Seminar: Statistical Decay of Complex Systems (Nuclei)

W. W. Udo Schröder,2013 ESTS Solar Power 1 Partially Sunny World 2 ESTS Solar Power SolarESTS Need 20 TW world wide harvest sunlight (total insolation 105 TW). Methods: Indirect (thermal) conversion to electricity: concentrated solar power plant (CSP) Passive heating Direct (photon e-,h exciton) conversion to el. :photo-voltaic (PV), amorphous Si, single crystal Si, thin-film, organic W. Udo Schröder, 2013 Free Power: Solar Radiation Solar Constant 2 4 RSE 8 2 Earth area AE 5.1 10 km 2 1 random exposed to Sun disk of area AREE R A directions SE 4 42AR 3 SATR 4 SE RSSSE 2 4 RSE E 2 8 4 RS 2 RSE=1.50∙10 km ST S 2 1.370kW m RSE Time averaged over spinning earth A 4 A E RSE 2 Seffective S4 0.343 kW m Albedo reflectivity,E 0.3 ( expt .) ESTS Solar Power SolarESTS mean power absorbed by Earth' s surface Effect of solar irradiation on Earth surface 2 is non-cumulative thermal equilibrium Seff 1 E S 4 0.240 kW m 퐴푛푔푙푒 표푓 푖푛푐푖푑푒푛푐푒 ≠ 900 푟푒푑푢푐푒푑 푟푎푑 푑푒푛푠푖푡푦 0 ′ 2 푅푂퐶@ 50 푙푎푡푖푡푢푑푒 → 푆 푒푓푓 ≈ 0.170 푘푊 푚 W. Udo Schröder, 2013 Average Daily Insolation 4 August in NY: (2-4)kWh/d·m2 Energy use US-NE: ESTS Solar Power SolarESTS (20-30) kWh/d·pers, twice that in US-SW http://rredc.nrel.gov/solar/old_data/ nsrdb/1961-1990/redbook/atlas/ W. Udo Schröder, 2013 Selective Filter Effect of Atmosphere Adapted from Liou, An Introduction to Atmospheric Intense solar radiation available at wave Radiation, Academic Press, lengths from the UV, over visible to IR. San Diego, 2002. Spectral gaps due to atmospheric absorption. Dispersion by Rayleigh scattering (blue sky) Utilization for electricity production: Solar thermal (CSP) thermal conversion 5 Photo-voltaic (PV) direct electrical Strong absorption conversion. of solar radiation in IR by atmosphere Important: collectors’ orientation toward Sun Log scale ESTS Solar Power SolarESTS Apparent orbits of Sun on sky require different tilt of sensors for best efficiency e. Can vary by De = ±15%. Concentrated Solar Power= CSP “Receivers” collect and focus sunlight, Tracking for q, f) best efficiency. Adapted from G. Boyle et al., Renewable energy, OUP W. Udo Schröder, 2013 CSP Plants World Wide Project Country Power Work Fluid Storage Commission (Mwe) _____________________________________________________________ 6 Liquid Sodium Sodium Steam Nitrate Salt/Water Steam Nitrate Salt/Water Steam Oil/Rock Steam Nitrate Salt Nitrate Salt Nitrate Salt Hitech Salt Hitech Salt Steam Steam, Water Air Ceramics Nitrate Salt Nitrate Salt Steam, sat. Steam ESTS Solar Power SolarESTS Air Ceramics Steam, sat. Steam, Water Nitrate Salt Nitrate Salt W. Udo Schröder, 2013 Line-Focus CSP Collectors 7 Steam Line Tracking Mirrors Line Focus ESTS Solar Power SolarESTS DT = 500- 4000C Typically, collector fluid=oil, produces superheated steam in a heat exchanger Currently largest trough systems generate 80 MWe. Overnight heat storage in molten salt (K/Na nitrate) storage tanks (remains liquid in large T range, large heat capacity) After DOE Energy Efficiency and Renewable Energies. W. Udo Schröder, 2013 Line-Focus CSP Collector Receiver Tube (oil) 8 “Solar One” Mojave Desert 1982-1988 Planned: 9 power plants in Mojave Desert (3 sites), total ESTS Solar Power SolarESTS 6 2 354 MWe, 2·10 m collector area. Efficiencies e = 0.16-0.18 W. Udo Schröder, 2013 Solar Tower Power Plant 9 Tracking Heliostats ESTS Solar Power SolarESTS 1982-1988: “Solar One”, 10-MW plant (Barstow/CA). 1996-1999: “Solar Two”, 10-MW, molten nitrate salt as primary medium. Spain: several operational thermal (water/steam) tower plants, 11-20 MW W. Udo Schröder, 2013 Heliostat Tracking Mirrors 10 ESTS Solar Power SolarESTS The Solar One “proof of principle” project produced 10 MW of electricity. Used 1,818 heliostat tracking mirrors, each covered area of 40 m² (430 ft²). Total area = 72,650 m² (782,000 ft²). W. Udo Schröder, 2013 Crescent Dunes Solar Energy Project The US Department of Energy invested $737 million into the Crescent Dunes Solar Energy Project in Nevada. Can generate power into the 11 night by using molten salt as energy storage medium. ≈ 20,000 heliostats focus sunlight onto receiver and heat working fluid (K/Na Nitrate salt) to 5660C. Salt retains its thermal energy for a relatively long time. Mixed with water produces steam to drive turbines and electric generator. ESTS Solar Power SolarESTS e ≈ (10-15)% predicted. W. Udo Schröder, 2013 Distributed Energy Storage Techniques Mechanical energy storage Gravitational, pumped hydropower, compressed-air, flywheels 12 Electrical/Electrochemical storage Super capacitors, supercon magnets Batteries: Lead-acid, Ni-Cd, Li-ion, redox- flow/fuel cells Chemical energy storage Water dissociation hydrogen ESTS Solar Power SolarESTS Thermal energy storage Change in internal heat energy (“sensible heat”), Phase change (transition) latent heat molten salt storage, thermo-chemical heat W. Udo Schröder, 2013 Survey: Electricity Storage Technologies 13 Energy: Science Technology & Society http://redmountaininsights.com/Utility-Energy-Storage-Market-Guide-I3550?ref=cc W. Udo Schröder, 2012 Thermal Energy Storage Materials Physical properties (i) Favorable phase equilibrium. (ii) High density. (iii) Small volume change. (iv) Low vapor pressure. 14 Kinetic properties (i) No supercooling. (ii) Sufficient crystallization rate. Chemical properties (i) Long-term chemical stability. (ii) Compatibility construction materials (iii) No toxicity. Thermal properties (iv) No fire hazard. (i) Suitable phase-transition temperature. ESTS Solar Power SolarESTS (ii) High latent heat of transition. Economics (iii) Good heat transfer. (i) Abundant. (ii) Available. (iii) Cost effective. Recent review of PCM storage materials: A. Sharma et al., Renewable and Sustainable Energy Reviews 13 (2009) 318– 345 W. Udo Schröder, 2013 Heat Transfer/Thermal Storage Materials For design of large production facilities, accurate physical and thermodynamic properties of must be known. Required data: 15 a) melting point; b) viscosity; c) apparent heat of fusion; d) thermal conductivity; e) heat capacity; f) density; g) volumetric expansion; h) vapor pressure. ESTS Solar Power SolarESTS “Designer materials” for heat transfer: mixtures of Water: cp(H2O)= 4.184 J/(g·°C) salts, control various thermodynamic parameters. CvH = 74.539 J/(mol·K) (25 °C) Water or oil have limited temperature range for liquid Heat of fusion =333.6 J/g phase vapor requires pressure vessels, pipes. Molten salts = good compromise. Cordaro et al., Sandia Lab, 1980s. W. Udo Schröder, 2013 Nitrate Salts: Thermodynamic Properties Non-ideal mixtures: Non- linear behavior, not proportional to mole fraction. Large enthalpy of fusion 16 stores large amount of energy in molten phase, recover upon fusion (solidification). Na/K nitrates (NaNO3, (KNO3) have suitable thermodynamic properties. ESTS Solar Power SolarESTS Water: cp(H2O)= 4.184 J/(g·°C) CvH = 74.539 J/(mol·K) (25 °C) Heat of fusion DHf = 333.6 J/g =6.01J/mol Heat of vaporization DHv = 40.7 kJ/mol Cordaro et al., Sandia Lab, 1980s. W. Udo Schröder, 2013 Concentrated Solar Power Generation 17 ESTS Solar Power SolarESTS Since molten salt is able to reach very high temperatures (over 1000 degrees Fahrenheit) and can hold more heat than the synthetic oil used in other CSP plants, the plant is able to continue to produce electricity even after the sun has gone down. W. Udo Schröder, 2013 Heat Transfer/Storage Thermal storage and heat exchange in solid material: Silica sand, ceramicc. Can be driven directly (store thermal energy by heating silica material), or in reverse (withdraw thermal energy to heat cold fluid) 18 The early trough plants used mineral oil as the heat-transfer and storage fluid; Solar Two: used molten salt (K/Na Nitrates, DH of fusion, phase change heat conductivity) ESTS Solar Power SolarESTS W. Udo Schröder, 2013 Heat Transfer/Storage 19 ESTS Solar Power SolarESTS W. Udo Schröder, 2013 Updraft Towers Solar chimney in Principle of operation: Manzanares/Spain Sunlight collector produces hot air, which escapes through chimney and produces draft driving a turbine. 20 ESTS Solar Power SolarESTS An Australian plan: construct (world's first large-scale) solar thermal power station Buronga in New South Wales. 200-MW 'Solar Mission' should produce enough electricity to power 200,000 homes, reducing CO2 emissions by 750,000 t Turbines are driven by heat rising from the transparent "collector" surrounding the tower. W. Udo Schröder, 2013 Not To Be: DESERTEC Energy-Association 21 ESTS Solar Power SolarESTS W. Udo Schröder, 2013 W. W. Udo Schröder,2013 ESTS Solar Power 22 Updraft Towers 23 ESTS Solar Power SolarESTS An Australian plan to construct the world's first large-scale solar thermal power station is taking shape at Buronga in the Wentworth Shire of New South Wales. The first 200MW power station in the 'Solar Mission' project will produce enough electricity to power 200,000 households while reducing greenhouse CO2 emissions by as much as 750,000 tonnes.The thermal power station generates electricity when turbines are driven by heat rising from the transparent "collector" surrounding the tower. W. Udo Schröder, 2013 24 According to the report, the median pre-tax value of such cash incentives ranged from $0.90/W to $1.20/W for systems installed in 2011, depending on system size. These incentives have declined significantly over time, falling by roughly 80 percent over the past decade, and by 21 percent to 43 percent from just 2010 to 2011. (Allan Chen, http://newscenter.lbl.gov/news- releases/2012/11/27/the-installed-price-of-solar-photovoltaic-systems-in-the-u-s-continues-to- decline-at-a-rapid-pace/) An interesting consideration regarding cost-effectiveness and subsidies is that in its early Energy: Science, Technology, Society years, nuclear fission technology received subsidy support of $19 per kilo watt hour produced, compared to $8.90 per kilo watt hour for solar, and just $0.57 per kilo watt hour for wind power [ Badcock, J., and Lenzen, M.

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