What are wood pellets?
Wood pellets are a compacted type of bioenergy. They are typically made of timber waste, sawdust and agricultural waste that is dried and processed into a densely compressed cylindrical pellet measuring about 1cm long, resembling rabbit and chicken food. Because they have a low moisture and ash content pellets burn very efficiently to produce heat and electricity. As a result, wood pellets are generally used in direct burning devices such as domestic wood heaters and commercial furnaces and boilers.
Pellets are mainly used for residential heating, although there are an increasing number of commercial scale users – such as hospitals, swimming pools, retirement homes etc – using pellets to generate electricity. Pellets are also increasingly being used in large-scale coal power plants to help produce electricity in a more environmentally-friendly manner. Globally, the US, Canada and Europe are currently the biggest suppliers and consumers of pellets but significant demand is also anticipated from Japan and Korea.
EnviroHeat Australia has been producing wood pellets for heating since 2013. Our pellets are sold in 15kg bags and large bulk bags and we will deliver to your door. Wood pellets are also available from retailers such as Barbeque Galore and Barbeques Bizarre.
Check out our blog post for more information. 6 things to know about pellets.
Source: Clean Energy Council
What are the benefits of using wood pellets?
Wood pellets offer many unique benefits, such as:
- Pellets can provide an economic and social boost for rural and regional communities by using local content, creating local employment and encouraging new and innovative farming techniques.
- Pellets can provide a use for wood by-products – such as sawdust – that would otherwise have no market value. As Australia is one of the top 20 producers of sawdust excess from forestry in the world, this presents opportunities for Australia to use sawdust for domestic renewable energy generation or for export. (A large global export market exists for wood pellets, with some 9 million tonnes of wood pellets traded annually.)
- Because pellets have consistent quality and size they are easy to transport, store and handle. This allows cost-efficient transportation and automatic operation for heat and power, for residential homes and large-scale power plants.
- Existing coal power plants can be modified to produce a percentage (typically 3 and 15%) of its electricity from pellets rather than coal (this is known as ‘co-firing’). Co-firing is a cost- effective way to reduce carbon emissions because it utilises existing infrastructure, such as power plants, ports and storage facilities. As a result, minimal capital expenditure is required. Co-firing using wood pellets is widely adopted globally and has been successfully piloted in Australia. Recent studies suggest that if Queensland were to substitute just 3% of coal used in its coal power stations with pellets, it would achieve carbon emission reductions in the order of 1.4 million tonnes per year.
Source: Clean Energy Council
How eco friendly are wood pellets?
The pellets emit far less carbon emissions than regular wood; they burn cleaner, longer and provide you with more heat. Our locally manufactured wood pellets are a compacted type of bioenergy. They are typically made of timber waste, sawdust and agricultural waste that is dried and processed into a densely compressed cylindrical pellet measuring about 1cm long, resembling rabbit and chicken food. Because they have a low moisture and ash content pellets burn very efficiently to produce heat and electricity.
How do pellet heaters work?
Pellet heaters are an attractive way to heat your home, providing the warmth and ambiance of a traditional log burner with the convenience and ease of use of gas or electric heaters. Unlike a log burner, there is no more fiddling, smoke and mess to get the fire started and to keep it running, simply turn the heater on and it does the work. And like a gas or reverse cycle unit, you can set a desired room temperature, running time or heat output. Pellet heaters also have a visible flame and produce some radiant heat, like a traditional log burner.
THE FIRST CLEVER BIT IS THE BURNING OF THE PELLETS…
Wood pellets (around 6mm diameter and 10-20mm long) are augured from a hopper at the top of the heater into a fully enclosed burn chamber or “fire pot”. The first pellet is ignited using a small electric element to get it going. From there combustion process is fan forced to maximise burn temperature (700degC plus) ensuring an incredibly efficient process with almost zero smog or ash. Rather than a log, where most of it is smouldering away and the potential energy going up the chimney as smoke or settling as unburnt particle in ash, the pellets are fed in only as required and are always white hot. You can be pumping a beautiful radiant heat into your house in under ten minutes.
THE SECOND CLEVER BIT IS GETTING THE HEAT INTO YOUR HOME…
The heat from the burn chamber is fed through a high quality plate heat exchanger where almost every bit of energy is extracted and left in your room rather than going up the chimney.
The combination of the advanced burn chamber and heat exchanger make these pellet heaters the most efficient and clean method for using wood and bioenergy to heat your home.
THE THIRD CLEVER BIT IS THE SMART CONTROL….
The amount of heat produced is determined by the rate that the pellets are fed into the burn chamber. This is controlled by either setting the thermostat (set the temperature you want for your room), a manual switch to control pellet feed or even a remote where you can set temperatures and timing. Yes these can turn on 15min before you wake up so you can warm your toes while sipping your morning cup of tea.
Are they cost effective?
Yes! Pellet heaters have similar running costs to log burners and are cheaper to run than gas and electric heaters (see our blog post on running costs) so they are definitely a financially viable way to heat your home. In comparison to a reverse cycle air-conditioner they might be a little bit more expensive per unit of heat put into the room. That said you’ll find yourself requiring far less heat because it is right where you need it in front of you rather than heating up all of the space between you and the ceiling. Also with rising gas and electricity costs and an increasing price on carbon, pellet heaters will become even more attractive!
Pellet heaters can achieve up to 95% efficiency but what does this mean?
The efficiency of a heater is a measure of its ability to turn the energy in the fuel into heat that enters the room. It affects how much the heater costs to run and tells us how much of the energy in the fuel is wasted (that is, heat going up the flue rather than into the room or fuel turning into smoke rather than heat).
An open fire place might run at about 10% efficiency which means that 90% of the potential energy in the log is either lost as heat through the chimney or lost as smoke due to the log not being burnt at high enough temperatures. There is a bit more to it than that but that describes it fairly well and unfortunately means that as beautiful as open fires are, they don’t effectively heat a room and they produce an enormous amount of pollution.
A “Pot Belly” log burner might get up to 40% efficiency as it does a much better job than the open fire place in ensuring the log is burning at a good temperature and getting more of the heat into the room rather than up the flue. A modern, high-quality slow combustion heater does an even better job and can get up to 70% efficiency with everything running really well. That said, you often find these heaters not being run at their optimum operating conditions with wood not being properly dry or sap free, manual feed of logs not being optimised and heaters being ‘choked down’ at night cutting out oxygen and causing more smoke. Furthermore, because it takes a while to get the heater going and you can’t just switch them off when you go to bed or leave the house, the overall efficiency of the process can be considerably less depending on how its used.
With a pellet heater, they automatically control the pellets and oxygen feed to keep the heater burning at the optimum efficiency. The pellets themselves are very high in energy density, have low moisture (our pellets have a moisture content of less that 6% while firewood is considered “dry” if it has a moisture content of less than 15%) and are sap free. Furthermore they have efficient heat exchangers that ensure that almost all of the heat generated in the burning process ends up in your room rather than outside. The other big benefit is that you can turn it on and off when you need it and keep the room at the right temperature rather than guessing. So not only is the heater more efficient, but the way you will use it will be more efficient.
How much heat will a pellet heater produce?
We sell two sizes of heater, 8kW models (the Malu, Lia and Nina) and 12kW models (Bianca Lux). To put that in perspective they put out more heat than the same size (in physical dimension) wood log heater (due to the increased efficiency) and about on par with a similar sized gas heater. A very large split system (reverse cycle) produces around 8kW in its heating phase which we’d consider a mid size pellet heater.
Are they suitable for all types of homes - ie including apartments?
Pellet heaters are suitable for all types of homes including apartments, townhouses and villas.
Do they give off a characteristic smell, like wood burning fires?
No. Because the pellets are burnt within the chamber and no on-going smoke is released through the flue.
Are wood pellet heaters gaining in popularity among homeowners, architects and designers?
Although pellet heaters have been used in many European, American and Asian households for many years, they have only recently entered the market in Australia. Architects and homeowners are enjoying the unique, attractive design of our Italian pellet heaters. It is important to note that the quality of pellet heaters differs between manufacturers.
What size rooms are they suitable for? Ie how large a room can they heat?
We stock both 8kW and 12kW heaters which can heat rooms anywhere up to 120 sqm and 180sqm respectively. This being said, as important as the size of the heater is the climate zone the house is located in, the thermal qualities of the house (ie how well is retains heat) and the desired room temperature. We’ve installed heaters across Australia and are more than happy to provide advice about the appropriate size heater for your situation.
Comparisons between other alternative wood heaters
Sometimes heating your home with wood can be more economical and environmentally friendly than the alternatives; particularly if you have easy access to wood supplies. While wood fires do generate carbon dioxide and particulate matter, other fossil fuels may generate more greenhouse gases when issues such as extraction and transportation are taken into account.
Fossil fuels are also carbon sources that have been locked away for millions of years, whereas wood is part of the current carbon cycle. Burning wood is considered carbon neutral. Wood is also a relatively easily renewable resource.
However, the key to environmentally friendly wood heating comes down to three things:
- The efficiency of the heater
- The type and quality of the wood
- How the heater is operated
Type of wood heating
There are many factors that will influence efficiency and economy in comparison to fossil fuel counterparts. Wood heaters with high efficiency scores use less wood to generate the same amount of heat, therefore also creating less emissions – if the heater is operated correctly.
Radiant vs convective heating
Radiant wood heaters create the majority of their heat (66%) from the flames and heat people and objects directly rather than heating the air. A convection heater heats and circulates warm air around a room.
While an open fire is a joy to watch, fireplaces are generally very inefficient – only achieving around 5 – 10% efficiency. The fireplace itself is quite expensive to construct and requires a lot of materials. Additionally, an open fireplace only provides heat directly in front of the fire. Much of the heat can be lost not only through the flue, but through the rear wall which is usually outside the home.
An open fire’s efficiency can be greatly improved (up to 35%) by the use of a fireplace insert which is a hollow, metal structure built into fireplace, allowing for a greater degree of convection heating rather than relying purely on radiant heat.
Pot belly stove heater
Pot belly and similar wood heaters have an efficiency generally in the 25–40%; although according to the compliancy tag on mine, which is a relatively new model, it’s 47%.
A pot belly stove generates convective and radiant heat and are a good choice for heating small areas; particularly where space is an issue.
When I firstly installed my potbelly in a smallish area, the first night I was sweating even though the temperatures outside were below freezing. There is a bit of a learning curve in using them to get the right level of heat and particularly having them burn overnight. Pot bellies offer air flow controls which help control the rate the wood burns.
Slow combustion heaters.
Slow combustion heaters are a step up in efficiency – up to 70%. This is due to an airtight firebox, additional airflow controls and air inlets plus secondary combustion chambers to improve efficiency. They are the best option for heating large areas and can be fitted with a fan to help move heat more evenly around the room.
Wood pellet stoves
While not seen much in Australia yet, I understand that wood pellet heaters are very popular in other countries such as the USA. The wood pellets are usually made from sawdust waste from mills that has been compacted. Wood pellet heaters are reported to be incredibly efficient, offering combustion efficiencies of over 90%! Emissions are also said to be very low in comparison to other forms of combustion heating. Wood pellets can also be burned in normal slow combustion heaters and potbelly stoves, but without such high levels of efficiency.
Selecting a wood heater
A good wood heater for a large area can be quite an investment., so when choosing a wood heater, it’s best to consult an expert who can advise you based on issues such as climate, room size etc.
In my case, installing a slow combustion heater in such a small area wouldn’t have been effective as at medium and high burn settings, I would have sweltered. At low burn settings, too many emissions would have been created, so the pot belly was the best choice.
As a general guideline, aim for 1 to 1.5 kilowatts (kW) for each 10 m2 (108 square feet) of area needing to be heated. Always check the compliancy plate for efficiency ratings too. A slightly more efficient heater may cost a few bucks more, but will save you a ton of money (plus wood and emissions) in the long run. Also check and compare the compliancy label for emissions ratings.
Source: Michael Bloch
Green Living Tips.com
Green Living Tips is an online resource powered by renewable energy offering a wide variety of earth friendly tips, green guides, advice and environment related news to help consumers and business reduce costs, consumption and environmental impact .
What about the smog?
When it comes to wood heaters, smog is generally caused by wet and sappy wood burnt in an inefficient stove at low temperatures. With pellet heaters, the pellets are guaranteed to come with a super low moisture content, no sap and will always burn at high temperatures and optimal efficiency. They pretty much burn with no smoke at all except at start up where you see less than a few puffs until it fires up. They are so efficient and smog free that they are approved for use in most European and North American towns and cities. Our Palazzetti heaters release just 1% of the emissions of the average log burner in an Australian home and just 4% of the emissions of a high quality log burner that meets the yet to be introduced 2019 standards. Please go here for further details on smoke emissions. That said if you have a very acute allergy to wood smoke then this style of heating is probably not for you.
More from the Clean Energy Council:
It is commonly thought that burning wood is bad for the environment. However, Australia has stringent controls on emissions from wood combustion. Furthermore, pellets are a highly refined heating fuel, which, in the case of EnviroHeat Australia pellets, are dried to a uniform 6% moisture content. They are burned in well-controlled systems that run extremely hot and with sufficient airflow to ensure complete combustion. This is in contrast to normal wood which has a 20-40% moisture content that can prevent complete burning, resulting in smoke and emissions from wood particles that have failed to completely combust. As an example, about 2 million tonnes of pellets are burned annually in the US. However, particle emissions from wood pellets amount to less than 1% of the particle emissions caused by forest fires and less than 2% of the emissions from less well-controlled wood combustion, such as open fireplaces and wood stoves.
What about deforestation?
All of our pellets are made from local waste biomass or selectively harvested plantation pruning’s and thinning’s. We will ensure that we are always planting more trees than we are ever harvesting and as a result will have a net positive impact on revegetation, biodiversity, reducing salinity and erosion while also removing carbon from the atmosphere. Unfortunately in some countries forests have been exploited for their biomass in an unsustainable fashion. That is why it is important to know where your pellets have come from so you can contribute to improving the environment rather than damaging it. If you’d like to know more about our ethics and manufacturing plant please visit the “Wandoo Rise” page or contact us directly.
More from the Clean Energy Council:
Provided that wood pellets are supplied from forest resources that are managed and harvested in a sustainable manner – such as from the use of wood by-products from plantation timber – wood pellets offer a low-carbon, renewable energy source. It is estimated there is enough wood by-product from forest industry activities in Australia to supply 3000 gigawatt-hours of renewable energy per year without harvesting a single extra tree. Additionally, pellets from wood by-products are recognised as being carbon neutral under the Kyoto Protocol. This is because if wood by-products were left to decompose, they will return carbon to the atmosphere. When wood pellets are burned to produce heat or power, the same amount of carbon returns to the atmosphere. However, unlike an electric or oil heating system, no fossil fuels are used.
Surely there is energy and carbon that goes in manufacturing the pellets?
We have conducted a detailed Life Cycle Assessment to understand what the carbon impacts are with producing wood pellets from collecting waste biomass or harvesting plantation material, through to transport, processing and even including things like the impacts of making the plant equipment and running the business. For every tonne of wood pellets we make there is about 100kg of CO2e produced as a result. About 70% of this is in the energy used to run the plant which is why we will begin a transition to renewable energy for the factory. Another 25% is associated with the transport of the biomass to the factory and the pellets back to you and again this is why we have already started to run our vehicles on biofuels. Our goal is to turn 100kgCO2e/tonne into 20kgCO2e/tonne by 2015. Who knows we might even go better!
Even with the 100kg of CO2e per tonne of pellets you will have about 2% of the carbon footprint using a wood pellet heater when compared to an old electric bar heater and about 10% of the carbon footprint when compared to gas or a high efficiency reverse cycle unit.
Further to this we haven’t included all of the trees we have planted in the first place that sequester carbon into the roots and soil while continuing to regrow as we prune and thin. With this factored into the equation buying and using wood pellets from EnviroHeat will definitely result in a net carbon offset.
Bioenergy: Myths and Facts
As explained by the Clean Energy Council, May 2012. Bioenergy: Myths and Facts
Basic installation requirements
The heaters need to be installed in accordance with AS/NZS 2918:2001 “Domestic solid fuel burning appliances – Installation”
- The end of the flue needs to be 600mm above the roof line. It also needs to be 1500mm from any opening into the house.
- If the heater is going on carpet (or other flammable floor covering) you will need a hearth underneath. This needs to be minimum 6mm of non flammable material and depending on which model you have it will need to 300mm protruding from the front and 150mm on sides and back.
You will also need a standard 240V power supply to plug into. The heaters all come with about 1500mm of power cord.
Could you give us a rough idea of running costs and how many pellets we will use?
This is one of the most difficult questions to answer because there are so many factors at play: the climate zone the house is in; the size of the space to be heated; the thermal qualities of the house (how well it retains heat and whether it has good passive heating); the temperature you find comfortable; and how often you are at home.
However, one estimate of costs we have made, which we think represents moderate use in a mild climate, suggests running costs of $3.30 a day. This compares to $4.00 for mains gas (in WA) and $6.60 for bottled gas. This amount of use would equate to a yearly consumption of 600kg of pellets or 40 bags. We have further details on these cost estimates here and pellet consumption here.
Alternatively, if you have ever used a log burner and if you are heating for the same amount of time and to the same room temperature, you should expect to consume roughly half to a third the tonnage of pellets as you do firewood. The average household in WA that operates a wood fire consumes 2.5 tonnes of firewood; this would translate to about 1 tonne of pellets.