DEVELOPMENT OF DIRECT-USE GEOTHERMAL PROJECTS

DEVELOPMENT OF DIRECT-USE GEOTHERMAL PROJECTS Tonya Toni Boyd used with permission Dr. John W. Lund, PE Emeritus Director Geo-Heat Center

GEO-HEAT CENTER BACKGROUND Established in 1975 Based on the Oregon Institute of Technology campus a geothermally heated campus with 192 o F water With addition of two geothermal power plants (2 MWe) and a 2 MWe solar array, the campus will be 100% on renewable energy the first in the world! Technical assistance provided to persons, private firms and governments in all 50 states and 60 countries. Funded mainly by the U.S. Department of Energy Office of Geothermal Technologies

SERVICES PROVIDED BY GHC Technical assistance direct-use, small scale electric power generation and geothermal heat pumps. Feasibility studies both engineering and economic Information dissemination Quarterly Bulletin, technical papers, and conferences proceedings. Data bases 12,000 well/springs in 16 western states. Outreach training, speakers, booths, and site visits. Geothermal Direct-Use Engineering and Design Guidebook 454 pages most available on-line

WEBSITE ACTIVITIES http://geoheat.oit.edu Over 1900 files (320 MB of information) Example of yearly activity: Average hits/day 11,000 Average users/day 2,000 Average downloaded PDF files/day 4,000 68% of users from the U.S. 10% of users are international 22% of users are from unknown locations

INTRODUCTION TO DIRECT-USE Direct-use geothermal provides heat and/or cooling to buildings, greenhouses, aquaculture ponds and industrial processes. Need to match the resource with the needs of the user to be successful Economics and markets are important Each project is unique!!! Each project needs a leader or champion ( hero )!!!

INTRODUCTION 2 Development of a projects should be approached in phases to minimize risk Size of the project determines the amount of exploration and development that can be economically justified. For a single home the risk is high with minimum information economically available Larger projects can justified more investigations and resource characterization, thus reducing the risk (i.e. district heating and industrial process applications) - a feasibility study is appropriate and may be necessary

Levels of exploration and reservoir confirmation Proposed well

ADVANTAGES OF DIRECT-USE OF GEOTHERMAL ENERGY Can use low- to intermediate temperature resources (< 300 o F) These resources are more wide-spread (80+ countries) and are often at shallow depths Direct heat use (no conversion high efficiency) Use conventional water-well drilling equipment Use conventional, off-the-shelf equipment (allow for temperature and chemistry of fluid) Minimum start-up-time Quicker return on investment (as compared to power projects)

SELECTING THE USE I have this resource, what do I do with it? Information needed to answer this question: What is the extent and depth of the resource What is the temperature and flow rate? What is the chemistry of the resource? What are the potential markets and income? Do you have the experience or can you hire it? Do you have the financing ROI ok? Do you own or can you lease the resource?

Courtesy of the Geothermal Education Office

IN SUMMARY: DIRECT-USE HEATING AND COOLING PROJECTS INCLUDES: Swimming, bathing and balneology Space heating and cooling Including district (heating/cooling) systems Agriculture applications Greenhouse and covered ground heating Aquaculture applications Fish pond and raceway heating Industrial processes Including food and grain drying Mineral extraction and processing

SPAS AND POOLS Use of low temperature resource <140 o F Temperature and mineral content important Drinking the water and using muds also important <85 o F for pools and <110 o F for spa water Water used directly desirable flow through May need to be treated (chlorine) Secondary water heated through HE Mixing required with higher temperature resource Covered and uncovered pools ( 1:2.5 heat needs)

Colorado, Hungary, New Zealand and Arkansas

SPACE AND DISTRICT HEATING Heating (and cooling) of individual buildings or a group of buildings District heating requires a high thermal load density >0.7 million Btu/hr/acre or a favorability ratio of 2.5 (ratio of resource available/resource utilized) Peaking with fossil fuel often economically viable as geothermal can provide 50% of the load 80 to 90% of the time. However, district heating is capital intensive especially the distribution network (pipelines) 35 to 75% of total Typical savings of 30 to 50% compared to natural gas, and higher when compared to electricity

100 ( o C) -20-15 Fossil fuel 75-10 PEAKING BOILER (6%) -5 Geothermal 50 0 GEOTHERMAL HEAT PUMP (31%) 5 25 10 GEOTHERMAL (63%) DOMESTIC HOT WATER 15 0 0 2000 4000 6000 HOURS PER YEAR 8000 Meeting peak demand with fossil fuel

DOWNHOLE HEAT EXCHANGERS Used by homes individual or shared in: Klamath Falls, Oregon Rotorua and Taupo, New Zealand Cesme, Turkey Closed loop of pipe in well (coil or DHE) Clean secondary water used Only heat extracted from well Wells 10 to 12 inches in diameter Casing 2 inches smaller - clearance

DOWNHOLE HEAT EXCHANGER DESIGN perforations DHE with promoter pipe DHE with perforated casing Both create a vertical convection cell of heated water

Black iron pipe vs. PEX pipe Downhole heat exchangers 600 in KF

KLAMATH FALLS, OREGON DISTRICT HEATING SYSTEM Completed 1983 $2.33 million DOE-PON Two wells 367/900 ft. deep 219/212 o F 700 /765 gpm max Pipeline: 4,040 ft. 8 inch steel Preinsulated direct buried & sidewalk utilidor Heat Exchanger building 2 plate heat exchangers - each 10.0 million Btu/hr Injection well 1,235 ft, deep 2,500 ft. from production zone

Klamath Falls district heating system

Production Well Injection Well Geo Production District Heat Supply and Return Heated Buildings Greenhouse Snowmelt Klamath Falls district heating system

IFA Nursery 4 acres trees seedlings OTHER KLAMATH FALLS GEOTHERMAL USES ON THE DISTRICT HEATING SYSTEM

GREENHOUSES A variety of crops can be raised: vegetables, flowers, house plants, trees Various heating systems can be used Geothermal reduces costs and allows operation in colder climates Temperate climate zone: 100 Btu/ft 2 /hr 5 acre facility: 22 million Btu/hr (6.5 MWt) peak Annual requirement with LF of 0.45 = 100billion Btu/yr (28 million kwhr/yr)

32 50 68 86 104 125 100 Temperature 0 F LETTUCE TOMATO 75 50 25 0 CUCUMBER 0 5 10 15 20 25 30 35 40 Temperature 0 C

Greenhouse heating systems

Greenhouses shapes and designs USA, Iceland and Hungary

Osarian greenhouses, Kenya 1,000,000 roses/day shipped overseas

AQUACULTURE Raising catfish, bass, tilapia, shrimp and tropical fish and even alligators Temperature of water from 55 to 90 o F Increase growth rate by 50 to 100% Water quality and disease control important when using the geothermal water directly Outdoor pond in temperate climate zone: 250 Btu/hr/ft 2 5 acre facility: 50 million Btu/hr (15 MWt) peak With LF of 0.60 = 260 billion Btu/yr (77 million kwhr/yr)

100 32 Cows 50 Temperature 0 F 68 86 104 Chickens 80 Trout 60 40 Shrimp Catfish 20 0 0 10 20 30 40 Temperature 0 C

Typical aquaculture facilities

Gone Fishing African Cichlids

Alligators, Idaho Eels, Slovakia Tilapia and cat fish

INDUSTRIAL Generally require higher temperatures as compared to space heating : >200 o F. High energy consumption Year-around operation Drying of timber, extracting minerals, concrete block curing, leather tanning, milk pasteurization, borate and boric acid production, and dehydration of vegetables and fruit are examples They also tend to have high load factors in the range of 0.4 to 0.7 which reduce the unit cost of energy.

0 C 10 0 38 0 66 0 93 0 121 0 149 0 0 F 50 0 100 0 150 0 200 0 250 0 300 0 Food processing Cement drying Furniture Leather Lumber Pulp and paper Biogas processes Concrete block curing Aggregate drying Soil warming Metal parts washing Pasteurization Malt beverages Distilled liquor Aquaculture Fruit & vegetable drying Mushroom culture Blanching and cooking Beet sugar extraction Soft drinks Greenhousing 0 C 10 0 38 0 66 0 93 0 121 0 149 0 0 F 50 0 100 0 150 0 200 0 250 0 300 0 Application temperature ( 0 F, 0 C)

Heap leaching, milk pasteurization, onion dehydration, timber drying Industrial applications

140ºF geo. 30 lb/hr 4 t/yr dried HE Air flow Tomato drying - Greece

REFRIGERATION/SNOW MELTING Lithium bromide system (most common uses water as the refrigerant) Supplies chilled water for space and process cooling above the freezing point The higher temperature, the more efficient (can use geothermal fluids below 200 o F) however, >240 o F better for 100% efficiency) Units are now available down to 176 o F @ 100% efficiency Ammonia absorption used for refrigeration below freezing normally large capacity and require geothermal temperatures above 250 o F only one in operation worldwide (Alaska) @ 165 o F; however, using 40 o F cooling water from a stream (large ΔT). Snow melting using PEX pipes under or in pavement : 100 to 150 Btu/hr/ft 2 typical

Oregon Institute of Technology chiller 192 o F producing 45 o F chilled water @ 600 gpm 1 MWt installed 500 kwt net

Chena Hot Springs Resort Ice Museum 85 gpm @ 165 o F geothermal 80 gpm @ 40 o F river water. -4 o F @ 55 gpm to museum Absorption chiller 33 kw

Klamath Falls snow melting system

New geothermal snowmelt system on campus

SELECTING THE EQUIPMENT FOR DIRECT-USE PROJECTS Geothermal fluids often must be isolated to prevent corrosion and scaling Normally need a plate HE to isolate the fluid Care to prevent oxygen from entering the system Dissolved gases and species such as boron and arsenic can be harmful to plants and fish. Hydrogen sulfide attacks copper and solder. Carbon dioxide can be used in greenhouses. Peaking or backup fossil fuel plants often used

130 0 F (55 0 C) PLATE HEAT EXCHANGER ENERGY 170 0 F (75 0 C) USER SYSTEM 180 0 F (80 0 C) PRODUCTION WELLHEAD EQUIPMENT GEOTHERMAL 140 0 F (60 0 C) INJECTION WELLHEAD EQUIPMENT PEAKING/ BACKUP UNIT Typical direct-use system equipment

NEW TRENDS COMBINED HEAT AND POWER PLANTS Low temperature resources used for binary power production and cascaded for direct use Temperatures as low as 200 o F are being used Makes efficient use of the resources Improves economics Increases employment

Combined heat and power project example

CHENA HOT SPRINGS, ALASKA United Technologies Corporation 200 kwe Carrier converted vapor-compression cycle chiller to a Rankine cycle that uses R-134a refrigerant Installed in July of 2006 Lowest temperature geothermal use for power generation in the world 165 o F resource and 40 o F cooling water

OREGON INSTITUTE OF TECHNOLOGY BINARY POWER PLANT 280 kw electric 198 o F geothermal water Cost: $1,000,000 Provides 10% of campus electricity 2 nd power plant planned @ 1.75 kw With solar array - 100% of campus electrical energy supplied. Water cascaded to heat all of campus at 165 o F

SUMMARY OF POTENTIAL GEOTHERMAL APPLICATIONS 40 to 90 o F: geothermal heat pumps for heating and cooling 90 to 140 o F: spas and pool heating; greenhouse and aquaculture heating, snow melting; radiant floor heating 140 to 200 o F: space heating using baseboard hot water and forced-air systems 200 to 300 o F: industrial processing, cooling and refrigeration >200 o F: binary power generation >350 o F: flash steam electric power generation

FUTURE DEVELOPMENTS Collocated resources and use Within 5 miles apart Sites with high heat and cooling load density >0.7 million Btu/hr/acre Food and grain dehydration Especially in tropical areas where spoilage is common Greenhouses in colder climates Aquaculture to optimize growth even in mild climates Combined heat and power projects cascading Mineral extraction (silica, zinc, gold, etc.)

CONCLUSIONS Many possible direct-uses of geothermal fluids Number of parameters will limit choices: Temperature, flow rate, chemistry and land availability Market available, and do you have the expertise to provide the product (i.e. heat and/or flowers/fish, etc.) Can you get the product to the user economically (i.e. pipelines or truck/rail/airline transportation) Availability of capital, income and ROI/payback Can you attract investors (i.e. minimize the risk) Alternative to consider combined heat and power project to better utilize the resource and help the bottom line

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