2. What is NCSEA?
Our Mission
Drive policy and market development to create clean energy
jobs, economic opportunities and affordable energy to benefit
all of North Carolina.
The NC Sustainable Energy Association is a 501(c)(3) nonprofit
membership organization of consumers, businesses,
government, utilities and nonprofits interested in North
Carolina's sustainable energy future.
2
3. What is Geothermal?
•Includes both Geothermal Energy and Ground
Source Heat Pump (GSHP) technologies:
• Geothermal energy technologies utilize the thermal
energy stored in the Earth to generate electricity
• GSHPs are central heating and cooling systems that
increase efficiency by transferring heat to or from the
ground
3
12. How Efficient is a GSHP?
•According to the International Ground Source Heat
Pump Association, GSHPs are:
• 50-70% more efficient than comparable heating systems
• 20-40% more efficient than comparable cooling systems
12
16. What are the Costs Associated
with Installing a GSHP?
16
Development of a Multi-Objective Sizing Method for Borehole Heat Exchangers during the Early Design Phase, 2017
17. How Much is an Average GSHP?
•Residential:
• $2,500/ton for the system itself
• 5-10 year payback
17
Guide to Geothermal Heat Pumps, 2011
18. How Does a GSHP Compare to
Traditional HVAC Systems?
18
Geothermal Heat Pumps in K-12 Schools: A Case Study of the Lincoln, Nebraska, Schools (Shonder, Martin, and Hughes; 2000)
19. GSHPs in NC
•From 2007-2018, over $30 million has been
invested in Geothermal systems in the state
• 0.2% of direct spending in clean energy development by
technology
•Over 7,600 geothermal systems were installed in NC
from 2007-2018
• 49.8% of renewable energy systems installed over that
period
19
22. Geothermal Industry in NC
•According to NCSEA’s 2018 Clean Energy Industry
Census:
• 225 companies active in the sector (7% of the clean
energy industry)
• 1,075 jobs (4%)
• $252 million in revenue (2%)
22
23. Geothermal Industry in NC
23
33%
21%
17%
10% 10% 10%
0%
5%
10%
15%
20%
25%
30%
35%
40%
Installer and
developer of
ground source
heat pump
systems
Sub-contractor
and/or loop
installer
Designer of
ground source
heat pump
systems
Manufacturer
and distributor of
ground source
heat pump
systems
Well-driller Other
Percent
of
Question
Respondents
Business Activities
24. Geothermal Industry in NC
24
30%
14%
18%
17%
10%
6%
5%
0%
5%
10%
15%
20%
25%
30%
35%
Residential
single family
Residential
multi-family
Commercial
< 4,000 ft2
Commercial
> 4,000 ft2
Industrial
and/or
Commercial
Military Other
Percent
of
Question
Respondents
Customer Base
25. Geothermal Industry in NC
25
23.36%
28.47%
21.17%
16.06%
7.30%
3.65%
0%
5%
10%
15%
20%
25%
30%
35%
Open loop heat
pump systems
Vertical closed
loop heat
pump systems
Horizontal
closed loop
heat pump
systems
Lake loops
and/or pond
loops
Commercial
water source
heat pump
Other
Percent
of
Question
Respondents
Geothermal System Type
26. What Contributed to Growth of
GSHPs in NC?
•NC’s 35% renewable energy tax credit that expired
at the end of 2015 and the federal residential
renewable energy 30% tax credit that expired at the
end of 2016
• The federal tax credit was brought back at 30% in 2018,
with step downs eventually to 22% in 2022, but has no
maximum value limit
26
I’m not sure if this needed to be included, but wanted to be sure.
Generating electricity using geothermal technology is very site specific, and NC is not one of the few places in the US where the geothermal potential is worthwhile. So, rather than generating electricity with geothermal resources, geothermal in NC is in the form of ground source heat pumps (GSHPs).
Over the course of the year, once you get to a certain subsurface depth, the temperature stays fairly constant. And this relative constant temperature is what ground source heat pumps take advantage of to remove heat in the summer and to collect heat in the winter.
The main types refer to whether the system reuses the liquid in the pipes that transfers heat between the ground or water and the home or building and the subcategories refer to whether the system’s piping is built deep into the ground over a small area or shallowly over a large area.
The main types refer to whether the system reuses the liquid in the pipes that transfers heat between the ground or water and the home or building and the subcategories refer to whether the system’s piping is built deep into the ground over a small area or shallowly over a large area.
These systems have sealed pipes that contain a working fluid that is warmed or cooled by the ground or water and sent through a heat pump in the structure that it serves. The fluid travels back to begin the process over again.
Open loop geothermal systems exchange heat by pumping groundwater through the system directly and without recycling it.
In locations with less available horizontal space, the pipes can be buried in deep vertical shafts.
In areas with appropriately sized bodies of water, pipes may be sunk beneath the surface to achieve the same exchange of heat as if they were underground.
Those numbers are from: https://igshpa.org/geothermal/
Boreholes being drilled for closed vertical loop system
Area dug up for closed horizontal loop system
Lake system being sunk into its associated body of water
This table is based on the costs associated with installing GSHPs as part of apartments in Korea, but the point I wanted to make with this slide is that the most significant individual component of the cost is the drilling itself since it’s almost half the total cost. Adding these costs together results in a $3,767.50 per refrigeration ton ($/RT) system cost.
Based on a study done by the Oak Ridge National Lab back in the late 1990s comparing a modeled GSHP with conventional HVAC systems of various types for an elementary school in Lincoln, Nebraska, the GSHP system was found to have the lowest life cycle cost when compared to the other systems, mostly due to reduced maintenance and fuel costs.
ACC – air-cooled chiller
VAV – variable air volume air handling system
WCC – water-cooled chiller
CV – constant volume air handling system
Due to NC’s lack of sufficient geothermal potential, geothermal in this state is in the form of ground source heat pumps. All of these stats are from the last five RTI reports.
Due to NC’s lack of sufficient geothermal potential, geothermal in this state is in the form of ground source heat pumps. All of these stats are from the last five RTI reports.
Since the upfront cost of a system is relatively high (~$25-30k for a 3,000 sqft home), incentives are primarily what increase adoption.
The overall cost of the technology will not change significantly since, unlike solar PV technology, the equivalent capacity factor in this case will not really change. Instead, another way to support GSHPs is if they are considered for energy efficiency rebates offered by utilities.
