3Global Primary Energy Consumption IndividualAccumulated
4Global Primary Energy Consumption In 2008, total worldwide energy consumption was 474 exajoules (132,000 TWh). This is equivalent to an average power use of 15 terawatts (2.0×1010 hp). Based upon some attempted estimates, making strong assumptions, the annual potential for renewable energy are of the order of:solar energy 1,575 EJ (438,000 TWh),wind power 640 EJ (180,000 TWh),geothermal energy 5,000 EJ (1,400,000 TWh),biomass 276 EJ (77,000 TWh),hydropower 50 EJ (14,000 TWh) andocean energy 1 EJ (280 TWh)."Consumption by fuel, 1965–2008" (XLS). Statistical Review of World Energy BP. 8 June Archived from the original on 26 July Retrieved 24 October 2009.World Energy Assessment (WEA). UNDP, New YorkJohansson, T. B., McCormick, K., Neij, L., & Turkenburg, W. (2004). The Potentials of Renewable Energy: Thematic Background Paper. Thematic Paper prepared for the International Conference on Renewable Energies, Bonn. Retrieved 6 July 2008, fromde Vries BJM, van Vuuren DP, Hoogwijk MM (2007). "Renewable energy sources: Their global potential for the first-half of the 21st century at a global level: An integrated approach". Energy Policy 35: 2590–2610. doi: /j.enpol
5Conversion between energy and power Unit ConversionEnergyHow?3600Value of energy in TWh can be obtained by multiplying value of energy in EJbyConversion between energy and powerHow?Value of equivalent power in TW can be obtained by multiplying thecorresponding value of energy in EJ byWhy? Explained later.
6Electric Energy Consumption Consumption of electric energy is measured in watt-hours (written W·h, equal to Watt x Hour)1 W·h = 3600 joule = calorie.Electric and electronic devices consume electric energy to generate desired output (i.e. light, heat, motion, etc.). During operation, some part of the energy is consumed in unintended output, such as waste heat. See Electrical Efficiency .In 2008, the world total of electricity production and consumption was 20,279 TWh (terawatt-hours). This number corresponds to an average consumption rate of around 2.3 terawatts continuously during the year. The total energy needed to produce this power is roughly a factor 2 to 3 higher because the efficiency of power plants is roughly 30-50%, see Electricity generation. The generated power is thus in the order of 5 TW. This is approximately a third of the total energy consumption of 15 TW, see World energy consumption.16816TWh (83%) of electric energy was consumed by final users. The difference of 3464TWh (17%) was consumed in the process of generating power and consumed as transmission loss and all most consumed at misuse.
7Global and Electric Energy Consumptions Total worldwide energy consumptionWorld total of electricity consumptionElectric energy consumed by final users(The difference of 3464 TWh (17%) was consumed in the process of generating power and consumed as transmission loss and all most consumed at misuse.)Energy needed to produce the world total of electricity consumption(Efficiency of power plants is roughly 30-50%, say, 44%)
9Global Solar Energy Flows petawatts (PW)(1 PW = 1,000,000,000,000,000 Watts)PW = 1015 W
10Standard SI Prefixes for Watt SI multiples for watt (W)SubmultiplesMultiplesValueSymbolName10−1 WdWdeciwatt101 WdaWdecawatt10−2 WcWcentiwatt102 WhWhectowatt10−3 WmWmilliwatt103 WkWkilowatt10−6 WµWmicrowatt106 WMWmegawatt10−9 WnWnanowatt109 WGWgigawatt10−12 WpWpicowatt1012 WTWterawatt10−15 WfWfemtowatt1015 WPWpetawatt10−18 WaWattowatt1018 WEWexawatt10−21 WzWzeptowatt1021 WZWzettawatt10−24 WyWyoctowatt1024 WYWyottawattCommon multiples are in bold face
11Outstanding solar potential compared to all other energy sources Compared with 174 PW (174,000 TW) of total incoming solar radiation
12Yearly Solar Fluxes & Human Energy Consumption Equivalent to non-reflected solar power of 122 PWYearly Solar fluxes & Human Energy ConsumptionSolar3,850,000 EJWind2,250 EJBiomass potential100–300 EJPrimary energy use (2010)539 EJElectricity (2010)66.5 EJEJ = 1018 J
13Equivalence of Solar Fluxes PowerEnergyFluxTotal174 PW5,487,264 EJ/yr1367 W/m2Non-reflected122 PW3,850,000 EJ/yr957 W/m2Total incoming solar radiation 174 PWReflected radiation 52 PWNon-reflected radiation 174 – 52 = 122 PW
14Equivalence of Solar Fluxes PowerEnergyFluxTotal174 PW5,487,264 EJ/yr1367 W/m2Non-reflected122 PW3,850,000 EJ/yr957 W/m2Irradiance (power flux) normal to the sun radiationCircumference of earth sphere km ( = D)Area of cross section of earth sphere passing through sphere center= r2 = (40000 / 2 / )2 = 108 km2
15Earth Dimensions Radius 6378.1 km (equatorial) 6356.8 km (polar) Circumference km (equatorial) km (meridional) Surface area km2
27Blackbody Radiation Spectrum Overlay The irradiance of the sun on the outer atmosphere when the sun and earth are spaced at 1 AU - the mean earth/sun distance of 149,597,890 km - is called the solar constant. Currently accepted values are about 1360 W m-2 (the NASA value given in ASTM E a is 1353 ±21 W m-2). The World Metrological Organization (WMO) promotes a value of 1367 W m-2. The solar constant is the total integrated irradiance over the entire spectrum (the area under the curve in Fig. 1 plus the 3.7% at shorter and longer wavelengths).Excellent Explanation
28Black body RadiationBlack-body radiation is the type of electromagnetic radiation within or surrounding a body in thermodynamic equilibrium with its environment, or emitted by a black body (an opaque and non-reflective body) held at constant, uniform temperature. The radiation has a specific spectrum and intensity that depends only on the temperature of the body.Peter Theodore Landsberg (1990). "Chapter 13: Bosons: black-body radiation". Thermodynamics and statistical mechanics (Reprint of Oxford University Press 1978 ed.). Courier Dover Publications. pp. 208 ff. ISBNPlanck's law describes the spectral radiance of electromagnetic radiation at all wavelengths from a black body at temperature T. As a function of frequency ν, Planck's law is written as orIt can be converted to an expression for I'(λ,T) in wavelength units by substituting ν by c / λ and evaluatingor and from , we haveso or The above equation is energy per unit wavelength per unit solid angle.
30Black body Radiation Curve at 5800 K The spectrum of the Sun's solar radiation is close to that of a black body with a temperature of about 5,800 K peaking at a wavelength of 500 nm.
31Interactive tool for Black Body Radiation There is an online, interactive tool from the University of Colorado for investigating the spectrum of various blackbodies. Here is the link to run it online: PhET Interactive Simulation of the Blackbody Spectrum.
32Simple Solar Spectral Model for Direct and Diffuse Irradiance Black body radiation spectrum as overlay curveTerrestrial absorptionRAYLEIGH SCATTERINGAEROSOL SCATTERING AND ABSORPTIONWATER VAPOR ABSORPTIONOZONE AND UNIFORMLY MIXED GAS ABSORPTIONFraunhofer lines
33Rayleigh Scattering and Mie Scattering Selective scattering (or Rayleigh scattering) occurs when certain particles are more effective at scattering a particular wavelength of light. Molecules much smaller than the wavelength of the radiation, like oxygen and nitrogen for example, are more effective at scattering shorter wavelengths of light (blue and violet). The selective scattering by air molecules is responsible for producing our blue skies on a clear sunny day.Another type of scattering (called Mie Scattering) is responsible for the white appearance of clouds. Cloud droplets with a diameter of 20 micrometers or so are large enough to scatter all visible wavelengths more or less equally. This means that almost all of the light which enters clouds will be scattered. Because all wavelengths are scattered, clouds appear to be white.
39Transparent Window of Atmosphere Black-body temperature K (Earth)The Earth’s atmosphere is not completely opaque to longwave. There is a transparent transmission band extending from 8 to 13 microns, in the center of the terrestrial thermal black body curve. This allows up to 30% of the longwave to escape.
40Fraunhofer LinesIn the Sun, Fraunhofer lines are seen from gas in the outer regions of the Sun, which are too cold to directly produce emission lines of the elements they represent. (seen as absorption lines)"Spectrum of blue sky" by Spectrum of blue sky.png : Remember the dotDerivative work : Eric Bajart - Spectrum of blue sky.png. Licensed under GFDL via Wikimedia Commons -
41Labeling of Fraunhofer Lines "Fraunhofer lines" by Fraunhofer_lines.jpg: nl:Gebruiker:MaureenVSpectrum-sRGB.svg: PhroodFraunhofer_lines_DE.svg: *Fraunhofer_lines.jpg: Saperaud 19:26, 5. Jul. 2005derivative work: Cepheiden (talk)derivative work: Cepheiden (talk) - Fraunhofer_lines.jpgSpectrum-sRGB.svgFraunhofer_lines_DE.svg. Licensed under Public Domain via Wikimedia Commons -Dark lines in the solar spectrum are caused by absorption by chemical elements in the Solar atmosphere. Some of the observed features were identified as telluric lines originating from absorption in oxygen molecules in the Earth's atmosphere.
42Telluric SpectrumThe solar spectrum from 2958 to 5400 Å is essentially clear of any terrestrial lines. Red of 5400 Å weak H2O lines begin to appear, at first two weak H2O bands (Camy-Peyret et al. 1985). By 5790 Å H2O is joined by O2. Thus for solar flux spectra obtained from ground based facilities, a correction for the telluric spectrum should be undertaken. The discrete terrestrial absorbers are illustrated in the figure. It is apparent from the figure that telluric lines have a substantial effect on a large part of the visible and near-infrared spectrum.The Astrophysical Journal Supplement Series, 195:6 (8pp), 2011 July
43Illustration of Telluric Contamination The near infrared night sky of Castanet-Tolosan observatory. The sky line emission background is here detected during an observation of SS433 object with a LISA spectrograph (IR version - R = 800).HPS street lamp view from my balcony observatory (Castanet-Tolosan observatory) !Emission lines identification in the sky background of SS433 spectrum. "blue" labeled line are artificial (HPS lamps). Note the telluric airglow emission at 6300 A and the rich atmospheric OH spectrum.
44Standard Solar Spectra The AM1.5 Global spectrum is designed for flat plate modules and has an integrated power of 1000 W/m2 (100 mW/cm2).The AM1.5 Direct (+circumsolar) spectrum is defined for solar concentrator work. It includes the direct beam from the sun plus the circumsolar component in a disk 2.5 degrees around the sun. The direct plus circumsolar spectrum has an integrated power density of 900 W/m2.The AM0 spectrum is the standard spectrum for space applications and has an integrated power of W/m2.
45Global, Direct, and Diffuse Insolation Direct, diffuse, and total insolation for a standard atmosphere, with relative air mass of 1.5.
46Global, Direct, and Diffuse Insolation Global Horizontal Radiation - also called Global Horizontal Irradiance; total solar radiation; the sum of Direct Normal Irradiance (DNI), Diffuse Horizontal Irradiance (DHI), and ground-reflected radiation; however, because ground reflected radiation is usually insignificant compared to direct and diffuse, for all practical purposes global radiation is said to be the sum of direct and diffuse radiation onlyGHI = DHI + DNI * cos (Z)where Z is the solar zenith angle.
48Solar Spectra at Various Air Masses "Simulated direct irradiance spectra for air mass=0 to 10 with SMARTS 2.9.5" by Solar Gate - My own calculations and graphing. Licensed under CC BY-SA 3.0 via Wikimedia Commons -
49Air Mass (AM)The air mass coefficient defines the direct optical path length through the Earth's atmosphere, expressed as a ratio relative to the path length vertically upwards, i.e. at the zenith.AM0The solar spectrum outside the atmosphere, approximated by the 5,800 K black body, is referred to as "AM0", meaning "zero atmospheres".AM1The spectrum after travelling through the atmosphere to sea level with the sun directly overhead is referred to, by definition, as "AM1". This means "one atmosphere".AM1.5The spectrum after travelling through “1.5 atmosphere” thickness to sea level, corresponding to a solar zenith angle of =48.2°.48.2o
50Air Mass Coefficient (Approximation) The air mass coefficient defines the direct optical path length through the Earth's atmosphere, expressed as a ratio relative to the path length vertically upwards, i.e. at the zenith.(reasonably accurate for values of up to around 75o)
51Purpose of Introducing Air Mass The original purpose of introducing the idea of air mass is to specify the zenith angle of solar irradiance so that the final irradiance power flux can be estimated by consideration of both (1) the attenuation of the irradiance passing through the atmosphere and (2) the attenuation by increased angle of incident.angle of incidentHowever, the estimation is complicated and the precise values still have to resort to experiment measurements. (especially true at high zenith angles)
53Air Mass Coefficient (Modified Spherical) Schoenberg, E Theoretische Photometrie, Über die Extinktion des Lichtes in der Erdatmosphäre. In Handbuch der Astrophysik. Band II, erste Hälfte. Berlin: Springer.Spherical model of the Earth’s atmosphere: Geometry for computing a diagonal path through the Earth’s atmosphere. Atmospheric effects on optical transmission, at an angle z to the normal, can be modelled as a path of length s, as if the atmosphere is concentrated uniformly in approximately the lower 9 km. This path is known as the Airmass. The Air mass coefficient is defined as the ratio s/yatm. This model does not apply at non-optical wavelengths where higher layers of the atmosphere affect transmission, for example: the ozone layer at higher ultraviolet frequencies and the ionosphere at lower radio frequencies.Essentially all the atmospheric effects are due to the atmospheric mass in the lower half of the Troposphere.Courtesy of Neil Clarke
55Kasten & YoungSphericalKasten and Young (1989)Plane Parallel
56Air Mass Coefficient (Schoenberg) Hardly any difference for z < 70o.Kasten F, Young AT. Revised optical air mass tables and approximation formula. Applied Optics [Internet] ;28:4735–4738. Available from:
57Standard Solar Irradiance Power Formulawhere solar intensity external to the Earth's atmosphere Io = kW/m2, and the factor of 1.1 is derived assuming that the diffuse component is 10% of the direct component.ZAMformulaASTM G-173degreeW/m2-13531347.90°1104023°1.09102030°1.15101045°1.4195048.2°1.59301000.460°284070°2.971075°3.862080°5.647085°1027090°3820Meinel, A. B. and Meinel, M. P. (1976). Applied Solar Energy Addison Wesley Publishing Co.
58Equivalence of Solar Fluxes PowerEnergyFluxTotal174 PW5,487,264 EJ/yr1367 W/m2Non-reflected122 PW3,850,000 EJ/yr957 W/m2Compared with formula value of 1040 W/m2 at AM1.Non-reflected irradiance (power flux)Circumference of earth sphere km ( = D)Area of cross section of earth sphere passing through sphere center= r2 = (40000 / 2 / )2 = 108 km2
59Peak Sun HoursThe average daily solar insolation in units of kWh/m2 per day is sometimes referred to as "peak sun hours". The term "peak sun hours" refers to the solar insolation which a particular location would receive if the sun were shining at its maximum value for a certain number of hours. Since the peak solar radiation is 1 kW/m2, the number of peak sun hours is numerically identical to the average daily solar insolation. For example, a location that receives 8 kWh/m2 per day can be said to have received 8 hours of sun per day at 1 kW/m2. Being able to calculate the peak sun hours is useful because PV modules are often rated at an input rating of 1kW/m2.
60ExercisePlease estimate the area of solar panel required to provide annual global electricity consumption of 80 EJ, assuming the solar panel is located at a location that receives 5 kWh/m2 per day, and the energy conversion efficiency of solar panel is 44%.
61Solar Energy is Abundant The above map shows the area of PV cells of current efficiency (10%) required to supply ALL the WORLDS current energy requirements (electrical/transport/heating!). The RED area shows the area required if the efficiency approached 100%.