This article was written by Savannah Marshall and originally published in the Lions Talk Science blog by the students of Penn State College of Medicine.
As researchers, we set out to improve human health. However, laboratory research in the US emits over 21 million metric tons of carbon dioxide every year.(1,2) The relationship between carbon emissions and harm to humanity is difficult to quantify, however, researchers at Columbia University reported in Nature Communications that every million metric tons of CO2 emissions causes ~226 climate change-related deaths.(3) This leaves laboratory research responsible for ~5,000 deaths annually. So, what can we do to avoid devastating the future of life on Earth while trying to improve overall human health and lifespan?
The average lab uses more energy per square foot than a hospital.(1) As illustrated in Figure 1, lighting uses about 13% of the energy consumed, and heating, cooling, and ventilation use a whopping 60%, on average.(4) The plug load, or the energy pulled in from outlets, accounts for 22% of lab energy use, and is the easiest category on which we can have an impact.(4) Let’s analyze this plug load by looking at the usage of some general equipment present in most labs.
To avoid boring you with the kilowatt hours (kWh) of each piece of equipment, I will use something more tangible: a ‘home’s-worth’ of energy. The average home in the US is ~2,500 sq. ft. and uses ~30 kWh of energy per day.5 For reference, the house shown in Figure 2 is an average sized home. Now to blow your mind: ultra-low temperature (ULT) freezers (a.k.a. -80°C freezers) use one full home’s worth of energy every day and -20°C freezers use one-half a home’s worth! But that is not even the worst of it. Autoclaves use as much energy as 3 homes and a fume hood uses 3.5 homes’ worth!(4) I did the math and my lab has four fume hoods, three -80°C freezers, two -20°C freezers and one autoclave, and thus consumes as much energy as 21 homes! That total doesn’t even include refrigerators, cold rooms, biosafety cabinets, incubators, water baths, shakers, or centrifuges! Since plug load only accounts for about 22% of a lab’s energy usage,(4) my lab nets the energy use of over 100 homes. Each one of our labs is literally using enough energy to power a small village! This statistic might seem discouraging, but I only point out this monstrous energy consumption to emphasize the surprisingly large impact just a few small changes can make.
Here’s the good news: significantly reducing energy use is easier than you may think! Just a 30% reduction in energy usage by all labs in the US would be equivalent to removing 1.3 million cars from the roads.(1) A 30% decrease may sound impossible, but it can be accomplished with just a few changes. The first and most important thing you can do is close your fume hood sash when it is not in use. The main problem with an open fume hood is that it is constantly sucking air from the building and pushing it back outside; however, the energy use of the actual fume hood is not what is so costly. The energy waste is due to the fact that the fume hood takes all that heated or cooled air (which alone uses over half of the lab’s energy to create) and pumps it right back out of the building.(4) Fume hoods effectively replace all the treated air in your lab multiple times a day. Closing the sash when you are done working can cut a fume hood’s energy use in half.(4) You just saved more than one entire home’s worth of energy! Wasn’t that easy? Not to mention closing the sash should already be habit for safety reasons as it is made for chemical and biohazard containment.
Now let’s talk about how you use your biosafety cabinet (BSC). Do you leave the UV light on overnight for sterilization? Well, it may be time to reconsider this habit. These lights quickly lose efficiency when left on for long periods of time, so this practice may be jeopardizing your work. It has been found that 30 minutes of UV light followed by an ethanol wipe is sufficient for sterilization.(4) In fact, UV light usage in BSCs is not even recommended by the NIH, CDC, or NSF.7 While we are here, remember to replace this UV bulb regularly to keep it running efficiently.
Now to discuss the elephant in the room, ULT freezers. The first key practice to adopt is regularly defrosting all freezers to keep the pumps running efficiently. There is no specific time frame for how often you should be doing this, but if the frost has built up too much to simply brush out, then it is time for a full defrost. You can avoid frequent defrosts by brushing out frost as often as you can.(4) The next step is to regularly vacuum the freezer coils behind the unit to maintain efficient heat exchange. And finally, this step might make you cringe, but bear with me: setting your ULT freezers to -70°C instead of -80°C can result in 35% energy savings.(4) This might sound like a hard sell to your PI, but here are the facts:
Before freezers were even able to reach -80°C, all were set to -70°C without issue. The switch to -80°C was a result of marketing by manufacturers to demonstrate superior ULT freezers, rather than a demonstrated scientific need for sample integrity.(7) The University of Colorado has switched nearly ¾ of all their ULT freezers from -80°C to -70°C without any demonstrated sample vulnerability.(7) How can I say that with such certainty? Well, they kept track of every sample that has been stored at -70°C and for how long on a publicly available database. Check it out!
Nevertheless, even with this rigorous approach to proving sample stability at -70°C, I empathize with the difficulty of bringing this topic up to your PI. My advice is to start by suggesting initially changing only one freezer to -70°C for samples that are validated on the database. You can also use this conversation as an opportunity to encourage your lab to create a cleaning and maintenance schedule for freezers and other equipment. Finally, if you have heard of the freezer challenge from My Green Lab, I applaud you. Click here to enter this year’s contest to earn points while learning responsible freezer practices.
I’d like to end with a few final tips for reducing energy use. Since lighting uses 13% of a lab’s energy, it is a competitor of some energy-hogging equipment mentioned previously.(4) Turning off lights at night and on weekends can cut lighting energy use by half!(4) Talk to your lab to establish a last-person-out routine that includes turning off lights as well as any equipment that does not need to be on overnight. But what if you want your water bath warm and centrifuge cold in the morning? Well, in the modern day of technology, we have these nifty things called outlet timers. Timers are an easy way to have equipment turn off automatically at night and be ready for use in the morning. To further reduce plug load, look to the energy-hogging autoclave (that uses 3 homes’ worth of energy) to see if it can be turned off when not in use. This will not only save over a home’s worth of energy, but also hundreds of gallons of water every day!(4) Along these lines, try to consolidate autoclave loads when possible and consider making a schedule for the researchers that share the autoclave. Speaking of teamwork, consider sharing other minimally used equipment among labs and unplug duplicates.
Look how easy it is to reduce your labs energy usage by several homes’ worth! This article highlights the main changes you can make to enact significant energy savings. Imagine the impact if every researcher heeded this advice. Spread the word, talk to your fellow researchers, make use of social media, and most importantly, lead by example!
About the Author
Guest Author Savannah Marshall is a Ph.D. candidate at Penn State College of Medicine where she studies the role of brain iron overload in neurodegeneration. Through her research, she has discovered her passion for lab sustainability. She is a My Green Lab Ambassador and her on-campus efforts include the creation of the Graduate Student Association Sustainability Committee and the Penn State College of Medicine Green Team which works with campus facilities to implement and optimize recycling streams for lab and hospital waste.
(1) Giarrusso, J. How to optimize your lab’s energy efficiency without compromising its compliance or safety. (2014). https://blog.se.com/building-management/2014/04/03/optimize-labs-energy-efficiency-without-compromising-compliance-safety/
(2) epa.org. Greenhouse Gas Emissions from a Typical Passenger Vehicle.https://www.epa.gov/greenvehicles/greenhouse-gas-emissions-typical-passenger-vehicle (2018).
(3) Bressler, R. D. The mortality cost of carbon. Nat. Commun. 12, 4467 (2021).
(4) My Green Lab. My Green Lab Ambassador Program. Activation Energy. https://www.mygreenlab.org/ambassador-program.html
(5) How Much Energy Does a House Use? Constellation https://blog.constellation.com/2021/02/25/average-home-power-usage/ (2021).
(6) Dauenhauer & Associates. House Plans 2001 to 2500 SQ. FT. Best Price House Plans. http://www.bestpricehouseplans.com/house-plans-2001-to-2500-sq-ft/
(7) Norberg, A. How Much Does That Lab Equipment Consume Anyways? (2015) Boulder, Colorado.
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