This is one of a series of occasional stories on the measures that Schools at Harvard are taking to reduce greenhouse gas emissions.

Going green at Harvard Medical School (HMS) means implementing sustainability measures in classrooms, offices, and — perhaps most challenging — laboratories.

In 2008, Harvard President Drew Faust announced the University’s goal to reduce greenhouse gas emissions 30 percent by 2016 (from 2006 levels, including growth). In response to this goal, HMS has developed and is implementing a Greenhouse Gas Reduction Plan.

Optimizing the performance of mechanical, electrical, and other systems in buildings, a process called recommissioning, will help the School to reach its greenhouse gas goal. In the Warren Alpert building, the first at HMS to undergo formal recommissioning, laboratories present unique obstacles.

“In a normal environment, you can recirculate air and introduce a percentage of fresh, outside air,” said Peter Stroup, director of facilities and maintenance operations at HMS. “In the laboratories, you always need 100 percent fresh air. That’s extremely intensive because you have to take all of that outdoor air and condition it — whether you humidify, dehumidify, cool, or heat it — before it gets into the lab. It’s a huge challenge for us in terms of reducing energy usage because we’re not reusing any portion of that air. The question for us then is how best do we manage temperature, and how best do we manage the number of times we change the air in a room per hour?”

In addition to recommissioning efforts, HMS has invested in green renovations. The DePace Lab, renovated in 2008, was the first wet lab at Harvard to achieve LEED certification. The School has also re-examined its waste stream. Reusable biohazard boxes and sharps containers (for the disposal of needles, syringes, etc.) are the latest in a series of waste-saving measures.

“The previous sharps containers were made of plastic, and the entire container needed to be disposed of after each use. The biohazardous waste boxes were big cardboard boxes that needed to be double-bagged, and the entire box and the bags were disposed of,” said Longwood sustainability program manager Claire Berezowitz.

In the wake of a successful pilot program, which started in 2009, the entire campus has converted to reusable plastic containers made by Stericycle.

“The boxes are picked up by Stericycle, emptied, sterilized, and returned, so we’ve eliminated the need to buy cardboard and have it destroyed,” says Robert Christiano, associate director of Campus Operations, who was instrumental in establishing and managing the reusable sharps and the reusable biohazardous waste box programs.

“With the biohazard boxes alone, we’ve saved over 21,000 cardboard boxes from going into the waste stream,” said Berezowitz.

Last year, HMS facilities completed an evaluation of water-saving units for autoclaves, devices that use steam to sterilize laboratory equipment.

“When the autoclave discharges its wastewater, the water is too hot to be returned to the city system, so it has to be quenched with cooler water in order to get it to the right temperature for discharge, about 100 degrees,” said Stroup.

“The old system would continuously dump tap water into something that looks like a funnel beneath the autoclave,” said Allen Hebert, HMS energy specialist. “The new water saver collects the water that’s being dispensed at 200 degrees and quenches it with domestic water, but only to the extent that it needs — it doesn’t dump water down the drain constantly. If you have five gallons that need to be quenched, it will dump in a gallon to cool it down. … The savings are very substantial.”

HMS is proceeding with the installation of the water-saving units in more than 50 remaining autoclaves on campus. These units are expected to save $200,000 worth of water per year.

Additionally, HMS expects to install electric steam generators in the autoclaves, with a projected savings of more than $500,000 worth of steam per year. These portable steam generators will produce 200-degree clean steam for autoclave units on an as-needed basis, eliminating the need to remain connected to a constant supply of gas-fired central steam.

“The difference is that the steam we buy is much more greenhouse gas intensive than electricity is,” said Stroup. “We’re experimenting with this so that we can reduce our footprint.”

As part of the School’s greenhouse gas reduction plan, HMS facilities created an energy metering website, which tracks the School’s energy usage. The interactive tool updates every 15 minutes with real-time data collected by meters located in buildings throughout the campus. The tool can also be used to compare historical energy usage patterns by hour, day, week, or month.

“You can look at total campus usage, individual building usage, or by utility,” said Stroup. “We had that information available on our website previously, but not in such concise a format, and now it has been translated into more understandable units, like number of trees or barrels of oil consumed, which each of us can better relate to.”

The dashboard is displayed on a touch-screen monitor in the office building at 641 Huntington Ave. (recently certified LEED Gold), and four additional monitors will soon be deployed in other common areas across the campus.

HMS facilities and operations staff work closely with the student group SEAM (Students for Environmental Awareness in Medicine). A tap water filtration system, the direct result of collaboration between SEAM members and staff, was installed off the second-floor atrium in the Tosteson Medical Education Center (TMEC) in May 2010. Developed as an alternative to Poland Springs bubblers (which carry a significant carbon footprint), the system has two cold water dispensers, one hot water dispenser, as well as a sink, and has become a popular spot for socializing between classes.

“I saw the water project as intersecting a lot of different concerns — public health, environmental, and economic,” said Devan Darby, a student leader of SEAM who received a Green Carpet Award from the Office for Sustainability for her work on the hydration station. “It’s a very tangible thing that has made a difference.”

“In a graduate school of this size, we have a compact community,” said SEAM member Jana Jarolimova. “We’re making relatively small changes, but by being connected to the rest of the HMS community and getting enough people to make those changes too, we can actually have an impact.”

A look inside: Currier House