It is winter. It is cold (most of the time), so we heat our buildings. We burn fossil fuels to do so. We release carbon dioxide. In recent years at Williams, heating fuels accounted for more than 50% of our greenhouse gas emissions. Check out the 2007 emissions report.

Heating our buildings is a complicated business. Most campus buildings get heat from the steam that is produced at the central heating plant, that big building with a stack on the south side of campus near the rink. In the past, we have burned primarily No.6 heating fuel to generate steam (and some electricity) that is then piped underground across the campus and into your dorm.

But this year is different.

In an effort to reduce our emissions we increased our heating budget to be able to purchase and burn more natural gas. Natural gas emits about 30% less carbon dioxide than No. 6 but is usually a lot more expensive per unit of energy. And using more gas isn’t as easy as just writing a check and flipping a switch.

Unlike oil, gas can’t be stored on site. It has to travel a long way through a pipeline that starts in New Orleans and ends pretty much where we are. Being among the last customers on a long pipeline means that supply can be limited and prices be can high, as others use up the gas on its trip here.

Buying natural gas isn’t easy. We have to predict weeks and months ahead of time how much gas we will need on any given day. This wouldn’t be so bad if temperatures remained constant. But as you have seen, or rather felt, weather can be unpredictable. If we use less natural gas than we predicted, we have to sell the surplus, suffering a loss and if we need more, we have to buy, typically at a higher price.

Fortunately, we have been able to lock in a base amount of gas in the plant, and burn oil to adjust for the fluctuations in demand. Thanks to the efforts of Tom Miller, the manager of the heating plant and the staff, who work 24 hours per day, 7 days per week we have been able to manage this process. Co-firing natural gas and residual oil is much more complicated than burning one or the other, and we owe our thanks to these people, who having been dealing with those complications.

Don Clark, the Utilities Manager, has been keeping the budget under control by purchasing “firm” gas. The firmness doesn’t have anything to do with the physical properties of the gas but rather the purchase contract. We can’t burn No.6 oil in shoulder seasons (Fall and Spring) due to our emissions permit, so we buy “interruptible” gas. This means that the gas company can “interrupt” our service at any time if the demand from their other customers is high. In the winter, the interruptible gas is not available so we have to purchase firm or non-interruptible gas. Even then, when the gas supplier has committed to supplying the specified quantity, the utility or pipeline operator can restrict the delivery of the gas.

I won’t even get into how we have been selling some of our firm gas when the daily market price has been high so we have more funds to buy extra gas on days when the prices are lower.

But so far this year, things have worked out.

While there are still a few months of winter to go, it looks as though our heating fuel split will be about 35% oil, 65% gas. In a typical year, the split is usually the opposite. The projected emissions savings are about 2000 metric tonnes of carbon dioxide equivalent, approximately a 14% decrease.

You can help out by keeping the temperature turned down in your room when you are not in or are sleeping. Dressing warmly can help too. Put on a sweater, or woolly socks or something warm around your neck before you turn up the heat. And, if you get the chance, thank the people at Facilities for their work to keep you comfortable and our environment sustainable.

Thoughts? Go to the Sustainability Blog or send an email to Stephanie Boyd (sboyd@williams.edu) to comment.