Yellowstone National Park has a difficult challenge ahead in dealing with rising energy costs
and concerns of carbon emissions. To deal with this challenge, Yellowstone has tasked itself with
reducing its energy consumption by 15%, fossil fuel consumption by 18%, and greenhouse gas
emissions by 30% below 2003 levels. The University of Michigan team spent 18 months conducting a
facility energy audit on 25 buildings within the park with the goal of adding the park’s green team
to achieve these goals. The goals also included providing building specific energy improvement
recommendations that could be applied to similar buildings, and exploring policies hindering the
development of renewable energy resources in the park.
To achieve these goals, data was collect about each building from several different
sources. Two years of historical energy use data was gathered in the form of electricity bills and
fuel invoices. Use and maintenance information was collected through interviews with key building
and maintenance personnel. Each building was audited for building envelope characteristics, HVAC
systems, lighting layout and design, and other industrial electronics. This was done by surveying
the buildings in person and looking at building blueprints when available. The building surveys
included an infrared camera audit which allowed the team to “see” issues areas in the building
envelope and systems. Recommendations were developed by looking for improvements in
equipment, building envelope, maintenance practices, building use and behavior, and lighting.
While each building was analyzed, several common park wide recommendations became
apparent. These included lighting upgrades, weather stripping and caulking, maintenance, vending
machine management, smart power strips, monitoring and benchmarking, and behavioral changes.
Lighting upgrade recommendations take advantage of recent reductions in LED, CFL, and T5
light prices. Upgrading to these lighting types reduces energy consumption and overall demand, while
maintaining lighting intensity and quality. These upgrades may not be cost effective to perform in the
near term, but it is important to consider these lighting technologies in any future renovations or new
construction. Other lighting upgrades include installing occupancy sensors in common areas and
installing photo sensors near windows to reduce artificial lighting when there is ample sunlight.
Maintaining weather-stripping and caulking is important to minimize the building leaks.
The pictures taken with the infrared camera revealed that this maintenance was lacking in many of
the buildings. Improving the maintenance schedule will greatly reduce the energy consumed by a
building’s HVAC system. Many of the vending machines in the park are old and run continuously.
New vending machines have sensors that reduce the energy consumed when there are few or no
people using the machine. Old vending machines can be upgraded with off-the-shelf-components
to reduce their energy use. Similarly to the vending machine upgrades, smart power strips reduce
the amount of energy consumed by “vampire” loads, or loads caused by electronics that are
plugged in, but not turned on. These strips work by shutting down the outlets on the strip when
specified equipment is turned off, like a workstation computer.
Current park practices of tracking electricity bills and fuel invoices do not accurately and
sufficiently monitor how and where energy is being used. Current practices also do not allow for
establishing a good baseline or benchmarking against other buildings of similar type. Using a
program like Energy Star Portfolio Manager allows for quality benchmarking, as well as increasing
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the viability of energy use. Improving the systems that use energy in a building is only partially the
solution. Changes in how the occupants use the building is just as important. To address this, the
team recommends variety of techniques to better education the park staff on energy management
programs and on how to include the park staff in future energy management improvements.
In addition to the park wide upgrades, it is recommended that the Gardiner Heritage
Center establish a more extensive program to maintain the seals on the cold storage equipment in
the building. Infrared pictures of the equipment indicated that some units where leaking more cold
air than others. Similarly, upright freezers should be considered for upgrades to Energy Star rated
chest freezers. This may not be cost effective for newer upright units, but should be considered
for any future freezer purchases.
The lower Mammoth residences are currently being upgraded, but extra care should be
taken to verify that wall insulation is present. It was observed in an infrared picture that a small
strip of insulation was likely to be missing in #562. Appliances upgrades are also recommended for
all residences.
The Mammoth Community Center is a prime example of how building uses change over time
and how this creates a building which uses an excess of energy. Many electronic devices were
found throughout the building and a thorough audit should be done to remove all unused and
unnecessary electronics. Boiler pipes should be insulated as it was found with the infrared camera
that much of the heat was emitted into the boiler room itself. From an overall building use
perspective, the Community Center has much of its space unused, yet those spaces are still being
heated. Considerations should be made on either modifying the builds systems to allow for these
spaces to be shut down completely, or renovating the building to better suit its current uses.
The Mammoth Fleet Operations Garage is a large consumer of energy in comparison to the
other buildings audited. This allows for a large impact when energy efficiency measures are
implemented. Although, the nature of the work being performed in the garage bays makes major
changes to the energy systems difficult. Current heating units in the work bays are hung from the
rafters and attempt to heat the entire space. Upgrading these to allow for heating of the works
would allow for a large reduction in energy consumption. Similarly to the Community Center, the
boiler pipes supplying hot water to the building should be insulated.
The YCC facilities, both dorms and the mess hall, are buildings where use varies seasonally.
Upgrading heating systems to radiant propane heating, replacing the electric baseboard heaters
along with insulating hot water pipes, and reducing hot water heaters set points are all simple
steps to reduce the energy consumption of these buildings. Other advanced upgrades to these
buildings include occupancy and motion sensors on all common area lighting, and heat recovery
from walk-in freezers and refrigerators.
While most of the buildings audited are older, the Old Faithful Visitor Center is a new,
LEED Gold certified building, but there are still energy improvements that can be made. These
improvements are centered on developing a better understanding of how the energy management
systems in the building can be deployed.
The Canyon Visitor Education Center, while being recently renovated, has several
opportunities to reduce its energy use. The lighting systems used on the education displays do not
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utilize many new bulb technologies, the lighting in the building is not considering the natural light
in the building, and older HVAC and AHU components could be supplemented with variable
frequency drives to improve their energy performance.
Being off the grid, the Lamar Buffalo Ranch already had many energy efficiency measures in
place. However Lamar does not have an accurate understanding of how much energy it consumes
and when it is using this energy. Currently, the amount of energy produced by the solar array must be
back calculated based on generator run time and propane use is calculated from propane delivery
invoices. These techniques only allow for the accuracy of energy use to be on a yearly time scale.
Additional metering would allow for a large increase in accuracy, as well as better inform decisions
about expanding renewable energy production and upgrades to the generator systems.
The park has a wide variety of water treatment facilities which all make use of large
batteries of pumps performing various tasks. Pumps which are regularly throttled by valves, cycled
on and off to control flow and output, or which are run intermittently for maintenance reasons
could use less energy by installing variable frequency drive control. There are electronic units
which control the electricity inputs to a pump and control the flow and output of the pump. When
a pump does not have this control, while on, it uses the maximum amount of energy it is rated for.
Variable frequency drives reduce the energy demands when pump demands are also reduced.
This project also considered how the park can institutionalize sustainable practices in order
to improve its existing environmental management strategies. The park’s sustainability efforts are
currently led by the park’s Green Team, which is a small interdisciplinary group based in the
Mammoth administrative area. Although this group has done many things to improve sustainability
in the park, there is still room for improvement. This group should include a wider coalition of
park employees in order to make sustainability a park-wide priority and more achievable goal. The
Green Team should consider working more closely with the departments in the park, and outside of
the park, that plan, design, and maintain the built environment at the park. This includes the
planning department, the Denver Service Center, interpretation and exhibit design, as well as
maintenance and operations. Developing a broad interdepartmental strategy to improve
sustainability at multiple scales will eliminate many of the problems between building design and
function that the team noticed at the park.
While the primary purpose of this project was to reduce energy demand within the park,
the team also developed a guide to help the park consider renewable energy options in order to
increase the park’s supply of electricity. Developing renewable energy in the park is a measure to
both significantly mitigate and adapt to climate change. There are many limitations on developing
renewable energy within the park, such as historic preservation areas and concerns about
viewsheds. However, there are also many areas within the park that are zoned as administrative
areas that the park should prioritize for these types of projects. Technology such as solar
photovoltaics, solar hot water, small wind turbines, and hybrid systems would be appropriate for
most administrative areas within the park. However, before moving forward with a renewable
energy strategy, the park should either negotiate a better rate for net generation from the electric
company or develop energy storage capabilities. While the National Park Service has prioritized
off-grid areas for renewable energy development, because it is usually much cheaper than a grid
connection, this is not the best strategy to reduce the park’s carbon footprint. Because the local
grid is very carbon intensive, in order to more meaningfully address climate change mitigation the
park should prioritize renewable energy development in on-grid areas.