OCEAN POWER. No pollution. Offshore Wind: Noise, Aesthetics, Birds, Radar, Ship Collisions

Transcription

1 OCEAN POWER Advantages Renewable No pollution Disdvantages Expensive Offshore Wind: Noise, Aesthetics, Birds, Radar, Ship Collisions Future: Rapid development of offshore wind farms Increased use of other types?

2 MCT Marine Current Turbine Concept

3 Hydrokinetics 40 kw turbine Mississippi R. MIT Tech. Rev.

4 ALTERNATIVE ENERGY SOURCES HYDROELECTRIC, WIND, GEOTHERMAL, TIDAL, SOLAR WORLD ENERGY CONSUMPTION total equivalent to 18.4 x W continuous (2012) World Elec. 2.5 x W continuous (2012) USA electrical energy use 2016: x W cont x10 12 peak demand on 7/06 = 1.4 kw ea. = MWe (1 GW) power plants GLOBAL RENEWABLE SUPPLIES Solar 174,000 x W Hydrologic Potential 2.9 x W Photosynthesis 40 x W Conduction & Convection 31 x W Tidal 3 x W

5 TIDAL ENERGY Gravitational Bulge 2 High, 2 Low tides per day Original Kinetic Energy of Earth-Moon system Not solar energy Examples Rance Estuary, Brittany, France Tides to 44' tides English Channel) Floodgates, turbines peak capacity = 240 MW; avg output = 62 MW Bay of Fundy (tides of 18-50') Significant potential but undeveloped Total Amount Available on Earth 3 TW 16,000 MW realistically (<1%) < 2% of world's electrical use

6 Two Hi Tides, Two Low Tides per Day Moon most important Spring Tide Neap Tide

7 Bay of Fundy Tides Nova Scotia /pg4%20panoramas.htm

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9 750 m long 13 m high Average 68 MW

10 Wiki

11 Rance Estuary 240 MW peak /T206/4longtour.htm

12 TIDAL POWER Advantages Renewable No pollution Disadvantages Expensive Available in very few areas Small total amount available Future: Increased use with local benefit only

13 GEOTHERMAL ENERGY HEAT FLOW: Geothermal Gradient: avg ~25 C/km (range ~15 to 75 C/km) Heat flow = 59 mw/m 2 => 32 x W over Earth's surface Earth's Surface Area = 4 π R 2 = 5.08 x m 2 Heat Production (approx. steady state- but much higher in past e.g. 26 Al) Concentrated in crust: 238 U 235 U 232 Th 40 K decay; release heat High gradient areas limited geographically Volcanic areas Plate Boundaries (e.g. Ring of Fire) World reserves (top 3 km): est. 8 x J Many Countries USA (47%) Philippines Mexico Italy New Zealand Japan Iceland Total ~ 8400 MWe Regionally important, but globally insignificant for electricity generation Possibly very important for space heating.

14 mw/m 2 SMU/Blackwell

15 Bumpass Hell, CA Criss

16 GEOTHERMAL FIELDS Dry Steam Geysers, CA < 2000 MWe Larderello Italy Sufficient for San Francisco + Oakland Wet Steam Wairakei, NZ Brines: Corrosion, scaling problems Imperial Valley 320 C; >25 wt % salts Hot Dry Rock Geopressured Zones: TX & LA m depth Hot water (175 C) & methane; Potential mechanical energy (overpressure) Low Grade Heat: (space heating) Iceland, Idaho St. Louis- home heating and cooling systems now commercially available

17 GEYSERS < 2000 MW Sufficient for San Francisco + Oakland Steam field ~ 5 x 15 miles Reservoir: ~ 240 C superheated steam > 300 wells; avg. depth 7900' >50 miles of steam lines Reinject condensate Environmentally benign, except H 2 S As Hg etc. Geology J-K Franciscan rocks- ancient subduction complex Fractured greywacke-main host of steam reservoir Low porosity: % avg. 2.3% Underlying, cross-cutting Pleistocene felsic pluton ( Ma; Clear Lake Volcs) Active magma chamber must be present nearby Commercial Development: First Production: 1960 (12 MW) Field peaked in 2100 MW Production now 11%/yr; now 900 MW => Now injecting treated wastewater from Santa Rosa => Continued reduction in steam production expected => Not Renewable!

18 The Geysers, CA 900 MW

19 Idaho State Capitol The only geothermally-heated capitol building in the USA visitid.org

20 BOISE, ID NREL

21 Geothermal Aquaculture in

22 Geothermal Aquaculture in Southern Idaho

23 Reyjkjavik Iceland ~100% geothermal /types/geotherm/

24 Deep, Enhanced Geothermal Schiegg et al (2015) JES 26, 37-46

25 GEOTHERMAL ENERGY Advantages Clean, Renewable (?), No combustion Always Available Ubiquitous (low grade) Much potential for space heating Disdvantages Future: Hottest systems are not really renewable Hot Systems are rare Brines EQs? Minor electrical power production Hot dry rock; Electro-pulse boring Greatly increased use for space heating

26 BIOMASS San Diego Nov 2009 Landfill methane Sewage, animal waste fermentation => CH 4 Combustion of forest residues Alternative fuels from crops Ethanol Biodiesel NREL

27 Distillation Columns Windsor, CO 40 Mgal/y NREL

28 Granite City, IL Criss

29 usda.gov

30 Corn 130 bushels per 70 lbs / bushel ~ 4 tons/acre USA per capita energy consumption 3.3 tons oil 3.8 tons coal 1.7 tons gas 8.8 tons/y Ethanol: less pollution but lower fuel economy E85 (85% ethanol : 15% gasoline) E10 (10% ethanol : 90% gasoline) ~ 5 billion gal/year < 2% of USA oil consumption (which is 19 Mbbl/day = 0.8 Bgal/d)

31 Pimentel, D and Patzek, TW (2005), Natural Resources Research, v. 14#1, p Ethanol production using corn grain required 29% more fossil energy than the ethanol fuel produced Ethanol production using switchgrass required 50% more fossil energy than the ethanol fuel produced Ethanol production using wood biomass grain required 57% more fossil energy than the ethanol fuel produced Biodiesel production using soybean required 27% more fossil energy than the biodiesel fuel produced Biodiesel production using sunflower required 118% more fossil energy than the biodiesel fuel produced Ethanol production does not provide a net energy balance, ethanol is not a renewable energy source, is not an economical fuel, and its production and use contribute to air, water, and soil pollution...

32 Sugar Cane Alcohol Car Brazil T206/3longtour.htm

33 Wheelabrator, Shasta 49 MW Biomass (Wood Chips) Power Plant Anderson, CA, NREL

34 BIOMASS POWER Advantages Renewable No net CO2 production Available throughout world Disadvantages Expensive Food cost increase Net energy loss in many cases Future: Increased use for fuels Cellulosic ethanol

35 ALTERNATIVE ENERGY SOURCES HYDROELECTRIC, WIND, GEOTHERMAL, TIDAL, SOLAR WORLD ENERGY CONSUMPTION total equivalent to 18.4 x W continuous (2012) World Elec. 2.5 x W continuous (2012) USA electrical energy use 2016: x W cont x10 12 peak demand on 7/06 = 1.4 kw ea. = MWe (1 GW) power plants GLOBAL RENEWABLE SUPPLIES Solar 174,000 x W Hydrologic Potential 2.9 x W Photosynthesis 40 x W Conduction & Convection 31 x W Tidal 3 x W

36 4/26/17 12:00UT NASA SOHO