Chemical, Biological and Environmental Engineering Geothermal
Energy
Slide 2
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
Slide 3
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)
Slide 4
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?)
Slide 5
Advanced Materials and Sustainable Energy Lab CBEE Approaches
to Geothermal
Slide 6
Advanced Materials and Sustainable Energy Lab CBEE Hydrothermal
system and temperature gradient Example temperature gradient
Usually listed as T in o C/km
Slide 7
Advanced Materials and Sustainable Energy Lab CBEE Gradient has
strong impact on facility costs
Slide 8
Advanced Materials and Sustainable Energy Lab CBEE Estimates of
electricity cost
Slide 9
Advanced Materials and Sustainable Energy Lab CBEE
Slide 10
Advanced Materials and Sustainable Energy Lab CBEE Geothermal
Installations
Slide 11
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
Slide 12
Chemical, Biological and Environmental Engineering Ocean
Energy
Slide 13
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
Slide 14
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
Slide 15
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)
Slide 16
Advanced Materials and Sustainable Energy Lab CBEE
Slide 17
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)
Slide 18
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
Slide 19
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.
Slide 20
Advanced Materials and Sustainable Energy Lab CBEE Sites with
tidal opportunities
Slide 21
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
Slide 22
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
Slide 23
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
Slide 24
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)
Slide 25
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.
Slide 26
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
Slide 27
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
Slide 28
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
Slide 29
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
Slide 30
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)
Slide 31
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)
Slide 32
Oregon State University, School of Electrical Engineering and
Computer Science Linear Test Bed with SeaBeav & Wave Energy
Team
Slide 33
Advanced Materials and Sustainable Energy Lab CBEE OSUs
work
Slide 34
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.
Slide 35
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
Slide 36
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
Slide 37
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