NREL Publishes Strategies To Reduce Energy Costs in Commercial Buildings, Including Hospitals

Plug and Process Load Reduction Strategies Are Key to Intelligent Whole Building Systems Operation

Sept. 2, 2025 | By Dana Strongin | Contact media relations

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Managing commercial buildings is all about being more efficient and reducing costs. When the building itself is already efficient, where is the next place to look?

The answer may seem small, but it is everywhere: everything that gets plugged into an outlet and all the equipment that is hardwired into the building to support its processes. This everyday aspect is its own focus area in building science. The field of plug and process loads (PPLs) research focuses on energy usage in buildings not associated with heating, ventilating, and air conditioning (HVAC), lighting, water heating, or other major end use needed for basic building operation. Think about all the devices like computers and printers and larger loads like kitchen equipment, elevators/escalators, and medical imaging equipment.

The U.S. Energy Information Administration estimates PPLs consume about 28% of primary energy in U.S. commercial buildings. And while commercial buildings are making strides in lowering energy usage across HVAC and lighting systems, the sector requires major innovation in both the technologies and controls of PPLs to make a significant impact on costly utility bills and peak energy demand.

“There are so many items in a building that give it its functionality—elevators, computers, television displays, kitchen equipment, water fountains, refrigerators, laundry machines, networking equipment, and so much more,” said Robin Tuttle, NREL PPL research project manager. “Because the list of devices and equipment contributing to plug and process loads is seemingly infinite, designing strategies to lower building operational costs without impacting comfort or relying on occupant behavior is very challenging.”

Energy is equal to average power multiplied by time, so to reduce energy usage from PPLs, either power or time used has to decrease. NREL buildings researchers are tackling this challenge from both sides to provide critical insights into optimizing PPLs. Through research funded by the U.S. Department of Energy and its Better Buildings initiative, new methodologies provide baseline data to improve the efficiency of equipment, and innovative control strategies ensure whole building systems are operating intelligently.

A Closer Look at Magnetic Resonance Imaging Systems

The NREL research team is focusing on opportunities in medical imaging equipment, which is an unaddressed energy load for most hospitals and healthcare facilities. The Medical Physics article "A semi-automatic analytical methodology for characterizing the energy consumption of MRI systems using load duration curves" introduces a methodology to categorize energy use of the energy-intensive medical equipment without the challenges associated with extracting and processing individual scanner logs.

The relatively simple, semiautomatic methodology for quantifying the energy consumption of magnetic resonance imaging (MRI) scanners only requires power data for the scanners and creates a load duration curve to identify time spent in the various operating modes. Load duration curves are a fundamental tool used across various fields to analyze and understand load behavior over time.

By implementing this methodology jointly developed by NREL and its partners at University of California (UC) Davis Health, the study identified nonproductive modes and found that MRI scanners spent a significant amount of time (76% to 80%) in modes such as idle or low-power states. For example, one MRI scanner consumed up to 184 kWh per day in idle mode during weekends. That is more than $27 per day per machine (at $0.15/kWh) of operational cost while not scanning patients.

In addition to methodology development, the PPL team provided technical support to UC Davis Health for procuring and installing power meters on several of its MRI systems. The team worked with radiologists and facilities staff to identify the correct metering setup to collect the data needed to develop the load duration curve method.

Similarly, the PPL team also worked with University of Michigan Medicine to procure and install power meters on their MRI systems to monitor energy use and identify savings opportunities. Out of this metering work, the PPL team developed a medical imaging equipment energy efficiency fact sheet for healthcare facility owners and operators, describing imaging equipment energy and operating cost reduction strategies and how facilities can set up their own metering studies to uncover savings opportunities.

“The publications and fact sheet reflect the power of collaboration—combining the expertise of medical physicists, radiologists, healthcare facility managers, manufacturers, and NREL researchers to identify the cost-reduction opportunities,” said Omkar Ghatpande, an electrical engineering researcher at NREL. “This project would not have been possible without the valuable partnership and support of the hospitals involved.”

The PPL team will continue their research on MRI systems, including applying the load duration curve method to MRI power data from several hospitals across the country, uncovering broader trends in MRI operation and energy behavior, and identifying additional opportunities for reducing energy costs in healthcare facilities through operational strategies. They also hope to expand their research to additional medical imaging equipment modalities, such as computed tomography (CT) scanners.

Finding Paths Forward for All Commercial Buildings

Beyond healthcare facilities, what should top the list for PPL research across commercial buildings? To find out, NREL researchers interviewed more than 40 commercial stakeholders—from facility managers to energy management technology companies—to understand what drivers and barriers they face for implementing PPL efficiency and control.

Published in Energy Efficiency, "Pathways to commercial building plug and process load efficiency and control" details the team’s findings. They identified several pathways to support increased uptake of PPL efficiency and control in the commercial sector. These include developing and sharing more case studies and best practices, adding funding opportunities, gathering and sharing data on baseline PPL energy use, including PPLs in commercial energy codes, and promoting company efficiency goals.

“These pathways identify some of most viable ways for PPL reduction in commercial buildings,” said Kim Trenbath, manager of the Communities and Urban Science group at NREL. “While these may seem straightforward, capturing energy savings through PPLs while offering a high level of service is challenging, especially as the number of electronics increases. There is a huge opportunity for technological breakthroughs that meet user needs while possessing the ability to reduce load.”

Ultimately, the team hopes to expand on this research and build collaborative efforts to help make the pathways realities.

“This study offers a clear roadmap, not just for our research team but for the entire commercial buildings industry, to guide PPL research, development, and deployment efforts,” added Amy Van Sant, PPL team lead and mechanical engineer at NREL. "We are excited to work alongside building owners, operators, and fellow researchers to turn these pathways into action."

Establishing a Plug and Process Load Reduction Strategy

Interested in addressing energy costs in your commercial building? NREL’s quick start guide will help building owners and energy managers achieve cost savings through PPL energy use reduction in their facilities. It packages extensive PPL research into an easy-to-use set of instructions and provides quick references to useful tools, websites, and databases. Get started with the following four steps:

1. Establish a plug and process load champion.
2. Institutionalize plug and process load measures.
3. Benchmark current equipment and operations with a walkthrough.
4. Develop a business case for addressing plug and process loads.
5. Check out the Better Buildings website for more resources.

Learn more about NREL’s cutting-edge research to drive affordable energy solutions and strengthen the reliability of energy systems for American buildings.