Oceanic Energy. Assistant Professor Mazen Abualtayef. Environmental Engineering Department Islamic University of Gaza, Palestine

Transcription

1 Oceanic Energy Assistant Professor Mazen Abualtayef Environmental Engineering Department Islamic University of Gaza, Palestine 1

2 Adapted from a presentation by Professor S.R. Lawrence Leeds School of Business, Environmental Studies University of Colorado, Boulder, CO, USA 2

3 Course Outline Renewable Hydro Power Wind Energy Oceanic Energy Solar Power Geothermal Biomass Sustainable Hydrogen & Fuel Cells Nuclear Fossil Fuel Innovation Exotic Technologies Integration Distributed Generation 3

4 Oceanic Energy Outline Overview Tidal Power Technologies Environmental Impacts Economics Future Promise Wave Energy Technologies Environmental Impacts Economics Future Promise Assessment 4

5 Overview of Oceanic Energy 5

6 Sources of New Energy Boyle, Renewable Energy, Oxford University Press (2004) 6

7 Global Primary Energy Sources 2002 Boyle, Renewable Energy, Oxford University Press (2004) 7

8 Renewable Energy Use 2001 Boyle, Renewable Energy, Oxford University Press (2004) 8

9 Tidal Power 9

10 Tidal Motions Boyle, Renewable Energy, Oxford University Press (2004) 10

11 Tidal Forces Boyle, Renewable Energy, Oxford University Press (2004) 11

12 Natural Tidal Bottlenecks Boyle, Renewable Energy, Oxford University Press (2004) 12

13 Tidal Energy Technologies 1. Tidal Turbine Farms 2. Tidal Barrages (dams) 13

14 1. Tidal Turbine Farms MCT Swan turbines Deep water current turbines Oscillating turbines Polo turbines Land tides 14

15 Tidal Turbines (MCT Seagen) Video 750 kw 1.5 MW m rotors 3 m pile RPM Deployed in multi-unit farms or arrays Like a wind farm, but Water 800x denser than air Smaller rotors More closely spaced MCT Seagen Pile MCT: Marine current turbines 15

16 Tidal Turbines (Swanturbines) Direct drive to generator علب التروس No gearboxes Gravity base (concrete block) Versus a bored foundation Fixed pitch turbine blades Improved reliability But trades off efficiency Video 16

17 Deeper Water Current Turbine Video Boyle, Renewable Energy, Oxford University Press (2004) 17

18 Oscillating Tidal Turbine Oscillates up and down 150 kw prototype operational (2003) Plans for 3 5 MW prototypes Boyle, Renewable Energy, Oxford University Press (2004) 18

19 Polo Tidal Turbine Vertical turbine blades Rotates under a حلقة مربوطة tethered ring 50 m in diameter 20 m deep 600 tons Max power 12 MW Boyle, Renewable Energy, Oxford University Press (2004) 19

20 Power from Land Tides (!) 20

21 Advantages of Tidal Turbines Low Visual Impact Mainly, if not totally submerged. Low Noise Pollution Sound levels transmitted are very low High Predictability Tides predicted years in advance, unlike wind High Power Density Much smaller turbines than wind turbines for the same power 21

22 Disadvantages of Tidal Turbines High maintenance costs High power distribution costs Somewhat limited upside capacity Intermittent power generation 22

23 2. Tidal Barrage Schemes Barrages Offshore lagoons Fences 23

24 Definitions Barrage An artificial dam to increase the depth of water for use in irrigation or navigation, or in this case, generating electricity. Flood Ebb The rise of the tide toward land (rising tide) The return of the tide to the sea (falling tide) 24

25 Potential Tidal Barrage Sites Only about 20 sites in the world have been identified as possible tidal barrage stations Boyle, Renewable Energy, Oxford University Press (2004) 25

26 Schematic of Tidal Barrage Boyle, Renewable Energy, Oxford University Press (2004) 26

27 Cross Section of a Tidal Barrage 27

28 Tidal Barrage Bulb Turbine Boyle, Renewable Energy, Oxford University Press (2004) 28

29 Tidal Barrage Rim Generator Canada. An annual output of 50GWh Boyle, Renewable Energy, Oxford University Press (2004) 29

30 Tidal Barrage Tubular Turbine Boyle, Renewable Energy, Oxford University Press (2004) 30

31 Sihwa Lake Tidal Power Barrage Sihawa lake (South Korea) This 254 MW (10x25.4MW), $250 million project is the first world s largest Mean tidal range is 5.6m The basin area was reduced to around 30 km 2 Video 31

32 La Rance Tidal Power Barrage Video Rance River estuary, Brittany (France) 2 nd Largest in world (1 st in Korea) Completed in MW bulb turbines (240 MW) 5.4 meter diameter Capacity factor of ~40% Maximum annual energy: 2.1 TWh Realized annual energy: 840 GWh Electric cost: 1.8 /kwh Boyle, Renewable Energy, Oxford University Press (2004) 32 Tester et al., Sustainable Energy, MIT Press, 2005

33 La Rance Tidal Power Barrage The system used consists of a dam 330m long and a 22km 2 basin with a tidal range of 8.5m, it incorporates a lock to allow passage for small craft Construction cost: 95m (1967) about 580m (2009) 33

34 La Rance River, Saint Malo 34

35 La Rance Barrage Schematic Boyle, Renewable Energy, Oxford University Press (2004) 35

36 Cross Section of La Rance Barrage river sea Tide going out 36

37 La Rance Turbine Exhibit 37

38 Tidal Barrage Energy Calculations E E R = range (height) of tide (in m) A = area of tidal pool (in km 2 ) m = mass of water g = 9.81 m/s 2 = gravitational constant = 1025 kg/m 3 = density of seawater 0.40 = capacity factor (20-40%) mgr / R 2 ( AR) gr / A 2 kwh per tidal cycle Assuming 706 tidal cycles per year (12 hrs 24 min per cycle) 6 2 E yr R A Tester et al., Sustainable Energy, MIT Press,

39 La Rance Barrage Example = 40% R = 8.5 m A = 22 km 2 6 E R E E yr yr yr GWh/yr 2 A (0.40)(8.5 2 )(22) Tester et al., Sustainable Energy, MIT Press,

40 Proposed Severn Barrage (1989) Video 40

41 Proposed Severn Barrage (1989) Never constructed, but instructive Boyle, Renewable Energy, Oxford University Press (2004) 41

42 Proposed Severn Barrage (1989) Severn River estuary Border between Wales and England MW turbine generators (9.0m dia) 8,640 MW total capacity 17 TWh average energy output Ebb generation with flow pumping 16 km total barrage length $15 billion estimated cost (1989) 42

43 Severn Barrage Layout Boyle, Renewable Energy, Oxford University Press (2004) 43

44 Severn Barrage Proposal Effect on Tide Levels Boyle, Renewable Energy, Oxford University Press (2004) 44

45 Severn Barrage Proposal Power Generation over Time Boyle, Renewable Energy, Oxford University Press (2004) 45

46 Severn Barrage Proposal Capital Costs ~$15 billion (1988 costs) Boyle, Tester Renewable et al., Sustainable Energy, Energy, Oxford MIT University Press, Press 2005 (2004) 46

47 Severn Barrage Proposal Energy Costs ~10 /kwh (1989 costs) Boyle, Renewable Energy, Oxford University Press (2004) 47

48 Severn Barrage Proposal Capital Costs versus Energy Costs 1p 2 Boyle, Renewable Energy, Oxford University Press (2004) 48

49 Offshore Tidal Lagoon Read this article Friends of the Earth Briefing: Tidal Lagoon vs. Barrage Boyle, Renewable Energy, Oxford University Press (2004) 49

50 Tidal Fence Array of vertical axis tidal turbines No effect on tide levels Less environmental impact than a barrage 1000 MW peak (600 MW average) fences soon Boyle, Renewable Energy, Oxford University Press (2004) 50

51 Promising Tidal Energy Sites Country Location TWh/yr GW Canada Fundy Bay Cumberland USA Alaska Passamaquody Argentina San Jose Gulf Russia Orkhotsk Sea India Camby Kutch Korea 10 Australia

52 Tidal Barrage Environmental Factors Changes in estuary ecosystems Less variation in tidal range Fewer mud flats Less turbidity clearer water More light, more life Accumulation of silt Concentration of pollution in silt Visual clutter 52

53 Advantages of Tidal Barrages High predictability Tides predicted years in advance, unlike wind Similar to low-head dams Known technology Protection against floods Benefits for transportation (bridge) Some environmental benefits 53

54 Disadvantages of Tidal Turbines High capital costs Few attractive tidal power sites worldwide Intermittent power generation Silt accumulation behind barrage Accumulation of pollutants in mud Changes to estuary ecosystem 54

55 Wave Energy 55

56 Wave Structure Boyle, Renewable Energy, Oxford University Press (2004) 56

57 Wave Frequency and Amplitude Boyle, Renewable Energy, Oxford University Press (2004) 57

58 Wave Patterns over Time Boyle, Renewable Energy, Oxford University Press (2004) 58

59 Wave Power Calculations H s2 = Significant wave height (m) T e = average wave period (sec) P = Power in kw per meter of wave crest length P Example: H s = 3m, T e = 10sec 2 H s T e 2 P 2 2 H ste kw m Gaza: H s = 1m, T e = 7sec P 2 H T s e 3. 5 kw m 59

60 Global Wave Energy Averages Average wave energy (est.) in kw/m (kw per meter of wave length) 60

61 Wave Energy Potential Potential of 1,500 7,500 TWh/year 10 and 50% of the world s yearly electricity demand IEA (International Energy Agency) 200,000 MW installed wave and tidal energy power forecast by 2050 Power production of 6 TWh/y Load factor of 0.35 DTI and Carbon Trust (UK) Independent of the different estimates the potential for a pollution free energy generation is enormous. 61

62 Wave Energy Technologies 62

63 Wave Concentration Effects Boyle, Renewable Energy, Oxford University Press (2004) 63

64 Tapered Channel (Tapchan) 64

65 Oscillating Water Column 65

66 Oscillating Column Cross-Section Boyle, Renewable Energy, Oxford University Press (2004) 66

67 LIMPET Oscillating Water Column Completed 2000 Scottish Isles Two counter-rotating Wells turbines Two generators 500 kw max power Boyle, Renewable Energy, Oxford University Press (2004) 67

68 Mighty Whale Design Japan 68

69 Might Whale Design Boyle, Renewable Energy, Oxford University Press (2004) 69

70 Turbines for Wave Energy Turbine used in Mighty Whale Boyle, Renewable Energy, Oxford University Press (2004) 70

71 Ocean Wave Conversion System 71

72 Wave Conversion System in Action 72

73 Wave Dragon Wave Dragon Copenhagen, Denmark Click Picture for Video 73

74 Wave Dragon Energy Output in a 24kW/m wave climate = 12 GWh/year in a 36kW/m wave climate = 20 GWh/year in a 48kW/m wave climate = 35 GWh/year in a 60kW/m wave climate = 43 GWh/year in a 72kW/m wave climate = 52 GWh/year. 74

75 Declining Wave Energy Costs Boyle, Renewable Energy, Oxford University Press (2004) 75

76 Wave Energy Power Distribution Boyle, Renewable Energy, Oxford University Press (2004) 76

77 Wave Energy Supply vs. Electric Demand Boyle, Renewable Energy, Oxford University Press (2004) 77

78 Wave Energy Environmental Impacts 78

79 Wave Energy Environmental Impact Little chemical pollution Little visual impact Some hazard to shipping No problem for migrating fish, marine life Extract small fraction of overall wave energy Little impact on coastlines Release little CO 2, SO 2, and NO x 11g, 0.03g, and 0.05g / kwh respectively Boyle, Renewable Energy, Oxford University Press (2004) 79

80 Wave Energy Summary 80

81 Wave Power Advantages Onshore wave energy systems can be incorporated into harbor walls and coastal protection Reduce/share system costs Providing dual use Create calm sea space behind wave energy systems Development of mariculture Other commercial and recreational uses; Long-term operational life time of plant Non-polluting and inexhaustible supply of energy 81

82 Wave Power Disadvantages High capital costs for initial construction High maintenance costs Wave energy is an intermittent resource Requires favorable wave climate. Investment of power transmission cables to shore Degradation of scenic ocean front views Interference with other uses of coastal and offshore areas navigation, fishing, and recreation if not properly sited Reduced wave heights may affect beach processes in the littoral zone 82

83 Wave Energy Summary Potential as significant power supply (1 TW) Intermittence problems mitigated by integration with general energy supply system Many different alternative designs Complimentary to other renewable and conventional energy technologies 83

84 Future Promise 84

85 World Oceanic Energy Potentials (GW) Source Tides Waves Currents OTEC 1 Salinity World electric 2 World hydro Potential (est) 2,500 GW 2, , ,000 1,000,000 4,000 Practical (est) 20 GW NPA 4 2, Temperature gradients 2 As of Along coastlines 4 Not presently available Tester et al., Sustainable Energy, MIT Press,

86 Specific carbon dioxide emissions of various fuels 86

87 Solar Power Next Week 87