G E O T H E R M A LG E O T H E R M A L

Geothermal Electric PowerGeothermal

Electric Power

Chuck Kutscher

NREL

May 20, 2004

G E O T H E R M A LG E O T H E R M A L

Advantages of Geothermal EnergyAdvantages of Geothermal EnergyEnvironmentally sound

Resources last the life of the plant

High plant availability (over 95%)

Provides steady base load power

Relatively low cost (4 to 8 cents per kWh)

G E O T H E R M A LG E O T H E R M A L

Geothermal DomainsGeothermal Domains

Saturation

Hydro-thermal

Reservoir

HighTemperature

Permeability

FracturingRequired

Water InjectionRequired

Fracturing andWater InjectionRequired

Note: Must Have Mobile water,Heat And Permeability To Havea Potentially Viable System. ThisCombination Can be Natural(Hydrothermal System) or Created(an EGS System –Must always Have Hot Rock, Can Then FractureAnd Inject Water)

Enhanced Geothermal

System

G E O T H E R M A LG E O T H E R M A L

Hottest Known Geothermal RegionsHottest Known Geothermal Regions

Geothermal Power PlantsGeothermal Power Plants

G E O T H E R M A LG E O T H E R M A L

Today’s PlantsToday’s Plants8,000 MWe being generated in 21 countries

22 plants in U.S. (mostly California and Nevada) providing 2,200 MWe

Hydrothermal resources could provide additional 20,000 MWe in U.S., 75,000 MWe in developing nations; hot dry rock resource is immense

G E O T H E R M A LG E O T H E R M A L

Power Production DirectUses

5-10K MWEstimatedDevelopableResourceBy 2010

© Geothermal Education Office 2000

G E O T H E R M A LG E O T H E R M A L

Installed CapacityInstalled Capacity

Installed:

About 2800 MW (electric)

Over 600 MW (heat)400 MW under development

(electric)

60 MWt

2500 MWe114 MWt

28 MWt

30 MWt

54 MWt

40 MWe51 MWt

200 MWe69 MWt

102 MWt

22 MWtGreater Than 20 MW

Less than 20 MW

30 MWe

185 MW Salton Sea

(under development)

100 MW Glass Mountain

(under development)

40 MW Steamboat

(under development)

10 MW Raft River

(under development)25 MW Sulfur Hot Springs

(under development)

30 MW Ormat

(under development)

G E O T H E R M A LG E O T H E R M A L

Plant Type vs. TemperaturePlant Type vs. Temperature

Flash steam175oC(350oF)

Binary cycle90oC(195oF)

0oC32oF)

G E O T H E R M A LG E O T H E R M A L

G A02-50683-22

Generator

Steam

ProductionWell

InjectionWellGeothermal Zone

Waste Brine

Water

Air and Water Vapor

Air

DirectHeatUses

Air

G E O T H E R M A LG E O T H E R M A L

G A02-50683-24

Generator

Iso-Butane

ProductionWell

InjectionWellGeothermal Zone

Water

Heat Exchanger

Air and Water Vapor

Air

Pump

Air

Water

CoolBrine

Condenser

G E O T H E R M A LG E O T H E R M A L

Plant CostsPlant Costs

Flash ($/kW)

Binary ($/kW)

Exp./drilling 700 500

Equip. 750 1600

TOTAL 1,450 2,100

G E O T H E R M A LG E O T H E R M A L

DOE RoleDOE RoleR&D and deployment activities to enable US industry to expand geothermal energy use

Priorities are exploration and drilling to reduce risks and up-front costs. Immediate gains anticipated from enhanced conversion technology

Goal is 20,000 MWe hydrothermal and 20,000 MWe enhanced geothermal plants by 2020

G E O T H E R M A LG E O T H E R M A L

Geothermal Program Strategic Thrusts- 6 National Labs Involved

Geothermal Program Strategic Thrusts- 6 National Labs Involved

Drilling• Advanced Drilling System• High-speed data link

Reservoir Engineering• Enhanced Geothermal

Systems• Tracer injection

experiments

Energy Conversion• Small modular power

systems• Improved heat

rejection• Kalina cycle

demonstration

Exploration• Integrated

geophysical methods

• 3-D seismic analysis

G E O T H E R M A LG E O T H E R M A L

NREL Energy Conversion Research

NREL Energy Conversion Research

G E O T H E R M A LG E O T H E R M A L

Potential Impacts of Power Plant R&DPotential Impacts of Power Plant R&D

Area Improvement

2% – 3%Reduced O&M

3% – 5%Off-design enhancement

5% – 7%Cycle efficiency

8% – 10%Heat exchangers

G E O T H E R M A LG E O T H E R M A L

PLANT OPTIMIZATIONPLANT OPTIMIZATION

Conceived and developed the R&D-100 award winning Advanced Direct Contact Condenser

G E O T H E R M A LG E O T H E R M A L

Fluent Analysis:3 Rows of TubesFluent Analysis:3 Rows of Tubes

G E O T H E R M A LG E O T H E R M A L

Flow Comparison: Plain Fins vs. Tabbed Fins

Flow Comparison: Plain Fins vs. Tabbed Fins

PlainPlain

TabbedTabbed

G E O T H E R M A LG E O T H E R M A L

SRC Prototype High-Performance “t-fin”Heat Exchanger

SRC Prototype High-Performance “t-fin”Heat Exchanger

G E O T H E R M A LG E O T H E R M A L

Power Productionwith Evaporative Pre-cooling

Power Productionwith Evaporative Pre-cooling

Total Kilowatt-hours Produced

500000550000600000650000700000750000800000850000900000

1 2 3 4 5 6 7 8 9 10 11 12Month

Kilo

wat

t-hou

rs

No EnhancementSpray CoolingMunters CoolingDeluge CoolingHybrid Cooling

G E O T H E R M A LG E O T H E R M A L

Field MeasurementsField Measurements

Munters system

Hybrid system

G E O T H E R M A LG E O T H E R M A LHeat Exchanger CoatingsHeat Exchanger Coatings

NREL-BNL-industry partnerships

Cost-effective thermally conductive polymer coating (PPS composite liner with a zinc phosphate primer) protects carbon steel tubes

Developed through lab and field tests

In process of being commercialized

PI: T. Sugama, BNLPI: K. Gawlik, NREL

G E O T H E R M A LG E O T H E R M A L

Innovative Cycles ResearchInnovative Cycles Research•Aimed at lower temperature resources, especially suitable for enhanced geothermal systems

•Should exceed efficiency of simple binary cycles at lower cost

•Prefer robustness, simplicity, environmental friendly cycles

•Building 1.3 MW mixed hydrocarbon working fluid plant, analyzing other cycles

G E O T H E R M A LG E O T H E R M A L

Analysis SupportAnalysis Support

Cost trends in geothermal

Production tax credit report

By-product value

Program emphasis

PI: W. Short, L. Vimmerstedt, NREL

G E O T H E R M A LG E O T H E R M A LPromoting Geothermal Energy through

Outreach Materials and ActivitiesPromoting Geothermal Energy through

Outreach Materials and ActivitiesBeautiful products for the Program

PI: B. Green, NREL

G E O T H E R M A LG E O T H E R M A L

Technology SummaryTechnology SummaryClean, reliable base load power

Large plants ~5 cents/kWh, small plants ~7 cents/kWh

R&D underway to reduce risks and costs

Expect renewed interest with production tax credit

G E O T H E R M A LG E O T H E R M A L

Direct Uses andGeothermal Heat Pumps

Direct Uses andGeothermal Heat Pumps

G E O T H E R M A LG E O T H E R M A L

Direct UsesDirect UsesBalneology (hot spring and spa bathing)

Agriculture (greenhouse and soil warming)

Aquaculture (fish, prawn, and alligator farming)

Industrial Uses (product drying and warming)

Residential and District Heating

G E O T H E R M A LG E O T H E R M A L

Worldwide Geothermal Direct UseWorldwide Geothermal Direct UseDirect uses of geothermal water supply over 11,000 thermal megawatts in over 40 countries.

Another 35 countries use natural hot springs for bathing but have not yet developed their geothermal reservoirs for commercial use.

G E O T H E R M A LG E O T H E R M A L

District Heating in Western U.S.District Heating in Western U.S.

There are 18 district heating systems operating in the western United States.

Over 270 cities in the western U.S. areclose enough to geothermal reservoirsto use district heating.

G E O T H E R M A LG E O T H E R M A L

Geothermal Heat PumpsGeothermal Heat Pumps

Use ground as source/sink for a heat pump instead of air

$7,500 for 3-ton system compared to $4,000 conventional furnace/AC

2-10 year payback

500,000 systems in U.S. today

G E O T H E R M A LG E O T H E R M A L

Heat Pump in WinterHeat Pump in Winter

Heat is collected from

underground & transferredto the building

G E O T H E R M A LG E O T H E R M A L

Heat Pump in SummerHeat Pump in Summer

Heat is collected from

the building & transferredto the ground

Advantages of Geothermal EnergyGeothermal DomainsHottest Known Geothermal RegionsGeothermal Power PlantsToday’s PlantsInstalled CapacityPlant Type vs. TemperaturePlant CostsDOE RoleGeothermal Program Strategic Thrusts- 6 National Labs InvolvedNREL Energy Conversion ResearchPotential Impacts of Power Plant R&DPLANT OPTIMIZATIONFluent Analysis:3 Rows of TubesFlow Comparison: Plain Fins vs. Tabbed FinsSRC Prototype High-Performance “t-fin”Heat ExchangerPower Productionwith Evaporative Pre-coolingField MeasurementsHeat Exchanger CoatingsInnovative Cycles ResearchAnalysis SupportPromoting Geothermal Energy through Outreach Materials and ActivitiesDirect Uses andGeothermal Heat PumpsDirect UsesWorldwide Geothermal Direct UseDistrict Heating in Western U.S.Geothermal Heat PumpsHeat Pump in WinterHeat Pump in Summer