Centuries ago, biomass was the only real option for heating a building. Now, many Pennsylvanians still use biomass in modern, clean, high-efficiency devices to heat their homes, businesses, or industries. Wood is still the main option for biomass heat, but it is not the only one--grass-based pellets and briquettes are used by some, and homeowners even use corn as a fuel. Biomass heating systems are used in everything from the smallest apartment to large hospitals and factories. Is biomass heat right for you? Depending on your situation and needs, the answer may well be a resounding "yes."
Homeowners are the most common user of biomass heat in Pennsylvania, and there are several types of heating system available:
- Cordwood stoves or inserts: While fireplaces were common in colonial days, they are so inefficient (usually less than 20 percent) that they are not really recommended for heating today. Instead, woodstoves and fireplace inserts provide a much more efficient and clean way to heat a home with wood. Newer stoves and inserts have efficiencies of about 60 percent. (Older wood stoves and inserts are not as efficient or as clean. If you have a stove that is older than 1988, consider upgrading--your fire will burn cleaner, and you'll end up using less fuel.)
- Cordwood furnaces or boilers: While woodstoves heat air directly, boilers heat water, and the hot water is used to heat the home. Outdoor wood boilers are the most common type in Pennsylvania, but indoor units are available as well. Recently, outdoor wood boilers received a bit of a smoky reputation (see inset). However, newer models are much cleaner and more efficient.
- Pellet stoves: Pellet stoves are the most efficient type of biomass heating system for homes. The easy handling and uniform properties of pellets allow these stoves to have efficiencies of over 80 percent and make them the obvious choice for many homeowners. One thing to keep in mind is that stoves designed for wood pellets are usually not suitable for grass-based pellets or corn. Be sure to only use the type of fuel pellet recommended by the stove's manufacturer. Most pellet stoves require manual loading of the fuel, but some larger models use a "bulk bin" and an automatic feed system.
Outdoor wood boilers have received a bad reputation in recent years due to the tendency of some boiler owners to "smolder" their fuel (i.e., they provide enough air to the boiler to keep the wood burning slightly, but not enough to burn up the soot that is produced when wood is heated). Not only is that inefficient, it also tends to be smoky. Newer wood boilers are both more efficient and cleaner burning, and owners should avoid running their boilers in a low- heat "smolder" mode. Some local governments have outlawed or severely limited the use of outdoor wood boilers--be sure to check on local ordinances before making any purchasing decisions.
When it comes to home heating using biomass, you trade effort for cost savings. Cordwood is very inexpensive if you cut and haul it yourself, but it requires a lot of effort. You can pay a bit more to have it cut and delivered to your home, but you still need to light and tend the fire, as well as remove ashes. Wood pellet stoves and biomass stoves are even easier to tend, but the pellet fuel is more costly than cordwood. If you are considering biomass heat for your home, here are some key questions to ask:
- Would you enjoy doing a few chores to run and maintain a biomass heating system? For many of us, building and tending a fire can be a fun and rewarding part of the rhythm of daily life. However, it does require some regular effort.
- Do you have space to store fuel? Cordwood (logs) requires space outdoors for a stack of wood. Pellets need to be stored in a dry location, such as a garage.
- Do you have a locally available supply of fuel? If you live in Pennsylvania, the answer to that is undoubtedly "yes" for wood or wood pellets. Grass-based fuel pellets are a little tougher to find, but they are available in some areas.
- Is your home's layout suitable for a biomass heating system? Woodstoves, inserts, and most pellet stoves only heat the area directly adjacent to the stove. If your home has an "open plan," then more of it can benefit from a single stove.
- Do you live in an area where air quality is a concern? This is less of an issue than many people think. However, it is worth considering. Some cities have special regulations about biomass stoves, and you should check into that before you buy. Newer biomass heating systems are cleaner than older models, and pellet stoves tend to be the cleanest options of all.
So, to conclude, in the right setting, biomass heat is an outstanding way to provide clean, renewable, cost-effective heat for your home.
For Schools and Institutions
Biomass heat is also popular for schools, hospitals, and other institutions. The lower cost and local renewable supply of wood (usually in the form of wood chips) make it an attractive option throughout the state, while some facilities opt for briquettes made from field-grown grasses.
Commercial-scale biomass heating systems are large and rather impressive devices. Automated fuel delivery and ash-handling systems keep regular maintenance at a minimum, while sophisticated combustion and emissions controls ensure both high efficiency and clean operation that is suitable for the most sensitive environments.
Is your school, hospital, or other facility well suited for biomass heat? Here are a few questions to ask:
- Do you want to reduce energy costs? Biomass heat can dramatically reduce energy costs for a facility. For example, a recently installed school biomass heating system is cutting that facility's bills by about $250,000 per year. However, achieving these savings means you must be willing to pay the initial cost of the biomass heating system.
- Does your facility use hot water or steam heat? Commercial-scale biomass heating systems are best suited for providing heat in the form of either hot water or steam. Other types of heating (e.g., hot air furnaces, rooftop units) can be adapted to biomass heat as well, but it is usually more complicated (and expensive).
- Do you need to replace your existing boiler? When your old boiler is at the end of its useful life, replacing it with a biomass system rather than a fossil fuel boiler can be a great option. If you have to spend money on equipment regardless, why not choose a replacement that is cost effective and renewable?
- Do you have space to install a new boiler and fuel storage area? Commercial boilers and their associated piping take up a lot of space (2,000-4,000 feet of floor area, with a high ceiling, is a typical requirement). If you already have open space in a utility room or mechanical room, using that existing space rather than building a new structure is a very cost-effective approach.
- Does your facility have easy access for fuel delivery? Your biomass boiler will need fuel delivery--probably twice a week during mid-winter and less often during the rest of the heating season. Your driveway will need to be set up so that a large truck can back up to the fuel storage bin and unload; most fuel deliveries use a "walking floor" trailer that pushes the fuel out of the back of the trailer.
- Are there fuel suppliers available in the region? If you live anywhere in Pennsylvania, the answer to that question is a definite yes. They don't call it "Penn's Woods" for nothing. However, it is important to check around to find out who your local suppliers are and how they operate so you won't be surprised by anything down the road. Most commercial scale facilities request annual bids for fuel delivery and provide a "fuel specification" to outline exactly what type of biomass fuel they require.
Industries can gain a great deal of benefit from switching to biomass heat--most of the wood products industry uses biomass heat for drying kilns and other purposes, but other operations stand to gain as well. If your operation has a significant steam or hot water load and has space for a biomass boiler, you should consider switching over. The most common biomass fuel is wood chips. Some facilities choose to have the chips prepared and delivered, while other operations receive extremely inexpensive waste wood from landscaping and other operations, then process it into chips and store it onsite. The choice of one approach or the other depends on your willingness to trade labor and time for fuel cost.
Where to Go from Here
The two best things to do are to start shopping around and to talk to other folks who use biomass heat. That'll help you understand what it entails and whether it will work for you or not.
Institutional, commercial, and industrial facilities
Some great resources are available on the Internet for schools, institutions, and businesses that are interested in biomass heat. Visit Penn State Extension's website." Also check out Pennsylvania Fuels for Schools and Communities.
Prepared by Dan Ciolkosz, extension associate, Department of Agricultural and Biological Engineering