The energy debate
The energy debate has for a long time been discussing if there are good alternatives to fossil fuels.
It started decades ago but really got a boost in the 1970s primarily as a consequence of the “oil crisis”, the oil embargo in 1973, from political and supply security reasons and as an attempt to finding means to becoming less dependent on the limited resource that fossil fuel really is.
Since then, also the environmental aspect has become a key motivation for finding substitutes or alternatives that causes less emission of greenhouse gases compared to burning fossil fuels.
Quite a few “solutions” have been presented over the years but none has actually been developed or adopted at a sufficient scale to make a significant reduction in the total demand for and use of fossil fuels.
Still making a relative small contribution to the overall energy supply, generation of electrical power from wind and from solar radiation currently shows a considerable growth rate.
However, it would only be fair to mention that in certain geographical regions biofuel is an important element of the automotive fuel mix.
The use of ethanol as an additive to gasoline in Brazil, around 20%, is one such example.
Brazil has a well developed biofuel industry where ethanol made out of sugar cane is largely used to reduce the amount of fossil fuel being used. The ethanol is used as a gasoline additive.
Biofuel a part of the solution
Many people seem to agree that using biofuels could be one out of several viable solutions in trying to reduce the emission of greenhouse gases into the atmosphere.
Since biofuel is produced from renewable biomass, the use of biofuel also would contribute to reducing the dependency of limited fossil resources.
Combustion of biofuel release greenhouse gases
Let it be clear, combustion of biofuels do emit greenhouse gases, primarily carbon dioxide (CO2) to the atmosphere, in similar amounts as for fossil fuels.
Depending on the fuel type and how it is used, also other substances such as carbon particulates, carbon monoxide, hydrocarbons, NOx and other gases may be emitted.
Is combustion of biofuel less harmful?
However, combustion of biofuels is considered less harmful to the environment than combustion of fossil fuels.
The amount of carbon dioxide emitted when biofuel is combusted is similar to the amount of carbon dioxide that already has been captured and stored through the photosynthesis and growth of the plants, provided the biofuel is produced from trees or other plant material.
Further it is considered that a similar amount of the carbon dioxide emitted when biomass or biofuel is combusted would have been released anyway, had the biomass undergone natural decomposition.
These are the main reasons why biofuel often is regarded as carbon or climate neutral.
If the biomass undergoes anaerobic decomposition (decomposition without oxygen/air) some of the carbon contained within the biomass will be transformed into methane rather than into carbon dioxide.
Methane is a hydrocarbon gas, which is considered to contribute strongly to the greenhouse effect if emitted into the atmosphere.
Anaerobic decomposition may take place if biomass is disposed at a landfill or other places where the supply of oxygen during decomposition is limited or if the biomass is consumed and digested by living creatures.
On the other hand when biogas is intentionally produced it is the same process that takes place but the production, storage and distribution of the gas would be in controlled environments causing limited or no methane emissions into the atmosphere.
Various types of biofuel
only way emissions from aircrafts may be reduced
the usage is still insignificant.
There are different categories of biofuel being used in gasoline, diesel and natural gas engines, some types can be used without causing any problems to the engines or devices, others will require more testing and possibly modifications to engines before they can safely be used.
The main categories of biofuels are:
- Various types of biodiesel
- FAME (Fatty Acid Methyl Esters)
- HVO (Hydrotreated Vegetable Oil) (Today HVO is also produced from waste and residue fat fractions coming from food, fish and slaughterhouse industries as well as from forestry residue.
- Renewable paraffinic Diesel)
- BTL (biomass To Liquid, through the Fischer-Tropsch synthesis)
- GTL (Gas To Liquid)
- And several more names and raw materials.
- Ethanol which is the main substitute for gasoline (but also used in some diesel enginees
- Biogas, mainly methane but also some butane and propane produced from biomass as substitutes for fossil natural gas.
The terms HVO, BTL, GTL and Renewable Diesel are often mixed in day life speak, also the terms Synthetic Diesel or Advanced biodiesel are used for the same products.
Since the car or engine manufacturers do not yet fully approve liquid biofuels as adequate replacements for fossil fuels, liquid biofuel in most cases is only used as an additive that is mixed into the fossil fuel.
An exception to this is second-generation biodiesel such as HVO that is approved by most truck manufacturers.
However, since the availability is scarce and the price is high the use is so far very limited.
Normally 5 – 10% biodiesel or bioethanol may be blended into petroleum based fuel without harming the engines currently being used.
Many older fuel injection engines are sensitive to biofuel and therefore biofuel might not be possible to use at all.
Here are a couple of sources indicating which car models that may run on biofuels:
|Fossil fuel||Renewable - Biofuels|
|Fossil diesel||Biodiesel||HVO||Synthetic biodiesel|
|Produced from||Fossil crude oil||Vegetable/plant oil, rapeseed and oil palm||Vegetable/plant oil, waste fat from animals and fish||All forms of biomass including forestry residue|
|Method||Refining including a variety of distillation, purification and other processes||Esterification (fats mixed with alcohol)||Hydrotreating||Gasification and Fischer – Tropsch processes|
|Product||Fossil diesel||Traditional biodiesel (FAME/RME)||Advanced biodiesel/Renewable diesel||Advanced biodiesel/Renewable diesel/synthetic biodiesel|
Yes there is a controversy.
The reason for the disagreements and occasionally a very heated debate is coming from;
On one side a genuine desire to replace fossil fuels with something that is renewable and less polluting but mixed with a “dash” of commercial and political preferences.
On the other side the uncertainties and in some cases the proven negative effects from producing and using biofuels, also combined with commercial interests, skepticism and general reluctance to change.
The controversy over biofuels has two main issues mainly connected to replacing liquid fuels such as gasoline and diesel with biofuels.
The use of biogas, also a biofuel is more straightforward and may in most cases replace natural gas as the primary fuel without causing any major issues.
This may be summarized with the two main questions:
1. It is questioned if the production and usage of biofuels really is environmental friendly and if the greenhouse gas emissions actually will be reduced?
2. Will biofuel harm the engines, and will the car manufacturers approve it?
1. Is production and use of biofuels really environmental friendly?
Biomass includes all living matter and the remains of it.
In the context of discussing energy and fuels, biomass often is used as a common expression for raw material used for biofuel production or even as a fuel itself.
Examples of biomass used for biofuel production would include:
- Wood and forestry residues
- Various food and animal feed crops
- Cereal straw
- Oil palms
- Vegetable oils, fish oils and animal fats.
As we already have pointed out combustion of biofuels do release similar amounts of carbon dioxide and in some cases other undesired substances as combustion of fossil fuels.
However as pointed out above, combustion of biofuel is often seen as carbon neutral since the carbon dioxide already is a part of the continuous carbon cycle.
So what is the problem?
Using (food) crops for fuel production may indirectly or directly lead to deforestation and drainage of marshlands, which in many cases would cause increased emissions of greenhouse gases into the atmosphere.
Whether land needs to be cleared to replace “lost” food or animal feed crop (indirect) or it is needed to actually make space for the new crops meant for biomass production itself (direct), such land use change could and in many cases will be the reason for increased greenhouse gas emissions into the atmosphere.
This would of course be the case for whatever reason deforestation and drainage is done and not only when this is done as a consequence of biofuel production.
This effect is called, either Indirect Land Use Change, ILUC. or if new land areas needs to be cultivated as a direct consequence of the biomass production, Direct Land Use Change, DLUC.
When second generation or advanced biofuels are produced from waste containing vegetable oils or animal fats, or residue from forestry, which they often may be, the raw material would cause hardly any land use change.
Therefore production of this type of biofuel would be regarded as less harmful to the environment.
Why is Land Use Change a problem?
Marshlands, peatlands and forests store large amounts of carbon, which may be released as CO2 or other greenhouse gases into the atmosphere if the land is drained or the forest is cleared to prepare for growing crops, such as oil palm trees, soya beans or canola, suitable and often used for biofuel production.
When peatlands or marshlands are drained, peat is gradually oxidized such that CO2 is emitted into the atmosphere.
However, the uptake of carbon by the new crops and effective use of co-products from biofuel production can partly compensate these emissions.
Palm oil, what about it?
Palm oil is the crop that currently is the most commonly used raw material for biofuel and ironically also is the crop that counts for the highest amount of land use change emissions (ILUC/DLUC) per unit of fuel or energy produced.
It has been estimated that palm oil production counts for Land Use Change emissions close to 230 grams of carbon dioxide equivalents per energy unit (Mega Joule) contained in the produced biofuel (gCO2/MJ).
Most of these CO2 emissions are caused by peat land oxidation and conversion of natural vegetation.
If the quantity of carbon dioxide emissions caused by growing palm oil trees is compared to the Land Use Change emissions caused by growing various “short rotation crops”, mainly used as raw material for production of advanced biofuels, we may see that the difference in land use change emissions is considerable.
The estimated emission from growing cereal straws is around 16 gCO2/MJ, for perennials it is negative around -12 gCO2/MJ and for short rot plants it is even lower, around -29 gCO2/MJ.
Please note that these numbers are estimates only, presented by a study report named “The land use change impact of biofuels consumed in the EU”, prepared by a cooperation between Ecofys, IIASA and E4tech for the European commission in 2015.
The basis for the study is the EU biofuel policy up to 2020.
The study report also presents numbers for the aggregated EU 2020 Biofuel mix scenarios, which estimates LUC related emissions to 97 gCO2/MJ.
It is important to be aware that the numbers presented are estimates only, with a variety of assumptions and scenarios.
LUC cannot accurately be observed or measured.
Therefore the effect is estimated through the use of models and simulations.
The full study report that the above numbers are based on may be accessed here: “The land use change impact of biofuels consumed in the EU”
This is why the use of palm oil currently is attracting a lot of negative attention, not only as a raw material for biofuel production but also for other purposes.
The additional emissions of greenhouse gases caused by land use change is the single main reason for questioning if production and use of biofuels really is environmental friendly and also is the factor that in some cases makes the use of biofuel worse than using fossil fuels in respect of greenhouse gas emission.
Also when biofuel is produced carbon dioxide is released.
When biofuel is produced energy is needed and if this energy do not come from renewable sources, there will be carbon dioxide emissions related to the energy production.
Additional emissions when producing biodiesel
Both the FAME and HVO processes normally use intermediates produced from natural gas.
The need for natural gas is about the same in both the FAME and HVO processes were methanol is used for the FAME process and hydrogen (“Hydrotreated”) for the HVO process.
The methanol could of course have been made from biomass but in most cases it is produced from fossil sources.
The hydrogen could be produced by using electrolysis but unless the electricity is produced from renewable sources this too cause emission of carbon dioxide.
Using electrolysis for the hydrogen production would in most cases not be viable from a cost and efficiency perspective.
2. Will the engine be harmed?
Most car and truck engines have not been approved by the manufacturers for more than 10% (some engines less) of ethanol being mixed into the gasoline and not more than 7% of first generation biodiesel being mixed into the diesel fuel.
Higher contents are likely to causing problems and in some cases even damage to the engine unless the appropriate modifications to the engine have been made.
Here are a couple of sources indicating which car models that may run on biofuels:
There are exceptions; some owners have had their engines modified to be able to handle a higher amount of biofuel without harming the engine.
Some countries have adapted policies requiring a higher blend of biofuel and subsequently nation wide modification program for the engines.
Brazil is the world’s second largest producer of ethanol fuel and is considered having a sustainable biofuel economy based on their efficient sugar cane industry.
The regulatory blend of ethanol into fossil gasoline has varied but has now for several years been around 20% (in periods as much as 25%).
Advanced biodiesel (i.e. HVO, second-generation biodiesel, synthetic diesel etc. …) is approved by most truck engine manufacturers.
Even if advanced biodiesel consist of hydrocarbon chains similar to the composition of most fossil diesel, typically from 10 to 20 hydrocarbon (HC) molecules chained together, the engine manufacturers have not yet to any extent approved it for use in smaller vehicles.
The reason for this is not entirely clear.
Two factors that could be among the reasons are:
- Extensive testing by the engine manufacturers for smaller vehicles has not yet taken place.
- Advanced biodiesel do not fulfill the current EU and ISO specification for auto diesel, due to it’s lower density; biodiesel approximately 780 grams/liter compared to 800 – 845 grams/liter for fossil diesel.
There is one difference though; between the chemical composition of advanced biodiesel and fossil diesel that is aromatics, which is a part of the chemical composition of fossil diesel but not advanced biodiesel. Aromatics are not favorable for clean combustion.
In addition advanced biodiesel needs lubricity additive, around 2% if used alone or in high blends this due to lower lubricity characteristics of advanced biodiesel.
What might the damage be?
The most commonly known potential engine problems related to use of traditional liquid biofuels:
- Oxidation – Corrosion and waxing
- Cold weather sensitiveness – Waxing and clogging
- Solvent properties – Clogging
- Oil dilution
- Water contamination
There are several reasons why engines might be damaged from the use of traditional liquid biofuels.
Biofuels such as ethanol made from fermentation and first generation biodiesel (FAME/RME), basically made by chemically reacting fatty acids and alcohol, have a different chemical composition and therefore different characteristics than fossil fuels.
The main difference being that the main component of fossil fuels is hydrocarbon while ethanol (C2H5OH ) and biodiesel (for example C15H31CH3CO2) also includes oxygen and have different molecule structure from fossil fuels.
The oxygen compound of the biofuel can lead to oxidation under certain circumstances, potentially causing corrosion of engine parts and also oxidation of the fuel itself, potentially causing waxing and subsequently clogging of filters and nozzles.
This is in particular harmful for components made out of plastic or natural rubber such as hoses, gaskets, filters, seals, pump diaphragms and similar components that might swell in the presence of alcohol.
Some biofuels are less suitable in cold weather, which also might cause waxing, and clogged filters and nozzles. This is in particular the case for first generation biodiesel made from recycled cooking oil.
Biofuels are “good” solvents and therefore have a cleaning effect of the interior of and engine. Cleaning is as such good but when old deposits get carried around inside the engine they could contaminate another part of the engine and that could be a filter, a nozzle or any other narrow passage within the engine that as a consequence is being clogged.
Biofuels are less stable than fossil fuels and therefore might more easily deteriorate over time.
Fuel leaking into the engine oil and deposits of the fuel injection nozzles are other potential undesired effects.
This is in particular the case for older engines with fuel injection systems.
All gasoline has a tendency to change due to weather and moisture content, but ethanol exacerbates this problem.
A higher concentration of alcohol(ethanol) in a gas tank means that more water might be absorbed compared to straight gasoline.
If the water concentration gets high enough, the alcohol and water will drop out of suspension, turning the fuel into a thick substance that the engine cannot use. This may happen at any stage of the transport, storage and usage process, even getting worse as it goes along.
The different physical properties and chemical composition of biofuels compared to fossil fuels have an impact on the engine behavior.
When Biodiesel is used in vehicles equipped with diesel particulate filter a larger amount of post – injected fuel is required for the achievement of the right temperature inside the filter for the oxidation of the soot. This is due to the lower, lower heating value of the biodiesel.
This could possibly result in a larger oil dilution, more smoke and higher fuel consumption.
On the positive side the oxygen content of the biodiesel causes more complete combustion with lower CO and particle emissions than for fossil diesel as a result. It has a higher cetane number providing better knock protection and lower sulfur emission
No wonder there are controversies
“DLUC” “ILUC” “Palm-oil”
“Rainforest-demolition” “Engine-damage” “Environmental-friendly”
“Environmental-neutral” “Waxing” “Biodiveristy”
“Reduced-carbon-emissions” “Fuel-security” “Water-use”
The debated topics and the claimed pros and cons are numerous.
There is still a lot of research and development to be done related to methods and techniques for production of biofuels.
Since the full environmental impacts from the production and use of biofuel cannot be measured it has to be identified through estimates and simulations that are based on a variety of assumptions and criteria. A sure source for speculation, biased positions and disagreement
In addition the policy and decision makers as well as the public debate is influenced by a number of players with different motivation and preferences that are not always based on scientific facts.
Even the scientist disagree on how to estimate and deal with the consequences of production and use of biofuel
With this in mind and policymakers that wants to appear as having the desired decisiveness we are not surprised that controversy arise and that questionable decisions sometimes are being made.