Geothermal Technology & How It Works
Geothermal technology uses the constant and abundant energy source below the earth surface, to extract heat in the winter and to deposit unwanted heat in the summer. When it is cold outside, it is 45 degrees in the ground; and when it is hot outside, it is 45 degrees in the ground. Requiring little energy compared to less efficient conventional cooling systems, the constant 45 degree ground temperature will efficiently absorb unwanted heat while conventional cooling systems dump unwanted heat into an already warm outside atmosphere. In the case of heating, geothermal systems use the earth’s already warmer than outside air temperatures to heat, compared to conventional systems which must create the necessary energy to heat from nothing.
Geothermal energy is up to 400% more efficient than conventional heating and cooling systems. For every unit of energy input to run heating and cooling equipment, 4 units of energy are transferred from the ground. By transferring heat to and from the ground, geothermal technology capitalizes the use of thermal energy already in the ground while reducing the need to produce or create additional energy. Conventional heating and cooling systems require the production or creation of more energy to achieve the same result.
The West Union district geothermal system is made up of three parts:
- The ground loop system; 132 vertical wells (300 ft deep) in the courthouse lawn
- The district distribution system - over 5,500 feet of 8 inch pipes in the streets. This connects to 70 business and building lots in downtown West Union
- Customer-owned piping and HVAC equipment utilize the shared system’s water and glycol antifreeze solution to heat or cool their buildings
Cost & Benefits
The old adage “timing is everything” best explains the backstory of West Union’s shared geothermal system. Here are some relevant contributing factors to our unique community owned shared geothermal system.
- In 2006 the city of West Union became a Main Street Iowa community. Main Street communities use a community based approach toward downtown revitalization.
- In 2007, the West Union City Council began visioning a needed downtown street rehabilitation.
- In 2008, the agency which houses Main Street Iowa, the Iowa Economic Development Authority (formerly the Iowa Department of Economic Development) was in the hunt for a community to participate in an integrated streetscape sustainable strategies project.
- As a rural Iowa county seat, with a consolidated school district, and a town in the Turkey River Watershed, with contributing downtown stormwater runoff, the city of West Union was a top consideration for the green pilot project.
The total price tag for Green Streetscapes project including: the bioswales, LED street lighting, permeable paved streets and sidewalks; Civic Plaza; and the district geothermal system was $10.5 million. $7.5 million in outside funding was secured for the project. This left a $2.7 million city investment.
The district geothermal system portion of the project was $2.2 million. The following grant dollars were used to pay for the construction cost of the geothermal system:
- The Federal Department of Energy: $1 million
- Community Development Block Grant: $1 million
- The Environmental Protection Agency Grant:$500,000
- Main Street Iowa: $100 K
Grants covered 100% of the cost of the geothermal system’s construction. City of West Union taxpayers have not paid, and do not, contribute to the ongoing costs of the shared geothermal district. User fees, paid by users of the system, pay to operate and maintain the system. No portion of local property taxes are used to pay for the geothermal system.
2019’s operating expense was $31,000. These figures include insurance, taxes, monitoring, service, administration, reporting, electricity costs, city leasing, equipment repair and materials. It’s important to note that the system’s ongoing costs are entirely paid by the existing users of the system. No city funds are used to operate, maintain or repair the system.
- This study project is in the process of analyzing the direct and indirect benefits of West Union’s geothermal system. Direct benefits might include reduced heating and cooling energy costs and reduced carbon emissions for the system users. Spending less on energy improves the bottom line for the connected shared geothermal system user. When community members spend less on energy they have more flexibility to spend in other ways which may indirectly benefit the common good.
- Also, building owners, workers, tenants and customers of the downtown geo connected buildings experience a more comfortable, consistent, temperature and humidity controlled environment.
- Further, when the cost to do business in downtown buildings decreases, the district could become a more attractive place to do business. This could indirectly benefit the community by offering a potentially more diverse selection of services.
- As a community adopting clean electrification measures, widespread use of highly efficient geothermal energy in West Union would reduce the town’s demand for unpredictably priced natural gas.
- Local qualified HVAC contractors will benefit from this successful shared geothermal system. As more property owners convert to ground source heat pumps local contractors will be needed to professionally install these systems.
- The demand for solar contractors could also increase because solar powered heat pumps are an additional method for reducing the cost to heat and cool buildings.
- West Union is implementing local clean energy ownership strategies such as; energy efficiency projects in city buildings; solar powering city infrastructure; and facilitating the use of a unique, community owned, public geothermal system. The implementation of these strategies will directly lead to a community reaping the benefits of clean energy prosperity and environmental stewardship. Ideally, this model will attract new residents and businesses to the community, stimulate local spending, wealth retention, and significantly reduce the town’s carbon footprint.
Currently, the LLC made of the systems users leases the system from the city and is responsible for operating it. The system is maintained by the user group through a monthly tonnage fee. The city does not subsidize operating the system.
It is possible more users of the system would lower the cost per customer. The costs to operate the system are mostly fixed costs. The cost of electricity, the largest variable cost of the system, is only about 10% of current annual expenses. With more customers the fixed costs could be spread over more users. This would lower the needed tonnage rate to operate the system.
How to Use
The project team will share informational and educational resources with current property owners who have stubbed geothermal connections. These resources will be electronically available for city officials to use in the future.
Tax Credits and rebates can help lower the initial investment cost of installing a new geothermal system in your building. View a list of available incentives here.
The system has plenty of additional capacity to add users within the existing geothermal district. Over 60 downtown locations have geothermal piping installed to their building or lot that could hook into the existing system.
Currently there are 11 users with a combined heating/cooling capacity of 265 tons. Initial analysis suggests several additional customers could use the system without need for additional capital expenditures. Further study could help determine the maximum capacity of the existing wellfield.
The system was designed to have additional capacity with 252 additional geothermal wells in Lions Park which could increase the capacity of the system by an additional 500 tons. Grant funding limited the expansion of this portion of the project beyond the existing single test well site and pumphouse. Further development would mean a significant construction expense so would only happen if there were adequate demand for expansion.
City Ownership & Operation
It is quite feasible the city could maintain and service the city owned asset as a self supporting activity and at a savings for current users. The city would form a separate enterprise fund to account for operating expenses and revenues separate from the city’s general fund.
Reliable and local operation of the system could gain traction for increasing connections to the system. City operation would have intangible value of goodwill and be an exercise in trust building with the current and potential users.
The city’s operation of the downtown geothermal system would not mean additional tax burden for West Union taxpayers. The system users and not taxpayers would cover the cost of operation. This is in contrast to other city amenities such as swimming pool expenses which are passed on to taxpayers regardless if the taxpayer directly benefits or uses the amenity.
In the event the city takes over operation of the district geothermal system a separate enterprise fund would be developed and general fund dollars would not be used to subsidize the system. In January of 2010, the Iowa Utilities Board (IUB) staff concluded IUB does not have jurisdiction over West Union’s proposed geothermal system. Therefore, the system would not need to operate as regulated or unregulated utility.
Individual equipment will last generally the same amount of time as a conventional furnace and AC (15-25 years). The geothermal system itself, the wells and distribution piping, will last up to 100 years.
During the planning stages of the West Union Green Pilot Streetscapes initiative, the project preliminarily included the possibility of a heated streets and sidewalks feature. This feature was cost prohibitive and seen as an “extra” which was not very practical or efficient. In order to contain the project cost and to minimize the tax asking and to stretch the grant dollars, this feature was eliminated from the project. The “heated sidewalk” feature was a concept that may have functioned, but was simply not a practical feature or a priority.