When considering other feed stocks from which to produce renewable fuels and in any great quantity, we have at least four alternative feedstock paths.
1) Grow broad-acre oil seed crops
2) Utilise used cooking oils and animal fats and tallows
3) Grow oil bearing trees.
4) Develop and investigate other untapped feed-stocks
Growing oil seed crops
With regards to oil producing crops, obviously there has been a lot of time and effort spent in developing the oil seed crops we currently grow. Climate warming, salinity, land degradation and fertility issues are now creating new problems that may stand in the way of developing a reliable and continuous feed stock supply. A reliable feed stock supply is the key to any industry, and all it takes is a drought to remind us all of that fact. The more diverse the supply, the more guaranteed the supply.
Looking at the current varieties of broad-acre crop options we have, an important consideration is, therefore, what oil crop to grow. Obviously, the higher yielding oilseed crops will be the most economic crops to grow and process, but looking at overseas experience, I would suggest that Government policy, availability of supply, profitability, environmental and social issues are the keys areas to consider.
Rapeseed is commonly grown in Europe as a non-food crop on set-aside land.
In 1992 under the Common Agriculture Policy, an obligation was introduced to take 15% of the arable land out of food production. It was this legislation that grew the bio-fuel industry in Europe as farmers under the scheme were allowed to produce “non-food” crops and receive income. Between 4 and 7.5 million hectares are set-aside annually for the production of non food crops and the majority of this is rapeseed and Sunflower for bio-diesel and oleo-chemicals, and a smaller portion for the production of bio-ethanol from cereals and sugar-beet.
In Europe, bio-diesel produced from set-aside policy accounts for 0.5% of total fuel consumption.
Even though the majority of oilseed grown in Europe is rapeseed, in Australia I understand there is growing concern with regards to cross pollination issues effecting the quality of the domestic crush for human consumption.
Although Canola is the most common oil crop grown in Australia, it has its drawbacks. Canola, has a low water use efficiency…in other words its ability to maximise yield from available moisture is low. As everyone is aware, the last 6 years we have had extremely variable rainfall, and that combined with late season frost events has resulted in yield losses. I had actually removed Canola from the crop rotation, simply because the risk of crop failure was too high. Speaking to plant breeders at VIDA, (Victorian Institute of Dryland Agriculture) I soon began to appreciate the potential benefits of growing and using Mustard seed oil, but at the moment, Canola quality Mustards lines are still in the pipeline.
Another alternative crop is Safflower. It is a summer crop, and once it is established, it doesn’t need substantial rain to produce seed. It has a very robust root system that is able to source its water demands adequately from the sub soil. Unfortunately, there are two main drawbacks, the first is the lack of moisture in the sub soil for next years crop, and secondly, it is hard to crush. Safflower has a lot of husk and lower oil content. Canola is by far easier to crush, but then the renewable fuels industry is competing for market share with the domestic demand for oil.. Essentially, what we need is an oil bearing crop that produces a lot of low grade oil and is cheap to grow. The crop ideally would be drought and disease tolerant and the by-products would give a valuable return to off set production costs and encourage new products. Sounds like a bit of a tall order.
Perhaps not. There is currently a project being ran in the US looking at the potential of using Mustard hybrids to produce a cheap, reliable, inedible oil for bio-diesel production, while then being able to use the press cake as a natural pesticide to reduce the use of chemical pesticides in the environment, (such as methyl bromide).
The three main pesticide compounds (ITC, OZT and SCN) which come from the breakdown of glucosinolates, have been found to be effective on several hundred pests.
Other observations include toxicity to dormant seeds, inhibited seed germination and biomass growth and the pesticide compounds have a half life of 48 hours and break down into soil nutrients.
Perhaps another consideration for an alternative oil seed crop is wild radish. Wild radish can contain up to 48% oil. It is unsuitable for human consumption but would be suitable for bio-diesel. As most farmers know, wild radish has adapted itself to be a very resilient and problematic weed, it possesses a very hardy nature and shows good drought tolerance.
Used oils, fats & tallows
Other sources of oil include used cooking oils, restaurant grease and tallows and fats from slaughter houses to produce bio-diesel. Because of the high Free Fatty Acid content of these oil sources, bio-diesel from this feedstock has a high cloud point.
The cloud point is approximately16 degrees C for 100% pure tallow bio-diesel, and it is interesting to note the cloud point can be altered by blending a varying percentage of fresh vegetable oil with the tallow. Seasonal conditions obviously influence the use of tallow bio-diesel and even in southern Australia, it would be possible to run 100% bio-diesel during the summer months.
Fats and tallows require more intensive processing than virgin oil, to achieve acceptable bio-diesel yields. Single stage base reactions result in low bio-diesel yields, but now most bio-diesel processing plants use a two or three stage reaction process (which is suitable for both virgin and waste vegetable oil). As a result, processing plants have the capacity to change between feed-stocks without having to change processing methods.
Other ways to solve the cloud point issues with bio-diesel made from fats and tallows is to blend the bio-diesel with petroleum diesel (eg B20 - 20% bio-diesel, 80% diesel). Alternatively, it would be very simple conversion to fit a dual fuel system that used a heating source (such as engine heat, radiator coolant or in line electric heaters) to pre heat the fuel before combustion.
Used in the correct situation, bio-diesel from fats and tallows would find the appropriate markets and be a very successful fuel.
Oil bearing trees
Another potential source of oil could be oil bearing trees. The highest yielding sources of oil commonly grown are Coconut and Palm tree oil. Unfortunately, these trees are suited for the tropics and not the drier inland regions of Australia.
A tree that has some potential to be adapted to inland Australia, is the Jatropha tree. It is especially resistant to drought and can be planted in desert climates. The Jatropha plant is a bush that can live for up to 40 years and can be grown from seeds or cuttings. It quickly establishes itself and will produce seed year round if irrigated. Under irrigation, Jatropha can produce in excess of 1900 litres of oil per hectare each year. The Jatropha tree is native to the Americas, but thanks to the Portuguese has been spread around the world and is common in places such as Brazil, Fiji, Honduras, India, Jamaica, Panama, Puerto Rico, El Salvador, Mexico and much of South Africa. Jatropha is used to make soap, food, medicine, poison and is rumoured by traditional people to contain a cure for cancer.
The attractive aspect of growing oil from trees is that it could be easily integrated into a number of Government and environmental initiatives. We are only too aware of the problems associated with the over clearing of land, and it is possible Jatropha could be planted to help reverse the effects of soil erosion. It may even be possible to adapt the bush to be suitable to regions where salinity and waterlogging is a problem.
Being a tree (bush), it is possible that once established into a plantation, an alternative income stream may be derived from the sale of carbon credits. Once the plant has reached the end of its productive life, the trees could be used to make products such as paper and ethanol, or even be used to fire Biomass power stations.
As you will have noticed in the oilseed table, there are a number of unusual oil sources that exist, that are not being utilised (and are the by product of an established industry, ie grape-seed oil). Another such oil source is rice bran oil.
There is potential to produce bio-diesel from rice bran oil. It has been estimated that 700,000 tonnes of rice bran oil could be extracted from the 20% of world paddy production that is currently processed in two stage mills. This equates to 231 million gallons of bio-diesel a year. If it was possible to extract the oil from the other 2.8 million tonnes that is processed in single stage mills that would make available another 924 million gallons of bio-diesel. This raises the question, is it a matter of growing lots of oil bearing crops or is it simply a matter of identifying wasted feed-stocks and using our resources better?
In the book, “From the Fryer to the Fuel tank”, the possibility of growing oil from algae is examined. The US Department of Energy funded a $25 million project to examine strains of algae which consume CO2 and produce oil. At the Roswell site, diatom-algae was found to have a tremendous growth rate. The test pond was 1000 square meters and over a twelve month period 7,600 litres of algae oil was produced. In comparison, the same size area when sown with high yielding Canola plants was only capable of producing 190 litres of oil.
The researchers concluded that 200,000 hectares of algae ponds would be capable of producing 3.8 billion litres of oil. Oil producing algae can be grown in saline water so there is no competition between algae agriculture and food agriculture.
I have concentrated mainly on bio-diesel, but a lot of opportunity also lies in the production of ethanol from cellulose. Biomass such as agricultural wastes, straw, leaves, grass clippings, sawdust or old newspapers can be used. All of a sudden waste from the timber industry becomes a valuable source of fuel. Even if the ethanol is not used as a renewable fuel in petrol engines, it can be used in bio-diesel production.
Bio-mass, can also be used to produce renewable electricity. Babcock & Brown and National Power have recently announced plans to build a Biomass power station in South Australia, and will use plantation waste, sawmill and timber waste and manufacturing residues to fire the 30MW plant.
The bio-fuel industry could have a big impact on rural Australia and agriculture. Diversification of crops, new crops offering drought and disease tolerance and crops that may be able to be grown on non-productive land (such as salt tolerant oil bearing trees). We would see the provision of alternative income streams for farmers, the establishment of energy providers and processing facilities in towns and communities. This in turn would see hundreds of jobs created, new businesses spring up providing service industries and new industries making products from by-products. Our country towns would once again become attractive places to live, reducing the stress on city infrastructure that has been caused by years of urban drift. We would reduce our national deficit and reliance on overseas energy providers, and finally, we may start to treat our environment with the respect it deserves. Our planet provides all our needs. We don’t need a new colony on Mars, we would eventually deplete that planet as well. All we need to do is to learn to look after our own home, and use our resources to their full potential.
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