Farmers spin straw into energy gold… just not in Australia

On our property in south-west Victoria we are about to prepare for burning about 1000 hectares of stubbles, usually with 2-3 tonnes of straw per hectare. All around us other farmers are doing the same – totalling tens of thousands of hectares locally, and many millions of hectares across the higher production cropping parts of Australia.

Usually stubble burning is restricted to those higher rainfall areas where the large amounts of straw can make it difficult to sow and where burning also removes the problem pests of slugs and mites that would afflict the next year’s germinating crop.

So we are still talking many millions of tonnes of straw about to go up in smoke, where each tonne has the energy value of nearly double that of brown coal, and similar to that of dry wood.p31_130901-KP-burn1 jpg

While the canola stalk is quite hard to get a clean burn over the paddock, and burning wheat stubble can be also be patchy and unsatisfying unless it is dry and warm with the wind just right, the barley and oat stubbles are an arsonist’s delight.

After getting the downwind side burning back maybe 50 metres from the break around the edge you then fire the whole paddock, and the roar of burning and the colour of the smoke and flames is deeply satisfying.

But we know that this practice may not be allowed here much longer. It has been illegal for many years in the EU, where anyone torching straw like this would be heavily fined or jailed.

Instead in the EU, and increasingly in the USA, Ukraine and elsewhere, this straw and stalk would be being used for production of energy in its various forms – including conversion to ethanol (up to 270 litres of ethanol per tonne of straw), fuelling of small to midsize regional power plants (of 5-30 MW-e), for industrial heat production, or even chopped and mixed in with high-nitrogen content materials (like chicken manure or slaughter wastes) for production of biogas.

In some countries they pelletise it for use as bedding for racehorses, for absorbent litter for fuel or chemical spills and even for household heating. And here and elsewhere people are proving that straw can be turned into a renewable diesel fuel.

The capital costs of straw-fuelled combined heat and power plants are often less than the cost per MW of electricity produced by wind farms, and far more effective in displacing fossil fuel use, as this source of renewable electricity is available to suit demand, just as electricity is from gas or coal-fired plants.

The full utilisation of the heat produced by these plants means they have an energy conversion efficiency of about 85 per cent and significantly improves their economics. It also means there is no need for cooling towers with their high use of potable water.

Countries and regions where these plants are located appreciate the permanent jobs created (significantly more jobs per MW of energy produced than with any other renewable energy source), and as the straw comes from local farmers, they are getting more income.

In Denmark, the furnace ash with its balance of nutrients is returned to the farm fields that provided the straw. And because the heat and electricity, and sometimes transport fuel or upgraded biogas, comes from within the community this money stays cycling within the economy of the region instead of being ‘exported’.

All of these factors together have meant that Danes, Poles, Swedes, Chinese, Italians, Brazilians and others have invested in developing this biomass resource.

Inbicon_13704497323622
Inbicon’s biomass refinery in Kalundborg, Denmark

Denmark was a leader through the 1980s in developing modern equipment for using straw for farm heating. Legislation there in 1993, enacted as part of phasing out coal use, stipulated use of at least one million tonnes a year of straw for energy production, and part of this is in straw-fuelled combined heat and power plants.

Denmark was also where production of ethanol from straw was perfected (with a pilot plant supplying the ethanol for VIP cars for the 2009 COP 15 summit in Copenhagen).

The first commercial-scale European cellulosic ethanol plant is at Crescentino in Italy, and produces about 50 million litres a year from over 200,000 tonnes a year of crop residues.

Danish designs for straw-fuelled furnaces have been exported widely, including to the UK, Spain and China, and China is now the world leader in implementing ‘modern’ straw-to-energy technologies. More than 10 million tonnes a year there fuel up to 40 regional power stations, and yet more straw is used there in gasification systems and in anaerobic digestion, as well as in pilot plants making cellulosic ethanol. With up to 300 million tonnes of straw annually available China is only just beginning to make use of this resource.

But here on our farm, as with cereal and oil seed growers in higher rainfall regions across Australia, we are likely to be burning our stubbles for quite a few years yet, as no one in positions of power and influence (or in state and federal policy development) seems to know about all these other options, or appears to care.

Andrew Lang is a farmer and farm forester in SW Victoria, and is a vice president and board member of the World Bioenergy Association

Comments

17 responses to “Farmers spin straw into energy gold… just not in Australia”

  1. Tim Forcey Avatar
    Tim Forcey

    Thanks for this article Andrew.

    1. Alan Baird Avatar
      Alan Baird

      Yes, useful stuff.

  2. Peter B Avatar
    Peter B

    An increasing number of farmers, after having livestock take off/feed off as much of the stubble as possible, then direct drill the next crop seeds through the stubble. Leaving the stubble increases ground cover stopping wind erosion and adding carbon to our generally depleted ancient soils. All of the Ukraine, Western Europe and a good portion of the USA have soil types as good as or better than our Darling Downs with carbon content and reliable rainfall we can only dream of in our grain belt. Bagasse i.e. stubble and leaf material from our tropical and subtropical sugar industry is just marginal except where it is used for co-generation in the processing plants.
    Burning stubble was the general practice before the 1950/60s where the short term fillip from the potash of the burning and the clearing for next planting was also necessary because of older less powerful tractors and the unavailability of direct drill.
    To use stubble in Australia for methanol would require soil analysis by farm, individual cost benefit analysis vis sheep in mixed farms etc, subsidies for transport/production because of our relatively lower farm density and either a co-op arrangement and/or shares in a methanol plant for it to be viable.
    Recovering our depleted soils should be our first national priority.

    1. Andrew Lang Avatar
      Andrew Lang

      You are right in some of this (but wrong in others) but your statements are a bit absolute and theoretical. It’s like that academic’s statement ‘Yes, I see it works in practice but let’s see if it will work in theory’.
      Here we are working with what is economc and practical, and stubble burning is very much a part of this at present. What has changed is cultivation. Now it is almost all direct drilling and often into raised bed systems.
      If this straw was to be used to make ethanol – Victoria’s economically available threshed straw coming out of the back of the headers (approx 1 million tonnes) could produce about 270 litres per tonne (so 270 million litres) plus about 300 kg of lignin/tonne (300,000 tonnes) which can be used as a high energy pelleted furnace fuel or as a feedstock for high-value substitutes for petrochemicals. The ash (minerals like potassium, phosphorus, calcium, sulphur) from this goes back to the paddocks. Other fermentation process wastes also can go as furnace fuel and the ash from this also goes back.
      It all means import replacement, jobs and a significant amount of near zero emission transport fuel (displacing import and use of about 200 million liters of petrol, and reducing fuel GHG-e emissions by maybe 200,000 tonnes a year).
      You could do the same rough calculations for using straw as a furnace fuel.

      The straw on lower rainfall cropping regions is not touched (it is short anyway and may only be 1-2 tonne/ha, so not enough to clog up planting equipment), and in times of drought this would apply to higher rainfall regions. reduced stubble and the plant roots still leave a lot of organic carbon on the site, though much of this is broken down by microbial activity over the coming autumn, winter & spring, with release of CO2 back to the atmosphere.
      As it is the point of all this si that we will be bruning it all and so will everyone else in the the more productive cropping regions and there are better practical options.

  3. Bungarra Avatar
    Bungarra

    When work on stubble utilization is considered, there is the issue of maximizing the value of the products. During the first Oil Shock, in discussions with an product development executive from Dow Chemicals, USA, when asked if the higher oil prices marked the end of pesticides as we knew it then, he made the comment ‘no problems, any form of reduced carbon can be considered for a feed stock’.

    I would suggest that fuels and heat should be the final byproducts of such an industry, with fine chemicals the highest priority. One is starting with products which have huge range of organism which can process them, so get the bugs to produce the high value products, then process/burn the residues. We need high value products and knowledge which can be exported in 747’s, not super tankers, together with a good royalty stream from the inventions.

    Lets extend our farming into vats and include that in the system. There has been some work on changing the structure of cellulose in corn to make it more assessable to for fermentation and digestible for ruminates. This is just the logical extension. We have been fermenting grains and fruits for some time.

    1. Andrew Lang Avatar
      Andrew Lang

      when Denmark was looking at its potential to produce jet biofuels it discovered that in theory anyway it could do this by better utilising the same amount of biomass it presently puts into combined heat and power plants and direct heating plants.
      It required development to process it via other pathways and produce biofuels and still have almost as much thermal output as currently. This is outlined in the NIRAS report – search ‘Sustainable Fuels for aviation. An analysis of Danish Achievement and opportunities’.
      Of course this would reqire a heap more capital invesment, but this is something the Danes (and other countries in the EU – particularly in the Nordic region and central Europe) seem to be able to contemplate.

      1. Bungarra Avatar
        Bungarra

        I would suggest that the problem is in our world view that investing using monies from taxing our mineral/fuel wealth is contrary to good economics. Our great grandchildren with thank us. We also should be demanding like Norway did that all equipment for the mines and well be built here. It is not going away.

  4. Peter F Avatar
    Peter F

    Andrew
    Very interesting article, big plus for distpatchability of power and effectivly turning useless CO2 emissions into useful and I am sure low stubble plus furnace ash is a better seed bed than burnt ground
    1. Do you have any figures/even guestimates for the amount of straw that would be available in Australia
    2. Given that Denmark etc. have a lot of district heating systems and much more need for heat their EROI is much better than Australia’s
    3. Europeans tend to get much higher yields and therefore within a given travel radius of a plant the amount of straw is much higher so that in Australia the costs of harvesting and transport are higher thus hampering the economics, do you have any idea how much it would cost in energy terms to harvest and transport straw an average of say 50km. How does that compare to the energy content of the straw
    4. is their any estimate of improved yields if any

    1. Bungarra Avatar
      Bungarra

      The harvest index for wheat is about 30 -35 % for the winter cereal belt in Australia. However, not all can be collected, so one could suggest that allowing for sufficient to maintain soil cover etc, we could look at at the same tonnages as for grains for winter cereals. However, depending on the economics of the system, one could see some changes to the harvest index.

      The plant breeders have been pushing to maximize yields. Change the requirements, and crops can / should be changed.

      Returning nutirents is an essentual aspect of the maintaance of any system. Collecting weeds seeds via the harvesting process is also a significant benefit to reduce the impact of herbicide resistance in Australian systems.

    2. Andrew Lang Avatar
      Andrew Lang

      1. straw production is about 0.8 of weight of grain from most cereal crops. In Victoria there is about 3.1 million ha under mainly cereal crops and average yields in the higher rainfall areas (about 1 million ha) where most stubble bruiing happens are 3-4 tonne/ha.
      About 1 tonne of straw or stalk is coming out of the back of the header (along with weed seeds and missed grain), so for Victoria alone the most economically avialble straw is this threshed material which can be collected directly from this windreew or even at the back of the header in movement by a trailed baler.
      This threshed material across Australia might be 10 million tonnes.
      2. you are quite right, but the two lines of EROI are only separated by time (meaning where they are now we will be in 5-10 years depending on issues including prices of other fuels, carbon tax etc).
      3. Costs of baling, fuel, wages, machinery and transport in Denmark, etc., are higher than here – partly due to size of fields, maximum size of trucks on roads and wetter climate (moving more water around). My impression is that our costs are very similar to theirs but there they have positive impacts of legislation and carbon tax making the economics work better overall.
      Generally speaking the energy is in the order of 1 unit to gather and transport vs 25-35 units of energy in this when used as a fuel
      4. we lose a lot of nutrient by burning – lost in the smoke plume up through 5-10,000 feet, though it may comes down elsewhere – like in Gippsland or in rain in NZ. If we reduce stubble standing volumes by removal of 30-50% and then replace this nutrient as ash that is better (we still lost most nitrogen and carbohydrates but his is often lost anyway through microbal action over winter).
      5. Weed eradication from burning is very minor as it is a fast moving flame that does not burn very hot to heat enough at or just below ground level. but removal of this threshed straw by intercepting it before it hits the ground direct into a baler (or a chaf cart) gets a lot of othersie problematic weed seed (i.e, annual rye grass)

      1. Peter F Avatar
        Peter F

        Thanks Andrew
        I have a model of potential renewable energy sources in Australia I will add this in.

  5. Farmer Dave Avatar
    Farmer Dave

    Thank you, Andrew for this great article and your continued advocacy of bioenergy and other uses of biomass. It is astonishing how far behind Australia is in this area.

    Even if one discounts the carbon emission reductions from biomass used for energy and other products, there is a great rural and regional development incentive to progress these mature technologies. Indeed, there is a trilogy of economic benefits available from the kinds of developments you have described.

    (1) As you point out in your article, bioenergy developments are excellent employers of people per energy output.

    (2) If the bioenergy replaces a current energy source that comes from outside the region, then meeting the energy need from local sources stops the previous economic leakage represented by buying the energy into the region. A good example is Tasmania, which spends about a billion dollars a year on petroleum products; nearly all of that money leaks out of the island. Most or all of the gas (pipeline and bottled) used for heat could be easily replaced by locally sourced wood pellets, wood chips, or biogas, and some of the liquid fuels could be replaced by ethanol or other biomass derived fuels. There are good examples from around the world (e.g. Burlington, Vermont, Güssing, Austria) of communities who have built strong local economies by systematically reducing economic leakage.

    (3) Some of the technologies are modest in scale and therefore modest in their capital requirments, making them accessible to construction and ownership by local cooperatives, further ensuring that economic benefits are kept in the local community.

    A community based group in North East Tasmania is in the very early stages of forming a local cooperative in order to pursue bioenergy and other advanced biomass opportunities.

  6. Sean Avatar
    Sean

    Andrew, You need to organise compaction of straw into pellets, which could displace both coal and wood heating.

    There is some 20 million tons of straw waste out there every year.

    1. Andrew Lang Avatar
      Andrew Lang

      thanks, the figure I have been given for pelleting is that it adds about $35/metric tonne to the price of the straw which may be $60-80 at the farm gate.
      But i agree as an initial option and pelleting is already an economic process for some uses and particularly to produce absorbent litter for racehorses – my understanding is that this is presently mainly imported. The straw can be a filler for animal feed pellets. I am sure there would be other uses and even just as a mulch for gardeners. I do know that there are makers of heating systems designed to run on straw pellets. But straw is not able to be used as a larger fraction of the feed for coal or wood fired systems (maybe a 10-15% mix is ok) due to the fact that its ash has a low melting point, and the the combustion gases can be quite high in corrosive metal chlorides. So specialist straw furnaces are designed to cope with this.

  7. Leigh Baker Avatar

    What are the options for local community-owned economic development, especially towards generating products that meet local needs?
    Scotland has community-owned tidal and there’s community-owned solar underway in Boggabri, Shoalhaven and Lismore.
    Could some nimble entrepreneurial thinking be more use in developing a business model that delivers services and returns profits to the region?

    1. Leigh Baker Avatar

      Is there something that could be adapted from HarvestPower US, for example?
      http://cleantechnica.com/2015/02/05/harvest-power-rebuilds-topsoil-produces-energy-process/

  8. Andrew Avatar
    Andrew

    Hi Andrew,
    Just read your interesting article. Sounds like the bones of a project. Has there been any attempt to put together a project feasibility paper demonstrating its bankability and/or state support required to get it funded?

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