What About the Smoke?

Part II in a series about wood heat in Haines

Smoke from burning brush piles and a cruise ship visible over Haines on a late August rainy day. Connelly Lake hydropower could eliminate the need for cruise ships to power up and biomass heat could eliminate the brush pile burning.

The long term outlook for renewable energy in the Haines Borough is bright indeed!  There are projects for the future that could make Haines the envy of the country when the goal is to reduce dependence on fossil fuel.  But many of these projects are in the distant future and it is the immediate interim period where woody biomass can play an active role.

No doubt the cleanest possible source of large-scale energy to accommodate present and future needs for the Haines Borough is hydro power.  The Connelly Lake proposal appears to be the best option to provide this energy while at the same time getting the Borough off the submarine cable from Skagway and away from supplemental diesel.   But funding, permitting and construction of such a large hydro facility is realistically years away.  An interim measure until electricity is abundant and affordable could be biomass from our local forests.

In the last issue of Haines News the question of wood supply was addressed and found to really be a non-issue.  The temperate rain forest surrounding us is prolific in producing biomass. But another concern is that of emissions – particulate matter and other pollutants from wood smoke.

When most people visualize wood heat they picture a chimney puffing out blue smoke.  Indeed, that is the case in Haines because most people are not burning dry wood and are using very inefficient wood stoves.  That need not be the case with central woody biomass heating. New boiler and gasification systems are very efficient and with proper air pollution control equipment produce very low emissions and very little residual ash.

To provide a background for the issue of smoke pollution, consider some case studies from other communities now utilizing biomass heat.

The St. Paul Example:  Twenty four years ago, the city of St. Paul, Minnesota decided to clean up the air in the downtown area and at the same time lower their dependence on fossil fuels as well as dispose of wood waste from the many timber mills in the central Minnesota area.

St. Paul District Energy used wood chips and other waste wood to generate power for the downtown area replacing coal-fired and gas systems.  The heat generated in power production now warms 31 million square feet of downtown buildings.  In the process, sulfur dioxide and particulate emissions were reduced by 60%.  Before the project, 98% of the energy in the downtown area was generated by gas and coal. Today, only 23% is generated from this source – the remainder from woody biomass.

Montana “Fuels for Schools” Program – Another pace-setter in woody biomass heating systems is the “Fuels for Schools” program now being implemented and analyzed in the intermountain West of the Lower 48.   In a study with the Forest Service, investigation of air quality in the wood boiler systems used without pollution control equipment in western Montana schools revealed less particulate matter, nitrogen oxide and carbon dioxide than coal but slightly more than wood.  But with installation of air pollution control devices such as filters or cyclones, particulate matter was reduced from 70 percent to 99 percent.

Besides being cleaner burning here is the eye-catching news about biomass heat.   Quoting from the above-mentioned “Fuels for Schools” report, “Unlike the traditional fuels, such as coal, oil, natural gas, or propane, wood has net neutral carbon dioxide emissions because wood is a part of the natural carbon cycle.  Living trees continually uptake carbon dioxide throughout their lifespan.  Therefore, as long as trees are grown to replace wood that is burned in a boiler, wood combustion does not increase total atmospheric carbon.”

It was the carbon-neutral idea in the last article of Haines News that focused attention on the Haines State Forest as the principal wood supplier.   The harvested area on these managed lands would quickly be reforested and not converted to some other use.  Why not have a carbon-neutral footprint?

It doesn’t take too much imagination to see other ways woody fuel could improve air quality in the Chilkat Valley.  Ever notice all those brush piles burning from road construction, lot and right-of-way clearing?  Why not chip that brush and use it to heat the public buildings in an efficient boiler?

The stacks from new boiler systems do not usually show any smoke except at start-up.  On cold days, white steam can be seen but it is composed of water vapor.  The wood chip heat boiler that heats the Craig schools on Prince of Wales Island sits in the middle of a residential subdivision.  The system had been operating for several months before many residents were even aware that it was in use.

Woody biomass can consist of chips, pellets or cordwood.  Regardless of the shape, wood as fuel is lower in sulfur than fossil fuels and can go a long way toward cleaning up the air if properly designed.  There are problems to consider such as how to get the wood chipped in our area where there are no large mills to generate waste and how to dry the chips.  But local loggers have expressed an interest in supplying wood chips if the need is there.  Until Connelly Lake comes on line providing enough power to convert to electric boilers, why not utilize the other local renewable resource – wood?

Sources cited:

• District Energy St. Paul—Making Wood Work: Local Energy Solutions, October 16, 2007.
• FuelsforSchools.info

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