RENEWABLE ESTER BASE OILS FOR SUSTAINABLE LUBRICANTS: A TRANSPARENT & SCIENTIFIC APPROACH
When talking about a sustainable lubricant, it is not only important to consider its effect when spilled in the environment; the global environmental footprint should also be taken into account. When performing studies through life cycle assessments (LCA), comparing different base oils and raw materials, it begs the question: Are renewable base oils always the best option?
ARE RENEWABLE BASED OILS ALWAYS THE BEST OPTION?
The honest answer is: it depends. A renewable ester is mainly obtained from vegetable oils or animal fats. The crops necessary to produce these oils require an intensive agricultural phase. During this growth phase a lot of energy is used to fertilize the land, harvest the crops, separate the seeds and extract the oil. For this reason, the greenhouse gas emissions (GHG) related to the production of a bio-based product can be higher than those of a petrochemical base oil. There are a lot of data available, which make use of different assumptions, and where many interpretations are possible. This can cause contradicting messages and a lack of real clarity when assessing the sustainability of a product.
One way to scientifically approach the sustainability questions is to use cradle-to-gate or cradle-to-grave LCA's that take into account various environmental impacts. Performing a complete LCA is complex and requires information on multiple impacts along the full product cycle to be available. In current assessments, most emphasis is put on Global Warming Potential (GWP): the carbon footprint of products can be estimated by using the 'Climate change singe-score' method (IPCC 2021 100y). In a cradle-togate approach, the sum of the GHG emissions released into the atmosphere to obtain the final product from the raw materials production to the gate of the manufacturer, is called the product carbon footprint (PCF).
ARE ENVIRONMENTAL ASSESSMENTS ENOUGH TO UNDERSTAND THE REAL ENVIRONMENTAL IMPACT OF A PRODUCT?
There are of course some limitations to LCA analysis and carbon footprint calculations as these require assumptions, which are sometimes hidden, and often open for interpretation. For example, some renewable raw materials can have a different impact based on the assumptions made. For palm oil and palm derivatives it is important to understand whether or not the impact of land use and potential deforestation is taken into account. For tallow there are different views on whether it can be considered as a by-product from meat production, and thus as a waste with no impact at all, or rather as a co-product, with a share of the total impact.
At Oleon, we consider land use and possible deforestation risks in the carbon footprint calculations. We transparently report our numbers and communicate openly with our customers and all stakeholders about the progress we make to guarantee a deforestation free supply chain. We also do make a conscious choice not to consider tallow as a waste: in order to estimate the carbon footprint of tallow we use an economic allocation, taking into account the percentage of emissions in the global meat production that correspond to its economic value. This approach is used consistently for all our products derived from tallow-based raw materials.
HOW TO INCLUDE RENEWABILITY OF THE FEEDSTOCKS AND HOW TO USE THE PRINCIPLE OF BIOGENIC CARBON CONTENT?
The impact of the renewable carbon content should not be neglected. During the growth phase, plants will absorb CO2 from the atmosphere and embed it into their bio-mass (leaves, seeds, fruits,...). This embedded carbon, known as biogenic carbon content (BCC), may be stored into a product or released again to the atmosphere, when for instance an oil is burned or completely decomposed. This cycle does not contribute to further increasing the atmospheric CO2 as the biogenic CO2 that is emitted had been extracted from the atmosphere initially.
Many companies and institutions have different ways of including this biogenic carbon content in their LCA's. Some subtract it from the cradleto-gate product carbon footprint calculations, resulting in negative values for certain products.
Currently, there are no explicit rules about how to include renewable carbon in the studies and only some general guidelines exist. Thus, comparison of different base oils calculated by different companies requires some caution.
What is Oleon’s approach on the biogenic carbon content?
At Oleon we believe that bio-based materials, when responsibly sourced, are indeed part of the solution to reduce global GHG emissions and drive the economy towards a net zero economy. Their renewable nature can provide an effective way to make our economy more circular and reduce the use of fossil resources.
While bio-based esters could show very low or negative carbon footprints when biogenic cabron content would be deducted, we do not want to only show these values. We believe that today there are not enough scientific arguments, nor a global and standardized approach, to do so and this could be misleading for our customers. When making assumptions and choices, we believe it is not the intent to choose the most favorable ones, but the most robust ones, based on science and proven facts. When communicating on LCA's and product carbon footprint values, we share our assumptions, as well as the biogenic carbon content, so that our customers can consider how they would like to use them in their further studies.
HOW TO PUT THIS IN PRACTICE?
The above approach is illustrated with an example comparing the product carbon footprint of some typical Group IV/V lubricant base oils. Different assumptions where made where the approach on biogenic carbon content and also the reporting is slightly different.
Ester 1 is based on raw materials derived from palm, a differentiation is made between (a) palm, modelized in the LCA calculations as a product linked to deforestation, (b) certified palm, modelized in the LCA calculations as a product not linked to deforestation.
Ester 2 is based on raw materials derived from tallow, a differentiation is made between (a) tallow considered as a co-product and hence linking a certain part of the emissions to the product, (b) tallow considered as a by-product or waste and hence no emissions are linked to the product.
The values for PAO 4 are taken from literature and are used in this example to illustrate the difference between renewable and non-renewable raw materials.
ESTER 1 - EXAMPLE OF DIFFERENT APPROACHES
As shown in the below graphs (A,B,C), there is a big impact on the partial product carbon footprint when using different assumptions on the raw materials used. The difference between Ester 1a and 1b is that for Ester 1a, a deforestation ‘penalty’ is applied on the total emissions generated by the palm-based raw material.
Apart from the difference in the assumptions for the raw materials, there are also various ways to report and to include the renewability of the feedstock. Graph A, B and C all illustrate a different way of reporting:
R Graph A: A cradle-to-gate LCA was performed according to the Climate change singe-score method (IPCC 2013 100y) and the ISO Standards. The blue and light grey bars that are shown, illustrate the product carbon footprint (= climate impact of the product considering the GHG emissions caused from cradleto-gate, expressed as carbon dioxide equivalent), the green bars represent the biogenic CO2 content that is removed from the atmosphere during the biomass carbon cycle by the renewable raw material. This way of reporting allows to differentiate between both values and to use them however suits best for further calculations.
R Graph B: A cradle-to-gate LCA was performed according to the Climate change singe-score method (IPCC 2013 100y) and the ISO Standards. The blue and light grey bars that are shown illustrate the product carbon footprint (= climate impact of the product considering the GHG emissions caused from cradle-to- gate, expressed as carbon dioxide equivalent), including the biogenic CO2 removals. This way of reporting does not allow to differentiate between the emissions caused by the production and the emissions removed as biogenic carbon content.
R Graph C: In graph C the point of view is that you cannot subtract the biogenic CO2 content in a cradle-to-gate analysis, as this would mean that this biogenic CO2 is not released back into the atmosphere for more than 100y. In practice this is almost never the case. Hence a cradle-to-grave approach is used, according to the same methods and standards as above, however with the following assumptions:
J The use phase is the same for all products shown and is thus neglected in the comparison.
J All products are completely burned at the end of life, hence releasing their fossil carbon content.
This way of reporting shows that whenever a product is burned, the biogenic CO2 emissions linked to the renewable part of the product, that are released during the incineration, should not be counted in the calculation. This because they were already present in the atmosphere and captured by the crop to produce the raw materials. Here you can clearly see that for an ester that contains mainly renewable raw materials the end-of-life impact can be a lot lower than for a petrochemical product where the incineration only adds additional CO2 to the atmosphere.
At Oleon we prefer to report as shown in graph A or C, to provide the most transparent information on the environmental impact of our products.
Product carbon footprint: Cradle-to-gate
Product carbon footprint: Cradle-to-gate
Product carbon footprint: Cradle-to-grave
ESTER 2 – EXAMPLE OF DIFFERENT APPROACHES
For ester 2 the example is completely the same apart from the fact that we now have an ester based on tallow and that there are different assumptions made on the impact of this raw material. The difference between Ester 2a and 2b is that for Ester 2a tallow is considered as a co-product and hence has emissions linked to it and that for Ester 2b, tallow is considered as a waste, resulting in much lower values on the carbon footprint of the ester.
Product carbon footprint: Cradle-to-gate
Product carbon footprint: Cradle-to-gate
carbon footprint: Cradle-to-grave
As mentioned before, at Oleon we make a conscious choice not to consider tallow as a waste. Hence when we report on tallow-based esters this will be in line with the data as shown for Ester 2a and not 2b. Again, similar as in the previous example, in order to report in the most transparent way, our preference is to report as illustrated in graph A or C.
Conclusion
At Oleon, our purpose is to Serve the Earth. "Serving the Earth” means helping to meet two major challenges: the climate emergency and population growth. Taking on these challenges means we have to change our habits and our choices. That is why we continuously push ourselves to develop and improve our product portfolio, by using responsibly sourced renewable raw materials, and making the most sustainable choices to reduce the impact on the planet. Starting from these renewable raw materials, our ambition is to offer, in an innovative way, a full range of safe and sustainable solutions driving the global transition to a net-zero carbon economy. We strive to do this in a responsible and scientific way, to be transparent to our customers and to help them make the best choice.
Over 80% of our current offering consists out of bio-based esters with a renewable carbon content of 75% or higher and a biodegradability of at least 60% or higher. With over 40 esters on the LuSC-list, Oleon is one of the largest players in supplying environmentally friendly base-oils for all types of Lubricants. Our Radialube® portfolio includes base oils for Automotive, Metalworking, Hydraulics, Gear oils, Greases, Stern tube oils and many more.
Lotje Smolders Market Manager Lubricants - Oleon
“WITH OVER 40 ESTERS ON THE LUSC-LIST, OLEON IS ONE OF THE LARGEST PLAYERS IN SUPPLYING ENVIRONMENTALLY FRIENDLY BASE OILS FOR ALL TYPES OF LUBRICANTS