West Campus Steam Plant

The transformation of Duke’s West Campus Steam Plant since its initial construction in 1929 is a testament to the university’s increasing commitment to sustainable resource consumption. The building, which provides space and process heat for more than 7 million sq. ft. of facilities, was renovated and restored in 2009 and 2010. Most significantly, the renovations involved transitioning from burning coal to natural gas, a switch that allowed Duke to entirely eliminate the use of coal in campus steam plants by April 2011. This project earned Silver Certification under the LEED-NC v2009 rating system.

Sustainable Site Features

There was little choice in selecting the site for the renovated West Campus Steam Plant given the nature of the project, however, it is notable that no additional land was developed throughout the project’s duration. In fact, the developed footprint of the steam plant was reduced by 30% as a result of the removal of ash and lime silos and the coal pile. This feature, in combination with the site’s close proximity to dense residential, service, and business facilities, helps to preserve valuable open green space on Duke’s Medical Campus and minimize urban sprawl.

Because the steam plant is situated alongside Duke’s Medical Campus, public transportation via the University’s network of low-emission buses is easily accessible by building occupants. To further encourage the use of public transportation and carpooling, the facility’s parking capacity was not increased.

Remediation of the land surrounding the plant, where coal was previously stored, was conducted, and a large portion of this land was restored with native vegetation in order to promote biodiversity and rainwater infiltration. The heat island effect was mitigated through both non-roof and rooftop measures. These included using pavement with high solar reflectance, planting tall trees to shade the site, and installing a light-colored flat roof, respectively.

Water Efficiency

Native, drought tolerant vegetation that requires little to no additional irrigation was selected to replace coal piles surrounding the newly renovated steam plant. Additionally, the project leads were able to reduce water consumption by more than 20% within the building with the introduction of 15 high-efficiency Miura boilers. Advanced monitoring and control systems along with the addition of a condensate polishing system, which allows for the effective reuse of process water, also help to reduce the steam plant’s overall water consumption.

Energy Efficiency

By switching fuels from coal to natural gas, the west campus steam plant became inherently more energy efficient as combined cycle natural gas plants are up to 10% more efficient than coal powered plants. In addition to this immediate source of energy savings, the steam plant was also outfitted with a number of advanced energy saving technologies that include a custom flue-gas heat recovery system (HRS) that is expected to increase the boilers’ efficiencies to nearly 90% through preheating. This increased efficiency translates to a steam system emission reduction of nearly 40%.

Fuel polishing systems and a new hybrid programmable-logic-controller and supervisory-control-and-data-acquisition system also combine to minimize energy consumption.

In order to ensure that all mechanical, electrical and plumbing systems functioned as expected, thorough commissioning of each of these subsystems was carried out prior to operation.

Indoor Air Quality

A number of measures were undertaken in the design of the West Campus Steam Plant to ensure a high quality indoor environment. The indoor space is ventilated at a rate of more than 30% above the ASHRAE minimum requirement, and permanent monitoring systems are installed to measure CO2 concentrations in densely occupied and naturally ventilated spaces. Low-emission flooring was installed to minimize the risk of indoor VOC buildup, and the use of urea-formaldehyde resins was eliminated in all interior wood products.

Temperature and lighting controls were installed for a majority of use-spaces within the steam plant to allow occupants to adapt the environmental conditions to personal preferences. Additionally, occupants had the opportunity to voice concerns about their level of comfort indoors.

Overall, the cleanliness of the renovated natural gas steam plant cannot be compared to that of coal-powered plants, which are often caked in layers of soot and coal particulates.

Resource Management

In renovating the West Campus Steam Plant, project leads worked to maintain as much of the original structure as possible by performing in depth assessments of the building’s material integrity. Overall, over 75% of the original structure was reused, including a large portion of the floors and walls. Construction waste from both demolition and new construction activities was managed through the development of a Construction Waste Management Plan. As a result, over 75% of the construction waste was recycled or salvaged for reuse. Additionally, over 20% of the new building materials by cost were derived from recycled products, and 10% were extracted and manufactured locally.

Integration of Sustainability in Design and Construction Process

The process of renovating the West Campus Steam Plant was made especially challenging by the fact that the plant needed to continue functioning throughout the renovation. This requirement necessitated careful phasing and sequencing techniques, and in many cases, an hour-by-hour work breakdown structure was devised.

The use of a 3D building information model (BIM) was integral throughout the design and construction phases, as it avoided space conflicts in the highly intricate aboveground and underground wiring and pipe systems.

All equipment for the renovation was preordered to minimize delays. This valuable foresight resulted from early collaboration between architects and engineers in design charrettes.