Introduction

With the rising cost of petroleum-based diesel and heating fuel, there is a growing interest in determining if on-farm biodiesel production could be a feasible and economic farm-grown replacement for this farm input. This document provides background information on biodiesel and outlines many factors to consider when determining whether producing biodiesel on-farm for farm use would be a practical and economic option for your situation. Recommendations for further reading and study are also provided to assist you in evaluating the safety and fuel quality aspects of small-scale biodiesel production.

Background on biodiesel

The idea of using plant-based oils, such as soybean oil or canola oil, to fuel an internal combustion engine is as old as the diesel engine itself. Rudolph Diesel, inventor of the diesel engine, used peanut oil to demonstrate his new invention at the Paris World's Exhibition in 1900. Throughout the 20^th century, however, petroleum-based diesel fuel has been relatively cheap and convenient. As a result, diesel engines have been refined through the years to work well with this fuel source. Petroleum diesel flows more easily (i.e. is less viscous) than either plant or animal based fats and oils. As a result, using non-petroleum-based oils in today’s diesel engines requires either modifying the vehicle’s fuel system to accept these slower flowing oils or modifying the oil or fat itself so that it can be used directly in a diesel engine. The chemical process commonly used make bio-oils less viscous, turning them into “biodiesel”is called “transesterification”.

The chemical transesterification of feedstock oils is a relatively straight-forward, although not necessarily simple, process. It can be described, in general, as follows:

100 kg feedstock oil + 10 kg methanol < ^catalyst > 100 kg FAME + 10 kg glycerol

where: FAME refers to “Fatty Acid Methyl Esters” or “biodiesel”

catalyst refers to a small amount of a compound – typically potassium hydroxide or sodium hydroxide (lye) that helps to drive the chemical reaction shown.

The FAME or biodiesel that results from this reaction can be considered “raw” because numerous contaminants, such as soap and alcohol will remain. In order for the biodiesel to meet the American Society of Testing and Materials (ASTM) D6751 fuel quality standard for biodiesel, subsequent processing is needed to remove these contaminants. Using biodiesel that does not meet this standard risks damaging the diesel engine it is used in as well as nullifying engine manufacturer warranties.

The chemical manipulation of vegetable oils to produce biodiesel requires that toxic and hazardous chemicals be handled by the producer. A full discussion surrounding the safety and quality associated with small-scale biodiesel production is beyond the scope of this document. However, it is recommended that readers seriously consider these aspects as well as the economic realities presented in this paper before proceeding with on-farm biodiesel production. Comprehensive sources for further information on small-scale biodiesel production safety and quality include; Kemp (2006) and the Canadian International Grains Institute (CIGI) website. Details on both of theses sources are listed in this document’s reference section. CIGI also offers a one-day workshop on biodiesel production using their mobile trailer for interested groups.

Biodiesel vs. straight vegetable oil

It is important to note the difference between using biodiesel and straight vegetable oil (SVO) as a fuel for diesel engines. Biodiesel, as a product of the transesterification process, flows more like petrol-diesel. SVOs do not go through the transesterification step, but must be heated prior to leaving the vehicle’s fuel tank so they will flow more readily through the fuel delivery system. As well, mechanically expelled new oils need to be filtered to ensure gums and other resins are removed from the oil prior to their use as a fuel. Used vegetable oils also need to be filtered to remove any foreign particulates and other contaminants.

Some groups, particularly in Europe, are experimenting with the idea of mixing petrol diesel and SVO in various proportions, but often at a 1:1 ratio. This avoids the need to modify the vehicle’s fuel delivery system while simultaneously avoiding the safety issues of extra processing associated with biodiesel production. More long-term experience is required to assess the impact such an approach has on common diesel engine wear and maintenance.

Benefits and drawbacks of using biodiesel

Many people question the net environmental benefit of using biodiesel or SVO for fuel instead of traditional petro-diesel. There is also societal concern over the impact biodiesel production could have on the food supply.

In general, biodiesel production yields more net energy than petro-diesel. Studies suggest that for every unit of fossil fuel used to produce biodiesel, the biodiesel made will yield 3.2 units of fuel energy. On the other hand, for every unit of fossil fuel used to produce petro-diesel, petro-diesel will yield about 0.83 units of fuel energy. This efficiency ratio is likely to fall further as world oil reserves become less convenient to extract.

Fuelling a vehicle with biodiesel can also lower tailpipe emissions. From a greenhouse gas perspective, for each litre of fossil fuel displaced by biodiesel, 2.2 kg less CO₂ is added to the atmosphere. As well, biodiesel is naturally low in sulphur. Removing sulphur from petro-diesel, a requirement for diesel fuel sold today in Canada, requires additional refining, resulting in additional carbon emissions.

Biodiesel can be used in its pure form or alternatively mixed in various proportions with petro-diesel. A B20 biodiesel, for example, is a mixture of 20 per cent biodiesel and 80 per cent petrol-diesel. The chart below shows the results of a 2002 US-EPA study that investigated the change in emissions levels from heavy-duty highway engines for various soybean-based biodiesel blends. It shows that emissions decreased for all air contaminants monitored except for nitrogen oxide emissions (NO_x). This is a significant greenhouse gas. However, technology to treat the exhaust gases to reduce NO_x emissions does exist.

Figure 1. Change in Heavy-Duty Diesel Engine Emissions for Various Levels of Biodiesel Use (Source: US-EPA, 2002)

Besides the potential to increase NO_x emissions, there are other factors that could also be considered drawbacks for biodiesel including:

• Cold weather performance. As air temperatures drop, waxes in the biodiesel will begin to crystallize and the biodiesel will begin to gel, clogging a vehicle’s fuel supply lines and filters. Biodiesels made from rendered animal fats will gel at higher temperatures than those produced from oilseeds such as canola. Gelling is a certainty regardless of the biodiesel’s feedstock oil given the winter temperatures experienced in Ontario. Mixing biodiesel with No. 1 petro-diesel fuel can “winterize” the biodiesel, in much the same way that No. 2 petro-diesel is “winterized”. Other fuel conditioners are also on the market. Under Ontario climatic conditions, winter mixes in excess of B20 will likely risk fuel problems on the colder days. Moving the disabled vehicle to a warmer location would overcome the problem.
  
  
• Biodiesel has slightly lower energy content than No. 2 petro-diesel. As such, fuel consumption may be slightly higher. Various experiences with biodiesel have concluded that one should expect a zero to five per cent increase in fuel consumption with biodiesel for the same energy output.

Using biodiesel could also risk voiding original manufacturer (OEM) engine warranties. Many who have experimented with using biodiesel have evidence to suggest years of trouble-free operation, but you should determine what your risk tolerance is before using biodiesel in your valuable equipment.

Finally, what impact does biodiesel have on the world’s food supply?

• Oil derived from locally grown oilseed crops could never meet the demand for diesel fuel. For example, in Ontario, the province’s five year (2004-2008) average soybean production has been 2,441,200 tonnes. Canola production is much less for the same period at 32,660 tonnes. Even if all of the oilseed extracted from these oilseed crops could be converted to biodiesel, it would offset about nine per cent of Ontario’s annual on-road diesel fuel consumption of 5.3 billion litres.
  
  
• Inedible animal fats and used vegetable oils are another feedstock for biodiesel production. Even if all of these Ontario products were dedicated to biodiesel production, they would add an additional two per cent of the supply needed for annual on-road diesel consumption.

Growing crops solely for the purpose of biodiesel production is currently not sustainable. Future technological advances to improve the efficiencies of both diesel engines and oil production from plants, however, could improve this current situation.

Are there opportunities for on-farm biodiesel production in Ontario?

Waste or used vegetable oils and animals fats are the most economical feedstocks for biodiesel production. There is only a limited supply of waste oils and if they are not available, the largest potential on-farm source of feedstock oil in this province is soybeans. Pressing soybeans yields not only oil, but also soybean meal. Ontario livestock producers often grow soybeans on a portion of their land base, sell the harvested beans and subsequently purchase soy meal to include in their livestock feed rations. Let us explore further the value-added potential of on-farm soybean processing.

Determining how to extract the oil from the oilseed is the first step. When selecting an oil expeller, it is wise to choose one that has a higher extraction efficiency because it will improve the profitability potential.

Oilseed	Expeller-Pressed Oil Yield (L/tonne)	Expeller-Pressed Meal Yield (kg/tonne)
Soybeans	80 - 112	890 - 860
Canola	160 - 360	810 - 610

Table 1 shows the volume of oil that can be expected from soybean and canola seed. Oil content of the common seed crops will vary depending on variety and crop growing conditions.

Table 2 provides guidance on the amount of mechanically pressed soybean meal that could be included in the ration of selected livestock. Estimates for canola meal are also shown. The lower values for canola are due to the generally recognized lower palatability of canola meal as a livestock feed. The amounts assume a higher level of fat (energy) content in the on-farm processed meal than with off-farm (solvent extracted) meal, because it is assumed all oil on-farm extraction would be achieved through mechanical pressing. While efficiencies can vary among mechanical presses, expeller presses generally leave 45-50 per cent of the oil contained in the oilseed in the meal. A solvent-type approach, used in industry, leaves about six per cent but is very costly and not feasible on-farm.

Livestock Type	Typical Weight Range (kg)	Average Daily Meal Consumption Potential (kg/day/450 kg of livestock weight)
		Soybean Meal	Canola Meal
Dairy Cow	550 - 700	1.1	0.63
Beef Cow	550 -700	0.6	0.29
Beef Feeder	180 - 635	0.40	0.20
Dairy Goat	75 - 95	1.3	0.79
Broiler Chicken	0 - 2.6	4.31	-
Feeder Hog	27 - 118	3 - 41,2	-

Notes:

Values shown in columns 3 and 4 above are not intended for use in developing detailed feed rations for livestock, but as a guide to estimate the approximate potential for a livestock farm to utilize the meal by-product from on-farm oilseed crushing. Neither do these values represent peak potential consumption rates for the livestock types listed, but “average” annual amounts.

¹ Assumes meal product has processed sufficiently to destroy trypsin inhibitor.

² Range given is due to the base grain used in the hog ration. If corn-based, use the lower value. If wheat-based, use the higher value.

Depending on the type of livestock fed, the extra oil left in the meal with expeller pressing could demand a price premium. For example, dairy producers may be interested in including additional fat in their cows’ diet to affect the fat content of the milk produced. Hog producers may be less interested, because additional fat in the animal’s diet will encourage “soft fat” in the resulting meat. As well, with monogastric animals such as hogs and chickens, further heat treatment of mechanically-pressed meal may be needed to destroy the trypsin inhibitor that would otherwise lead to poor protein absorption. This will depend on the temperatures the oilseed is subjected to as it passes through the expeller.

Income from the sale of the meal by-product is critical if oilseeds are to be crushed and the new oil used for biodiesel production. Livestock producers may have the on-farm capacity to feed this by-product, while cash-crop soybean or canola growers would need to establish a reliable market for the meal generated.

Figure 2. Oilseed expellers can range in terms of oil extraction efficiency. While lower cost units may be more attractive initially, more expensive expellers with a higher oil extraction efficiency and lower maintenance costs often prove more economical.

Biodiesel Cost of Production Spreadsheet

A series of spreadsheets have been prepared to assist in evaluating the cost of production for specific small-scale biodiesel production situations. They also point out the key factors affecting the cost of producing biodiesel, such as meal price. These spreadsheets were developed initially by Roy Arnott, P.Ag., Business Development Specialist with Manitoba Agriculture, Food and Rural Initiatives. They have been modified to reflect Ontario cropping practices and costs. Inputs to the spreadsheet include the following:

Special thanks goes to Roy Arnott, P.Ag. roy.arnott@gov.mb.ca, Business Development Specialist, Manitoba Agriculture, Food and Rural Initiatives, Pembina, MB, who developed the biodiesel cost of production spreadsheet that was used as the foundation of this analysis and modified to reflect Ontario circumstances.