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We cannot switch to a 100-percent renewable energy source to power all the buildings in the United States and Canada. We will absolutely have rolling brownouts unless a stock of fossil-fuel energy is ready to catch the droops in a transition to renewable energy production.
Are those statements still true? More communities are finding a way to operate on a higher percentage of renewable energy, but there is still a big gap to fill. Is fossil fuel the source of energy required to smooth the flow of renewable energy, or are we overlooking something that is right in front of us?
The Rohrs lived in rural Missouri for about 25 years. My parents sold our house in Park City, Utah, and purchased a farm near Springfield, Mo. We had the luxury and responsibility of a large, rural property. At least once a year, a big tree on our property would die or get struck by lightning.
Neighbors would either let the tree rot in place, burn it in a big pile or gather it up for firewood. Local entrepreneurs filled their pickup trucks with split wood and parked in the local supermarket lot with a dollar sign on the dash, advertising the delivered price of a cord of wood.
What happened next with the harvested firewood was a mix of highs and lows from a clean energy perspective. In the worst cases, the wood was used to start a fire to burn trash. This was not an ideal outcome; it was an inexpensive way to dispose of trash on a rural lot, but an unwanted source of point-source pollution.
Some homes used simple, outdoor wood boilers to supplement propane usage. Without proper attention, the fires could burn down and produce smoggy emissions. The cold-burning, low-hanging smoke billowing around a property is the reputation many wood boilers have.
Some communities completely ban wood boilers because homeowner intervention is not reliable enough to prevent high-particulate-matter burns. There is definitely an art to keeping a wood boiler burning hot all day with a steady supply of logs.
The future of wood energy is an efficient, hot-burning and low-particulate-matter-emitting boiler. Typically, these boilers are imported from European countries with strict emission regulations. Pellets or wood chips may be used instead of cordwood to provide a consistent, easier-to-manage source of fuel. Low-moisture-percentage fuel and sustained, high-temperature burns take these appliances out of the dark ages of wood power.
Could wood power scale to support a larger community? Homes in rural areas that have a lot of wood on their property may not need any additional infrastructure. The suburban homes miles away likely would not have a sustainable supply of wood on site. These homes generally have large propane tanks for heating energy.
Is there potential for district suppliers of wood pellets and chips to displace rural propane and fuel-oil suppliers?
Wood boiler systems
If you drive to the east end of Michigan’s Upper Peninsula, there is a chain of islands that extend into Lake Huron and cross into Ontario. In a city named Wikwemikong, a wood fuel network is a reality. Two hundred homes rely on a distribution hub of wood pellets, similar to rural propane service.
A distribution truck pulls under an elevated storage silo that fills the trailer with pellets, similar to a coal plant. The truck drives around to fill storage rooms or small silos with pellets that island residents can use for feeding modern wood boilers (https://bit.ly/3OWGIbm).
Sioux Manitowabi, Wikwemikong’s energy planner, gives a tour of the facilities in its distribution system in this YouTube video (https://bit.ly/3vIsq7A). He states: “We are one of the first First Nations to be doing this in Canada. Thinking green, going green for our community, providing heating energy at a low cost for our residents.”
With a wood boiler at the heart of the system and a low-temperature hydronic distribution to match, these systems are a winning strategy. Buffer tanks maximize cycle efficiency of the boilers. Electronically commutated motor pumps and radiant heating distribution provide ideal efficiency and comfort.
To evaluate if wood is a good fit for a community, you must start with a basic question: What is the difference between deforestation and sustainably harvested wood fuel in my area? If you chopped down all the trees on a 100-acre farm and burned them in a year, you have not sustainably harvested the land. You have destroyed a vast carbon sink and may return to fossil-fuel reliance afterward.
If you have an equilibrium of trees-harvested-to-trees-planted, with enough time allowed for seeds to grow into mature trees, wood is a sustainable fuel in your area. This scenario is possible in much of Canada and the northern United States.
If you want to learn more about these modern wood systems, one of my favorite designers in this sector is Biothermic Wood Energy Systems, located in Thunder Bay, Ontario (www.biothermic.ca). Brothers Mike and Vince Rutter are passionate about reimagining wood in a sustainable way.
When looking at the total operational value of wood boilers, “using biomass to generate electricity is roughly 25-percent efficient,” states Mike Rutter. “However, well-designed thermal systems are 80-percent to 90-percent efficient.”
In Phoenix, sunlight is the most abundant renewable resource. In Rock Springs, Wyo., wind is likely the most accessible renewable energy resource. At the end of a dirt road in a tree-packed, rural community in Oregon, wood could be the most viable, renewable choice.
Solar and wind do not require chainsaws, backhoes, transport trucks, wood splitters and storage facilities to supply energy to the devices that convert the sunlight/wind into electricity.
However, if wood processing is done within a small radius of the customers, the environmental impact is lower. Also, if your neighborhood is packed with trees and there are not many hours of sunlight to catch in a day, solar may not be the best option.
No single fuel or energy source will be the perfect, sustainable solution for every home in North America. Modern wood boiler technology is underused. For rural communities that are not likely to see utility-scale wind or solar farms come online in the near future, wood could be a viable alternative to fossil fuels that contributes to a future with a better sustainable energy mix. l
Max Rohr is the education and industry engagement manager with Caleffi North America. After graduating from the University of Utah, he began his manufacturing career at the Caleffi headquarters in Italy. Since then, he worked for several HVAC/P industry companies in the manufacturers’ rep and wholesale distribution channels before returning to Caleffi in 2020. He can be reached at firstname.lastname@example.org and on Instagram @caleffi_na_max.