, sulphur dioxide traditional formed by production of other forms of electricity like coal [11]. Nevertheless, there are a number of negative environmental considerations on the impact of the solar energy adoption. Firstly, utility-scale solar energy farms do require vast areas of land in order to be able to produce the utility-scale levels of energy needed to make it cost effective for energy suppliers or governments as seen earlier in [1, 3]. This means that land use disturbances might be common and include areas designated for wilderness or protected environmental areas. Secondly, there could be impacts to soil and water since construction of solar facilities will require grading of land and potentially altering the land to install PV panel infrastructure [11]. [11] Also asserts that, loss of wildlife habitat and interference with normal ecological patterns could lead to species being affected. 6. Business Applications Nevertheless, there has been a lot of development in the development of this technology. Issues of cost-effectiveness have spurred endless research efforts aimed at developing and fine-tuning new ways at making solar panels [12]. Traditional solar technology is beginning to encounter competition from emerging and rapidly evolving technologies such as thin-film solar and organic cells. The hope is that these new technologies will rapidly increase in efficiency and decrease the cost at the same time. Before discussing the business applications, it is important to understand the size of the market. The US alone uses more than 29 trillion kilowatt hours of energy each year. Unfortunately, only 314 million kilowatt hours of that energy consumption is from solar energy [12]. Put to scale, that is only 0.001$ of all of their energy needs. However, solar energy has the potential to produce 400 trillion kilowatt hours per year. There are a number of usage options available to businesses with respect to solar energy. The first usage option is a standard utility option where governments produce massive PV farms that can produce hundreds of megawatts of electricity and can sell them to residential and commercial customers just like any other energy source [12]. Another usage option is individual person or company owned PV panels placed on personal or business properties. The individual or business is generally responsible for maintenance as established by [3, 6, 8]. The third option is the solar city business model. Solar city would be a company that owns the solar panels and installs it on personal property and sells the customer the energy. In the solar city model, the company handles all maintenance of solar panels [12]. The hoarders of some CSP systems offer shaded regions that could be utilized for purposes e.g. greenhouse parking and chicken farm [13]. Integrated systems using power, shade and desalted water for creating a new environment for agriculture in desert areas could become realistic in the coming days as countermeasure to loss of arable land as well as desertification. This needs more examination of the possibilities as well as restrictions on similar systems [12, 13]. 7. Stages of the Technology Given that the sun is so rich in energy, there are two main reasons why it is not being adopted more widely by societies. The first reason is cost. Solar energy is about twice as more expensive to produce than coal and about 50 percent more expensive than natural gas [9]. In 2007, it was $0.38 per kilowatt hour to produce and in 2010, it dropped to just $0.08. The other reason is solar intermittency. It is difficult to store and discharge energy needs during non-daylight hours. Also, if the sun is not shining, the panels are not harvesting solar energy [9]. Nevertheless, there is some optimism in the future of solar energy adoption. It has become lost costly to produce solar energy over time. Moreover, many areas across the world have tremendous potential for concentrated solar energy [13]. In fact; Seville, Spain will become the first country in which electricity generated by sunshine will costs the same as electricity by fossil fuels. The Spanish are following Germany’s example who are also introducing legislation that will make it possible to supply clean electricity to the grid. Moreover, electricity utility companies have also realized that the sun is a new fuel [13].One company is experimenting with large mirror power plants. The power plants currently under construction should provide 300 megawatts, which is enough for a town the size of Seville. Mirrors measuring a 120 square meters each reflect sun onto just one point on a massive tower [13]. This results in high temperatures which are used to drive steam turbines to generate electricity. At this moment, these technologies are being developed in countries that believe in the economics of these types of projects. The Spanish are looking beyond their own borders and are involved in the construction of large solar power plants in Morocco and Algeria [13]. Nevertheless, power plants that concentrate sunshine are not new. In the Mojave Desert in the US, there are two big solar power plants where parabolic mirrors are used to produce steam and generate electricity. The plant in the desert was built more than 20 years and experience has shown that this is an extremely efficient concept. This plant is evidence that solar energy is reliable, dependable and absolutely ready for further expansion into other territories [11, 12] 8. Concentrating Solar Power Technologies Concentrating solar power technologies (CSP), bases on the idea of concen­trating solar rays for electricity production within conservative power cycles by use of steam/gas turbines and Stirling engines [6]. For concentration, many systems utilize glass mirrors that incessantly follow sun’s position. Specially designed receiver absorbs concen­trated sunbeam to decrease heat losses as per [4, 5]. A liquid flowing via the receiver carries away the heat towards the power sequence, where high pressure and temperature steam is produced to drive a turbine. Air, oil, water, as well as mol­ten salt, acts as heat transfer liquids. As seen earlier in [9], Power towers, parabolic troughs as well as linear Fresnel systems can be joined to vapor cycles of electric capacity of 5 to 200 MW, with thermal cycle of 30 – 40 % efficiencies. Dish-Stirling engines are utilized in decentralizing production generation in the 10 kW array. The general solar-electric efficiencies comprise of the change of solar energy to heat energy within the collector and the changing of the heat energy to electricity in the power block. The exchange efficiency of the power block is similar to fuel fired power plants. Power towers can attain extremely high operating temperatures of above 1000 °C, enabling them to generate hot air for gas turbine work [7, 9]. Gas turbines can also be used in joint cycles, resulting in very high conversion efficiencies of more than 50% of the thermal cycle. All of these technologies can work with fossil fuel and solar energy [4]. This hybrid system has the power to raise the value of CSP technology by raising its power accessibility and lowering its price by making more efficient use of the power block. Solar heat gathered during the day can be stored in molten salt, concrete or ceramics. At night, it can be removed from the storage to operate power block [4]. Also, solar energy can co-generate electricity as well as process heat. In this case, the main energy input is operated using efficiencies of approximately 85 %. Many applica­tions are used in the combined generation of industrial heat, sea water desalina­tion and district cooling [6]. Every concept has the perception of expanding their period of solar operation to base load by use of thermal energy stores as well as bigger collector fields. To produce one Megawatt-hour of solar electricity annually, a land of only 4 to 12 m² is needed [4]. These indicate that one km2 of dry land can constantly and forever produce as much electricity as any conservative 50 MW coal. Therefore, two major characteristics that make concentrating solar power a main technology in a prospect renewable energy supply are; it can offer secured power as needed by demand; its natural resource is incredibly abundant and virtually unlimited [8]. Their thermal storage ability and hybrid function with fuels permit CSP plants to generate power when needed. Their capacity credit and availability are thought to be 90 %. 9. The economics of solar energy There is an extensive array of solar energy technologies competing for diverse energy markets, particularly central power supply, grid-connected disseminated power production and off-grid applications [14]. For example, extensive PV as well as CSP technologies competes with technologies in search of serving the centralized gridiron. Alternatively, small-scale solar energy networks, which comprise dispersed energy resource networks, compete with several other technologies like off-grid wind power and diesel generation sets [14]. 10. Future Outlook As costs continue to drop in the production of solar energy, there is an anticipation of market penetration across much of the developed world, but primarily in the US. The solar city business model will grow in residential areas as costs go down, especially in states where energy costs are high and there is great potential for solar energy [8]. As solar energy becomes less expensive, there is an expectation of increased competition amongst energy suppliers. General Electric and other companies are exploring solar energy potential. As costs decrease, there will be more suppliers and increased competition [14]. Moreover,[14] asserts that the number of companies will consolidate and a few key players will emerge. Although at this time a dominant design has not emerged, there is an expectation that due to competition, a dominant design for panels will occur at some point in the future. In fact, there is a tremendous opportunity for solar energy through global adoption. If solar panels were to cover only 4 percent of the world’s desert areas with existing PV panels, this farm would supply enough energy to quench the world’s electricity needs. The sunlight hitting the Gobi desert alone would supply all the energy for the world’s demands [14]. 11. Prospects of CSP Research and Development A European industrial conglomerate has come up with the new parabolic trough collector SKAL-ET, which aspires to attain better performance as well as cost by recuperating the mechanical structure, the thermal and optical characteristics of the parabolic troughs. Another European Association has developed a simpler trough collector model with parted level mirrors according to the rule of Fresnel [8]. The high temperatures existing in solar towers can be used to impel steam cycles, gas turbines as well as joint cycle systems. Such operations promise approximately 35 % peak and 25 % yearly solar-electric effectiveness when attached to a joint cycle power plant [7, 8]. A solar receiver was invented within the European SOLGATE scheme for heating air on pressure by putting the volumetric absorber into a pressure container with a parabolic quartz window for solar energy incidence [3, 6]. Multi-tower solar assortments may be organized in the future in a way that the heliostat reflectors can point to a variety of tower receivers. Similar to other Fresnel systems, the straight, organized heliostats nearly totally cover the land region and form a clear, semi-shaded area below for farming or other purposes [14]. 12. Barriers to concentrated solar power There are some barriers that hamper the employment of solar energy technologies for generating electricity, as well as thermal reasons [8]. These barriers can be categorized as technical, institutional and economic. Technical barriers differ depending on technology type. For instance, in the case of PV, the major technical barriers are PV low conversion efficiencies modules; performance boundaries of system elements like inverters and batteries; and insufficient provision of raw materials like silicon [6]. Stand-alone PV systems have a storage issue, having a shorter battery life than that of the module. Additionally, secure dumping of batteries is difficult without a structured disposal process. Regarding solar thermal applications, we have two major technical barriers. They are limits to heat loss from storage systems and limitations in the heat carrying ability of the heat transfer liquids [2 -5]. Additionally, there are constraints regarding the system design and incorporation as well as working experience for solar system optimization. For instance, lack of incorporation of typical construction materials, codes, designs and standards make extensive utilization of solar space, as well as water heating tools, difficult [10]. In the case of CSP, technologies like the molten salt-in-tube receiver as well as the volumetric air receiver, both having energy storage networks need more skills to be proposed for large-scale utilization. In addition, solar energy has to function and compete in regards to energy network planned around conservative energy technologies [14]. The economic barriers are majorly concerns primary system costs. Financial institutions regard solar energy technologies to have strangely lofty risks while evaluating their creditworthiness [10]. This is because solar energy schemes have a brief history, long payback periods and little revenue stream. This entails elevated financial charges such as, interest rates to solar energy schemes. Apart from technical and economic constraints, PV, and concentrated solar thermal technologies experiences institutional barriers that reveal the innovation of the technologies noticeably [7]. This ranges from inadequate capacities for labour force training to systems for planning as well as coordinating policies and fiscal incentives. Insufficient numbers of satisfactorily trained individuals to prepare, establish and preserve solar energy systems is also a common barrier. 8. Conclusion In conclusion, there is an amazing potential for concentrated solar power. It is currently the most sustainable form of energy and it is the source of all other energies and will remain so until the sun burns out. The costs for solar energy will continue to decrease and in order for widespread adoption, solar technology will have to outpace other low-cost energy alternatives. That being said, if societies can truly harness the power of the sun, the world will truly become energy independent. References [1]. G. N. Tiwari, Solar energy technology advances. New York: Nova Science Publishers, 2006. [2.] D. Barlev, R. Vidu, and P. Stroeve, “Innovation in concentrated solar power”. Solar Energy Materials and Solar Cells, 2011, 95(10), 2703-2725. [3]. M. Boxwell, Solar electricity handbook: A simple practical guide to solar energy : how to design and install photovoltaic solar electric systems. Ryton on Dunsmore, Warwickshire, U.K: Greenstream Publishing, 2012. [4]. A. Evans, V. Strezov, and T. J. Evans, “Assessment of sustainability indicators for renewable energy technologies”. Renewable and sustainable energy reviews, 13(5), pp.1082-1088, 2009. [5]. R. Everett, G. Boyle, S. Peake and J. Ramage, Energy Systems and Sustainability: Power for a Sustainable Future. Oxford: Oxford Univerity Press, 2012. [6] V. Fthenakis, Sustainability of photovoltaics: “The case for thin-film solar cells”. Renewable and Sustainable Energy Reviews, 13(9), 2746-2750, 2009. [7]. H. P. Garg and J. Prakash, Solar energy: Fundamentals and applications. New Delhi: Tata McGraw-Hill, 2000. [8]. D. A. Lubin and D. C. Esty, “The sustainability imperative”. harvard business review, 88(5), pp.42-50, 2010. [9]. R. C. Neville, Solar energy conversion: The solar cell. Amsterdam: Elsevier, 1995. [10]. A. H. Slocum, D. S. Codd, J. Buongiorno, C. Forsberg, T. McKrell, J. C. Nave and A. Mitsos, “Concentrated solar power on demand”. Solar Energy,85(7), pp.1519-1529, 2011. [11]. S. P. Sukhatme, and J. K. Nayak, Solar energy: Principles of thermal collection and storage. New Delhi: Tata McGraw-Hill, 2008. [12]. P. Viebahn, Y. Lechon and F. Trieb, The potential role of concentrated solar power (CSP) in Africa and Europe—a dynamic assessment of technology development, cost development and life cycle inventories until 2050. Energy Policy, 39(8), pp.4420-4430, 2011. [13]. N. Armaroli and V. Balzani, Energy for a sustainable world. Weinheim: Wiley-VCH.2011. [14]. R. Wiser, G. Barbose, and E. Holt, Supporting solar power in renewables portfolio standards: Experience from the United States. Energy Policy, 39(7), pp.3894-3905, 2011. Read More