• Stewardship in action: Collaborating to conserve energy

gloved hands removing box from ultracold freezer compartment, several different laboratory specimens and materials visible in freezer, heavy frost on everything

By Amanda Holloway, Office of Sustainability, and Brandon Hill, Supply Chain Management

At Mayo Clinic, research drives everything we do for patients. Discovery and innovation are at the root of every new treatment and each expansion of our understanding of disease. Better experiences within the health care system for patients, care givers, and health care providers are also a result of scientific investigations.

At any given time – there are hundreds, if not thousands, of clinical trials, discovery science projects and translational research initiatives underway at Mayo Clinic. Many of these require temperature-controlled storage as part of their process. With Earth Day 2021 upon us, it seems an ideal time to highlight a collaboration to manage some of the most specialized of this type of equipment — ultracold freezers — that led to a reduced energy use footprint and real cost savings.

Mayo Clinic operates over 1,600 ultracold freezers in its laboratories and research areas. Ultracold freezers, also called ultralow temperature freezers, operate at temperatures between minus 40 and minus 86 degrees Celsius. These temperatures are needed to keep specimens viable for scientific testing and research. The freezers are also used to store critical items such as vaccines and other laboratory reagents.

Ultracold freezers consume a large amount of energy and, therefore, are expensive to operate. The energy required to operate one ultracold freezer can be as much as 30 kwh per day — similar to the amount of energy as consumed by the average U.S. home — and costs the laboratory several dollars a day.

In 2018, Mayo Clinic’s Supply Chain Management team led an initiative to standardize the purchasing of ultracold freezers. Historically, laboratories and research had purchased freezers from a variety of manufacturers, with a resultant variation in purchase and operating costs. Each laboratory's decision had long lasting effects on energy usage, as equipment can remain in service for 30 or 40 years or longer.

Supply Chain Management issued a request for proposals to potential suppliers and manufacturers, taking a 'total cost of ownership' approach that considered both the initial purchase cost and operating costs such as energy consumption and ongoing maintenance.  A multidisciplinary group comprised of members from Supply Chain management, research laboratories and the Department of Laboratory Medicine and Pathology, Sustainability and Facilities Management came together to set the requirements. They outlined criteria to evaluate the freezers and conducted side-by-side blinded trials, enabling an accurate and unbiased understanding of the performance of each product against the criteria and its competitors. 

The most energy-efficient freezers used up to 60% less energy than the other freezers. Thus, the 'total cost of ownership' approach showed that the most energy-efficient model also had the overall lowest cost over a 10-year period, despite a higher purchase price. As a result of this collaborative investigation, Mayo Clinic was able to consolidate purchasing and establish a more efficient repair and replacement process. This will steadily reduce projected energy use each of the next 10 years or so as Mayo replaces inefficient, outdated or broken freezers. Overall cost savings is anticipated to be in excess of $3.5 million.

Collaborating on the purchase and replacement of ultracold freezers is just one example of Mayo Clinic's Environmental Stewardship program in action. A reduction in energy also means a reduction in pollution associated with energy production. This benefits the environment as well as the bottom line — a win-win for our communities and for Mayo Clinic.


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