The College’s existing central steam plant provides heating for 25 buildings on the central campus. The system is old, inefficient, uses a fossil fuel (propane) and has a considerable risk of failure. Sweet Briar House and the Fitness and Athletics Center utilize local geothermal bore fields. Many of our residential rentals have been converted to heat pump systems.
To decide energy options for the central campus, we hired 2RW Consulting to conduct a campus-wide analysis of the College’s steam, electrical and HVAC-related systems. The report was completed in the fall of 2021.
To replace the existing centralized steam plant, 2RW investigated three options: (1) geothermal; (2) a new centralized plant operating on fossil fuels (propane); and (3) a decentralized cooling and heating system which would place equipment next to each building, utilize power generated through electricity and/or natural gas and connect to solar power sources or geothermal lines.
- Geothermal system: The mechanical installation alone is estimated to be $25-$30 million, most of it for bore field drilling. Bore fields will divide the campus into “precincts” (clusters of buildings), with each bore field serving different precincts. Electrical installation first cost investment is estimated to be $1-$1.25 million.
- Centralized system: The mechanical installation first cost investment is between $20-$25 million, with electrical installation first cost investment another $500,000-$750,000.
- Decentralized system: The mechanical installation first cost investment is estimated to be $12.5-$17.5 million, with electrical installation first cost investment at $3-3.5 million.
2RW recommends a campus-wide geothermal system, given our interest in sustainability and the existing geothermal systems used by Sweet Briar House and the FAC. Given the initial cost, however, a hybridized approach may make more sense. By combining geothermal and electrical usage, we may be able to balance the College’s capital commitments and operating costs over the longer term. Of course, all of these upgrades will need to tie in with systems in the buildings as we migrate away from our steam plant.
Before new systems are phased in, we must take steps to mitigate the risk of failure in our current steam plant. We are conducting an analysis to install steam shutoff valves to isolate specific legs of the steam system when necessary for maintenance. It will locate the sections in need of repair, which will extend the system’s life and reduce the steam return loss.
2RW also recommended that the College evaluate the campus’s antiquated electrical system. We will proceed with a survey to map out electrical distribution pathways and locate all primary transformers; verify existing primary conductor and transformer sizes; and perform condition assessments on conductors, conduit and transformers. 2RW also recommended that we install meters that will report data back to a central systems control at all buildings.
We are also implementing an electrical design for redundancy. Currently, the electrical feeds to the campus come from two separate directions and are not cross-connected to give us backup. We have engaged 2RW to determine a way to create a ring structure that would connect both of our north and south feeds together so that our campus would have redundancy if one of the two feeds went out. The project also examines removing the switching gear in the physical plant building.
The Stone House Group is advising us on potential solar fields. This consulting project is being carried out during the first half of 2022. We are examining the construction and external financing of an approximately 3 million watts (3 MW) solar field that could provide power to the entire campus. Ideal locations would be near our campus electrical feeds and aesthetically acceptable. Generating power through solar energy would reduce our utility costs and signal to the outside world our commitment to sustainability. As part of the project, we will also examine the creation of a separate solar field for auxiliary revenue generation.