Clean energy construction and design: harnessing the energy of tides, waves and waste.

AuthorGallion, Mari
PositionCLEAN SECTION: Clean Energy

When asked to come up with a source of renewable energy, most Alaskans naturally think of sources that can be used on a smaller scale; something that they can use to power their own homes and feed energy back into the grid, or to power a cluster of homes.

Solar power or wind power are popular options based on their relative accessibility for residential use. When considering the viability of these energy sources, it seems there are often arguments as to why they can or can not be put to practical use in Alaska (not enough sun for solar to be used year-round), or whatever area may be experiencing an energy crisis (cost of installing turbines, not enough wind, regulatory setbacks).

However, there are a few types of renewable and clean energy today that can boast consistent returns based on sources that are plentiful in Alaska: waste (biomass), tides and waves; and several Alaska and national companies are rising--or have already risen--to the challenge of harnessing this energy in a way that benefits both communities and the environment in which they live.

What the Heck is Biomass?

Many Alaskans are confused about what--exactly--biomass is. According to Bob Deering, biomass roadmap coordinator for the Tongass National Forest, USDA Forest Service, "When we talk about biomass, it's easy to get confused by imprecise terminology. Biomass itself has a broad definition, and practically anything derived sustainably from living matter, such as fish waste, municipal solid waste, sewage sludge, grasses and agricultural residue, counts."

In Alaska, "we're primarily talking about woody biomass--the stuff derived from trees," Deering says.

"Burning wood isn't really rocket science," Deering says. "Pretty much every Alaskan has built more than one over-sized campfire. But burning wood cleanly and efficiently ... that can get a little more technical. A lot of sophisticated engineering has gone into the science of burning wood."

Naturally, many Alaskans are familiar with the medium of cordwood. Wood chips, the next level of refinement, are predominantly used by larger commercial and industrial operations because this medium requires robust fuel storage and handling systems, and a tolerance for inconsistent fuel size and quality. But the creme de la creme of wood fuel is wood pellets.

"Pellets are made from ground up wood and sawdust, extruded out of a mill die at very precise specifications," Deering says. "Pellets tend to 'flow' much more easily than chips so fuel handling is greatly simplified, and their consistent physical properties allow for tight engineering tolerances.

"This yields high efficiencies, low emissions and reliable and simple operations," Deering says. "Pellet appliances also span a wide scale from very large commercial boilers to small residential unit heaters. Because pellets are a densified fuel, they can be cost-effectively transported long distances."

Although some question whether woody biomass can truly be considered a source of "clean" energy, according to Deering, woody biomass in its many forms is a practical solution, especially for Southeast Alaska, for many reasons. After all, when one considers the environmental impact of transportation of fuel sources, woody biomass seems to be the clear winner.

"The trees are located close to where we need the energy, and we can utilize it directly without having to ship it to far-away refineries, only to ship it all the way back from those far-away refineries," Deering says. "The fuel can be harvested and processed by small, local businesses, creating local jobs and keeping money in the local economies. For these very reasons, the Forest Service is developing a strategy for incorporating biomass energy into the forest management plans for Alaska."

"Conversion of Alaskan facilities from fuel oil to biomass heating has been accelerating rapidly over the past few years," Deering adds, "as the price of heating oil has skyrocketed and facility owners have become more familiar with biomass heating systems. Southeast has been no exception--three years ago there was one commercial-scale biomass system in place in the region, today there are eleven, with many more in the pipeline."

And where in the state, besides Southeast, can biomass be used economically?

"Generally speaking, biomass is an economical fuel replacement anywhere that natural gas is unavailable," Deering says. "Communities that are relying on expensive heating oil to meet thermal needs are excellent candidates for biomass. Pretty much any residential or commercial facility that's using oil heat is a candidate for biomass conversion--there are few technical reasons why it would not be possible."

Elementary School

Thorne Bay Elementary school in Prince of Wales Island was converted from oil to a cordwood system just this year. The school now has two Garn WHS-2000 325,000 Btu cordwood boiler systems, along with an accompanying greenhouse.

Construction for this project began in fall of 2012, and included clearing of the land for the boiler, the leveling of the site, and then the installation of the buried, preinsulated PEX piping to the two separate heat systems in the school--one in the main building, and one in the gym.

"The pre-fabricated boiler packages arrived in September and were brought to the site via a tractor trailer truck," Deering says. "Next the wood storage structure was built, with the foundation also poured for the adjacent greenhouse, which will also be heated by the boilers. The green house components are onsite, but it is not yet assembled."

And there will unfortunately be some lag time before the system is put to use. "These boilers were tested and commissioned the day after Thanksgiving 2012, but won't be put into service until next year because the wood storage...

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