Vegetable oil fuel

Vegetable oil, vegetable oil fuel, Pöl ( colloquial)

Biogenic

Rape oil

74.0 mm ² / s (20 ° C) ( max. 36.0 mm ² / s)

0.92 kg / L ( 15 ° C)

9.7 kWh / L = 10.5 kWh / kg

39.5 MJ / kg

40 CZ

317 ° C

Vegetable oil, vegetable oil fuel, Pöl ( colloquial)

Biogenic

• DIN 51605 ( rapeseed oil ) max. 36,0 mm ² / s
• Sunflower oil 68.9 mm ² / s ( 20 ° C)
• Soybean oil 63.5 mm ² / s ( 20 ° C)
• Linseed oil 51.0 mm ² / s ( 20 ° C)
• Olive oil 83.8 mm ² / s ( 20 ° C)
• Cottonseed 89.4 mm ² / s (20 ° C)
• Jatropha 71.0 mm ² / s (20 ° C)
• Coconut oil 21.7 mm ² / s ( 50 ° C)
• Palm oil 29.4 mm ² / s ( 50 ° C)
• Palm kernel oil 21.5 mm ² / s ( 50 ° C)

• Pre-standard DIN 51605 ( rapeseed oil ) 0.900 to 0.930 kg / L
• Sunflower oil 0.93 kg / L ( 15 ° C)
• Soybean oil 0.93 kg / L ( 15 ° C)
• Linseed oil 0.93 kg / L ( 15 ° C)
• Olive Oil 0.92 kg / L ( 15 ° C)
• Cottonseed 0.93 kg / L ( 15 ° C)
• Jatropha oil 0.91 kg / L ( 15 ° C)
• Coconut oil 0.87 kg / L ( 15 ° C)
• Palm Oil 0.92 kg / L ( 15 ° C)

9.2 kWh / L = 10.0 kWh / kg

• Sunflower oil 34.5 MJ / L = 37.1 MJ / kg
• Soybean oil 34.5 MJ / L = 37.1 MJ / kg
• Linseed oil 34.4 MJ / L = 37.0 MJ / kg
• Olive oil 34.8 MJ / L = 37.8 MJ / kg
• Cottonseed oil 34.2 MJ / L = 36.8 MJ / kg
• Jatropha oil 37.0 MJ / L = 40.7 MJ / kg
• Coconut oil 30.7 MJ / L = 35.3 MJ / kg
• Palm oil 34.0 MJ / L = 37.0 MJ / kg

• Sunflower oil 36 CZ
• Soybean oil 39 CZ
• Linseed oil 52 CZ
• Olive oil 37 CZ
• Cottonseed 41 CZ
• Jatropha oil 51 CZ
• Palm oil 42 CZ

• Sunflower oil 316 ° C.
• Soybean oil 350 ° C.
• Cottonseed 320 ° C
• Jatropha oil 240 ° C
• Palm oil 267 ° C

3.24 kg / L

Untreated vegetable oil, commonly abbreviated as Pölten, can be used as fuel for diesel engines in mobile and stationary applications. As a biofuel, it is one of the renewable energy sources. A distinction is vegetable oil fuel of biodiesel, which is produced by transesterification of vegetable oil.

• 9.1 Availability in Germany

History

The idea of ​​using vegetable oils as engine fuel dates back to Rudolf Diesel, the inventor of the diesel engine. The availability of cheap oil was the reason why more expensive alternatives such as vegetable oil for a long time did not find use as fuel.

Only after the oil crises of the 1970s was an increasing search for alternative fuels. The increasing awareness of environmental and climate protection at the end of the 20th century was mainly renewable energy back into the discussion.

Suitable plant oils

Most come in Germany rapeseed oil as a vegetable oil fuel used. However, there are many thousands of world oil crops that could be used as a fuel. In principle, all types of vegetable oil and animal oils are suitable for operation in converted vehicles. Chance put motorists also filtered liquid oils and edible fats. However, they must be carefully cleaned before use, drained and possibly also neutralized. With the use of vegetable oil as fuel high quality standards must be met in all cases.

Although Camelina oil has better properties on the market outweighs the proportion of rapeseed oil, as farmers can not derive a financial advantage from a mixed cultivation, still can use the press residues as fodder, as this is prohibited due to the feed regulation.

Properties

Vegetable oil represents one of the highest forms of energy generated by photosynthesis. The calorific value of 37 MJ / kg is significantly lower than the gasoline (43 MJ / kg), and diesel fuel according to EN 590 ( 42.5 MJ / kg), but higher than that of the coal (30 MJ / kg). The volume-based energy density is about 9.2 kWh per liter and thus between gasoline with 8.6 kWh / L and mineral diesel oil with 9.6 kWh / L.

Pure vegetable oil is mainly composed of triacylglycerols, ie Glycerol esters of long chain fatty acids (ie, not from alkanes ) and is less flammable (see flashpoint) than diesel. The ignition quality (cetane number ) is generally limited because not heated vegetable oil is atomized from the injection nozzle in the combustion chamber only insufficient ( therefore advantages and swirl chamber motors are more appropriate). Due to its higher viscosity, which increases further with decreasing temperature, the flow resistance in the fuel lines, the fuel injection pump and the injectors compared to the diesel fuel increased. Reason, some fuel injection systems such as common rail or pump injector work with vegetable oil outside its specification, which can lead to abnormal wear to total failure.

Use

Due to the opposite diesel fuels higher viscosity and lower cetane number of adaptation measures are necessary for ordinary diesel engines generally. These consist, for example, in the heating of the fuel to reduce the viscosity in the injection system just prior to entry. This technology is already known from multi-fuel engines.

Provision is the DIN standard DIN 51605 as a quality standard for vegetable oil fuel from rapeseed oil.

Vegetable oil -grade motors and heaters

With the use of vegetable oil is halved in about the emission of soot particles over the use of diesel fuel. Only when the engine is cold and insufficient atomization in the cylinder of emissions is visible increased. There are fewer emissions of particulate matter than diesel operation. Contamination by sulfur and heavy metals are largely eliminated.

In addition, vegetable oil can be used as fuel for heating systems in stationary applications.

Without retrofitting few older engines can be easily run on vegetable oil. It is usually to pre-chamber diesel engines. Important, the quality of the injection pump. Have proved to be in-line injection, eg Bosch. However, the modification of these engines is very easy. Umrüstschritte following are required:

• Installation of a heat exchanger, for example for heating of the fuel filter with the aid of cooling water.
• A fuel line having a larger cross-section
• Installation of a new filter
• During the winter season the vegetable oil at least 10% of winter diesel has to be supplied.

The reconstruction costs here at own installation about 200 to 600 euros.

Specially developed engines like the Elsbett engine or other multi-fuel engines have not succeeded because of the higher costs.

Modern engines are equipped with a common rail injection or pump-nozzle injection. To this end, there are now appropriate conversions, which are complex and ( accordingly) expensive. These are safe and proven to be effective. After the conversion, it is then possible to use next ( petroleum ) diesel and vegetable oil as fuel. Current technology compensated as much as possible of the high viscosity in the winter and also the lack of ease of striking. To this end, the vegetable oil is heated through a heat exchanger to 60 ° C. For cold starts, this is done electrically, with a warm engine on the cooling water. The manufacturers report of occasion problems below -8 ° C in winter. The pre-annealing and tempering takes a bit longer. During the winter season there is a risk of " freezing ". Since the solidification of the fuel starts in the lowest part of the tank where the fuel is leaking, the continuous extension of the fuel supply can not be guaranteed. Therefore, at low temperatures, the addition of petroleum diesel fuel ( " winter diesel " ) is advisable.

The conversion can be done on a one -tank or two -tank system:

When tank system is the fuel for the engine in a single tank, and at lower temperatures, diesel parts are mixed into the vegetable oil when refueling. Among the useful modifications include an enlarged cross section of the fuel line, a system for preheating the feed lines, the fuel filter and the injection pump. Depending on type and thermal environment of the engine just some of the measures are necessary.

In the two- tank system of the engine is started and warmed up with diesel fuel from a separate tank. The waste heat of the diesel engine pre-heats the rest of the system. Then, switched manually or fully automatically to the vegetable oil tank. In periods of low load such as idle speed or Teillastbereicht, should be used instead of diesel. In the full-load range up to 100 % vegetable oil can be used. Before extended off the engine should be switched in time to allow the injection system is filled again when restarting with diesel.

For some years there are deals to retrofit diesel engines for the direct operation with vegetable oil. Under terms like " BB.drive ", " BEAM Plus ", " eoil ", " Poeltec " inter alia conversions are offered on the Internet that focus not only on heated, but on carefully degassed rapeseed oil. Even a tiny gas content, it is outside effective claims caused in a modern high-pressure injection of steam bubbles ( cavitation), which destroys the material in the environment. It should be remembered, however, that even conventional diesel fuel to some extent contains gases. For this reason, methods that rely only on degassing, such as the eoil system, highly controversial. It should, further, that - when the ultrasonic degassing method is used - the ultrasound may be the cause of cavitation generated by the strong pressure fluctuations themselves, see (cavitation: it can come in the pressure minima of the oscillations of cavitation). Thus, the ultrasonic method would just trigger the sonicated system only what it claims to be avoided. Moreover, cavitation arises from the vapor bubbles a liquid; Mixed with air, of a vapor bubble, and as such are not condensable at normal temperature, in would dampen the contrary, collapsing of the vapor bubbles under the heat generation would be advantageous in order to avoid harmful effects of cavitation.

In addition to the online offerings, there are engineering companies, which have focused on the conversion of commercial vehicles to alternative fuels, such as vegetable oil, animal fat, biodiesel, spezialiesiert. The products, such as the " bioltec system" are always evolving to use vegetable oil in diesel engines with the latest emission standards. From a technical standpoint modern vehicle engines can be operated with biogenic pure fuels - in compliance with the current Euro 5 and EEV Emissionsverschriften.

The most sensible upgrading the current state of technology is mainly used in trucks, commercial vehicles and agricultural machines, because the conversion amortized due to the high specific fuel consumption of these vehicles within a few months.

The company Deutz AG has presented at Agritechnica 2007 in Hannover their Natural Fuel Engine. This makes it the first major motor manufacturer to offer a diesel engine with full warranty and motor management optimization for operation with rapeseed oil according to DIN 51605. This engine will be marketed mainly in the agricultural sector.

Problems with the use

Change the engine oil

Unburned fuel arrives - especially during cold starting and at high speed - the engine oil and deteriorating its lubricating properties and are formed in the engine oil polymer chains that can cluster together in clumps and clog pipes and filters. This problem occurs especially when using modern fully synthetic lubricating oils, obviously bind fully synthetic oils foreign substances (free radicals ) are particularly good at what they indeed are - if it is not too much.

Pure diesel fuel begins to evaporate at 55 ° C. Thus, the engine oil reaches the driving this temperature, the diesel fuel from the engine oil evaporates. As vegetable oil, in contrast to diesel fuel begins to evaporate until about 220 ° C and the engine oil never reaches this temperature, inevitably accumulates in the engine oil to vegetable oil. A conversion of the vehicle to run on vegetable oil can only slow this process down, but not prevent it. Therefore it is recommended in all cases to check the oil level regularly and to halve the oil change intervals.

Viscosity

Vegetable oil is much more viscous than diesel fuel, the fuel injection system of the engine is, however, designed for more fluid diesel fuel. The flash point of vegetable oil is about 165 ° C higher than that of diesel fuel. Both properties have a decisive influence on the combustion.

So a conversion must either adapt the engine to use with vegetable oil and / or modify the vegetable oil so that it comes to the properties of diesel as close as possible. To ensure complete combustion as possible, it is necessary to the vegetable oil when injected just as finely atomize such as diesel fuel. In addition, either adjust the viscosity of the vegetable oil to the diesel fuel or the fuel injection pressure can be increased. In practice, usually both options are used.

The viscosity of vegetable oil is highly temperature dependent, that is, the further the vegetable oil is heated, the thinner it gets. At room temperature, the viscosity of vegetable oil is approximately 100 times greater than that of diesel, which would lead to enormous forces in unmodified injection pumps. It was only at about 150 ° C is reached, the viscosity of vegetable oil diesel. Most Pöl is heated with a cooling water heat exchanger but only at 65-85 ° C.

Theoretically, it is also possible to increase only the injection pressure in accordance with, but the cost is very high, and the injection pressure is only slightly raised. Older injection This can be easily achieved by changing the opening pressure of the injector. Since the injection pump a bit longer need to construct the higher pressure, the fuel is injected later on; the injection timing must then be re-adjusted.

Admixture of diesel / gasoline

In addition to the heating of the admixture of diesel or gasoline is a way to alter the viscosity and the flash point of the vegetable oil. This technique is used by some refitters such as " Klümper vegetable oil technology" and " Danhag ".

Vegetable oil is thicker than diesel. Therefore, a mixture of diesel fuel and vegetable oil, regardless of the mixing ratio, never reach the viscosity of diesel fuel. A combination of mixing and warming has been proven in practice. Firstly then the vegetable oil at the same temperature is substantially thinner than without the addition of diesel fuel, on the other hand, the flash point of the mixture ( diesel) and 220 ° C is lowered to a value between 55 ° C ( vegetable oil ), which has a better combustion result.

Gasoline is less viscous than diesel, so that a vegetable oil - gasoline mixture can reach the viscosity of diesel. This is the case with a mixture ratio of approximately 60% to 40 % gasoline Poil. However, the gasoline added anti-knock agents inhibit the diesel engine, the auto-ignition of the mixture, that is, the cetane number decreases sharply, so that the motor starts bad and not that powerful. Therefore in this case need zündverbessernde additives which increase the cetane number to be added. In addition, the fuel addition deteriorates the lubrication properties of the vegetable oil, which can lead to damage to the fuel injection pump. Here, the addition of two-stroke oil helps. A mixture of 59% Poil, 39.5 % gasoline, 1% two-stroke oil, and 0.5 % had zündverbesserndem additive in a study at the University of Rostock in September 2011, a HFRR value of 160 microns, so lubricates almost three times as good as it the EN 590 for diesel fuel prescribes (460 microns ).

Storage

Vegetable oil should be stored in a cool and dark. The storage can be done easily in above-ground and underground tank systems, which due to their relatively constant low temperature underground facilities have advantages.

The advantage of the good biodegradability of the vegetable oil is associated with a poor aging resistance and deteriorates the storage stability. Bacterial contamination, oxidation and water enrichment are the main problems. Therefore, care must be taken in the storage of vegetable oil that prevents chemical reactions that degrade the quality of vegetable oil, such as

• Oxidation,
• Hydrolysis
• The polymerization and
• The enzymatic degradation.

The storage must therefore dark, cool place ( 5-10 ° C), dry and be done with less contact area with the air oxygen. The tanks, pipes and fittings shall be made of stainless steel (without catalytic alloys like copper) or opaque plastic (eg HDPE) exist and contain a water separating filter for ventilation. Underground tanks are low due to the mostly low storage temperature. The tanks should be cleaned regularly, as the sediments from impurities the progress of degradation by chemical reactions ( see above) accelerate.

In the production of vegetable oil in the oil mill following storage combination is common:

Occupational Safety and Health

Vegetable oil is non-toxic.

Denatured vegetable oil can smell or taste unpleasant. One, sponsored by Shell, Daimler- Chrysler, Volkswagen, and the Association of German Biofuel Industry Study of the Federal Agricultural Research Centre came to the conclusion that the emissions of a fueled with pure rapeseed oil diesel truck engine in comparison with fueled with conventional diesel engine about 30 times carcinogenic are. Experts of the Federal Environmental Agency demand in reference to this study, that trucks will not run on pure rapeseed oil. In particular, the staff in the truck workshops were at risk. These statements could meanwhile be refuted in a recent study of the Technology and Support Centre ( TFZ ), Straubing and bifa Environment Institute in Augsburg.

This study has revealed:

• Compared to diesel emissions, the vegetable oil emissions showed an approximately halved mutagenic effect when using the bioltec technology. The mutagenic effect is a measure of the carcinogenic potential of the exhaust gases.
• The particulate emissions are compared to pure diesel operation also approximately halved when using load-dependent defined vegetable oil / diesel mixtures.
• The result has been repeatedly confirmed in the study at different measurements and check measurements.

Taxation in Germany

Pure vegetable oil (rapeseed oil) as fuel as any fuel is subject to the Energy Tax Act ( the Energy ). The basic tax is 470.40 euros per 1000 liters, equivalent to 47.04 cents per liter of fuel. With the introduction of the Energy Tax Act in June 2006, the old Mineral Oil Tax Law ( MinöStG ) has replaced, issued " relief " that reduce the taxation of pure vegetable oil fuel. These reductions, which are granted only for rapeseed oil, the quality standard DIN V 51605 corresponds, in 2006 amounted to a full 100 %, thus no taxes for this plant oil fuels were incurred. Other plant oil fuels that do not meet the quality standard, however, are subject to the full tax rate.

With the other years, this relief was abolished gradually, making the taxation increases for the fuel. Adjustments were made in addition to the introduction of laws on 1 August 2006 to the years 2008, 2009 and 2013. For 2013, the discharge is still 21,40 EUR per 1000 liter (2.14 cents / liter), which corresponds to a discharge of 4.55 %, respectively.

The following table shows the taxation of pure plant oil fuels.

Biodiesel and vegetable oil for use as fuel in agriculture is tax-free. Biodiesel and vegetable oils that are used as heating fuel, were up to 31 December 2009, tax-exempt ( § 50 para 1 of the Energy ). As of 2010, they are taxed in conjunction with paragraph 4 EnergieStG with 6.135 cents per liter as light fuel oil according to § 2 paragraph 3, No. 1.

Quality standards

The properties of the vegetable oil differ, depending on from which plant they are derived. So camelina oil, for example liquid for longer than rapeseed oil. While diesel fuel uniform quality standards can be assured, this is not so easy for the vegetable oil. It is not available as a standard liquid, and there is no large-scale market, based on a central processing and would allow a controlled mixing of oils of different origins and thus constant quality.

In order to establish uniform quality standards for rapeseed oil is very commonly used, has a benchmark on 23 May 2000, the " LTV Working Group Distributed vegetable oil extraction, Weihenstephan " a formulated " quality standard for rapeseed oil as a fuel (RK Quality Standard) ". This was supported by the DIN 51605 fuels for oil engines - Requirements and test methods replaced - Fuel from rapeseed oil:

The volume of consumption and the performance characteristics are approximately the same for both (diesel and rapeseed oil) fuels. However, vegetable oil burns somewhat "soft " because the combustion proceeds slowly. A problem of the coke residue is seen by the engine manufacturer, whereby there is no or hardly any approvals for vegetable oil. In addition, vegetable oil tends in conjunction with the additives of the engine oil for the polymerization, ie, the formation of tight junctions and lumps. This will, in particular in short-distance operation, caused by the unavoidable entry of unburnt vegetable oil on the cylinder wall into the engine oil.

Market and costs

In Germany alone, there are according to a recent estimate of the VCD about 20,000 vehicles that run on vegetable oil. Vegetable oil filling stations or at oil mills, the price of pure vegetable oil including tax component is usually at a similar price level as diesel fuel at regular gas stations.

In contrast to conventional fuels rapeseed oil is available at only a few hundred filling stations in Germany. In addition, there are many suppliers and mills that offer vegetable oil in common for fueling quantities.

Refuelling of plant oil from 1 -liter bottles of retailing is possible everywhere ( food - refined oil meets DIN 51605 ), but uncomfortable. Furthermore, you would be required to be paid later incurred Taxes to the tax office. Many vegetable oil drivers operate therefore a reservoir with pump on a private estate ( Hoftankstelle ). A common size is about 1 m³. Small storage tanks are available some of them already for about 50 euros.

For agricultural producers of rapeseed oil is cheaper than agricultural diesel. In the year 2001 is a 5.6 million DM funded by the Consumer Protection Ministry " 100 tractors Program " has been launched: A total of 111 farm tractor from various manufacturers whose engines are at the current state of the emission standards EURO I and EURO II, were on vegetable oil operating converted to gain experience. The project ran from April 2001 to October 2005 and was managed by the Institute for Energy and Environmental Technology, University of Rostock.

The cost ( including VAT) for an upgrade amount, depending on the method of 360 € (1 tank) and 1,500 € (2- tank) to 4,000 € per engine or vehicle or stationary unit. For self installer sets from 260 € (1 tank) or 600 € (2- tank) are available. In some areas, public funding up to half the net cost of conversion will be offered.

Availability in Germany

Many suppliers offer vegetable oil in large quantities between storable in domestic tanks. The refueling with vegetable oil from food retailers ( salad oil bottles) is possible, but uncomfortable and due to the small packing units also very wasteful. Moreover, some supermarket chains have introduced a maximum discharge rate. Spontaneous demand can be met through normal diesel from the petrol station.

Vegetable oil can be produced locally by farmers with the help of small cheap oil presses at affordable cost. Because of the rapidly increasing tax burden from 2008 to vegetable oil as fuel in Germany is expected that the production of vegetable oil for farmers substantially less attractive and therefore the number of tank options decreases rapidly. In the filtration of vegetable oils for fuel quality today are cheap and high-quality filter systems on the market.

Environmental effects

The use of vegetable oils as fuel has environmental advantages and disadvantages that can not always be offset against each other. The German Federal Environment Agency ( UBA) said in 1999: " From the perspective of environmental protection and economic reasons is a promotion of the use of rapeseed oil and RME in the fuel sector will continue NOT to advocate. " (Lit.: Kraus et al, p 21). In March 2007, it says in the Internet presence of the UBA word " biodiesel ", however: " biodiesel or the cultivation of rape can make a small contribution to the conservation of fossil energy resources and climate protection. "

Climate

The use of vegetable oils as fuel is CO2-neutral in a broader sense. Although the oil only the amount of CO2 is released, the plants have previously taken by photosynthesis from the atmosphere. However, it is in production ( pressing) itself consumes a generally lower percentage of current or mineral fuel, and thus is strictly speaking also a minor amount of carbon dioxide released. In addition, the Order of the acreage needed including the energy demands for the production and logistics of fertilizer or pesticides ( plant protection agents and agents for disease, pest and weed control ) and harvesting energy, which also leads to the release of carbon dioxide.

The use of near-natural produced fuels leads a large scale and long run to lower CO2 emissions compared to petroleum. The water formed during the combustion, carbon dioxide is absorbed by the regrowing producer plants again and converted into energy.

The energy balance in the production of vegetable oils is shown inter alia by Poel -Tec. Thus, the factor for up vegetable oil is cheaper than that of biodiesel ( ~ 1.48 ), but less favorable than conventional fuels, which is at ~ 8.6. However, it is not considered in this illustration that the conventional diesel additionally chemically bound energy ( crude oil) has to be supplied, which is taken from a finite reservoir. In vegetable oil and biodiesel in return, the radiant energy of the sun is neglected, but which is present anyway and practically inexhaustible.

Resource protection

In view of the fossil resources depleting gain in the future raw materials for energy production and for the chemical industry, which are increasingly produced by agriculture, a greater importance. The oil companies take into account this development and invest in relevant research.

Water Protection

The risk of contamination of water (including groundwater) is not as great as with conventional petroleum-based fuels with vegetable oil. Whether vegetable oil, which is not used as food or feed, is considered hazardous for water depends on the composition. The main component of vegetable oils is with the code no. Listed 760 in Annex 1 of the Administrative Regulation on Substances Hazardous to Waters ( assessment) and thus " not hazardous for water ": triglycerides ( technically untreated or hydrogenated; fatty acid radical is saturated and unsaturated, with an even, unbranched carbon chain and carbon number ≥ 8). Because vegetable oil is not a pure substance but a mixture, the mixture rule VwVwS applies. Then, for example, components of the water hazard class 1 may only be contained to less than 3%, so that the substance is classified as " not hazardous for water ." Therefore may be hazardous for water in different plant species and oil extraction process, the oil, if it is ( as far as these do not comply with the code no. 661 in Annex 1 of the assessment) contains too much triglycerides with short-chain fatty acids, too much free fatty acids or other contaminants. On the subject of " Water pollution by biogenic oils " the Federal Environment Agency has conducted an expert meeting in June 2007. Consequently, the Commission has to assess water-hazardous substances, which advises the federal government, found that biogenic oils are classified as slightly hazardous for water into the Class 1, unless other risk characteristics occur.

Even natural substances can damage rivers, lakes and groundwater. So requires § 5 Water Act " shall exercise the prudence required in the circumstances to avoid an adverse change in the water properties ." A classification as " not hazardous for water " simply means that the particular requirements of § 62 and § 63 do not apply Water Act and the regulations pursuant thereto.

Fire protection

The fire hazard is to diesel oil or fuel oil, low, since ( see section below quality standard) is because of the flash point of 220 ° C at normal temperature non-flammable and can form explosive gas / air mixtures.

Space requirements

To calculate the theoretical area required to produce the fuel vegetable oil, the energy expenditure is added to the net energy yield:

For a net energy gain of 1 and k = 2.31 ​​is thus 2.31 ​​/ 1.31 = 1.76 spend on total energy. This factor is important in order to calculate, which surface is actually required to generate power. So you have to order 1.76 m² area used on a square meter of energy for another use, to provide than the energy production from agriculture, the economy available. More detail about the space requirements can be found under the heading of biodiesel.

Agricultural and regional policy effects

Vegetable oil fuel can be manufactured close to the agricultural producers with relatively simple means of even small oil mills. In case of increased demand, the reclamation of disused agricultural land offers. The transport from producer to consumer is comparatively short. Even the by-product of the production of oil and press cake is used as a high quality protein and energy sources as animal feed. The market is realized in the past years in decline. Was he lying in 2007 to 800,000 tons in yet, so he has slumped by 2009 literally to 100,000 tons. This is explained by the competition with the biodiesel in biofuel Report 2009/2010, associations see the reason in the biofuel policies of the government Merkel II that does not promote existing clean fuels on.

Differential effect of cultivation methods

A central importance both for the ecological balance as well as for the efficiency of the use of vegetable oil is the form of cultivation. One can distinguish here between two types:

• Cultivation in monoculture with mineral fertilizers
• Growing in mixed culture with biological fertilizers

Most scientific arguments ( such as the opinion of the UBA) based on the assumption that the necessary quantities of vegetable oil can be done by rape cultivation in monocultures with high fertilizer and pesticide use exclusively in intensive agriculture.

Core of the biological approach is the extensive use of all resources. Due to the mutual favoring the plants can also be largely dispensed with in addition to pesticides on fertilization. The sorting of the crops directly into the harvester. Leftover plant material can serve as a basis for fiber materials or processed as biomass to energy. The press cake obtained from the oil can be used as animal feed and then finally can be used as manure for biogas production. The digested residue can be applied as fertilizer then also. Proponents point out here that the cultivation of oil plants should not simply ignore their material and energy valuable by-products. Under this holistic approach, the superiority of modern bio- technology to mineral oil products will clearly.

Another possibility would be, according to the proponents in the extensive cultivation of erucic acid -rich nature of rape, which as a fuel was a more appropriate than the currently grown erucic acid - free bred oilseed rape ( so-called OO varieties as breeding goal the production of a good cooking oil have ).

It is further argued by proponents that are too little considered in the discussion other oil plant varieties which are used extensively in Germany tillable would like Sunflower, rocket, radish, wild mustard, turnip rape, false flax, linseed or hemp into consideration.