Overview of Geothermal Technologies
Overview of Geothermal Technologies Richard Desrosiers, LEP, P.G. GZA GeoEnvironmental, Inc.
Introduction to Geothermal Presented to:
Environmental Business Council of New England Presented by:
Richard J. Desrosiers, PG, LEP GZA GeoEnvironmental, Inc. Date:
April 11, 2012 2
Presentation Format Geothermal Basics Type of Ground Loops Permitting Consideration Life Cycle Analysis
Typical Design/Build Feasibility Study Test Well and Thermal Conductivity Test Design/Construction Permitting Issues Financial and Incentives 3
Geothermal
Geothermal – from the Greek words “geo” = earth and “thermos” = heat Geothermal – from deep bedrock heat geothermal - uses geologic resources (soil, bedrock, groundwater) to store energy in the earth (heat source or heat sink). – Uses a “heat pump/heat exchanging system” also referred to as “geoexchange” and ground source heat pumps”
4
Geothermal Hot Rocks
http://www.bing.com/images/search?q=deep+geothermal+sources+&FORM=IGRE&qpvt=deep+geothermal+sources+#
5
Earth’s Heat Source
http://www.bing.com/images/search?q=deep+geothermal+sources+&FORM=IGRE&qpvt=deep+geothermal+sources+#
6
Geothermal Power Plant
Geothermal Power Plant
http://www.bing.com/images/search?q=deep+geothermal+sources+&FORM=IGRE&qpvt=deep+geothermal+sources+#
7
Geothermal System
http://www.bing.com/images/search?q=deep+geothermal+sources+&FORM=IGRE&qpvt=deep+geothermal+sources+#
8
Favorable Geothermal Zone
http://www.bing.com/images/search?q=deep+geothermal+sources+&FORM=IGRE&qpvt=deep+geothermal+sources+#
9
geothermal Ground Source Heat Exchange • Geothermal System Types – Closed-Looped System – Open-Looped System – Standing Column System
• Heat Exchange – Heat pump
• Distribution – Water-to-water – Water-to-air
10
Geothermal - What’s that? A proven heat exchange system that used stored energy in the earth (soil, bedrock, groundwater) A “heat-sink” in the summer and a “heat source” in the winter. Exchanges BTUs Typical geothermal depths 400 to 1,500 feet. Annual New England ground temperature = 55ºF. Reduces overall energy consumption. Also referred to as “geo-exchange” or Ground Source Heat Pump (GSHP) 11
Geothermal Benefits Decrease reliance on fossil fuels Reduction in Carbon Footprint American College & University President’s Climate Commitment (2050) Applicable in “Net Zero” (energy consumption & carbon emissions)
Increase energy efficiency Less maintenance than fossil fuel systems = Lower life cycle costs; increasing your rate of return on investment LEED credits
Tax and utility incentives 12
Typical Geothermal Layout
13
How Does It Work?
Source: GeoExchange Website (www.geoexchange.org) 14
Elements of a Geo-exchange System
Taken from J. Lund, “Geothermal (Ground-source) Heat Pumps”, Presented at IIE, Cuernavaca, México, 2007
15
Elements of a Heat Pump System Heating Cycle
Cooling Cycle
Taken from J. Lund, “Geothermal (Ground-source) Heat Pumps”, Presented at IIE, Cuernavaca, México, 2007 16
Geothermal – SUMMER
GEOEXCHANGE SYSTEM CONCENTRATES/ CIRCULATES HEAT (BTUs)
Heat is Exchanged from liquid To Soil/Rock
Earth = HEAT SINK 17
Geothermal – WINTER
GEOEXCHANGE SYSTEM CONCENTRATES/ CIRCULATES HEAT (BTUs)
Heat is Exchanged to liquid from Soil /Rock Earth = HEAT SOURCE
18
Type:
Closed Loop System Depths typically 300 - 500 feet
Convection Heat Exchange Aquifer characteristics less important (flow and quality) Ground temperature, thermal conductivity and diffusivity are important Less maintenance – no well field pumps “Rules of Thumb” •150 - 200 feet per ton A "vertical" loop of a ground-based, or an open-loop ground-source heat pump. (Credit: WaterFurnace International) 19
Type:
Open Loop System Groundwater extraction up to 1,500 feet
Advection Heat Exchange Aquifer characteristics are important (yield, quality, temperature) Ability to inject water into soil/bedrock formations Increased permittingregulations More maintenance-pumps potential for fouling/scaling More efficient than closedloop (less wells) “Rules of Thumb” •30 – 100 feet per ton •2.5 – 3 gpm per ton A "vertical" loop of a ground-based, or an open-loop ground-source heat pump. (Credit: WaterFurnace International) 20
Type:
“Standing Column Well” Depths typically to 1,500 feet Conductive, Advection & Convection Heat Transfer Similar issues as Open-Loop Induced flow increases temperature recovery, increasing heat transfer May require “Bleed” to surface water or injection well Increased permitting, regulations “Rules of Thumb” • 37.5 to 50 ft/ton with bleed
• 50 to 75 ft/ton w/o bleed O’Neill
21
Definitions Geothermal Heat Pump Transfers heat from the ground to water or air distributed to the building Water-to-water (hydronic systems) Water-to-air
De-superheater Uses heat from the ground loop to produce domestic hot water Uses excess heat during cooling cycle Distribution System Ducted forces air Radiant floor heating with ducted cooling Hydronic (water as the heat-transfer medium) 22
Integrated Geothermal Approach = Hybrid Systems Conventional HVAC plus geothermal system Conventions system for peak (heating/cooling) demand Geothermal for normal/average operating demands Alternative to using 100% geothermal Combine geothermal wells and heat pumps with: Chillers or cooling towers to supplement cooling Solar thermal collectors to supplement heating Supplemental fossil fuel for heating Outside Air Energy Recovery Economic and/or design driven Limits number/cost of geothermal boreholes Limits geothermal to “average and not peak loads”
23
Geothermal Design A Phased Approach Define Geothermal Team Initial Feasibility Study Site-Specific Investigation & Testing Decision Point
System Design
Geothermal Specifications Number of Boreholes Distribution system
Geothermal Well Field Construction
Borehole field inspections & QA/QC Verification that construction adheres with specifications
System Commissioning 24
Geothermal Team Geothermal Team
Professional Engineer Professional Geologist IGSHPA Certified GeoDesigner, IGSHPA Accredited Installer
Design Team
Architects/ Engineers
Legal Team
Architect, Mechanical/HVAC Engineers, Commissioning agent Construction Contractor
construction manager
Client (Owner)
Geo-Science/ Geo-Designer
commissioning agent
Independent consultant No hidden agendas – not tied to any one method or technology 25
Selecting a Geothermal Consultant
Qualifications Professional accreditations • • • •
PE – Professional Engineer PG – Professional Geologist AI – IGSHPA Accredited Installer CGD – IGSHPA Certified GeoDesigner
Relevant Experience
Independent consultant No hidden agendas – not tied to any one method or technology 26
Feasibility Study
Define building’s peak heating/cooling load Identify if applying for LEED credits Hybrid or all geothermal
Review published/site-specific hydrogeologic & geologic data Define permitting and regulatory requirements Evaluate land area and preliminary well field layout Evaluation of potential geothermal system type Preliminary economic analysis
Potential funding mechanisms 27
Design Considerations – Close Loop
Aquifer characteristics less important Thermal conductivity and ground temperature Groundwater flow and quality less important
Geologic conditions may vary within well field Wells are typically shallower (300 to 500 feet) Potentially more wells requiring greater land area No well field “moving” parts (potentially less maintenance)
28
Design Considerations – Open Loop & Standing Column Wells Aquifer characteristics are important
System Fouling, scaling
Groundwater flow, temperature and quality Open Loop typically requires 3 gpm per ton
Ability to re-inject pumped water Formation issues (Bleed requirements for SCW) Surface Water discharge Permitting or regulating issues
Wells are typically deeper (up to 1,500 feet) Potentially less wells Potentially more maintenance (pumps and well screens issues)
Plate-and-Frame Heat Exchanger 29
Geothermal Test Well Study: Drill full-depth test well Typical well is used as part of final system layout/design Evaluate borehole geology and depth/quality of groundwater
Open Loop Pumping/yield test Water quality analyses Adjacent uses
Closed Loop Install down-hole geo-loop and fused U-bend (pressure test) Grout (stabilize 5 days) borehole/geo-loop (thermally enhanced) 30
Test Well Installation Closed-Loop
31
Test Well Installation
Installation of Geo-loop
Test Well
Preparing the well for grouting
32
48-hour Thermal Conductivity Test
Conduct minimum of five (5) days after setting the thermal grout; Estimate thermal conductivity (ability of geologic material borehole to transfer heat in Btu/hr-ft- oF); Thermal diffusivity (measures of how quickly temperature recovers in ft2/day); and Formation temperature oF.
33
Thermal Conductivity Test
34
Typical Test Well Result
35
Thermal Conductivity Values Formation Type
Thermal Conductivity (Btu/hr ft F)
Clays
0.3 – 1.1
Sand
0.5 – 1.2
Sand & Gravel
1.2 – 2.2
Granite
1.3 – 2.1
Limestone
1.4 – 2.2
Sandstone
1.2 – 2.0
Shale
0.6 – 1.4
Oklahoma State
Test Results Rock Type: Thermal Conductivity: Thermal Diffusivity: Formation Temperature:
Schist/gneiss 1.81 Btu/hr-ft-F 1.16 sq-ft/day 53.5-F 36
Design/Construction Design: Final well field layout in conjunction with GeoDesigner; Driller borehole specification & cutting/fluid management Supplier neutral specification and performance criteria; Permitting
Construction: Quality Control during:
Well drilling; Grouting (percent solids critical) Geo-loop installation; Local presence provides for unannounced Site visits
QA/QC audits 37
Ground Loop Components Vertical wells or horizontal/vertical pipe loops Header and return piping - polyethylene Antifreeze for closed loops – propylene glycol Safe, non-toxic, good heat transfer capacity
38
Construction Photo
Manifold
3,200 Ton System 39
Construction Photo
40
Why Consider Geothermal Cost to Deliver 1 MBtu System Type
Energy Cost
Delivered Cost ($/MBtu)
Cost Relative to GSHP
Savings Using Savings GSHP Using GSHP (%) ($/MBtu)
Ground Source Heat Pump
$0.15/kWh
$11.72
-
-
-
Natural Gas
$1.50/therm
$15.79
1.3
26%
$4.07
Air Source Heat Pump
$0.15/kWh
$21.98
1.9
47%
$10.26
Propane
$2.75/gal
$33.21
2.8
65%
$21.49
Fuel Oil
$4.00/gal
$35.71
3
67%
$23.99
Electrical
$0.15/kWh
$43.96
3.8
73%
$32.24
$50.00 $45.00 $40.00 $35.00 $30.00 $25.00 $20.00 $15.00 $10.00 $5.00 $0.00 Ground Source Heat Pump
Natural Gas
Air Source Heat Pump
Propane
Fuel Oil
Ref: Heat Spring Magazine 2012
Electrical 41
Changes in Utility Costs 25
4 20
3.5
3 15 2.5
2 10 1.5
1
5
Electrical Costs in Cents per kWh
Oil and Propane Cost in Dollars per Gallon
4.5
0.5
0 0 9-Jan-01 9-Jan-02 9-Jan-03 9-Jan-04 8-Jan-05 8-Jan-06 8-Jan-07 8-Jan-08 7-Jan-09 7-Jan-10 7-Jan-11
Oil
Propane Gas
Electrical costs – CT Department of Public Utility Control Oil and Propane costs – Policy Development and Planning Division – CT Energy Management
Electric 42
Conventional Roof Top HVAC Units vs Ground Source Heat Pump 9,000,000
8,000,000
Cash Flow (Dollars $)
7,000,000
6,000,000
5,000,000
4,000,000
3,000,000
2,000,000
1,000,000
0 0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
20 -Year Life Cycle Conventional Roof Top
Ground Source Heat Pump 43
Conventional Roof Top vs Ground Source Heat Pump 25,000,000 Conventional Roof Top Unit Ground Source Heat Pump Conventional Roof Top vs Ground Source Heat Pump
Dollars Cost in $) Cumulative Flow (Dollars Cash
25,000,000 20,000,000
20,000,000 15,000,000 15,000,000
10,000,000 10,000,000
5,000,000 5,000,000
0
0
1
2
3
4
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
0 5
Cycle 6 20 Year 7 8Life 9 10
11
12
13
14
15
16
17
18
19
20
20-Year Life Cycle 44
Summary of Findings
• First Costs – Greater for the Ground Source Heat Pump Systems • Annual Operational Costs – Less for the Ground Source Heat Pumps Systems • Final Assessment – Ground Source Heat Pump System was the more cost effective system – 8.2-year payback period
45
Geothermal Case Study Campus Setting
46
Campus Study
47
Energy Usages
Structure Type
1
Academic Building
3,263
Natural Gas
0%
100%
1
Administration Building
2,016
Natural Gas
0%
100%
1
Athletic Facility
237,000
CHP/Natural Gas
92%
8%
53
Undergraduate & Graduate Housing
0%
100%
64%2
36%2
Area “A” - Totals
Area Heating & Cooling (sq. ft.) Energy Sources
Energy Source (%) Central Independent1 Plant
No. Bldgs
97,859 Oil and Natural Gas 340,138
Note: 1) Independent Energy Source includes natural gas, fuel oil, propane or other energy sources not connected to the central heating plant. 2) The total energy source percentage is based on: (total structure square feet/total square feet of the total area) times the percentage of the energy source from either the central plant or independent sources.
48
Geothermal Boreholes and Distribution Network
49
Green House Gas Reductions
Eliminates fossil fuel to 55 structures and reduces steam load from a central plant Additional air conditioning provided with geothermal that is not currently in place Reduction of 2,300 metric tons of greenhouse gas emissions Equivalent to 522 passenger vehicles
50
Financial Incentives for Geothermal
Federal Tax Credits State Tax Credits Local Property Tax Abatements Utility Rebates
Where to start? Database of State Incentives for Renewables & Efficiency (www.dsireusa.org) (NC State)
51
Thermal Purchase Agreements Advantages Provides for the installation of geothermal loop field at no upfront costs Zero Payback Period and geothermal maintenance costs are 40 to 63% less than fossil fuels Demonstrates Environmental Stewardship Aid in the development of NetZero Energy Buildings Hedge against rising fossil fuel costs
Payments
Utility-like payments - fixed price per BTU/kWh 20-year long term contract Predictability of net operational increase expenses Treated as operational expense not impacting balance sheet and is deductable. 52
Which is Best? No single method is “best” Selection depends on:
Hydrogeology, Groundwater flow characteristics Groundwater quality, Permit considerations Future maintenance/monitoring tolerance Life Cycle Cost, Client’s risk tolerance
Typical Systems:
Closed Loop (simplest, may require more wells) Open Loop (more equipment, perhaps less wells) Standing Column (more complex) Water-to-water or Water-to-air (package systems) Can be designed in conjunction with traditional systems or stand alone; 53
GZA Contact Information
Old Faithful Geyser
Richard Desrosiers 860-858-3130 [email protected]
54
Introduction to Geothermal Presented to:
Environmental Business Council of New England Presented by:
Richard J. Desrosiers, PG, LEP GZA GeoEnvironmental, Inc. Date:
April 11, 2012 2
Presentation Format Geothermal Basics Type of Ground Loops Permitting Consideration Life Cycle Analysis
Typical Design/Build Feasibility Study Test Well and Thermal Conductivity Test Design/Construction Permitting Issues Financial and Incentives 3
Geothermal
Geothermal – from the Greek words “geo” = earth and “thermos” = heat Geothermal – from deep bedrock heat geothermal - uses geologic resources (soil, bedrock, groundwater) to store energy in the earth (heat source or heat sink). – Uses a “heat pump/heat exchanging system” also referred to as “geoexchange” and ground source heat pumps”
4
Geothermal Hot Rocks
http://www.bing.com/images/search?q=deep+geothermal+sources+&FORM=IGRE&qpvt=deep+geothermal+sources+#
5
Earth’s Heat Source
http://www.bing.com/images/search?q=deep+geothermal+sources+&FORM=IGRE&qpvt=deep+geothermal+sources+#
6
Geothermal Power Plant
Geothermal Power Plant
http://www.bing.com/images/search?q=deep+geothermal+sources+&FORM=IGRE&qpvt=deep+geothermal+sources+#
7
Geothermal System
http://www.bing.com/images/search?q=deep+geothermal+sources+&FORM=IGRE&qpvt=deep+geothermal+sources+#
8
Favorable Geothermal Zone
http://www.bing.com/images/search?q=deep+geothermal+sources+&FORM=IGRE&qpvt=deep+geothermal+sources+#
9
geothermal Ground Source Heat Exchange • Geothermal System Types – Closed-Looped System – Open-Looped System – Standing Column System
• Heat Exchange – Heat pump
• Distribution – Water-to-water – Water-to-air
10
Geothermal - What’s that? A proven heat exchange system that used stored energy in the earth (soil, bedrock, groundwater) A “heat-sink” in the summer and a “heat source” in the winter. Exchanges BTUs Typical geothermal depths 400 to 1,500 feet. Annual New England ground temperature = 55ºF. Reduces overall energy consumption. Also referred to as “geo-exchange” or Ground Source Heat Pump (GSHP) 11
Geothermal Benefits Decrease reliance on fossil fuels Reduction in Carbon Footprint American College & University President’s Climate Commitment (2050) Applicable in “Net Zero” (energy consumption & carbon emissions)
Increase energy efficiency Less maintenance than fossil fuel systems = Lower life cycle costs; increasing your rate of return on investment LEED credits
Tax and utility incentives 12
Typical Geothermal Layout
13
How Does It Work?
Source: GeoExchange Website (www.geoexchange.org) 14
Elements of a Geo-exchange System
Taken from J. Lund, “Geothermal (Ground-source) Heat Pumps”, Presented at IIE, Cuernavaca, México, 2007
15
Elements of a Heat Pump System Heating Cycle
Cooling Cycle
Taken from J. Lund, “Geothermal (Ground-source) Heat Pumps”, Presented at IIE, Cuernavaca, México, 2007 16
Geothermal – SUMMER
GEOEXCHANGE SYSTEM CONCENTRATES/ CIRCULATES HEAT (BTUs)
Heat is Exchanged from liquid To Soil/Rock
Earth = HEAT SINK 17
Geothermal – WINTER
GEOEXCHANGE SYSTEM CONCENTRATES/ CIRCULATES HEAT (BTUs)
Heat is Exchanged to liquid from Soil /Rock Earth = HEAT SOURCE
18
Type:
Closed Loop System Depths typically 300 - 500 feet
Convection Heat Exchange Aquifer characteristics less important (flow and quality) Ground temperature, thermal conductivity and diffusivity are important Less maintenance – no well field pumps “Rules of Thumb” •150 - 200 feet per ton A "vertical" loop of a ground-based, or an open-loop ground-source heat pump. (Credit: WaterFurnace International) 19
Type:
Open Loop System Groundwater extraction up to 1,500 feet
Advection Heat Exchange Aquifer characteristics are important (yield, quality, temperature) Ability to inject water into soil/bedrock formations Increased permittingregulations More maintenance-pumps potential for fouling/scaling More efficient than closedloop (less wells) “Rules of Thumb” •30 – 100 feet per ton •2.5 – 3 gpm per ton A "vertical" loop of a ground-based, or an open-loop ground-source heat pump. (Credit: WaterFurnace International) 20
Type:
“Standing Column Well” Depths typically to 1,500 feet Conductive, Advection & Convection Heat Transfer Similar issues as Open-Loop Induced flow increases temperature recovery, increasing heat transfer May require “Bleed” to surface water or injection well Increased permitting, regulations “Rules of Thumb” • 37.5 to 50 ft/ton with bleed
• 50 to 75 ft/ton w/o bleed O’Neill
21
Definitions Geothermal Heat Pump Transfers heat from the ground to water or air distributed to the building Water-to-water (hydronic systems) Water-to-air
De-superheater Uses heat from the ground loop to produce domestic hot water Uses excess heat during cooling cycle Distribution System Ducted forces air Radiant floor heating with ducted cooling Hydronic (water as the heat-transfer medium) 22
Integrated Geothermal Approach = Hybrid Systems Conventional HVAC plus geothermal system Conventions system for peak (heating/cooling) demand Geothermal for normal/average operating demands Alternative to using 100% geothermal Combine geothermal wells and heat pumps with: Chillers or cooling towers to supplement cooling Solar thermal collectors to supplement heating Supplemental fossil fuel for heating Outside Air Energy Recovery Economic and/or design driven Limits number/cost of geothermal boreholes Limits geothermal to “average and not peak loads”
23
Geothermal Design A Phased Approach Define Geothermal Team Initial Feasibility Study Site-Specific Investigation & Testing Decision Point
System Design
Geothermal Specifications Number of Boreholes Distribution system
Geothermal Well Field Construction
Borehole field inspections & QA/QC Verification that construction adheres with specifications
System Commissioning 24
Geothermal Team Geothermal Team
Professional Engineer Professional Geologist IGSHPA Certified GeoDesigner, IGSHPA Accredited Installer
Design Team
Architects/ Engineers
Legal Team
Architect, Mechanical/HVAC Engineers, Commissioning agent Construction Contractor
construction manager
Client (Owner)
Geo-Science/ Geo-Designer
commissioning agent
Independent consultant No hidden agendas – not tied to any one method or technology 25
Selecting a Geothermal Consultant
Qualifications Professional accreditations • • • •
PE – Professional Engineer PG – Professional Geologist AI – IGSHPA Accredited Installer CGD – IGSHPA Certified GeoDesigner
Relevant Experience
Independent consultant No hidden agendas – not tied to any one method or technology 26
Feasibility Study
Define building’s peak heating/cooling load Identify if applying for LEED credits Hybrid or all geothermal
Review published/site-specific hydrogeologic & geologic data Define permitting and regulatory requirements Evaluate land area and preliminary well field layout Evaluation of potential geothermal system type Preliminary economic analysis
Potential funding mechanisms 27
Design Considerations – Close Loop
Aquifer characteristics less important Thermal conductivity and ground temperature Groundwater flow and quality less important
Geologic conditions may vary within well field Wells are typically shallower (300 to 500 feet) Potentially more wells requiring greater land area No well field “moving” parts (potentially less maintenance)
28
Design Considerations – Open Loop & Standing Column Wells Aquifer characteristics are important
System Fouling, scaling
Groundwater flow, temperature and quality Open Loop typically requires 3 gpm per ton
Ability to re-inject pumped water Formation issues (Bleed requirements for SCW) Surface Water discharge Permitting or regulating issues
Wells are typically deeper (up to 1,500 feet) Potentially less wells Potentially more maintenance (pumps and well screens issues)
Plate-and-Frame Heat Exchanger 29
Geothermal Test Well Study: Drill full-depth test well Typical well is used as part of final system layout/design Evaluate borehole geology and depth/quality of groundwater
Open Loop Pumping/yield test Water quality analyses Adjacent uses
Closed Loop Install down-hole geo-loop and fused U-bend (pressure test) Grout (stabilize 5 days) borehole/geo-loop (thermally enhanced) 30
Test Well Installation Closed-Loop
31
Test Well Installation
Installation of Geo-loop
Test Well
Preparing the well for grouting
32
48-hour Thermal Conductivity Test
Conduct minimum of five (5) days after setting the thermal grout; Estimate thermal conductivity (ability of geologic material borehole to transfer heat in Btu/hr-ft- oF); Thermal diffusivity (measures of how quickly temperature recovers in ft2/day); and Formation temperature oF.
33
Thermal Conductivity Test
34
Typical Test Well Result
35
Thermal Conductivity Values Formation Type
Thermal Conductivity (Btu/hr ft F)
Clays
0.3 – 1.1
Sand
0.5 – 1.2
Sand & Gravel
1.2 – 2.2
Granite
1.3 – 2.1
Limestone
1.4 – 2.2
Sandstone
1.2 – 2.0
Shale
0.6 – 1.4
Oklahoma State
Test Results Rock Type: Thermal Conductivity: Thermal Diffusivity: Formation Temperature:
Schist/gneiss 1.81 Btu/hr-ft-F 1.16 sq-ft/day 53.5-F 36
Design/Construction Design: Final well field layout in conjunction with GeoDesigner; Driller borehole specification & cutting/fluid management Supplier neutral specification and performance criteria; Permitting
Construction: Quality Control during:
Well drilling; Grouting (percent solids critical) Geo-loop installation; Local presence provides for unannounced Site visits
QA/QC audits 37
Ground Loop Components Vertical wells or horizontal/vertical pipe loops Header and return piping - polyethylene Antifreeze for closed loops – propylene glycol Safe, non-toxic, good heat transfer capacity
38
Construction Photo
Manifold
3,200 Ton System 39
Construction Photo
40
Why Consider Geothermal Cost to Deliver 1 MBtu System Type
Energy Cost
Delivered Cost ($/MBtu)
Cost Relative to GSHP
Savings Using Savings GSHP Using GSHP (%) ($/MBtu)
Ground Source Heat Pump
$0.15/kWh
$11.72
-
-
-
Natural Gas
$1.50/therm
$15.79
1.3
26%
$4.07
Air Source Heat Pump
$0.15/kWh
$21.98
1.9
47%
$10.26
Propane
$2.75/gal
$33.21
2.8
65%
$21.49
Fuel Oil
$4.00/gal
$35.71
3
67%
$23.99
Electrical
$0.15/kWh
$43.96
3.8
73%
$32.24
$50.00 $45.00 $40.00 $35.00 $30.00 $25.00 $20.00 $15.00 $10.00 $5.00 $0.00 Ground Source Heat Pump
Natural Gas
Air Source Heat Pump
Propane
Fuel Oil
Ref: Heat Spring Magazine 2012
Electrical 41
Changes in Utility Costs 25
4 20
3.5
3 15 2.5
2 10 1.5
1
5
Electrical Costs in Cents per kWh
Oil and Propane Cost in Dollars per Gallon
4.5
0.5
0 0 9-Jan-01 9-Jan-02 9-Jan-03 9-Jan-04 8-Jan-05 8-Jan-06 8-Jan-07 8-Jan-08 7-Jan-09 7-Jan-10 7-Jan-11
Oil
Propane Gas
Electrical costs – CT Department of Public Utility Control Oil and Propane costs – Policy Development and Planning Division – CT Energy Management
Electric 42
Conventional Roof Top HVAC Units vs Ground Source Heat Pump 9,000,000
8,000,000
Cash Flow (Dollars $)
7,000,000
6,000,000
5,000,000
4,000,000
3,000,000
2,000,000
1,000,000
0 0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
20 -Year Life Cycle Conventional Roof Top
Ground Source Heat Pump 43
Conventional Roof Top vs Ground Source Heat Pump 25,000,000 Conventional Roof Top Unit Ground Source Heat Pump Conventional Roof Top vs Ground Source Heat Pump
Dollars Cost in $) Cumulative Flow (Dollars Cash
25,000,000 20,000,000
20,000,000 15,000,000 15,000,000
10,000,000 10,000,000
5,000,000 5,000,000
0
0
1
2
3
4
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
0 5
Cycle 6 20 Year 7 8Life 9 10
11
12
13
14
15
16
17
18
19
20
20-Year Life Cycle 44
Summary of Findings
• First Costs – Greater for the Ground Source Heat Pump Systems • Annual Operational Costs – Less for the Ground Source Heat Pumps Systems • Final Assessment – Ground Source Heat Pump System was the more cost effective system – 8.2-year payback period
45
Geothermal Case Study Campus Setting
46
Campus Study
47
Energy Usages
Structure Type
1
Academic Building
3,263
Natural Gas
0%
100%
1
Administration Building
2,016
Natural Gas
0%
100%
1
Athletic Facility
237,000
CHP/Natural Gas
92%
8%
53
Undergraduate & Graduate Housing
0%
100%
64%2
36%2
Area “A” - Totals
Area Heating & Cooling (sq. ft.) Energy Sources
Energy Source (%) Central Independent1 Plant
No. Bldgs
97,859 Oil and Natural Gas 340,138
Note: 1) Independent Energy Source includes natural gas, fuel oil, propane or other energy sources not connected to the central heating plant. 2) The total energy source percentage is based on: (total structure square feet/total square feet of the total area) times the percentage of the energy source from either the central plant or independent sources.
48
Geothermal Boreholes and Distribution Network
49
Green House Gas Reductions
Eliminates fossil fuel to 55 structures and reduces steam load from a central plant Additional air conditioning provided with geothermal that is not currently in place Reduction of 2,300 metric tons of greenhouse gas emissions Equivalent to 522 passenger vehicles
50
Financial Incentives for Geothermal
Federal Tax Credits State Tax Credits Local Property Tax Abatements Utility Rebates
Where to start? Database of State Incentives for Renewables & Efficiency (www.dsireusa.org) (NC State)
51
Thermal Purchase Agreements Advantages Provides for the installation of geothermal loop field at no upfront costs Zero Payback Period and geothermal maintenance costs are 40 to 63% less than fossil fuels Demonstrates Environmental Stewardship Aid in the development of NetZero Energy Buildings Hedge against rising fossil fuel costs
Payments
Utility-like payments - fixed price per BTU/kWh 20-year long term contract Predictability of net operational increase expenses Treated as operational expense not impacting balance sheet and is deductable. 52
Which is Best? No single method is “best” Selection depends on:
Hydrogeology, Groundwater flow characteristics Groundwater quality, Permit considerations Future maintenance/monitoring tolerance Life Cycle Cost, Client’s risk tolerance
Typical Systems:
Closed Loop (simplest, may require more wells) Open Loop (more equipment, perhaps less wells) Standing Column (more complex) Water-to-water or Water-to-air (package systems) Can be designed in conjunction with traditional systems or stand alone; 53
GZA Contact Information
Old Faithful Geyser
Richard Desrosiers 860-858-3130 [email protected]
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