Transcript Geothermal Technologies Program Overview

Geothermal Power Potential
Energy and Climate Mini-Workshop
November 3, 2008
Chuck Kutscher
National Renewable Energy Laboratory
Geothermal in the Energy Portfolio
Net Generation – 2006
Source: EIA Annual Energy Review 2007
U.S. Renewable Energy Electric Capacity
Sources: Chalk, AWEA, IEA, NREL, EIA, GEA
Geothermal Resources
Volcanic
Hydrothermal
Magma
Geopressured
Hot
water
Wells
Enhanced
Geothermal
System
Hot granite
Carbon Benefits
Advantages of Geothermal Energy
•
Environmentally sound
•
Resources last the life of the plant
•
High plant availability (over 95%)
•
Provides steady base load power
•
Relatively low cost (5 to 8 cents per kWh)
Today’s Status
• 8,000 MW generated in 21
countries
• In U.S. 3,000 MWe installed,
4,000 MWe under development
• DOE funding 21 companies
$43 million over 4 years for
EGS projects
• Cost 5-8¢/kWh with no PTC
• Capacity factor typically > 90%,
base load power
Hydrothermal Resource
GEOTHERMAL
Geothermal Power Plants
Plant Type vs. Temperature
Flash steam
175oC
(350oF)
90oC
(195oF)
0oC
32oF)
Binary cycle
Generator
Air and
Water Vapor
Steam
Air
Air
Water
Waste Brine
Production
Well
Geothermal Zone
Direct
Heat
Uses
Injection
Well
G A0 2 -5 0 6 8 3 -2 2
Generator
Air and
Water Vapor
Condenser
Iso-Butane
Air
Air
Heat Exchanger
Water
Water
Cool
Brine
Pump
Production
Well
Geothermal Zone
Injection
Well
G A0 2 -5 0 6 8 3 -2 4
Plant Costs
Favorable Geothermal Areas
and Known Systems
Geographic Distribution of Hydrothermal Resources
Identified Geothermal Resources
USGS, 2008
Undiscovered Resources
U.S. Hydrothermal
Electric Power Potential
100,000
Potential (MWe)
90,000
80,000
70,000
60,000
Undiscovered
50,000
Identified
40,000
30,000
20,000
10,000
0
95
50
5
Mean
Percent Confidence
Williams, et al., USGS Fact Sheet, “Assessment of Moderate- and High-Temperature
Geothermal Resources of the United States,” September 2008
Geothermal
Domains
Hydrothermal
Fluid Content
Permeability
Water Injection
Required
Fracturing
Required
Enhanced
Geothermal
System
Heat
Hot Dry Rock
(HDR) – Fracturing
and water injection
required
Note: System must have fluid
content, permeability, and heat
to be potentially viable. This
combination can be natural
(Hydrothermal) or created in
an enhanced geothermal
system.
Geographic Distribution of EGS
USGS, 2008
EGS Resource
Temperatures at 6 km Depth
EGS Steps
Source: NREL
The U.S. Enhanced Geothermal
System Resource
Source: MIT Study- The
Future of Geothermal Energy
MIT EGS Supply Curve:
10% of U.S. Capacity by Mid-Century
MIT EGS model predictions with today’s drilling and plant costs
and mature reservoir technology at 80 kg/s per production well
Break-even Price (¢/kWh)
12
10
8
6
4
2
2004 US $
0
10
100
1,000
10,000
EGS Capacity Scenario (MWe)
100,000
EGS Challenges
Geologic variability and uncertainty make the technical
challenges of EGS very different from other renewable
energy sources.
Technical
•
•
•
Site selection - regional exploration
techniques for EGS
Creating EGS under various geologic
environments
– achieving low flow impedance
– achieving sufficiently large
sustainable reservoir without short
circuiting (80 kg/s at 200°C)
– minimizing water loss
– microseismicity
Few EGS field experiments yet
conducted worldwide; only 25 kg/s
achieved at Soultz
EGS Challenges
Economic
•
•
•
•
Exploration cost and risk
Drilling, completion and reservoir stimulation costs
Capital cost of surface facilities
No commercial EGS site for benchmarking
Commercialization
• Validating EGS technology requires high risk field
experiments in a variety of geologic settings
• Limited Federal R&D funding
U.S. EGS Electric Power Potential
Potential (MWe)
800,000
700,000
600,000
500,000
400,000
300,000
200,000
100,000
0
95
50
5
Mean
Percent Confidence
Williams, et al., USGS Fact Sheet, “Assessment of Moderate- and High-Temperature
Geothermal Resources of the United States,” September 2008
ASES Study Supply Curve
LCOE (2004 ¢ / kWh)
20
18
16
current technology basis
14
12
with projected DOE gains
10
8
6
4
Bases for market penetration
studies using NEMS.
2
0
-
20
40
60
80
100
Cumulative Capacity (GW)
Geothermal Supply Curves
Hydrothermal
(Petty, Porro)
27 GW
Sedimentary EGS 25 GW
Co-produced fluids 44 GW
Basement EGS
4 GW
Geothermal Power Savings
• 50,000 MW by 2030
• 25% existing resources, 25% expanded,
50% from oil & gas wells
• 5 to 10 ¢/kWh
Carbon Savings: 83 MtC/yr