Luku 6 Uusiutuva energia. ELEC-C6001Sähköenergiatekniikka ja Prof. Jorma Kyyrä

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1 Luku 6 Uusiutuva energia ELEC-C6001Sähköenergiatekniikka ja Prof. Jorma Kyyrä

2 Sisältö Aurinkoenergia Tuulivoima Hydrokineettiset järjestelmät Geoterminen energia Biomassa Polttokennot Epäsäännöllinen energian tuotto Energiavarastot

3 Aurinkoenergia Auringon säteily avaruudessa on jopa 1,366 kw/m2 Maan pinnalla säteily on vaimeampaa useasta syystä johtuen, ilmakehä absorboi säteilyä ja säteily myös heijastuu partikkeleista Avaruuden säteilystä maan pinnalle päätyy 5-70 % Riippuu vuoden ja vuorokauden ajasta Paikasta maapallolla Suomessa auringon vuosittainen säteilyn määrä on n kwh/m² Tunnin aikana maapallon pinnalle tulee auringon säteilyenergiaa enemmän kuin koko ihmiskunta kuluttaa energiaa vuodessa

4 Center of sun ξ Center of earth Figure 6.1 Zenith angle ξ. 006x001.eps

5 kwh/m 2 /day > <2.0 Figure 6.2 Average solar energy in August in the United States; resolution is 40 km. (Courtesy of the USA National Renewable Energy Laboratory.) 006x002.eps

6 Clear sky insolation incident, horizontal surface (kwh/m 2 /day) Figure 6.3 NASA.) Average annual solar energy worldwide. (Courtesy of the National Aeronautic and Space Administration 006x003.eps

7 100% Density ratio 80% 60% 40% 2σ 20% 0% Time 24 Figure 6.4 A typical solar distribution function (solar power density in 24 h period). 006x004.eps

8 Figure 6.5 Passive thermosiphon hot water solar system. 006x005.tif

9 New supply of cold water Warm Warm water Lens T Sunrays Collector Figure 6.6 Thermosiphon hot water system. 006x006.eps

10 Receiver Collector mirror (a) Pipe Cold fluid Trough Sunrays Pipe Hot fluid (b) Trough Figure 6.7 Solar systems: (a) integrated solar combined cycle system and (b) concentrated trough. (Images are courtesy of the US Department of Energy, Washington, DC.) 006x007.eps

11 Empty space for extra electron Nucleus Electrons Figure 6.8 Silicon: atom and its crystal structures. 006x008.eps

12 Electron without bonding Si Si Si Extra space for electron Si Si Si Si Si Si P Si B Si Si Si Si Si Si n type p type Figure 6.9 Silicon (Si) doped with phosphorus (P) and boron (B). 006x009.eps

13 Lens I n-type p-type + Load Base Figure 6.10 Concentrating PV cell. 006x010.eps

14 Glass cover or lens Antireflective coating Contacts grid n-type material p-type Base Figure 6.11 Main parts of PV cell. 006x011.eps

15 Cathode (K) Cathode (K) n p V d I d Anode (A) Anode (A) Figure 6.12 Representation of a p n junction diode. 006x012.eps

16 V d I d + I d V l V s R Forwardbiased region I o Reverse-biased region V d Figure 6.13 Characteristic of p n junction diode. 006x013.eps

17 + I V Load I Figure 6.14 Representation of solar cell connected to load. 006x014.eps

18 Solar cell I s Id V=V d I Load Figure 6.15 Modeling of ideal cell with current source. 006x015.eps

19 I d I s I o Vd V d I=I s I d Q II Q I V d Q III Q IV Figure 6.16 Current volt characteristics of the PV cell. 006x016.eps

20 I I sc I mp P max P V mp V oc V d Figure 6.17 Current voltage and power voltage characteristics of PV cell. 006x017.eps

21 I s Id = I s V oc Figure 6.18 PV under open circuit condition. 006x018.eps

22 I s I d =0 I sc = I s Figure 6.19 PV under short circuit condition. 006x019.eps

23 I R 1 R 1 < R 2 < R 3 1 Load lines 2 R 2 3 R 3 V oc V Figure 6.20 Operating points of the solar cell connected to a resistive load. 006x020.eps

24 I ρ 3 ρ 1 < ρ 2 < ρ 3 ρ Load line ρ 1 1 V Figure 6.21 Effect of irradiance on the operating point. 006x021.eps

25 P ρ 1 < ρ 2 < ρ 3 ρ 1 ρ 2 ρ 3 V Figure 6.22 Effect of irradiance on PV output power. 006x022.eps

26 I T 1 > T 2 > T 3 T 1 3 Load line 1 2 T 2 T 3 V oc V Figure 6.23 Effect of temperature on the operating point. 006x023.eps

27 P T 1 > T 2 > T 3 T 1 T 2 T 3 V Figure 6.24 Effect of temperature on PV output power. 006x024.eps

28 Module or panel Array System Figure 6.25 PV module, PV array, and PV system. (Images courtesy of the US Department of Energy, Washington, DC.) 006x025.eps

29 I s1 I d1 V d1 Load I d2 V d2 I s2 Figure 6.26 Solar cells in series. 006x026.eps

30 I s = I s1 = I s2 V = V d1 + V d2 Load Figure 6.27 Equivalent circuit for solar cells in series. 006x027.eps

31 I s1 I d1 V d1 V Load I s2 I d2 V d2 Figure 6.28 Solar cells in parallel. 006x028.eps

32 I s = I s1 + I s2 V = V d1 = V d2 Load Figure 6.29 Equivalent circuit of solar cells in parallel. 006x029.eps

33 Current and power Current Power Voltage Figure 6.30 I V and P V characteristics of a single cell (current in A, voltage in V, and power in W). 006x030.eps

34 Module current and power Current Power Module voltage Figure 6.31 I V and P V characteristics of a single cell (current in A, voltage in V, and power in W). 006x031.eps

35 Solar cell R s I I s I d V d R p I p V Load I Figure 6.32 Model of real PV cell. 006x032.eps

36 Figure 6.33 Various photovoltaic systems. (Image courtesy of the US Department of Energy, Washington, DC.) 006x033.eps

37 Solar array House dc current Charger/ discharger Converter ac current Battery Local load Figure 6.34 Storage PV system. 006x034.eps

38 Solar array House dc current Converter ac current Meter To utility Local load Figure 6.35 Direct PV system. 006x035.eps

39 $6.0 $5.0 $5.0 $4.0 $/kwh $3.0 $2.0 $1.0 $1.5 $0.6 $0.4 $0.3 $ Year Figure 6.36 Price of kwh from PV systems. 006x036.eps

40 Figure 6.37 High power PV systems. (Images are courtesy of the US Department of Energy, Washington, DC.) 006x037.eps

41 6.2 Tuulienergia Käytetty jo tuhansia vuosia mm. purjehduksessa, noin 5000 sitten Egyptissä Ensimmäiset tuulimyllyt noin 3000 BC Kiinassa ja sen jälkeen Babyloniassa Ensimmäinen tuuliturbiinin rakensi Charles F. Brush 1888 Suurimmat tuulivoimalat ovat nykyään jopa 8 MW, 6.2.1, 6.2.2, , muu oheislukemista

42 World Wind Energy Association

43

44 Suomen tuulivoimatilasto, VTT

45 Tuulivoimalat Suomessa Nykyisten voimaloiden sijaintipaikat Uudet suunnitelmat kartalla

46 Suomen tuuliatlas index.html

47 Määritelmiä (1/2) Tuotanto roottorin pyyhkäisypinta-alaa kohti (kwh/m2): Tuotanto roottorin pyyhkäisypinta-alaa kohden kertoo, kuinka paljon energiaa on tuotettu roottorin pinta-alaan nähden. Nyrkkisääntönä on, että voimala on tuottanut hyvin, mikäli vuosituotannosta laskettu luku on yli 1000k Wh/m2. Huipunkäyttöaika th (h): Tuulivoimaloiden energiantuotanto vaihtelee välillä 0 % % nimellistehosta. Th kuvaa sen ajan pituutta, joka kuluisi vuodessa tuotetun energian tuottamiseen, mikäli tuulivoimala toimisi koko ajan nimellistehollaan Esimerkiksi 2500 tunnin huipunkäyttöaika sitä että laitos on tuottanut vuoden aikana energiamäärän, jonka laitos tuottaisi toimiessaan nimellistehollaan 2500 tuntia Mikäli tuulivoimalan vuotuinen huipunkäyttöaika on yli 2400 tuntia, on laitos tuottanut hyvin. Kapasiteettikerroin CF: Kapasiteettikerroin CF kertoo huipunkäyttöajan suhteessa vuoden tunteihin ja se kuvaa siten oleellisesti samaa asiaa kuin huipunkäyttöaika Kapasiteettikerroin on käytössä erityisesti englanninkielisessä kirjallisuudessa

48 Määritelmiä (2/2) Tuotantoindeksi IL (%) Tuotantoindeksi on sääasemilla mitattujen tuulennopeushavaintojen perusteella laskettu tuotanto suhteessa pitkän aikavälin havainnoista laskettuun keskimääräiseen tuotantoon Suomen tuulivoimatilastoissa keskimääräinen tuotanto on tällä hetkellä laskettu vuosien tuulennopeushavainnoista. Tuulennopeushavainnot muutetaan keskitehoksi käyttäen 1500 kw tuulivoimalaitoksen tehokäyrää ja huomioiden ilman tiheyden vaikutus tehontuotantoon Tuotantoindeksiä tarvitaan kun halutaan selvittää, kuinka tuulinen jokin tietty ajanjakso oli suhteessa pitkän aikavälin keskimääräiseen tuulisuuteen. Asia on erityisen tärkeä tuulivoimainvestointien yhteydessä, jolloin on selvitettävä mikä on tuotantoennuste voimalahankkeen eliniän ylitse.

49 Wind power class Resource potential Wind power classification Wind power density at 50 m W/m2 Wind speed a at 50 m m/s 3 Fair Good Excellent Outstanding Superb a Wind speeds are based on a welbul k value of 2.0 Wind speed a at 50 m mph Figure 6.38 US average wind power density map at 50 m above sea level. (Courtesy of the USA National Renewable Energy Laboratory.) 006x038.eps

50 Rotating blades Low-speed shaft High-speed shaft Housing Hub (Nacelle) generator Gear box Yaw Tower (a) Figure 6.39 (b) Basic components of a wind-generating system: (a) horizontal design and (b) main parts. 006x039.eps

51 (a) Figure 6.40 (a) Housing and (b) blade of a 1.8 MW wind generating system. (b) 006x040.eps

52 Upper camber Leading edge Airfoil Lower camber Trailing edge Figure 6.41 Airfoil. 006x041.eps

53 Center of gravity Mean camber line Cord line Figure 6.42 Mean camber line, center of gravity of airfoil, and cord line. 006x042.eps

54 w 1 w Airfoil w 2 Figure 6.43 Flow of air around airfoil. 006x043.eps

55 Pr 1 Airfoil Pr 2 Figure 6.44 Bernoulli s principle. 006x044.eps

56 Aerodynamic force Wind direction Airfoil Figure 6.45 Aerodynamic force. 006x045.eps

57 F w F L α F L F D F α F L F F D (a) (b) (c) w α F F D α F D F L F (d) (e) Figure 6.46 Aerodynamic forces and angle-of-attack: (a) horizontal position all aerodynamic force is lift; (b) positive angle-of attack aerodynamic force has lift and drag; (c) increasing positive angle-of attack, less lift, and more drag; (d) increasing positive angle-of attack until aerodynamic force is all drag; and (e) negative angle-of attack lift is reversed. 006x046.eps

58 Lift Maximum lift Stall Angle for zero lift α 0 α max α Figure 6.47 Lift force as a function of angle-of-attack. 006x047.eps

59 w α β Vertical motion of the center of gravity Cord line Figure 6.48 Relative wind speed, angle of attack and pitch angle. 006x048.eps

60 Captured power from wind P blade Input to gearbox P gear Input to generator P g Output power P out Losses in rotating blades and rotor mechanism Losses in gearbox Losses in generator Figure 6.49 Power flow of a wind turbine. 006x049.eps

61 P out P rated B C D A w min w B w max w Figure 6.50 Output power of wind turbine. 006x050.eps

62 v tip Blade ω r Figure 6.51 Tip velocity. 006x051.eps

63 C p C p max TSR ideal TSR Figure 6.52 Coefficient of performance as a function of TSR. 006x052.eps

64 C p C p max TSR ideal Stronger wind Weaker wind TSR Figure 6.53 Tracking maximum C p by adjusting the speed of the blade. 006x053.eps

65 C p β 1 > β 2 > β 3 β3 β 2 β 1 TSR Figure 6.54 Coefficient of performance as a function of pitch angle. 006x054.eps

66 C p β 1 > β 2 A C β 2 B β 1 TSR A TSR B TSR Figure 6.55 Tracking the maximum C p by changing the pitch angle. 006x055.eps

67 C p C px β 1 > β 2 X B β 2 C pc C β 1 TSR X TSR B TSR Figure 6.56 Spilling wind by adjusting pitch angle. 006x056.eps

68 Figure 6.57 Horizontal axis wind turbines. 006x057.tif

69 Figure 6.58 Lifting of gearbox and brakes of HAWT. (Courtesy of Paul Anderson through Wikipedia.) 006x058.tif

70 Figure 6.59 Vertical axis wind turbine. (Courtesy of US National Renewable Energy Lab.) 006x059.tif

71 Farm collection point Grid connection point HV-GSU point Trunk line G Gear box Grid GSU xfm Figure 6.60 Type 1 wind turbine system. 006x060.eps

72 Farm collection point G Gear box Rotor converter Figure 6.61 Type 2 wind turbine system. 006x061.eps

73 Farm collection point G Gear box ac/dc dc/ac dc link ac/dc dc/ac Link converter Rotor converter Figure 6.62 Type 3 wind turbine system. 006x062.eps

74 Farm collection point AC/AC G Full converter Figure 6.63 Type 4 wind turbine system. 006x063.eps

75 Figure 6.64 Type 4 6 MW wind turbine made by Enercon. 006x064.tif

76 Figure 6.65 DC.) Wind farm located in California. (Images are courtesy of the U.S. Department of Energy, Washington, 006x065.eps

77 Figure 6.66 Two megawatt offshore wind turbine farm in Denmark. (Image courtesy of LM Glasfiber Group.) 006x066.tif

78 Reactive power Generation range Q min n s Speed Figure 6.67 Reactive power of induction machine. 006x067.eps

79 n Time Q Time V V r Time Figure 6.68 Wind speed, reactive power, and terminal voltage. 006x068.eps

80 6.3 Hydrokineettiset järjestelmät Pienet vesivoimalat Vuorovesivoimalat Aaltoenergia Eri ratkaisujen periaateet, mutta mekaaniikan yhtälöt yms ovat oheislukemista.

81 Reservoir Penstock Generator Head Turbine Discharge Figure 6.69 Small hydroelectric system with reservoir. 006x069.eps

82 Power at the entrance of penstock P p-in Power at the end of penstock P p-out Blade power P blade Input power to generator P m Output electric power P g Penstock losses Hydro losses Turbine losses Generator losses Figure 6.70 Power flow in small hydroelectric system. 006x070.eps

83 Sea side Barrage Shore Lagoon side Turbine Lagoon side Sea side Water flow Water flow H high H low (a) Figure 6.71 Barrage tidal energy system: (a) high tide and (b) low tide. (b) 006x071.eps

84 Tidal height 24 h Datum H ebb1 Hebb2 H flow2 H flow1 Tidal period Time Figure 6.72 Semidiurnal tide. 006x072.eps

85 Generator Turbine Water flow Figure 6.73 Diversion-type small hydroelectric system. 006x073.eps

86 (a) (b) Figure 6.74 WS energy system: (a) turbine and (b) conceptual design of a farm. (Images courtesy of Marine Current Turbines Limited.) 006x074.eps

87 Crest Trough Amplitude (α) Height (h) Seawater level Wavelength (λ) Figure 6.75 Wave parameters. 006x075.eps

88 Float Wave Coil (mounted on enclose) V Magnets (anchored) Enclosure (mounted on float) Linear generator Anchor line Figure 6.76 Buoyant moored system. 006x076.eps

89 Figure 6.77 Buoyant actuator during the installation. (Courtesy of Carnegie Wave Energy through Wikipedia.) 006x077.tif

90 Float Wave Line Linear generator Figure 6.78 Buoyant moored system anchored on ocean floor. 006x078.eps

91 Float Hydroelectric power plant Seawater piston High pressure flow line Figure 6.79 Oyster system. 006x079.eps

92 Generator Wave G M Hydraulic motor Pistons Hinges G M Piston Hydraulic motor Figure 6.80 Main components of hinged contour system. 006x080.eps

93 Figure 6.81 HC system. (Courtesy of Pelamis Wave Energy through Wikipedia.) 006x081.tif

94 Figure 6.82 The front pontoon. (Courtesy of Pelamis Wave Energy through Wikipedia.) 006x082.tif

95 Linear generator Chamber Wave Figure 6.83 Oscillating column system. 006x083.eps

96 6.4 Geoenergia Lämpöpumput Sähkön tuotanto maalämmöllä Maalampövoimalat

97 2900 km Mantle Earth s crust 6370 km Outer core Inner core Center of earth Figure 6.84 Cross section of Earth. 006x084.eps

98 Temperature 40 km Depth Mantle km Figure 6.85 Geothermal gradient of Earth. 006x085.eps

99 Favorability of deep EGS Most favorable Least favorable N/A* No data** Identified hydrothermal site ( 90 C) Figure 6.86 Geothermal map of the United States. (Courtesy of the United States National Renewable Energy Laboratory.) EGS stands for enhanced geothermal system. 006x086.eps

100 Warm air to house Hot water tank Pump and heat exchangers Return cool air Ground Geo-exchanger Figure 6.87 Heat pump system. 006x087.eps

101 Figure 6.88 Steam generated from rain even in cold environment. 006x088.tif

102 Steam Rain water Rain water Steam reservoir Melton rock Figure 6.89 Geothermal reservoir. 006x089.eps

103 Hot water extraction Cold water injection Stimulated fractures Low-temperature sediment Hot rocks (Granite) 3 15 km Figure 6.90 Hot dry rock site. 006x090.eps

104 Steam Turbine G Cooling tower Mist eliminator Reservoir Heat Magma Figure 6.91 Reservoir type geothermal power plant. 006x091.eps

105 Thermal turbine Generator G Cooling tower Heat exchanger Stimulated fractures Low-temperature sediment Hot rocks (Granite) 3 15 km Figure 6.92 Hot dry rock geothermal power plant. 006x092.eps

106 Figure 6.93 The Geyser s in northern California the first geothermal power plant in the United States. 006x093.tif

107 Figure 6.94 Geothermal power plants in the United States in 2010 (numbers in MW; white numbers for existing installations; yellow for planned installation). (Courtesy of the USA National Renewable Energy Laboratory.) 006x094.tif

108 Turbine G Condenser Steam Stack Water pipes Furnace Filter Storage Light ash to landfills Heavy ash to landfills Figure 6.95 Biomass incineration power plant. 006x095.eps

109 6.6 Polttokennot Ensimmäiset polttokennot on kehitetty jo 1839 Francis Bacon 1939 ja sen jälkeen käytetty NASAn avaruuslennoilla Useimmat polttokennot käyttävät vetyä ja happea sähkön tuottamiseen. Sivutuotteena syntyy vettä. Osa polttokennoista voi käyttää polttoaineen suoraan metanolia eikä silloin tarvita erillistä reformointiprosessia vedyn tuottamiseen Luvussa 6.6 olevat kemian liittyvät asiat ovat oheislukemista.

110 Polttokennotyypit

111 H 2 O CO 2 CH 2 H 2 Water (H 2 O) O 2 Reformer CO 2 CO CO conversion H 2 Fuel cell Figure 6.96 Generation of hydrogen. 006x096.eps

112 Shell Electron Proton H H 2 Figure 6.97 Hydrogen atom and hydrogen gas. 006x097.eps

113 Load I Hydrogen (2H 2 ) + Hydrogen ions (4H + ) Oxygen (O 2 ) Anode Electrolyte Cathode Water (2H 2 O) Figure 6.98 PEM FC. 006x098.eps

114 Figure 6.99 PEM fuel cell. 006x099.tif

115 Load I Hydrogen (2H 2 ) + Hydroxyl ions (4OH ) Oxygen (O 2 ) Water (2H 2 O) Water (2H 2 O) Anode Electrolyte Cathode Water (2H 2 O) Figure Alkaline FC. 006x100.eps

116 Load I Hydrogen (2H 2 ) + Hydrogen ions (4H + ) Oxygen (O 2 ) Anode Electrolyte Cathode Water (2H 2 O) Figure Phosphoric acid FC. 006x101.eps

117 Load I Hydrogen (2H 2 ) + Oxygen ions (2O 2 ) Oxygen (O 2 ) Water (2H 2 O) Anode Electrolyte Cathode Figure Solid oxide FC. 006x102.eps

118 Load I Hydrogen (2H 2 ) Carbonate ions (2CO 3 2 ) Oxygen (O 2 ) Water (2H 2 O) Carbon dioxide (2CO 2 ) Anode Electrolyte Cathode Figure MCFC. 006x103.eps

119 Load I Methanol (CH 3 OH) + Hydrogen ions (6H + ) Oxygen (1.5O 2 ) Carbon dioxide (CO 3 ) Water (H 2 O) Anode Electrolyte Cathode Water (H 2 O) Figure DMFC. 006x104.eps

120 Renewable energy system Electricity Hydrogen generation Hydrogen Distribution infrastructure Co-Gen industrial use air conditioning, etc. Steam Oxygen Hydrogen Oxygen Steam Co-Gen industrial use air conditioning, etc. FC system FC system Water for drinking, agriculture, etc. Water Electricity Electricity Electricity Electric load Electric load Water Water for drinking, agriculture, etc. Utility grid Figure Hydrogen-based energy system. 006x105.eps

121 Gibbs free energy G Electric load Anode Cathode Enthalpy energy H Hydrogen Fuel cell Enthropy energy Q H 2 O Figure Gibbs free energy. 006x106.eps

122 Activation Ohmic Mass transport Power Voltage and power Voltage Current Figure Polarization and power curves of FC. 006x107.eps

123 1.6 Voltage (V) and power (W) Voltage Power Current (A) Figure Polarization and power curves of FC in Example x108.eps

124 6.8 Energiavarastot Uusiutuvan energian tuotanto on hyvin vaihtelevaa ja usein myös vaikea ennustaa etukäteen Tuotannon vaihdellessa tarvitaan Reservituotantoa Varastoja, joihin aiemmin yli tuotannon varastoitu energia varastoidaan Kulutuksen säännöstelyä Alessandro Volta kehitti akuston jo 1800, mutta energian laajamittainen ja taloudellinen varastointi on edelleen yksi tärkeimmistä avoimista kysymyksistä

125 Generated energy Consumed energy Figure Balance of electric energy. 006x109.eps

126 Figure PHS system. (Courtesy of the United States Army Corps of Engineers.) 006x110.tif

127 Energy from grid Exhaust Fuel Energy to grid Recuperator M Compressor Turbine G Motor Generator Cavern Figure Main components of compressed air energy storage system. 006x111.eps

128 Magnetic bearing Stator winding High-inertia rotor Stator winding Magnetic bearing Figure Main components of flywheel. 006x112.eps