Emissions to decrease as Central Heating Plant switches to natural gas

On a quiet Friday last month when the campus was mostly deserted for Veterans Day, Tufts Facilities shut down the Central Heating Plant located between Dowling and East Halls to have the chimney cleaned. No, it was not to help Santa stay soot- free this Christmas – it was the final step in getting the gas turned on for the winter.

The plant began using natural gas as its main fuel on November 30 and significantly lightened Tufts’ carbon footprint in Medford. CO2 emissions in FY 2012 in the Medford campus are estimated to decrease by 8% from FY 2011 levels despite a projected increase in energy consumption by 7.8%.

According to Tufts’ Director of Facilities Technical Services Betsy Isenstein, the transition is the result of “a fortunate confluence of events”.

Unbeknownst to most people who live and work on the Tufts Medford campus, the central heating plant was forced to switch fuels in the middle of last winter from burning No. 6 to No. 2 fuel oil because of a shipment of substandard No. 6 fuel that could not be used. No. 6 fuel oil (also known “bunker C” or residual fuel oil) is the heaviest, thickest, cheapest, and – not surprisingly – the dirtiest of six available grades of fuel oil in the US.

Shortly afterwards, a routine inspection led to the discovery of issues with two of the fuel tanks outside the central heating plant and prompted the university to move up scheduled upgrades for two boilers that were installed in the 80s. The upgraded boilers are not only more efficient, but they have the ability to burn both natural gas and No. 2 fuel oil.

With the price of natural gas at a historic low, the fuel switch made economic as well as environmental sense. National Grid installed a new gas line from Boston Avenue up to Central Heating Plant and upgraded 1,100 feet of gas main along Boston Avenue last summer in order to bring the amount of natural gas needed up the hill to supply the central heating plant.

Natural gas is the cleanest of fuels commonly used for residential and commercial space heating. Switching from No. 6 fuel oil to No. 2 last winter already reduced CO₂ emissions by about 7%,  switching from No. 6 to natural gas reduces CO₂ emissions by about 30%,  sulfur dioxide (SO₂) by over 99%, nitrous oxides (NO_x) by about 75% and particulate matter (PM_2.5) by about 96%.[1]

In contrast, No. 6 fuel oil comes from the “bottom of the barrel”. It is the sludge that remains after removal of distillates such as gasoline so it has a higher concentration of metals than other oil. Burning No. 6 fuel oil produces darker smoke and higher CO2 emissions than other types of fuel, and “sludge-burning” boilers have been identified as contributors to increased air pollution and consequently, a higher incidence of respiratory problems.

The transition has been smooth so far, according to Isenstein. Next spring, fuel storage will be replaced to better handle No. 2 fuel, which will only be used as a backup in case the gas supply fails. A third fuel tank installed in the late ‘50s will no longer be needed, so it will be removed next year and possibly replaced. The central plant heats almost every Tufts building on the hill between Professors Row and part of Boston Avenue. Three smaller plants and a number of stand alone boilers heat the rest of the Medford campus.

The fuel switch at the Central Heating Plant was a big win in terms of reducing greenhouse gas emissions through a single initiative, but given recent reports that 2010 was a record year for C02 emissions, there is still plenty of work to be done. Do your part by living sustainably and remember that all journeys begin with small steps. You can download the Green Guide to Living and Working at Tufts or visit the Office of Sustainability website to see how you can get involved in making the world a greener place.

---

[1] The Bottom of the Barrel: How the dirtiest heating oil pollutes our air and harms our health. M.J. Bradley & Associates LLC and the Urban Green Council for EDF, Dec 2009.