GEOTHERMAL ENERGY: Is it a viable option in an oil- induced energy crisis? By Adrien T. Robinson

GEOTHERMAL ENERGY:GEOTHERMAL ENERGY:

Is it a viable option in an oil-induced energy crisis?

By Adrien T. Robinson

Overview of Policy to Off-set Loss In Oil Imports

Overview of Policy to Off-set Loss In Oil Imports

A Two-Stage Approach:

Short Term (Several Years to a Decade) - Expand Use of Known Geothermal Resources Using Currently Available Technologies

Long-Term (Several Decades?) – Develop, Improve & Implement Technologies to Tap into Deep Geothermal Resources

Supplement These Efforts By Providing Gov’t Subsidy, Clean Air Credits and Tightening Pollution Regulations

Overview of Policy Cont’dOverview of Policy Cont’d Short Term Highlights & Achievable Goals:

Replace Current Oil Uses for Spacing ConditioningProvide Gov’t Subsidy to Minimize Capital Expenditure

– Justifiable Given the Environmental Benefits

Develop Last of Known Shallow Geothermal Sources Capable of Electricity Generation

– Expansion of Electricity Generation up to 19 GW

Overall, Offset Lost Energy 2-10% of Current Oil Imports

Overview of Policy Cont’dOverview of Policy Cont’d

Long-Term Highlights & Achievable Goals: Develop, Improve & Implement Technologies to Tap into Deep Geothermal Resources – Magma and Near Core Fluids

Capable of Replacing All Electricity Needs in U.S. and All Energy for Space Conditioning

Summary of ConclusionSummary of Conclusion

Short Term:Not a Viable Option to Replace 25% Loss in Oil Imports. Perhaps 2-10% Could Be Replaced in a Few Years to a Decade.

Long Term (Likely Decades):Capable of Replacing All Electricity Needs, Including All HVAC Applications

What is Geothermal Energy? What is Geothermal Energy?

Geo (Greek for earth) Thermal (heat)

Temp. of Shallow Crust (upper 10 ft.) Constant 55-75°F (13-24°C)

Up to 14,400°F (8,000°C) at Molten Core (approx. 4,000 mi. to center of core)

What is Geothermal Energy Cont’d?What is Geothermal Energy Cont’d?

Earth’s Crust Thickness: 3 to 35 Mi.Temperature Increases With Depth–Gradient: 50-87°F / Mile (17-30°C / km)

Basic Geothermal Systems Take Advantage of:

Heat Differential Between Ground and Indoor Air Temperatures – Heat Pump

Earth as a Natural Heat Source – Power Plants

Types of Geothermal Resources?Types of Geothermal Resources?

Geothermal Sources are Classified Based on: (1) Temperature, (2) Physical State of H20 (i.e. water or steam), and (3) Type of Energy Usage

Primary Classification is Resource Temperature:

Low Temperature Reservoir: 50-200 °F (10-94 °C)

High Temperature Reservoir: >200 °F

Brief History of Geothermal Energy Brief History of Geothermal Energy Paleo-Indians Usage

Dates Back 10,000 Years Use by Romans – Hot

Spas; Hot Running Water, Etc.

Early 1800s – Yellowstone Hot Springs and Hot Springs Arkansas

1830 1st Commercial Use; Asa Thompson sold Bath in Wooden Tub for $1

History of Geothermal Energy Cont’dHistory of Geothermal Energy Cont’d

In 1852, the Geysers Resort Hotel in San Fran. CA opened

108 Years later, 1st Geothermal Electricity Plant Opened at the Same Location – “The Gysers”

Basic Types of Geothermal Reservoirs Basic Types of Geothermal Reservoirs

3 General Classes of Geothermal UsesGround Source Heat Pump

Direct Source

Commercial Electricity Generation: Power Plants–Need High Capacity Geothermal

Reservoir; Generally Water / Steam >200°F

Types of Reservoirs Cont’dTypes of Reservoirs Cont’dLow Temperature Reservoirs:

Available almost anywhere on earthPredominantly Used for Heat Pumps–Space Heating

Other Common Uses:–Hot Water Production–Piped Under Roads / Sidewalks (Klamath

Falls, Oregon)–In Greenhouses to Grow Flowers, etc.–Industrial Uses: dry wood, pasteurize milk,

grow fish, etc.

Types of Reservoirs Cont’dTypes of Reservoirs Cont’d High Temperature Reservoirs:

Availability:–Can Occur Within a Couple of Miles of Earth’s

Surface Where Earth’s Crust Is Very Thin – i.e., Closer to Molten Magma at Core

Suitable for Commercial Production of Electricity–Power Plants Need High Capacity Geothermal

Reservoir – Water / Steam >220°F (105°C)Greatest Potential for Energy Output

What Makes a Good Geothermal

Reservoir for Generating Electricity? What Makes a Good Geothermal

Reservoir for Generating Electricity? Hot Geothermal Fluids Near Surface (<1-2 mi.)

Preferably in Excess of 300°F, but Electrical Generation Is Occurring at Temps. In the Low 200’s°F.

Proximity to Population Base Low Mineral and Gas Content Location on Private Land Proximity to Transmission Lines

Needed Technology: Are We Talking

Simple, Existing Technology or Star Wars? Needed Technology: Are We Talking

Simple, Existing Technology or Star Wars? Answer: Both.

Technology for HVAC in All Bldgs. in U.S. and for Electrical Generation From Shallow (1-2 Mi. Deep) Geothermal Reservoirs Already Exists and Is Proven

– Drawback: Number of Electricity Sources Is Limited

Technology for Tapping Deep (>3-6 Miles), Hot Dry Sources and Magma Is Not Yet Available

– Positive: Unlimited, Renewal Resource

The Geothermal Heat Pump

The Geothermal Heat Pump

Most Basic Form of Geothermal Usage What – takes advantage of stored heat of near

surface soil / water (Const. temp of 55-75 °F)

Winter Months – uses ground as a “heat source”–Transfers heat from warm subsurface to

facility

Summer Months – uses ground as a “heat sink”–Transfers heat from facility to ground

Heat Pump ComponentsHeat Pump Components 3 Main Parts:

Underground PipingPump / Heat Exchanger SystemIndoor Distribution System

System “Concentrates” Natural Heat Instead of Production of Heat by Combustion

Underground Piping ConfigurationsUnderground Piping Configurations

Vertical Installation:

150-500 ft. U-shaped pipe

Horizontal Inst.:

1000 ft. pipe buried at 4-8 feet below grade

Heat Pump UsesHeat Pump Uses

Predominantly Space Heating / CoolingCurrently Over 300,000 buildings in U.S.–Homes, Schools, Commercial Complexes,

and Industrial FacilitiesWater Heating for Hot Water

Desuperheaters – uses heat from heat pump’s compressor to heat facility’s hot waterSecond Heat Exchanger dedicated to hot water

HEAT PUMPS: WHAT DO THEY COSTHEAT PUMPS: WHAT DO THEY COST

Approx. $2,500 / ton of capacity$7,500 for 3 ton system – 2,500 – 3,000 ft2 homeA 3-ton gas-fired furnace and air conditioner would cost approx. $4,000

Positive Cash Flow InvestmentMonthly Energy Savings Likely to Exceed the Monthly Finance Charge for Borrowing the Additional $3,500

GEOTHERMAL HEAT PUMPS: DO THEY WORK?

GEOTHERMAL HEAT PUMPS: DO THEY WORK?

1993 EPA Study Conducted in 6 Different Climate Conditions1

Named Heat Pump as Most Efficient Heating and Cooling SystemReduction in Energy Consumption of 25%-75% Over Older, Conventional SystemsLowest Annual Operating Costs

Little Pollution Produced

HEAT PUMP EFFECTIVENESS IN VARIOUS CILMATES

HEAT PUMP EFFECTIVENESS IN VARIOUS CILMATES

Cold Climate - Minnesota House Owned by Dennis Eichinger

3,400 ft2; Avg. Monthly Energy Bill - $44Warm Climate – FL House Owned by Keith

Swilley2,000 ft2; Yearly Energy Bill - $253 ($0.69/day)

1997 Energy Value Housing Award

What do home Owners Say?What do home Owners Say?

Even Temperature – no cold spots, no fluctuation

Quite OperationLow MaintenanceFew Moving Parts – systems typically

last 30 yrs. or more; u/g systems frequently warranted up to 50 years.

HEAT PUMPS: HOW MUCH ENERGY SAVINGS?

HEAT PUMPS: HOW MUCH ENERGY SAVINGS?

2-5 kW for each residential application

Therefore, 1000 homes avoids the need to generate 2 to 5 MW capacity1

20kW for average commercial installations1

Currently 400,000 Heat Pumps in U.S.

1,500 MW of Heating & Cooling2

–Approx. Savings of 33.3 MM barrels oil/yr.–40,000 being added each year2

TYPES OF GEOTHERMAL POWER PLANTS

TYPES OF GEOTHERMAL POWER PLANTS

Different Types of Plants are Required to Take Advantage of the Particular Characteristics of Each Specific Geothermal Site

Main Types of Geothermal Power Plants:

Dry SteamFlash SteamBinary Cycle

Dry Steam Geothermal PlantsDry Steam Geothermal Plants

Uses Steam From Geothermal Reservoir Directly

Only Requires Removal of Rock Fragments From Steam Prior to Entering Turbines

Only Emissions Are Water Vapor

Dry Steam Geothermal Plants Cont’dDry Steam Geothermal Plants Cont’d

The “Geysers” in CAOpened in 1960

After 30 yrs. – temp. remains constant; pressure drop from 3.3 to 2.3 MPa near wells

Output–2700 MW; enough for San Francisco (pop. 780,000)1

Why Haven’t We Built More Dry Steam Geothermal

Plants?

Why Haven’t We Built More Dry Steam Geothermal

Plants?

Pro:Lowest Technology Required – Lowest Capital Costs

Con:Ideal Conditions Required–Few Sites Available (Very Rare) in U.S.

Flash Steam Geothermal Power Plants

Flash Steam Geothermal Power Plants

Injection of Deep, High-pressure Water Into Low-pressure Tanks; Water “Flashes” to Steam Used to Drive Turbines

Excess Water Returned to Maintain Pressure in Reservoir

Flash Steam Plants Cont’dFlash Steam Plants Cont’d

Steamboat Springs, NV Plant

Initial Conditions – Liquid H2O @ 240°C, Pressures of 24 MPa (hydrostatic pressure)

Binary Cycle Geothermal Power Plants

Binary Cycle Geothermal Power Plants

Moderately Hot Water (<175 °C) Passed Through Heat Exchanger

Heat Transferred to Secondary Fluid (Low B.P. Fluids (i.e., Propane or Isobutane) Which Is Vaporized (“Flashed”)

Binary Cycle Plants Cont’dBinary Cycle Plants Cont’d Higher Capital Cost

Needs High Efficiency Equip.

Water Never Contacts Turbine/generator Units

Water Returned Directly to Reservoir

No Plant Emissions!

Benefits of Geothermal Power Generation

Benefits of Geothermal Power Generation

Little to No PollutionFlash Plants Emit Only Excess SteamBinary Plants Have No Air or Liquid Emissions!–Expected to Be Dominant Type in Future

Lake County – Home of “The Geysers” Geothermal Plants – is One of the Only Counties to Meet CA’s Stringent Air Quality Standards.

Benefits of Geothermal Power Cont’d


Emission of Low Quantities of Greenhouse Gasses

Homegrown

Decreases Dependency On Foreign Energy



As Opposed to Burning Fossil Fuels, Current Geothermal Use Prevents the Yearly Emission of:1

22 MM tons of CO2

200k tons of SO2

80k tons of NOx110k tons of Particulates



Some Plants Produce Scale Which Is High in Minerals (Zinc and S)

But, The Minerals are Now Recyclable and Can be Sold For a Profit!

No Fuel Usage (storage, transfer, disposal, mining)



Reliability1:Plants Have Very Little Down Time - Avg. Availability is 90% or greater

60-70% for Coal and Nuclear Plants



Another Aspect of Resource Reliability

“Old Faithful” in Yellowstone National Park

Plants Have Been In Use in Italy Since 1913, New Zealand Since 1958 and in CA Since 1960



Minimal Land Use Compared to Other Energy Sources

Requires 400 M2 of Land Per GW of Power Over a 30 Year Period1

Compare That to Coal and Nuclear Plants Which Require Land for Plant, Mining for Fuel, Storage of Fuel and Wastes, Etc.

Disadvantages of Geothermal Energy Cont’d

Disadvantages of Geothermal Energy Cont’d

Start-up Costs Are High Geothermal Plants Require Significant Capital Expenditures, But the Fuel Is FreeCost - $1,500-$5,000 / Installed kW Depending on Plant Size, Resource Temp. And Chemistry1

Cost Of Power to ConsumerCurrently, $0.05 to $0.08 / Kwh2

Needs to Be $0.03 to Be Competitive

Disadvantages of Geothermal Energy Cont’dDisadvantages of Geothermal Energy Cont’d

Water can be corrosive to plant pipes, equipment

If water not replaced back into reservoir, subsidence can occur

How Much Water is Needed? Ea. MW requires 500 gpm @ 300°F; 1400 gpm @ 200°F.

Some high mineral / metal wastewater and solid waste is produced

Smelly gasses – H2S, Ammonia, Boron

Release of steam and hot water can be noisy

Disadvantages Cont’d – The Achilles Heel!Disadvantages Cont’d – The Achilles Heel!

Limited # of High Temp. Resources Capable of Electric Generation Using Current Technology

Current State of Geothermal Use in the U.S.

Current State of Geothermal Use in the U.S.

Currently there is approx. 3,000 MW of Electrical Power being Produced

2 times the production of solar and wind combined824 MW at “The Geysers” of CA alone

There is Approx. 3,900 MW of Direct Use Applications

400,000 Heat Pumps40 Greenhouses, 30 Fish Farms, 125 District Heating Projects, 10 Industrial Projects, 190 Resorts1

Past Growth of Geothermal UsagePast Growth of Geothermal Usage

Is There Any Room For Growth?Is There Any Room For Growth?A Gov’t Sponsored Survey Identified:

Over 9,000 Thermal Wells and SpringsOver 900 low-to-moderate Temperature Geothermal Resource Areas271 Collocated Communities

What is a Collocated Community?City/Community within 5 miles (8 km) of geothermal resource with temps. of at least 50 °C (122 °F)

Is There Any Room For Growth Cont’d

Is There Any Room For Growth Cont’d

Being A Collocated Community:Gives These Locations Excellent Potential for Near Term UseMakes Them Capable of Supporting Space Conditioning (Heating and Cooling) and Hot Water Applications

These 271 Cities/communities Represent 7.4 Million Persons

Potential Energy Savings – 18 MM Barrels Oil/year

Is There Any Room For Growth Cont’dIs There Any Room For Growth Cont’d

Using Today’s Technology, Approx. 6,500 MW Are Available

With Modest Technological Advances and Using Known Geothermal Reservoirs, Approx. 18,900 MW Would Be Available


The 18,900 MW (22k Bar./MW Energy) Of Electric Potential and 18MM Barrels of Oil Savings From the 271 Collocated Communities Represent Approx. 6% of Total U.S. Oil Consumption

Is That It? No. The Holy Grail of Geothermal Energy Development Is to Be Able to Tap the Unlimited Energy Closer to the Earth’s Core.


At Depths of 3-6 Miles, There Is Very Hot, Dry Rock The U.S., Japan, England, France, Germany and

Others Are Experimenting With Technologies to Develop This Resource

Needed Improvements In Drilling TechnologiesNeeded Ability to Enhance Subsurface PermeabilityNeeded Technology to Detect and Sample Prospective Geothermal Resources

Where Does That Leave Geothermal Potential in the U.S.

Where Does That Leave Geothermal Potential in the U.S.

The Technology Currently Exists to Provide Almost All Heating and Cooling Using Heat Pumps and About 6% of Total Energy Needs

Future Development of Deep Geothermal Resources Can Provide Enough Energy for All Electric and Space Conditioning Needs

Devising a Policy For Accelerating

Geothermal Use In the U.S. Devising a Policy For Accelerating

Geothermal Use In the U.S. The Current State of the Geothermal Technology Lends

Itself to a Two-phased Approach Targeting Short and Long Term Goals

Easy Targets – Achievable in the Short Term (Several Years to a Decade):

Phasing Out Systems Currently Using Oil For Heating Which Can Be Replaced With Geothermal Energy Quickly and With Available Technology

Implementing District Heating/Cooling Systems in the 271 Collocated Cities

Devising a Policy Cont’dDevising a Policy Cont’d

Continued Development of Moderate-temperature Geothermal Resources in 8 Western States With Binary-cycle Power Plants

Potential Energy Production – 18,900 MWOverall Potential Savings in Energy From

Implementation of the Above Short Term Measures – up to 6% of Total Oil Usage

Devising a Policy Cont’dDevising a Policy Cont’d

Long-Term Targets – Several Decades:Phasing Out All Use of Fossil Fuels for Space Conditioning

R&D for Technology to access the Unlimited Energy Source Closer to the Earth’s Core - Unlimited Electricity Source

Build Power Plants Capable of Providing All Electricity Needs in U.S.

Pros / Cons of Such a PolicyPros / Cons of Such a Policy

Pros:Clean Resource – Very Little Emissions or Overall Environmental ImpactDomestic Resource – Not Susceptible to Geopolitical ConflictEconomically Sound Alternative – The Fuel Is Free, Rate / KWh Likely to Be Competitive

Pros / Cons of Such a Policy Cont’dPros / Cons of Such a Policy Cont’d

Cons:Capital Cost - Significant Initial Investment will be required by Consumers and IndustryDuration - May Take Decades to Replace Significant Quantity of the Lost EnergyUncertainty - Replacing More Than a Few Percent of the Lost Energy Relies on Technological Advances, Both in Production and Usage

Mitigation of Policy Negatives:Mitigation of Policy Negatives:

Additional Policy Considerations and Justifications:Gov’t Subsidies to Off-set Capital Costs–Justifiable because of significant potential for

environmental savingsProvide Increased Clean Air Credits and Reduced Rates for Users of Geothermal Energy

– At the Same Time, Increase Rates for Heating Oil and Other Fossil Fuel Users

ConclusionConclusionShort Term (Several Years to a Decade): Not a Viable Option to Replace 25% Loss in Oil

Imports. At Best, a Valuable Supplement to Replace a Few % of the Lost Energy.

Some Valuable Side Effects:Production of Clean Energy–These Policies Are in Concurrence With

Goals of Most Pollution-related StatutesLess Reliance on Foreign Sources of EnergyReliable and Renewal Energy Source

Conclusion Cont’dConclusion Cont’d

Long Term (Likely Decades for Technology to Provide an Economically Feasible Option):

Biggest Impact in Electrical Generation Sectors – the Potential Exists to Provide All Energy Requirements in the U.S.

Energy Consumption for Space Heating and Cooling Could Also Change Dramatically

Documents

GEOTHERMAL ENERGY: Is it a viable option in an oil- induced energy crisis? By Adrien T. Robinson