Biomass Heating Systems for Broiler Sheds04 September 2013
Biomass heating systems and their application for broiler houses are explained by Byron Stein, editor of 'The Drumstick' for New South Wales Department of Primary Industries in Australia.
The author relates that he was recently listening to an interview with a large-scale chicken meat farmer in the United Kingdom who is using biomass heating technology rather than traditional liquified petroleum gas (LPG). What really raised his interest in the story are a couple of things the farmer said during the interview with the BBC. These were:
- "Our birds on average are converting 1.6kg of feed into 1kg of chicken, and this is something we have been able to improve recently because we have changed our heating system. We are running the houses much drier which the chickens appreciate, and in turn that is leading to very low levels of hock burn and pad burn."
- "These are ailments that chickens can have when the litter that they are running around on gets very wet but as you can see in this house, the litter conditions are extremely dry so levels of hock burn and dermatitis are very low."
- "We’ve slashed our figures from using LPG in the houses to using our biomass hot water system."
These statements raised some of questions, namely:
- What is biomass heating?
- Why is litter drier when using biomass heating instead of LPG?
- Is biomass heating cheaper to run than liquid petroleum gas (LPG) heating?
- Can dry litter really improve FCR?
- Is biomass heating feasible in Australia and has anyone crunched the numbers to show it can be economically viable?
This article explores some of these questions.
What is Biomass Heating?
Bioenergy is the energy released from biomass, which is any organic material which contains stored carbon. Biomass can include wood, crops and crop waste, grasses, livestock slurry and other forms of organic waste. As biomass sources can be consistently replenished - for example, by planting more trees - bioenergy is classed as renewable.
The heat from burning biomass can be distributed through sheds using either hot-water or hot-air systems. With hot-water systems, the heated water is piped through heat exchangers, a simple radiator and a fan, or a series of fin pipes to heat the air in poultry houses.
With hot-air systems the heating unit pulls air from a house, heats it, then returns the now hot air to the house. The hot air is then distributed throughout the house using some type of duct system or through the use of circulation fans.
What Does a Biomass Heater Look Like?
A biomass boiler is essentially a sophisticated large wood-burning stove that can heat an entire building, or several buildings. Unlike a wood-burning stove, a biomass boiler does the same job as a central-heating furnace (boiler) powered by natural gas, oil or electricity: it can provide your sheds with heating and hot water and it can even power modern underfloor central heating.
A biomass boiler does not require huge amounts of starting up, cleaning or maintenance. All you have to do is load in your biomass (generally, wood pellets, wood chips, chopped logs, cereal plants or a combination of them) and periodically - typically every two to eight weeks, depending on the appliance - empty out the ash, which you can recycle on your compost.
While wood-burning stoves have to be manually filled up with logs, biomass boilers are often completely automated: they have a large fuel hopper on the side that automatically tops up the furnace whenever necessary. Unlike with a coal fire, you do not have to mess around trying to get the fuel lit: biomass boilers have simple, electric ignition systems that do it all for you. It is perfectly possible to run a biomass boiler all year round.
Why is Litter Drier When Using Biomass Heating Than LPG?
This comes down to the type of heat generated by biomass heating versus LPG. The heat from a biomass system is typically a ‘dry’ heat, similar to the heat generated by a slow combustion wood fire heater in your home. LPG, on the other hand, produces a ‘moist heat’. This is because of the small amount of water contained within LPG. Think about the condensation problems associated with un-flued gas heaters in homes using LPG.
The difficulty with LPG is that whilst it provides heat to sheds, it also raises humidity levels, which makes keeping litter dry more challenging.
Is Biomass Heating Cheaper Than LPG?
This depends on a range of factors including:
- price of LPG
- price (sourcing and transport) of biomass fuel, for example wood chips, wood pellets, straw, paper waste, crop waste, plant waste, animal waste etc.
- the heating value of the biomass fuel (some things burn hotter than others)
- overall efficiency of the heating system, and
- government incentive schemes.
According to Mike Czarick and Brian Fairchild from the University of Georgia in the US, if LPG is in the vicinity of 25 cents per litre, then biomass heating systems will be hard to justify. As LPG approaches 50 cents a litre, biomass heating begins to become more financially attractive.
Another key issue to consider is the availability of biomass fuels. If sheds are located in areas where biomass fuels are readily available (wood mills, cropping areas etc.) then biomass may be a viable alternative to heating your sheds. However, if fuel is hard to come by and supply is inconsistent and associated with high transport costs, biomass might not be that feasible.
The University of Georgia has written a series of articles about biomass, including on the economic feasibility of biomass heating systems. (For a copy of their factsheet, click here.]
As mentioned, factors other than LPG prices will make biomass heating more or less attractive. One of these includes government rebates, subsidies and incentives. The farmer from the UK is more than likely taking advantage of generous subsidies and incentive schemes offered by the UK government. Are similar incentive schemes available in Australia? An answer to this question was not readily available at the time of printing.
Can Dry Litter Really Improve FCR?
The answer to this question depends on your current base or standard. If your shed litter is usually very moist to wet, in other words, the litter typically has a moisture content of greater than 30 per cent, then YES, drier litter may improve feed conversion ratios. If you run a pretty dry shed - less than 15 per cent litter moisture - you are unlikely to see any real benefit from drier litter.
Wet litter is usually associated with higher ammonia levels, disease, general malaise and consequently poor performance. A number of studies have shown that wet litter can be associated with poor feed conversion ratios. The solution is therefore to run the sheds drier if possible but as mentioned, this can be challenging when using LPG heating systems, which introduce more moisture into sheds.
Biomass heating may a solution for some as it is a ‘dry’ heat and may enable growers struggling to combat high humidity to keep their litter dry.
Is Biomass Heating Feasible in Australia?
Given the climate, availability of waste fuel sources, transport distances and fluctuating LPG prices, is biomass heating a feasible proposition in Australia?
There are several companies in Australia and New Zealand that have commercialised biomass heating and electricity generation for small and large industries. The author has contacted a few of these companies to help develop a business case for biomass heating solutions for chicken meat enterprises; he will report on this aspect in a subsequent article.