Burlington (again) eyes a harvest of heat from McNeil

This spring, some of Burlington's most forward-looking energy experts are asking us, again, to consider the humble path of plumbing.

Or the lack thereof.

To clarify: A handful of volunteers (collectively known as the Burlington District Energy Service, or more commonly, BURDES) suggest that we cast our gazes toward the Intervale.

Tourists need only steer toward the Winooski River and look up.

The smokestack has been there since 1984.

Why, we are asked, at this chilly latitude, does so much surplus heat still soar skyward from the wood-fired McNeil power station?

To be sure, the plant pulls its weight in other ways.

It reliably kicks off about 50 MW of power — enough to meet most of Burlington's total appetite for electricity (although due to joint ownership with other utilities, the city receives half of its output).

McNeil's fuel consists mostly of culled leftovers from the supervised harvest of more profitable timber. Most of the woodchips arrive by rail to the doorstep of the plant's burn box.

A considerable portion of fuel's heat billows, wasted, above the Queen City's skyline as scrubbed smoke and steam.

For seven years, BURDES members have been running numbers that indicate plausible alternatives to that exodus.

As the group's name suggests, its goal is "district" heat — the kind that's passed along (and metered) through a community, much like electricity.

Why bother?

For many of the same reasons people root for better public transit: Fewer smoking chimneys (or belching exhaust pipes) translates into greater energy efficiencies, cost benefits and cleaner air.

The practice has been around for centuries, notably in Europe. There, tight-fisted landowners have embraced the economies of heating buildings — and then progressively larger clusters of buildings — from a single, well-tended firebox.

In 2011, a study by St. Paul, Minn.-based Ever-Green Energy, commissioned by BURDES with a $70,000 federal stimulus grant, showed how most of the Queen City's northern downtown might be heated from McNeil.

The prevailing, downcast economic climate failed to fill that proposal's sails (the price tag, depending on the model, was $14.7 - $38.6 million).

A follow-up study by Ever-Green, released last month, takes a closer look at the balance between thermodynamics, the world of finance, and volatility in natural gas prices.

BURDES' latest proposal would bring McNeil's warmth into networks that already link many radiators, shower heads and sinks to central boilers at Fletcher Allen Health Care and the University of Vermont Trinity Campus.

Plant Manager John Irving, a member of BURDES, says it's no pipe dream.

"The only real question about district heat," he asks, "is where and when do we want it?"

Simmer down

Last week, much of McNeil's innards lay exposed and inert for annual maintenance.

White-suited technicians crept through 10-foot wide air ducts. Others, wearing chest-high waders, swabbed oil, steam and water lines.

McNeil will be 30 years old in June and is running better (cleaner and more efficiently) than ever, Irving said.

The addition of gear that would "harvest" heat from turbine steam and flue-gases would actually improve the overall efficiency of the plant, he added.

Before its next birthday, McNeil's 50 megawatt wood-burning dynamo will become the state's largest single producer of electricity. Not because it's growing, but because of the impending retirement of the current champion: the atomic-age, 600 megawatt Vermont Yankee nuclear plant in Vernon.

Both facilities have served as icons of progress to their respective champions.

Conversely, the "sustainable" credentials of both plants' fuel are debated among environmental experts (as are those of any wood or pellet stove — and, for that matter, of natural gas, and coal furnaces).

The slippery middle ground endorsed by most scientists: Almost every human-harnessed energy source of any scale comes with a downside.

Thermal excess is a common one.

Big turbines (hydro and wind turbines excepted) rely on super-heated steam to spin them — and cooling towers to release the leftovers.

Rejected advances

Thirty years ago, Ever-Green Energy worked with the city of St. Paul to construct a wood-fired co-generation plant (one that combines power generation with district heating).

Today, at prices adjusted for inflation, customers pay less for heat than they did before the plant was built, Ever-Green Senior Vice President Michael Ahern said on a recent visit.

During those same 30 years at McNeil, steam that passes through the turbine fins has bypassed outlets that were designed specifically to divert residual heat to Burlington.

That bypass, say co-generation advocates, makes about as much sense as a winter motorist foregoing the use of a car's heater — a system that, like an exhaust pipe, draws excess warmth from a laboring engine.

The gas factor

After a round of presentations with UVM and Fletcher Allen planners, Jan Schultz, a founding member of BURDES, joined Irving and Ever-Green's Ahern at a third-floor office at McNeil for an informal assessment of where things stand now.

The proven physics of heat extraction and re-distribution have never been in doubt, Irving said — and the two prospective institutional customers are receptive.

The draft business plan call for an independent, board-driven nonprofit group to manage the enterprise.

More aspects of the plan hover around financial forecasting.

"It really is a question of what natural gas prices do," Schultz said. "If they stay the same or increase, this will work.

"Ultimately, I'm doing this because I want to see a more resilient city," he added.

The city of St. Paul is banking on biomass.

Ahern outlined the rationale: Seasonal spikes in the price of natural gas, coupled with distribution bottlenecks (and the wildcard of increased exports overseas) are likely going to continue to play to the advantage of wood-chip fired plants, he said.

Investors familiar with district heat's time-tested technology will find it is "a very stable, very secure source of capital," Ahern said.

Not crazy

In an even more prolonged temptation to the Queen City, Montpelier made the leap to district heat in the 1940s, using a central oil boiler to service core municipal buildings, Town Manager Bill Fraser said.

In October, the capital plans to inaugurate an expanded version that ties into a wood-fired system connected to 17 state buildings.

"When people first hear about district heat, they say, 'You've got to be kidding me,'" Fraser said. "We forget that it's already working here.

"These aren't crazy systems," he added, "but you certainly have to make sure your numbers check out."

Contact Joel Banner Baird at 660-1843 or joelbaird@FreePressMedia.com. Follow him on Twitter at www.twitter.com/vtgoingup.

The D-word

We can think of "district heating" as your basic plumbing: pipes extending to and from a boiler.

For at least a century, throughout the chillier latitudes, ambitious minds have extended that plumbing to include neighbors in the loop — and even whole neighborhoods.

The tried-and-true benefits of district heating parallel those of public transit. Fewer smoking chimneys (or belching exhaust pipes) yield energy efficiencies, cost benefits and cleaner air.

More online

• Ever-Green Energy (consultants for McNeil district heat): www.ever-green Energy.com

• Burlington District Energy Service (BURDES — a citizens volunteer group): www.BurlingtonDistrict Energy.org

• Burlington Electric Department (McNeil page): http://bit.ly/McNeilBED