the future of geothermal energy -- can it become a major...
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Jeff TesterCroll Professor of Sustainable Energy Systems
School of Chemical and Biomolecular
EngineeringDirector of the Cornell Energy Institute
and Associate Director for Energy
Cornell Center for a Sustainable Future Cornell Universityjwt54@cornell .edu
607-254-7211
Geothermal energy today resources from hydrothermal systems to hot dry rock applications for direct heating/cooling and electricity
An assessment of US potential Lessons learned in 30+ years of progress on EGS technology A pathway to universal heat mining with technology improvements
The Future of Geothermal Energy --
Can it become a major supplier of primary energy in the U.S.?
Utilization of Geothermal Energy 1.
For Electricity --
As thermal energy for generating electricity2.
For Heating --
direct use of the thermal energy in district heating or in industrial processes
3.
For Geothermal Heat Pumps –
as a source or sink of moderate temperature energy in heating and cooling applications
Earth’s Geosphere
Looking to “inner space”
for opportunities in the Earth’s Geosphere
Accessible Pressure –Temperature DomainEarth’s Geosphere
Geothermal energy in use today
• An accessible, sufficiently high temperature rock mass underground
• Connected well system with ability for water to circulate through the rock mass to extract energy
• Production of hot water or steam at a sufficient rate and for long enough period of time to justify financial investment
• Means of directly utilizing or converting the thermal energy to electricity
Geothermal systems –
common characteristics and limitations
Hydrothermal Reservoirs
Geothermal started producing electricity in Italy at Larderello
in 1904 over 100 years ago
• In 50 years Iceland has transformed itself from a country 100% dependent on imported oil to a renewable energy supply based on geothermal and hydro
• >95% of all heating provided by geothermal district heating
• >20% of electricity from geothermal – remainder from hydro
• 2 world scale aluminum plants powered by geothermal
• Currently evolving its transport system to hydrogen/hybrid/electric systems based on high efficiency geothermal electricity
Geothermal has enabled Iceland’s transformation
Condensers and cooling towers, The Geysers, being fitted with direct contact condensers developed at NREL
The Blue Lagoon in Iceland
Today there are over 11,000 MWe
on-line or under construction--
USA --
4000+ MWe
up from 2544 MWe
in 2005
Total installed by December 2009 –
11,000 MWe
A.S. Batchelor, 2005; Bertani,2008; and GEA, 2009
How is Mexico doing?
Luis C.A. Gutiérrez‐Negrín1,3, Raúl Maya‐González2 and
José
Luis Quijano‐León3
1Geocónsul, 2Comisión Federal de Electricidad, 3Mexican Geothermal Association. Mexico
Session 5E: Country updates
Mexican Volcanic Belt
Los Azufres 188 MW
Cerritos Colorados (Potential: 75 MW)
Cerro Prieto 720 MW
Los Humeros 40 MW
Las Tres Vírgenes 10 MW
• Total geothermal‐electric
installed capacity (net): 958
MW• Total electric generation
in 2009: 6,793 GWh• National average CF:
80.9%• Fields and power units are
owned and operated by CFE
Total: 51,718 MW
• From its beginning in the Larderello Field in Italy in 1904, over 11,000 MWe of on-line capacity worldwide today
• Additional capacity with direct use and geothermal heat pumps (e.g >100,000 MWt worldwide)
• Current costs -- 7–10¢/kWh• Attractive technology for
dispatchable, base load power for both developed and developing countries
Geothermal energy today for heat and electricity
Condensers and cooling towers, The Geysers, being fitted with direct contact condensers developed at NREL
But geothermal today is limited tohigh grade, high gradient sites with existing
hydrothermal reservoirs !!
Enhanced/Engineered Geothermal Systems (EGS) could provide a pathway to universal heat mining
EGS defined broadly as engineered reservoirs that have been stimulated to emulate the production properties of high grade
commercial hydrothermal resources.
Average surface geothermal gradientfrom Blackwell and Richards, SMU (2006)
A range of resource types and gradeswithin the geothermal continuum
• Hydrothermal• Conduction-dominated
EGS• Volcanic EGS• Co-produced fluids• Geopressured
6
Three critical ingredients for successful heat mining 1. sufficient temperature
at reasonable depth2. sufficient permeability 3. sufficient hot water or
steam
The Future of Geothermal Energy
Environmental concerns and benefits
Benefits Land use – small “footprint” compared to alternatives Low emissions, carbon-free base load energy No storage or backup generation needed Adaptable for district heating and co-gen / CHP applications
Concerns Induced seismicity must be monitored and managedWater use –
will require effective control and
management, especially in arid regions
Ormat’s
5 MWe
organic binary plant in Nevada operates with no cooling water consumption!
Water availability and proper water management are important in certain regions
The footprint of geothermal power developments is small
Source -
The Future of Geothermal Energy, MIT report (2006)
Effect of Geothermal Deployment (EGS) on CO2 Emissions from US Electricity Generation1,2
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Curren
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100 G
W E
GS20
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EGS
300 G
W E
GS
Curren
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100 G
W E
GS20
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EGS
300 G
W E
GS
Curren
t
100 G
W E
GS20
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EGS
300 G
W E
GS50
0 GW
EGS
Bill
ion
Met
ric T
onne
s of
CO
2 pe
r yea
r
2006 EIA3
4092 TWh Generation1.0 TWe Capacity
2030 EIA Projection3
5800 TWh Generation1.2 TWe Capacity
Constant Growth to 2100Assuming 2030 Energy Mix
10200 TWh Generation2.3 TWe Capacity
Notes: 1. 95% capacity factor assumed for EGS 2. Assumes EGS offsets CO2 emissions from Coal and Natural Gas plants only 3. EIA Annual Energy Outlook 2007 15
The Geothermal Option –A undervalued opportunity for the US
?
Is there a feasible path from today’s hydrothermal systems with 3000 MWe
capacity to tomorrow’s Enhanced Geothermal Systems (EGS) with 100,000 MWe
or more capacity by 2050 ?
Average surface geothermal gradientfrom Blackwell and Richards, SMU (2006)
Hydrothermal
EGS
The Future of Geothermal Energy
Transitioning from Today’s Hydrothermal Systems toTomorrow’s Engineered Geothermal Systems (EGS)
An MIT–
led study by an 18-
member international panel
--
Primary goal: to provide an independent and comprehensive evaluation of EGS as a major US primary energy supplier
--
Secondary goal: –
to provide a framework for informing policy makers of what R&D support and policies are needed for EGS to have a major impact
Full report available athttp://www1.eere.energy.gov/geothermal/
future_geothermal.html
1.
Retirements of old coal and nuclear units
In the next 15 to 20 years 40 GWe of “old” coal-fired capacity will need to be retired or updated because of a failure to meet emissions standards
In the next 25 years, over 40 GWe of existing nuclear capacity will be beyond even generous re-licensing procedures
2.
Projected availability limitations and increasing prices for natural gas
are not favorable for large increases in electric generation capacity for the foreseeable future
3.
Public resistance to expanding nuclear power
is not likely to change in the foreseeable future due to concerns about waste and proliferation. Other environmental concerns will limit hydropower growth as well
4.
High costs of new clean coal plants
as they have to meet tightening emission standards and may have to deal with carbon sequestration.
5.
Infrastructure improvements
needed
for interruptible renewables including storage, inter-connections, and new T&D are large
A key motivation --
US electricity capacity is now at 1 TWe
(1,000,000 MWe) and threatened
Geothermal provides base load, dispatchable
power
Multidisciplinary EGS Assessment Team
Panel Members Jefferson Tester, chair, Cornell & MIT, chemical engineer Brian Anderson, University of West Virginia, chemical engineer Anthony S. Batchelor, GeoScience, Ltd, rock mechanics and geotechical engineer David Blackwell, Southern Methodist University, geophysicist Ronald DiPippo, power conversion consultant, mechanical engineer Elisabeth Drake, MIT, energy systems specialist, chemical engineer John Garnish, physical chemist, EU Energy Commission (retired) Bill Livesay, Drilling engineer and consultant Michal Moore, University of Calgary, resource economist Kenneth Nichols, Barber-Nichols, CEO (retired), power conversion specialist Susan Petty, Black Mountain Technology, reservoir engineer Nafi Toksoz, MIT, seismologist Ralph Veatch, reservoir stimulation consultant, petroleum engineer
Associate Panel Members Roy Baria, former Project Director of the EU EGS Soultz Project , geophysicist Enda Murphy and Chad Augustine, MIT chemical engineering research staff
Maria Richards and Petru Negraru, geophysists, SMU Research Staff
Support Staff Gwen Wilcox, MIT
The Future of Geothermal Energy
Estimated Temperaturesat Specific Depths
7
U.S. Geothermal resource is large and underutilized
1 EJ = 10+18
J or about 10+15
BTUAnnual US energy consumption = 100 EJ
Estimated total geothermal resource base and recoverable resource given in EJ or 10+18 Joules.
1,000,000 EJ10,000 x US use
A key question -- how much could be captured and used?
The Future of Geothermal Energy
30+ Year History of EGS Research
EGS COREKNOWLEDGE
BASE
CooperBasin
(Australia)
FentonHill(USA)
Soultz(EU)
Rose-manowes
(UK)
Hijiori
&Ogachi
(Japan)
FutureUS EGSProgram
Coso,DesertPeak(US)
Basel(Swiss)
Landau(German)
TBD
Developing stimulation methods to create a well-connected reservoir
The critical challenge technically is how to engineer the system to emulate the productivity of a good hydrothermal reservoir
Connectivity is achieved between injection and production wells by hydraulic pressurizationand fracturing
“snap shot” of microseismic events duringhydraulic fracturing at Soultz from Roy Baria
Mapped microseismic
events plotted in plan view during hydraulic stimulation in
the Cooper Basin In Australia
Scale in meters
Large stimulated reservoirvolumes are created byhydraulic pressurization
EGS Reservvoir
at Soultz, France from Baria, et al.
• Fenton Hill, Los Alamos US project• Rosemanowes, Cornwall, UK Project• Hijori, et al , Japanese Project• Soultz, France EU Project• Cooper Basin, Australia Project, et al.
• directional drilling to depths of 5+ km & 300+oC• diagnostics and models for characterizing size and
thermal hydraulic behavior of EGS reservoirs• hydraulically stimulate large >1km3 regions of rock• established injection/production well connectivity
within a factor of 2 to 3 of commercial levels• controlled/manageable water losses• manageable induced seismic and subsidence effects• net heat extraction achieved
R&D focused on developing technology to create reservoirs That emulate high-grade, hydrothermal systems
30+ years of field testing at
has resulted in much progress and many lessons learned
1. Commercial level of fluid production with anacceptable flow impedance thru the reservoir
2. Establish modularity and repeatability of the technology over a range of US sites
3. Lower development costs for low grade EGS systems
A robust research program in geoscience
and
engineering would contribute significantly to:• better characterization of in situ stresses and fracture propagation mechanisms
• improved hydraulic stimulation procedures• enhanced fracture mapping with improved
reservoir connectivity
• better understanding of induced seimicity• improved models of thermal hydraulic
performance
• improved understanding of borehole
breakout mechanisms and stability issues
Although much has been accomplishedthere are a few things left to do
And today the Australians are making progress
Cooper Basin geothermal resource. One of the best sites in world
for Hot Fractured Rock (HFR) geothermal electricity generation -
potential for 1000’s MW generating capacity.
in 2008 --
2010 Wellhead flow rate 18 kg/s
at 275 bar, 208 -
250 oC
And the Australians are continuing to make progress
0
20
40
60
80
100
% of
TotalCost
High GradeHydrothermal (<3 km)
Mid-Grade EGS (3-6 km)
Low Grade EGS (6-10 km)
Drilling and Reservoir Stimulation Power Plant
As EGS resource quality decreases, drilling and stimulation costs dominate
But the economics of EGS still need to be proven
Major impact with higher uncertainty and risk --• Flow rate per production well (20 to 80 kg/s )• Thermal drawdown rate / redrilling-rework periods (3% per year / 5-10 years)• Resource grade – defined by temperature or gradient = f(depth, location)• Financial parameters
• Debt/Equity Ratio (70/30 to reflect industry practice)• Debt rate of return (5.5 -8.0%)• Equity rate of return (17%)
• Drilling costs
Lesser impact but still important --• Surface plant capital costs• Exploration effectiveness and costs • Well field configuration -- 5 production wells / 4 injection wells• Flow impedance• Stimulation costs • Water losses • Taxes and other policy treatments
Factors controlling the economics of EGS
Parametric analysis of capital and levelized
electricity costs (LEC) : 1. Drilling depths: 3 km to 10 km2. Average temperature gradients from 10°C per km to 100°C per km 3. Production well flow rates of 20, 40, 60, 80 and 100 kg/s. 4. Geofluid production temperatures : 100°C - 400°C5. Six different drilling cost cases6. Two electricity price scenarios
0
2
4
6
8
10
12
10 100 1,000 10,000 100,000EGS Capacity Scenario (MWe)
Bre
ak-e
ven
Pric
e (¢
/kW
h)
MIT EGS model predictions with today’s drilling and
plant costsand mature reservoir
technology at 80 kg/s per production well
EGS supply curve
Economics of EGS –
sensitivity analysis and supply curve projections
DOE Workshop June 7, 2007 The Future of Geothermal EnergyHigh impact levels for EGS are estimated with a modest investment
for research, development and deployment over a 15 year period
Supply Curve for EGS Electricity
From Blackwell and Richards (June, 2007)
In simpler terms, with EGS working at depths to 6 kmall of the US becomes a viable geothermal resource
ACOCULCO ‐
‐
2 wells
about
2 km
deep
where
drilled
by CFE‐
Very
high
temperatures
( >300oC) ‐
But
very
low
permeability
–
requires
stimulation
Opportunities exist in Mexico for high grade EGS geothermal resourcessuitable for electric power generation
ACOCULCO‐Two
deep
wells
finished
in granite. Very
high
temperature
but
low
permeability
‐With
EGS
techniques
it
could
be fractured
to
increase
permeability
in
the
nearby
reservoir
of
both
wells
to
produce
some7 MW each
‐Or
to
build
a EGS by
hydraulic
fracturing
to
form
adoublet. Inject
water
in one
and
recover
steam
in the
other
The Future of Geothermal Energy
1.
Large, indigenous, accessible base load power resource – 14,000,000 EJ of stored thermal energy accessible with today’s technologies. Key point -- extractable amount of energy that could be recovered is not limited by resource size or availability
2.
Fits portfolio of sustainable renewable energy options
- EGS complements the existing portfolio and does not hamper the growth of solar, biomass, and wind in their most appropriate domains.
3. Scalable and environmentally friendly
– EGS plants have small foot prints and low emissions – carbon free and their modularity makes them easily scalable from large size plants.
4. Technically feasible
-- Major elements of the technology to capture and extract EGS are in place. Key remaining issue is to establish inter-well connectivity at commercial production rates – only a factor of 2 to 3 greater than current levels.
5.
Economic projections favorable
for high grade areas now with a credible learning path to provide competitive energy from mid- and low-grade resources
6.
Deployment costs modest
-- an investment of $200-400 million over 15 years would demonstrate EGS technology at a commercial scale at several US field sites to reduce risks for private investment and enable the development of 100,000 MWe.
7.
Supporting research costs reasonable
– about $40 million/yr needed for 15 years -- low in comparison to what other large impact US alternative energy programs will need to have the same impact on supply.
Summary of major findings
The Future of Geothermal Energy
Recommended path for enabling 100,000 MWefrom EGS by 2050
Support site specific resource assessment
Support 3-5 field EGS demonstrations at commercial-
scale production rates
Short term --
develop high grade EGS sites at the margins of hydrothermal reservoirs and in high gradient regions at depths of 3 to 6 km for power generation
Longer term develop lower grade EGS sites requiring deeper heat mining at depths >6 km for co-generation
Maintain vigorous R&D effort on subsurface science, geo-engineering, drilling, energy conversion, and systems analysis for EGS
Invest a total of $1000 million for deployment assistance and for research, development and demonstration over 10 years
Less than the price of one clean coal plant !And, provide a comparable amount of R&D support for conventional hydrothermal
Advanced Geothermal TechnologiesAdvanced Geothermal Technologies
1. Expanding direct use and cogeneration with lower grade resources
2. Spallation drilling using hydrothermal flames and jets --
MIT/ETH/Cornell
3. Increasing efficiency by going deeper to supercritical conditions (Icelandic IDDP)
4. Ultra high grade geothermal energy from submarine hydrothermal vents (Mexico, Hiriart, et al)
Pools, etc.
Comm.Space
Heating
Resid.Water Heating
Comm.WaterHeating
Comm. AC
Clothes Dryer
Resid.SpaceHeating
Resid. Refrig.
Industrial Process Steam
Resid. AC
Cooking
Opportunities for direct use below 250oC are substantial
Represents about 35% of total US demand in 2008
Fox, Sutter, Tester (2010)
US Energy demand versus temperature
Example 1 Advanced technology for continuous drilling
using thermal spallation/fusion
Low density oil-air flame drilling in open boreholes
Hydrothermalflames at
high density
usingCH4
, H2
, CH3
OH
Spallation drilling using hydrothermal jets
Flame jet spallation atatomspheric
pressures
• Visible combustion flames produced in a supercritical water environment ( P > 220 bar)
• Temperature at center of flame can reach over 3000 K, but subcritical water temps at wallsT ~ 2500 K/cm)
• Hydrogen, methanol and methane fuels considered
Research focus is on experimental and theoretical studies of hydrothermal flames and jets in supercritical water.
Contributing researchers –
Chad Augustine and Hildigunnur
Thorsteinssonand Prof. Philip von Rohr and colleagues at ETH in Zurich
Our research is extending spallation/fusion drilling to deep well drilling using hydrothermal jets
Drilling Costs –Actual and Predicted
Actual oil and gas well costs
JAS database
Actual geothermal well costsMIT and Sandia databases
Livesay
WellCost
Lite
model EGS well predictions +/-
25%
Advanced drilling technologies cases1-3
NB –normalization to 2004 $ using MIT drilling cost index
The Future of Geothermal Energy
0
5
10
15
20
25
30
Wel
lcos
t Lite
+25
%W
ellc
ost L
ite B
ase
Wel
lcos
t Lite
-25%
Cas
e 1
Cas
e 2
Cas
e 3
Wel
lcos
t Lite
+25
%W
ellc
ost L
ite B
ase
Wel
lcos
t Lite
-25%
Cas
e 1
Cas
e 2
Cas
e 3
Wel
lcos
t Lite
+25
%W
ellc
ost L
ite B
ase
Wel
lcos
t Lite
-25%
Cas
e 1
Cas
e 2
Cas
e 3
LEC
cen
ts/k
Wh
LEC - this study
Base Case Feasibility at 2050
High Case Feasibility at 2050
Predicted Breakeven Electricity Prices(LEC) 5 km and 60°C/km -
20 kg/s
60 kg/s 80 kg/s
The Future of Geothermal Energy
Levelized energy costs vary with resource grade and reservoir productivity and drilling costs
223.4¢
41.1¢
18.0¢ 13.2¢
64.3¢
12.9¢6.3¢ 5.3¢
32.3¢
7.6¢ 4.1¢ 4.3¢
0
50
100
150
200
250
20°C/km 40°C/km 60°C/km 80°C/km
Average Temperature Gradient
LEC
¢/k
Wh
Today's drilling technologywith 20 kg/s flow rate
Today's drilling technologywith 80 kg/s flow rate
Advanced drilling technologywith 80 kg/s flow rate
6 km depth
6 km depth
6 km depth 4 km depth
Accessible Pressure –Temperature DomainEarth’s Geosphere
Geothermal energy in use today
High efficiency electric power at supercritical conditions
Iceland moves toward utilizing supercritical geothermal water
Iceland’s natural supercritical water region
If IDDP is successful it will enable a new generation of ultra high efficiency geothermal power generation
Accessible Pressure –Temperature DomainEarth’s Geosphere
What
do we
know now
about
Ocean
Ridges
• There
are 67,000 km
of
Ocean
Ridges,
representing
30% of
all
heat
released
by the
earth
• 13,000 km
have
been
already
studied,
representing
20% of
the
Ridges
of
the
World
• 280 sites
of
geothermal
vents
have
been
discovered, representing
3,900
km
of
active vents
• Baker
has reported
“…up to
100 km
of
uninterrupted
vents…”
…. some
of
them
with
a thermal
power
of
up to
6,000 MWt…
• What
if
we
use only
1% of
the
known
vents
to
generate
electricity?
67,000 KmOcean
Ridges
13,000 KmExplored
3,900 Km
With
good
vents
1 % usable 39 km
!
T = 250°CTsink
10°C
10 cm
1 m
V = 1 m/s
Q= 240x4187x1x0.1=100 MWt
/m
Thermal
power
of
an
hydrothermal
vent
45% Carnot 90% Turbine
η
=10 %
Total transformation
efficiency
(0.1x0.45x0.90)
η
= 4
%
Specific
Electric Power= 100 MWt
x 0.04 = 4 MW/m
Total Electrical
Power
in 39 km……156 000 MW!!
Schematic representation of a binary submarine generator
Thank you for listeningThank you for listening
Please read our report athttp://www1.eere.energy.gov/geothermal/future_geothermal.html
Acknowledgements
We are especially grateful to the US DOE for its sponsorship and
to many members of US and international geothermal community for their assistance, including Roy Mink, Allan Jelacic, Joel Renner,Jay
Nathwani, Greg Mines, Gerry Nix, Martin Vorum, Chip Mansure, Steve Bauer, Doone
Wyborn, Ann Robertson-Tait, Pete Rose, Colin Williams, Mike Wright, Roland Horne, Hidda
Thorsteinsson
and Valgardur
Stefansson
Acknowledge Support for the Project provided by the Geothermal Division and its Laboratories
Idaho National Laboratory
National Renewable Energy Laboratory
Sandia National Laboratories
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