Every fall, when the cold weather starts to arrive in southern Ontario, our Energy department fires up our biomass boilers. We use biomass boilers to help heat our greenhouses because the fuel they use is renewable – making them a green energy source!
Let’s take a closer look at how biomass boilers work and what benefits they provide our farm, our community, and the environment.
How Do Biomass Boilers Work?
Fuel: Clean Waste Wood
A biomass boiler uses renewable fuel to create energy. We could use several different substances to power our biomass boilers (we’ve experimented with materials such as corn cobs and oat hull pellets), but we’ve come to the conclusion that the best fuel for our boilers is clean waste wood.
When we talk about clean waste wood, we are referring to wood that has not been chemically treated and that may have ended up in a landfill if we did not burn it in our biomass boilers. During the summer months, when we are not using our biomass boilers to heat our greenhouses, we are hard at work collecting as much clean wood as we can to fuel the boilers from October to May.
We acquire our clean waste wood from a few different local sources. A local wood products company will save broken pallets for us to burn, and Windsor Disposal Services (WDS) will sort and grind clean scrap wood out of their collections and deliver it to us.
One of our most unique sources of clean scrap wood is from Hiram Walker, a whiskey producer based in Windsor, ON. To date, we have received over 20,000 empty whiskey barrels from Hiram Walker that we have burned in our biomass boilers. With roughly 400 barrels arriving at our wood yard every month, this partnership with Hiram Walker has been positive for all parties involved – the wood provides us with a renewable fuel source, Hiram Walker can dispose of barrels in an environmentally-friendly way, and the barrels do not end up in a landfill! In addition to barrels, Hiram Walker also provides us with used bungs, wood shavings, and damaged pallets.
In addition to receiving wood from different sources in our community, we also burn any clean wood products that we have on our farm, including damaged pallets and scrap wood from construction sites.
When we are collecting scrap wood, our Energy team is continuously sorting through our supply to make sure all the wood that we have collected over the months is suitable for burning. This sorting is essential to keep our biomass boilers running efficiently and to avoid mechanical issues with our machinery.
Heating Our Greenhouses
The time of year when we start burning wood in our biomass boilers is largely determined by the weather and temperature outside. If the cold weather starts earlier in the fall, we fire up the biomass boilers early. If we have a longer summer with warmer temperatures maintained, we wait to start burning wood until the temperature outside starts to drop.
Once it’s time to fire up our biomass boilers, we start the process of grinding our clean wood products into small wood chips – the smaller size makes the wood more digestible for the boilers. We use different types of grinders for different types of wood products with outputs of up to 50 tons of wood chips every hour!
To grind up our whiskey barrels, we use a slow-speed shredder that rips the barrels apart but does not yet grind it down into a usable size. This shredder has a large magnet attached, so any steel bands from the barrels are easily separated from the wood. Once the steel has been separated, we can run the larger wood pieces through our regular grinders to cut the wood down to the proper size.
Next, the wood chips are introduced to our feeding system. With the help of a hydraulic walking floor, wood chips are fed into a chain conveyor and transported from our wood chip storage room to the fuel launch station bunker. When it’s time to burn the wood, the wood chips are moved from the bunker to the biomass boiler’s fire box (or combustion chamber). Inside the chamber, the wood chips are burned up in a fire that reaches 1200 degrees Celsius. We burn at such high temperatures in order to ensure a clean burn.
The heat that is produced from the boiler is captured and used to heat up water. This water can then be transported into our greenhouses through heating rails placed within each row of plants. If the water is not immediately sent into our greenhouses through the heating rails, it is stored in a hot water storage tank for use in the next 24-48 hours. The water we use to heat our greenhouses is continuously circulated and heated up to the optimal temperature for our plants – making it a closed-loop system.
As the wood burning season kicks into high gear, it is up to our Energy department to keep our wood yard organized and well-stocked, as well as to maintain the different pieces of equipment and machinery they use. From excavators to a pay loader to walking floor trailers and trucks, our Energy team needs to keep these machines in excellent condition in order to successfully fuel our biomass boilers and keep our greenhouses warm during the cold winter months.
It is also the responsibility of our Energy team to constantly monitor heat storage volumes, greenhouse temperatures, and boiler functionality. During the winter months, our Energy team is also called upon to use their special machinery for snow removal! Working with biomass boilers provides a wide variety of work for our Energy department.
Why We Use Biomass Boilers: The Impact
Biomass boilers allow our farm to produce the energy we need to heat our greenhouses in a sustainable way. By using a renewable fuel source such as clean waste wood, we are diverting this useful resource from landfills and keeping our greenhouses warm in the process.
With this program, we save roughly 15,000 tons of waste wood from entering landfills every year – that’s equivalent to 600 truckloads!
As wood is being burned, our Energy team is also collecting the ashes and saving them for later use – as we continue to expand our operations, these ashes will be spread underneath new parking lots and driveways to create a solid base! And the metal scraps we collect from the whiskey barrels? We send all of them to a local metal recycling company to ensure proper disposal and reuse. These are just more examples of how our team is constantly finding smarter ways to be efficient with important resources.
A Green Energy Strategy
Using biomass boilers to create greener energy is just one part of the overall energy strategy at NatureFresh Farms.
Interested in learning more about how we create, manage, and save energy? Read about our high efficiency energy screen technology, or catch up with Dave F., our Energy Manager, in his blog on energy management!