Ensuring Sustainable Operation of Laboratory Freezers

Bringing laboratory cold storage out of the shadows and into the light

Christina Greever

They lurk in hallways and equipment rooms, ever-present, ever-consuming, absolutely essential to the vast majority of scientific research endeavors, and yet usually neglected unless they cause trouble. Laboratory refrigerators and freezers should be recognized for what they are: incredibly useful tools and also outsized energy consumers. At least 58,000 ultralow temperature freezers (-70°C), 74,000 -20°C freezers, and 94,000 refrigerators exist within the scientific sector in California alone, consuming a combined conservative estimate of 780 Gwh/year. In California alone. That is the approximate energy use of 63,000 homes over the course of a year. Imagine the global impact of this type of equipment.

What is the International Laboratory Freezer Challenge?

Thankfully, there is a global competition seeking to curb the energy consumption of this type of laboratory equipment. The International Laboratory Freezer Challenge, now in its fifth year, seeks to help scientists realize the variety of benefits that result from dedicating a small amount of time and effort to their refrigerators and freezers each year. These benefits include:

  • Easier access to scientific samples
  • Prolonged integrity of samples through proper maintenance of refrigerators and freezers
  • Reduced energy costs for research institutions
  • A simple way to bring sustainability to research labs
  • Involvement in a fun competition that allows your lab to work together as a team
  • Promotion of biosafety and chemical safety by encouraging inventorying of samples
  • Reduction in energy consumption from refrigerators and freezers, with tangible benefits for communities and the planet.

What began as a small competition rooted in sound best practices has now grown to global scale, attracting the participation of 88 different research institutions in 2020 alone. It isn’t too late to join the 2021 Freezer Challenge either—there are still five months left before this year’s deadline of July 1, 2021. By participating, you can be a part of the 9.9 million kWh/year saved over the past five years. That’s enough to offset the carbon emissions associated with driving over 15 million miles! Winners of the Freezer Challenge are recognized at the annual International Institute for Sustainable Laboratories (I2SL) Conference and featured in an article in the journal Nature.

Participants are challenged to use well-evidenced criteria and best practices to implement sustainable freezer and refrigerator habits within their own laboratory. What starts as a friendly competition among laboratories ultimately helps scientists create a culture of sustainability within their organization. “For many participants, the Freezer Challenge opens the door to sustainability in the lab,” says My Green Lab CEO James Connelly. “By actively engaging in practices that reduce energy consumption and environmental impact, participants learn first-hand the change they can ignite. This positive shift in perspective allows scientists to build greener practices beyond the Freezer Challenge, ushering in a culture of sustainability in their labs,” continues Connelly. 

While it’s rare to see the cold storage chain discussed in popular media, the Freezer Challenge comes during a time of great interest in ultracold storage. Of the two mRNA COVID-19 vaccines now available in the United States, one requires ultralow temperatures at around -70°C, the other requires around -20°C. One estimate indicates that the US alone might need as many as 50,000 new freezers to support vaccine rollout, a process that has already been underway for many months. The best practices promoted via the International Laboratory Freezer Challenge are even more relevant than they were a year ago, as so many new cold storage units are coming online to support widespread vaccination efforts. The Freezer Challenge promotes practices that are relevant to any laboratory, clinical or otherwise, that has refrigerators and freezers.

How the Freezer Challenge got started

The first Freezer Challenge was dreamed up by Allen Doyle, MS, then of the University of California Davis along with his colleague Kathryn Ramirez-Aguilar, PhD, at the University of Colorado Boulder. Seeking to promote friendly competition between the campuses while encouraging sample clean-outs, regular defrosting of freezers, inventory updates, and the purchase of energy efficient freezers if new units were needed, the Freezer Challenge took form to benefit scientists and their science. In 2017, the Freezer Challenge was graciously handed over to the nonprofit organization the International Institute for Sustainable Laboratories (I2SL), which would enable the program to scale. I2SL enlisted the help of a second nonprofit, My Green Lab, to coordinate and help market the competition. Now a joint venture between the two organizations, the Freezer Challenge first went global in 2018.

Benefits of competing in the Freezer Challenge

While the Freezer Challenge seeks to promote sample accessibility and integrity and help labs reduce energy and costs, other benefits have proven advantageous to past participants. “For me, the Freezer Challenge serves as an annual reminder to go through all of our lab’s cold storage, reorganize freezers, and update the lab’s inventory,” says David Simpson, lab manager for Dr. Edward B. Chuong at the BioFrontiers Institute at the University of Colorado Boulder. “It’s rewarding on multiple levels, and as an added bonus, it’s a great way to gain recognition from your colleagues and coworkers,” continues Simpson. 

Deepa Kundadka, CEO of DKK Safety and Environmental, works with clients on lab safety and sustainability. She noted the employee engagement and leadership opportunities the Freezer Challenge has provided. “When my client won the Freezer Challenge award last year, they received increased visibility from management teams. And because the challenge notifies scientists of the amount of energy they save while participating, they felt a sense of accomplishment which made it worthwhile for them to be part of the program,” says Kundadka. 

Individual laboratories compete in the Freezer Challenge, and then the scores of multiple laboratories at the same research institution are aggregated for organizations to compete against one another too. Recent organizational winners of the Freezer Challenge have included the Massachusetts Institute of Technology with the Whitehead Institute, the National Institutes of Health, AstraZeneca, the University of Illinois Urbana-Champaign, the Centers for Disease Control and Prevention, and Charles River Laboratories. Will your laboratory or research organization win this year?

How to run your lab freezer as sustainably as possible

Best practices encouraged by the Freezer Challenge include defrosting freezers and cleaning dust from intake areas and coils, creating or updating sample inventories, discarding unneeded samples to free up space, retiring unneeded cold storage units, upgrading to energy efficient models, sharing refrigerator and freezer space with other lab groups, chilling up ultralow temperature freezers to -70°C, switching to higher density storage methods, and more. The beauty of the competition is that your lab can implement whichever best practices are most helpful to you—you don’t have to complete every action on the challenge scoresheet. It is certainly a “choose your own adventure” situation. Perhaps your lab dedicates one Friday afternoon per month to tackling a certain aspect of the Freezer Challenge. Or every lab member in your group commits to going through their freezer boxes and discarding unneeded samples over the course of a month, keeping track of what is discarded so you get credit. At the end of the Freezer Challenge, your lab is provided with an estimate of your energy savings as a result of participating and implementing various best practices. 

The goal of saving energy through efficient, effective sample storage in laboratories around the world is a possibility. By implementing optimal freezer and refrigerator management practices, the Freezer Challenge is turning this goal into a reality. 


Christina Greever

Christina Greever has been in the laboratory sustainability movement for five years, and has been involved with molecular biology research, behavioral neuroscience, research compliance, and science sustainability over the past 10. She is the sustainability program manager for the nonprofit organization My Green Lab where she provides subject-matter expertise, manages the International Laboratory Freezer Challenge, manages the My Green Lab Ambassador Program, and assists with various communication efforts. She was formerly the program assistant and outreach coordinator for the green labs program at the University of Colorado Boulder. She holds a bachelor’s degree in biology from Lewis & Clark College in Portland, Oregon, and currently resides in Salt Lake City.