Managing the consumption of energy on campus can lead to significant cost savings for NC State. The university manages its own complex network of energy distribution through several steam and utility plants, plus a vast network of steam and chilled water pipelines. The main two energy sources NC State uses are natural gas and electricity, which is in part produced at the Cates Steam Plant and by solar energy with the remaining purchased from the local utility firm. Fuel oil is used to a lesser degree and mostly when the university is asked to avoid use of natural gas during peak demand events, such as winter snow and extreme cold.
NC State’s Energy Management uses many strategies and industry best practices to reduce energy demand and costs:
- Electrical demand-side management saves money by reducing campus energy consumption peak when energy supply is constrained and costs are highest.
- Energy purchase optimization ensures electricity is supplied at the lowest cost. In some cases innovative, cost-saving arrangements are made with traditional utility companies.
- Peak shaving reduces energy costs by lowering consumption during the peak time of the day, when electric rates are the highest. Typically during the months of October to April from 11:15 a.m. to 1:00 p.m. and from 3:30 p.m. to 6:00 p.m., peak shaving is conducted when the outside air temperature is the highest during a billing cycle. By decreasing peak demand during these conditions, NC State can save as much as $20,000 to $75,000.
Operational and Maintenance Improvements
The vast network of campus utilities requires continual maintenance to ensure operational excellence and maximum energy savings.
- Steam traps devices remove condensate from steam pipes, allowing for more efficient distribution to campus. The university has a cost-saving Steam Trap Maintenance Program to reduce the trap defect rate and associated energy loss.
- NC State uses retro-commissioning (RCX) to identify operational and maintenance improvements in buildings and to ensure that every mechanical system achieves optimal performance and minimizes operational cost. A campus RCX team evaluates a building’s system and the building as whole to maximize operation through peak performance algorithms. System operation is improved and reduces energy waste by up to 15 percent. A properly implemented RCX project will yield a payback of less than three years.
- Reinvestment legislation passed by the North Carolina General Assembly (House Bill 1292 was ratified and became Session Law 2010-196) allows all University of North Carolina system schools such as NC State to keep 60 percent of savings resulting from energy conservation measures to be used solely for future energy saving measures.
Combined Heat and Power Plant
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. Featured projects include:
- 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 used in research consume vast amounts of energy on campus. Energy Management launched the Ultra-Low (ULT) Freezer Rebate Program in November 2011 to upgrade the university’s climate-controlled laboratory storage by providing cost-share funding to researchers for replacement of old, inefficient 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. 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 Research Center, Monteith Parking Garage, Poe Hall, Research I, Structures Lab, Tompkins Hall and 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 at Cates Utility Plant provides 11 megawatts of power to main campus, supplying one-third of main campus demand. The contract also upgrades Yarbrough Utility Plant on campus.