CONCENTRATING SOLAR POWER, THE PANACEA TO NIGERIA S POWER SUPPLY

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1 CONCENTRATING SOLAR POWER, THE PANACEA TO NIGERIA S POWER SUPPLY Idongesit Archibong, MIEEE MNSE Vice Chair, GOLD Institute of Electrical Electronics Engineers. Nigeria

2 Concentrating Solar Power Concentrating solar power (CSP) offers a utilityscale, firm, dispatchable renewable energy option that can help meet our nation's demand for electricity. CSP plants produce power by first using mirrors to focus sunlight to heat a working fluid. Ultimately, this high-temperature fluid is used to spin a turbine or power an engine that drives a generator. And the final product is electricity.

3 One way to classify concentrating solar power technologies is by how the various systems collect solar energy. The main CSP technology systems are: Linear Concentrator Systems Dish/Engine Systems Power Tower Systems Thermal Storage Solar chimney

4 Dish/Engine Systems The solar concentrator gathers solar energy from sun. The resulting beam of concentrated sunlight is reflected onto a thermal receiver that collects the solar heat. The dish is mounted on a structure that tracks the sun continuously throughout the day to reflect the highest percentage of sunlight possible onto the thermal receiver.

5 Power Conversion Unit Thermal receiver The thermal receiver is the interface between the dish and the engine/generator. It absorbs the concentrated beams of solar energy, converts them to heat, and transfers the heat to the engine/generator. Engine/generator. A thermal receiver can be a bank of tubes with a cooling fluid usually hydrogen or helium that typically is the heat-transfer medium and also the working fluid for an engine. Alternate thermal receivers are heat pipes, where the boiling and condensing of an intermediate fluid transfers the heat to the engine.

6 Power Tower Systems This technology uses numerous large, flat, sun-tracking mirrors, known as heliostats, to focus sunlight onto a receiver at the top of a tower. A heat-transfer fluid heated in the receiver is used to generate steam, which, in turn, is used in a conventional turbine generator to produce electricity. Some power towers use water/steam as the heattransfer fluid

7 Linear Fresnel Reflector Systems Parabolic Trough Systems Flat or slightly curved mirrors mounted on trackers on the ground are configured to reflect sunlight onto a receiver tube fixed in space above these mirrors.

8 Thermal Storage Two-Tank Direct System Two-Tank Indirect System Single-Tank Thermocline System This system stores thermal energy in a solid medium most commonly silica sand located in a single tank. At any time during operation, a portion of the medium is at high temperature and a portion is at low temperature.

9 Advanced Components and Systems Research and Development 1. Mirror Characterization and Testing 2. Advanced Optical Materials 3. Advanced Coatings

10 For example, reduced reflectivity of a solar mirror due to soiling can lead to an 8% 12% drop in performance between cleanings. The issue of soiling and cleaning must be dealt with before CSP plants are deployed on a massive scale in low-water desert environments. There are research works on advanced hard-coats, barriers, anti-soiling coatings, and cleaning characterization and testing. One study involves correlating scratch resistance and water and oxygen permeation rates of advanced hard-coats and barrier coatings with durability of solar mirrors.

11 Mirror Characterization and Testing Low-cost, high-performance, durable advanced optical materials are needed to meet the demands of advanced system designs and achieve the cost and performance goals to commercialize CSP technologies. The overall objective is to develop, validate, and aid the commercialization of advanced reflector systems that can dramatically reduce CSP costs.

12 Testing Standards for CSP Components and Systems CSP standards ensure that unreliable, defective systems are not deployed Reliability testing directly addresses factors that are vital to successfully commercializing CSP products, such as reasonable cost, performance, and durability.

13 Advanced Optical Materials R&D activities include optically characterizing advanced reflector materials, determining the lifetime of solar reflector materials by accelerated and outdoor testing of commercial and experimental materials, and supporting industry and program needs. Improving reliability, reduce installed capital cost of the solar field for parabolic troughs, and improve system reliability for dish and power tower systems.

14 Linear Concentrators Research and Development As part of its research program in concentrating solar power (CSP), the U.S Department of Energy sponsors research and development (R&D) for linear concentrator systems. The goals for linear concentrator R&D specifically, for parabolic troughs are to Improve the performance and lower the cost of parabolic trough collector systems Support the development of next-generation trough fields support the expansion of the U.S. trough industry

15 Thermal Energy Storage Modeling As part of its research program in concentrating solar power (CSP), the U.S Department of Energy (DOE) sponsors research and development (R&D) for thermal storage. The key goals for thermal storage R&D are to: Support industry in developing and deploying advanced heat-transfer fluids and thermal storage systems Develop and characterize advanced heat-transfer fluids and thermal-storage materials and systems to reduce storage costs Update and integrate thermal storage cost and performance models into CSP system models.

16 Advanced Heat-Transfer Fluids R&D Advanced heat-transfer fluids are essential for improving the operation of CSP systems. trough systems have used synthetic heattransfer oils, power towers have demonstrated direct steam generation and molten-salt working fluids, and dish/engine systems have used hydrogen and helium as working fluids. Further research and developments are geared toward developing heat-transfer and storage fluids that provide improved efficiency and lower cost for CSP systems.

17 While there remains a large potential for cost reductions from research and development on all elements of this technology, from global concepts to almost all elements, this potential could only be reached if there is an active marketplace for these technologies and entrepreneurs capable of integrating lessons from experience as well as concepts and materials from laboratories.

18 An active market place could also presumably reduce costs by mass production, economies of scale, reduction of risk premium and risk mitigation costs as the market develops, learning by doing of suppliers of parts and assemblers. In-depth studies suggest that full competitiveness could be reached for trough technology after the installation of 5,000 MW of capacity.

19 According to the International Energy Agency (2003), before 2030 some 4,700 GW of total power capacity is expected to be built worldwide, either as additional capacity or in replacement of existing capacity. The Greenpeace-ESTIA scenario considers that in 2040, CSP plants could total 630 GW.

20 NATIONAL NEEDS AND BENEFITS Solar energy can directly benefit the nation by substantially contributing toward resolving three national problems air quality, energy reliability and security, and economic development. Our nation s economic health and security increasingly depends on reliable, clean, abundant, and affordable energy.

21 Solar energy produces no pollution while harnessing the inexhaustible resource of sunlight. Furthermore, incorporating solar energy can reduce particulate emissions, which have been inextricably linked to adverse health effects, particularly on the elderly and children. Beyond electricity production, solar energy can be integrated into building designs to provide heat and light. Current applications of solar water heating have already lowered energy bills for millions of homes worldwide

22 CHALLENGES AND CONSTRAINTS. Solar technology has made huge technological and cost improvements, but more research and development remains to be done to make it cost-competitive with fossil fuels. Costs can be reduced by increasing demand for this technology worldwide, as well as through improved component design and advanced systems.

23 Advancements in the technology and the use of lowcost thermal storage will allow future concentrating solar power plants to operate for more hours during the day and shift solar power generation to evening hours. Researchers are developing lower cost solar concentrators, high-efficiency engine/generators, and high-performance receivers. The goal is to further develop the technology to increase acceptance of the systems and help the systems penetrate growing domestic and international energy markets.

24 Thank You for your attention?