Cogeneration Utility Plant
Whereas traditional power plants lose 60 percent of their energy from the burning of fuel, Cates Utility Plant converts this waste heat to steam, which is used to heat nearby buildings. A 2012 renovation equipped the facility with cogeneration technology, which utilizes two natural gas-fired 5.5 megawatt combustion turbines and two 50,000 pound per hour heat recovery steam generators to help supply energy to 8 million square feet of campus buildings. An interactive online graphic shows how the new facility operates. This estimated 35 percent efficiency improvement is expected to reduce the university’s greenhouse gas emissions by 8 percent. In addition to energy savings and helping NC State become more sustainable, the facility is also a resource for teaching students about energy efficient technologies. Financed by a $61 million performance contract with Ameresco, Inc., which guarantees energy savings, the facility will pay for itself in energy savings over 17 years – without using any additional state funding.
NC State utilizes highly-efficient LED (light-emitting diode) lighting where feasible. From parking decks and new construction to renovations and retrofits, the university is saving energy through this innovative technology.
- At the time of installation, NC State’s Bragaw Residence Hall was the largest installation of LED lights (1,500) at a residence hall in the country.
- Wolf Ridge campus apartments feature 4,182 LED lights that save energy and maintenance costs.
- LED greenhouse lights use just 35 percent of the energy as traditional lights in a university greenhouse.
Ultra-low (-86°F) freezers consume vast amounts of energy on campus. In order to address this issue, Energy Management launched the Ultra-Low (ULT) Freezer Rebate Program in November 2011. This rebate program upgraded the university’s climate-controlled laboratory storage by providing cost-share funding to researchers for replacement of old, inefficient, ULT low freezers with new, energy-efficient, equipment.
Building Automation Systems
Many campus buildings have control systems known as Building Automation Systems (BAS), which create the ability via a computer to schedule and control building temperature set points and schedules based on weather or other needs. Coordinating analysis of temperature and humidity conditions and the BAS, Energy Management can determine how much outside air should be used in HVAC systems. Minimizing outside air in the HVAC system saves energy since the air must be conditioned for temperature and moisture control before it can be delivered to an occupied building space.
Energy Performance Contracts
Performance contracts are a performance-based procurement method and financial mechanism for building renewal projects whereby the utility bill savings that result from the installation of new building systems pay for the project’s cost. With an established allowable payback period of 20 years and an aggregate principal amount of $100 million available, a “Guaranteed Energy Savings” performance contract (as defined in NC G.S. 143-64.17 legislation) obligates the contractor, a qualified energy services company, to pay the difference if at any time the savings fall short of the guarantee.
- NC State’s first performance contract was a 13-building, $17 million agreement with Schneider Electric. The project has an 11-year payback with an annual savings of roughly $1.7 million. Buildings include: Caldwell Hall, Carmichael Gym, College of Textiles, Cox Hall, Dabney Hall, McKimmon Center, Monteith Parking Garage, Poe Hall, Research I, Structures Lab, Tompkins Hall, Winston Hall
- A $61 million contract with Ameresco allows NC State to generate its own power for the first time through the installation of a gas-fed combined heat and power (CHP) system, which should pay for itself in 20 years. This new system provides 11 megawatts of power to main campus, supplying one-third of main campus demand. The contract also upgrades Yarbrough Utility Plants on campus.