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Chemical, Biological and Environmental Engineering Geothermal Energy

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Advanced Materials and Sustainable Energy Lab CBEE Geothermal Power Principle: Heat in earths core can be tapped for human use. Near-surface access to this heat is a potential energy source. Only large scale renewable that does not depend on sun US current: 2500 megawatts of electricity equivalent to three large nuclear power plants Potential: 12,000 megawatts by the year 2010 49,000 megawatts by 2030

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Advanced Materials and Sustainable Energy Lab CBEE Geothermal Resources Natural Hydrothermal reservoir Spontaneously produces hydrothermal fluid Hot water or water/steam mixture: Liquid dominated High quality steam (saturated?): vapor dominated Geopressurized Reservoir of pressurized hot water that does not generate hydrothermal fluid at surface Hot Dry Rock Rocks at ca. 200 o C+ but have no fluid Drill and inject water to generate fluid at surface Magma Molten rocks (650 o C+) at accessible depths Harvesting heat is a real problem (i.e., we dont know how to)

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Advanced Materials and Sustainable Energy Lab CBEE Issues Hydrothermal fluid can have entrained particles and/or salts and gases dissolved Vapor dominated: direct use Liquid dominated: Flash into steam (salts/entrained solids?) Can diminish deposition of solids by chemical treatment Run through heat exchanger What to do to spent hydrothermal fluid (brine like) Reinject (increases BWR?) Surface waste (environmental impact?)

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Advanced Materials and Sustainable Energy Lab CBEE Approaches to Geothermal

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Advanced Materials and Sustainable Energy Lab CBEE Hydrothermal system and temperature gradient Example temperature gradient Usually listed as T in o C/km

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Advanced Materials and Sustainable Energy Lab CBEE Gradient has strong impact on facility costs

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Advanced Materials and Sustainable Energy Lab CBEE Estimates of electricity cost

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Advanced Materials and Sustainable Energy Lab CBEE

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Advanced Materials and Sustainable Energy Lab CBEE Geothermal Installations

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Advanced Materials and Sustainable Energy Lab CBEE Geothermal heat pumps Also known as shallow geothermal Principle: use ground as heat source/heat sink, increase efficiency of heat pump *not* a direct source of energy, but efficiency booster -about 8 PJ/y -reduce need for new generating capacity

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Chemical, Biological and Environmental Engineering Ocean Energy

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Advanced Materials and Sustainable Energy Lab CBEE Ocean Energy Ocean Thermal Energy Conversion (OTEC) Use warm surface water (25 o C +) and cold deep (1km) water (5 o C) Tidal Energy Use water level differential between enclosed tidal basin and ocean, use water for low head hydro Wave Energy Capture surge/heave motion of water to power generator

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Advanced Materials and Sustainable Energy Lab CBEE OTEC Need to pump cold deep water to surface Hard to support weight of pipes, so needs to be built close to land (Hawaii and Taiwan (were) big on this) Can use cold water for other uses: HVAC, irrigation by condensation, aquaculture Operate on Rankine cycle Low pressure water Rankine (higher BWR because need to lower pressure) Organic Rankine cycle (butane, isobutane, methylamine, ammonia) Many big challenges Corrosion/biofouling of seawater systems is main one

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Advanced Materials and Sustainable Energy Lab CBEE OTEC Ocean Thermal Energy Conversion Use warm surface water (25 o C +) and cold deep (1km) water (5 o C)

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Advanced Materials and Sustainable Energy Lab CBEE

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Advanced Materials and Sustainable Energy Lab CBEE Tidal Power Use water level differential between enclosed tidal basin and ocean, use water for low head hydro Tides very predictable Principle dates back to roman era (I grew up not far from one)

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Advanced Materials and Sustainable Energy Lab CBEE Key parameter(s) Tidal period T (T 12.5h 4.5x10 4 s) Tide height h Tidal basin area A Theres a better model in the Hodges book, but we dont have the time to discuss in detail

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Advanced Materials and Sustainable Energy Lab CBEE La Rance The largest tidal power plant in the world is the 240 MW (max) La Rance in France, built in the 1960s. Average power generation is 68 MW 330m dam contains a 22 square km basin Average tides of 8m.

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Advanced Materials and Sustainable Energy Lab CBEE Sites with tidal opportunities

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Advanced Materials and Sustainable Energy Lab CBEE Tidal Power: hydrokinetic energy Under research (NNMREC!): Tidal stream systems working like wind turbines No dam required, just natural flows through currently established channels Admiralty Inlet, WA has 3.5 kts Sechelt Rapids, BC has 15 kts currents (!) 35 kW max capacity turbine

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Advanced Materials and Sustainable Energy Lab CBEE Impact of Tidal Systems Fish killed in turbines, stopped from natural spawning migrations (e.g., eel, salmon, plaice) Noise from turbines also must be considered Intertidal wet/dry habitat modified Water quality may be affected due to dampened transport Even tidal stream systems will affect this (big part of NNMERC work) Blockage to navigation

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Advanced Materials and Sustainable Energy Lab CBEE Wave Power Estimated as a very large resource (up to 2 TW worldwide technically accessible resource) Attempt to harness energy not new first descriptions date to 1799 Many concepts: Overtopping devices Oscillating water column (OWC) Floating devices (point absorbers, etc) hose pumps Hinged flap devices Etc The early bird gets the worm but the second mouse gets the cheese

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Advanced Materials and Sustainable Energy Lab CBEE How much power in a wave? Where P mcl is the power per meter of crest length is the wavelength of the wave Wave power potential per meter varies with the square of the wave height and linearly with the period. A 3 meter wave with an 8 second period produces about 36 kW/mcl A 15 meter wave with a 15 second period produces about 1.7 MW/mcl (there arent many 15 meter waves near shore, thank God)

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Oregon State University, School of Electrical Engineering and Computer Science Power From Ocean Waves [George Hagerman] Wave energy is strongest on the west coasts and increases toward the poles. At approx. 30 kW/mcl in the Northwest (yearly avg.), a single meter (3.3 feet) of wave has the raw energy to power about 23 homes.

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Advanced Materials and Sustainable Energy Lab CBEE Most devices capture heave energy only Therefore only of possible power harvested What does that mean for max efficiency? (dont have an answer) Heave (up and down) Surge (back and forward) Water particle orbital motion

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Advanced Materials and Sustainable Energy Lab CBEE Oscillating Water Column (OWC) Heave motion of water in enclosed chamber moves air in/out of chamber ( think Spouting Horn blowhole at Cape Perpetua) Air turbine in vent harnesses energy Can be onshore or offshore buoy For a great illustration see http://daedalus.gr/OWCsimulation2.html http://daedalus.gr/OWCsimulation2.html

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Advanced Materials and Sustainable Energy Lab CBEE Salters Duck Shape carefully chosen to follow particle trajectory 90% efficient with monochromatic waves (i.e., wave had exactly the right wavelength to fit the chosen shape) Efficiency decreased rapidly if detuned

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Advanced Materials and Sustainable Energy Lab CBEE Overtopping Devices Wave flows up a channel to create low head hydro Can use devices to focus waves into channel Example shown: tapered channel (TAPCHAN) Wave Dragon

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Advanced Materials and Sustainable Energy Lab CBEE Linear Generator Point Absorber (OSU!) Relative motion between two devices at surface History: 1998 AvJ started writing NSF proposals for wave energy (no one else working on this at the time) 2001 finally some funding ($500k cut to $280k due to NSF budget) 2004 concept picks up steam 2008 Northwest National Marine Renewable Energy Center (NNMERC)

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Oregon State University, School of Electrical Engineering and Computer Science OSU Strategic Facilities to Advance Wave Energy O.H. Hinsdale Wave Research Lab (HWRL) Wallace Energy Systems & Renewables Facility (WESRF)

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Oregon State University, School of Electrical Engineering and Computer Science Linear Test Bed with SeaBeav & Wave Energy Team

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Advanced Materials and Sustainable Energy Lab CBEE OSUs work

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Oregon State University, School of Electrical Engineering and Computer Science National Marine Renewable Energy Center Demonstrate and compare existing technologies Research and develop advanced systems Investigate efficient and reliable utility integration/intermittency issues Advance wave forecasting technologies Conduct experimental and numerical modeling for device and wave park array optimization Evaluate potential environmental and ecosystem impacts Establish protocols for outreach/engagement and how the ocean community best interacts with wave energy devices and parks Refine wave energy power measurement standards Improve wave energy device identification/navigation standards Offer wave energy educational workshops Enable enhanced testing of instruments, etc.

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Advanced Materials and Sustainable Energy Lab CBEE Lysekil project Buoy floating at surface pulls on cable driving generator OPT generator is at surface (on buoy) instead of on bottom This is what is going into Reedsport

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Advanced Materials and Sustainable Energy Lab CBEE Submerged buoyancy device Archimedes wave swing Pressure from wave at surface decreases volume of trapped air Buoyancy decreases, float sinks harvesting energy

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Advanced Materials and Sustainable Energy Lab CBEE Initial industrial development Worlds first large experimental wave park in Portugal (early bird or second mouse?) Three Pelamis devices: 142m long, 3.5 m diameter (700 tons of steel) Hydraulic ram between each segment harvests power 2.25 MW capacity