Are Biofuels the Way Forward?

Are Biofuels the Way Forward?

Disclaimer: I am not an expert in the field of biofuels research, nor do I claim to be. The motivation for this article is to provide a basic overview of biofuels, and to encourage readers to ask questions and conduct their own research. Both of which I will be doing myself. Please read this article with a recognition that I am not an expert, and please give me feedback if you believe I have portrayed an incorrect image of the topic in question.

When we think of fuels, we typically think of those that have spent millions of years maturing deep under the earths surface, created by the intense heat and pressure that is exerted on the fossilised remains of living organisms that used to inhabit our earth. But arising from the whitepapers of academics across the world, has been a different fuel source with the potential to induce a paradigm shift in what we refer to as fuel. This fuel source is biofuels. The idea that biofuels could revolutionise the way we live our lives has been coming to fruition over the last few decades, but there are many things which need to be considered, too many for me to cover exhaustively in this article.

What are biofuels?

Biofuels are a source of renewable fuel derived from natural matter such as wood, algae, biomass, and food crops. They are typically segmented into 3 categories, 1st, 2nd and 3rd generation. These different generational categories help to characterise different biofuels in terms of their cost, energy output and environmental friendliness. So what defines each of these 3 generations? That's a good question, to which I have given a brief explanation below.

1st Generation

These are produced from edible crops and food-based feedstocks such as corn, sugarcane and wheat. They are typically produced via simple processes such as fermentation or direct extraction, and are often the cheapest and most readily available generation of biofuels to produce. However, due to the use of edible food crops in their production, 1st gen biofuels come with the risk that they may compete for arable land and resources with the food production industry, which may contribute to food price increases and additional deforestation.

2nd Generation

Generally more complex to produce than 1st gen biofuels, they are produced from non-food feedstocks, through the conversion of lignocellulosic biomass into simpler sugars, which can then be fermented into biofuels. Non-food feedstocks include agricultural residues and dedicated energy crops such as switchgrass. Given that 2nd gen biofuels use non-food feedstocks, they compete indirectly with the food production industry, whereas 1st gen competes with food production in a more direct manner. Therefore, 2nd gens may be seen as a more eco-friendly and socially acceptable biofuel than 1st gens. This comes at a cost though as 2nd gens have a higher water consumption requirement during production, driving up costs, and therefore slowing down their potential commercial uptake.

3rd Generation

3rd gens are primarily derived from algae, bacteria, and other microorganisms. These are grown in controlled environments to produce oily substances called lipids, which are then converted into biofuels. They are generally the most sustainable generation, as they can make use of non-arable land and wastewater facilities. 3rd gens come with a potential for effective carbon sequestration ,due to the excessive requirement of CO2 in the growth stages of algae. However, they are expensive and technically challenging to commercialise given the large water and nutrient requirements.

Generally, a good way to look at this is that higher generations of biofuels are: more expensive, more complex to produce and less readily available, but more efficient and more environmentally friendly. This is not definitive, but generally these trends are true.

Biofuels are most widely utilised in the transportation sector, where they can be used as a pure replacement for fossil fuels, but predominantly, they are blended with fossil fuels like gasoline and diesel for use in all vehicles powered by combustion. However, biofuels can be put to use in almost any sector as a source of energy, as they release energy upon combustion just the same as traditional fossil fuels. Because of this, it is often said that biofuels will be easier to uptake on a commercial scale as the infrastructure to support them like pipelines and combustions engines are already in place globally, unlike other things such as the electrification of transport which requires huge new investment to provide sufficient amounts of charging stations.

2019 writing from National Geographic says that in the US, most fuel consists of 90% petroleum based gasoline, and 10% ethanol, one of the most common biofuels. This is sold under the name of "E10". In Brazil, this fuel mix can contain up to 27% ethanol, with sugarcane being used as the main feedstock. When used as part of a fuel mixture, the biofuel used is correspondent to its petroleum based counterpart, (ethanol is combined with petroleum based gasoline, and biodiesel is combined with petroleum based diesel). In 2020, liquid biofuels accounted to 4% of global transport energy demand, and is expected to grow to around 14% by 2050, meaning yes, biofuels are currently in use, but not on a scale large enough to meet the climate goals set out by many nations, and even if this 14% expectation comes to fruition, is this enough? I don't believe so.

How sustainable are they compared to currently used fuels?

The underlying premise of why biofuels are considered sustainable by many, is that the CO2 released into the atmosphere during their combustion, is roughly balanced by the CO2 absorbed during the growth of the feedstock that is used to create the fuel itself. So rather than digging up new fossil fuels, combusting them and emitting additional CO2 into the atmosphere, we can use biofuels as a sort of "middle man" for creating a circular, carbon net-zero, fuel system, which may in some cases become carbon-negative, as a biofuel may absorb more carbon during its production than it emits during combustion. In essence, biofuels may not reduce real CO2 emissions, but rather net CO2 emissions, meaning they are a much cleaner option than the fossil fuels currently in use. Some figures (such as those presented by Dr. Jason Hallet of Imperial College London) say that 2nd gen biofuels can offer an 80% reduction in carbon intensity compared to petroleum.

Theoretically.

There are without a doubt many factors involved in the production of biofuels that can hinder their sustainability credentials. The growth of feedstocks, whether these are food or non-food based, requires large amounts of water to cultivate, which can apply added pressure to the already high levels of water scarcity being experienced in many regions of the world. Unsurprisingly, feedstock choices must be considered, as each feedstock comes with its own underlying sustainability credentials. Algae and non-food biomasses are generally much more environmentally friendly than food-based feedstocks, due to reduced water consumption, soil erosion and pesticide use.

Algae has some additional advantages. The first being a higher biomass growth rate, meaning that, compared to food-based feedstocks, they can convert energy from sunlight and other resources into organic matter at a higher rate, likely resulting in a more efficient supply of lipids for biofuel production. However, just because algae can theoretically provide a more efficient supply of feedstock, it doesn't mean it can provide this improved efficiency on a commercial scale. The commercialisation of algal feedstocks comes with many technical challenges such as infrastructure upgrades from lab and pilot-scale facilities to industrial-scale facilities, compatibility with current energy infrastructure and lipids extraction to name just a few. The uptake of algal feedstocks on a commercial scale is subject to the amount of resources that are devoted to research in the field over the coming decades.

The other advantage that algal feedstocks have over food-based, and even non-food based, feedstocks is that they have an incredibly high potential for carbon sequestration. Part of this high potential is in fact derived from the rapid growth rates they experience, which of course requires a rapid intake of CO2 for photosynthesis, meaning algae have to be highly effective photosynthesisers, and are therefore highly effective carbon sinks. Algae often has a higher carbon content per unit of biomass compared to other plants, meaning the same amount of CO2 can be sequestered by a smaller volume of algae, reducing land-use requirements.

Ethanol based biofuels also offer additional advantages over petroleum based fuels, as they contain oxygen in their molecular structure, which promotes a higher proportion of complete combustion reactions. More complete and controlled combustion is promoted by the higher octane rating of ethanol compared to petrol, which can also reduce engine knocking (uncontrolled and premature ignition of the air-fuel mixture in an engine's cylinders).

Complete combustion is more environmentally friendly than the often incomplete combustion that occurs from petrol, as it emits a lower proportion of Carbon Monoxide (CO), (although higher CO2 proportion). Less CO content emitted means less particulate matter and therefore reduced health risks as a result. So if we look at the intrinsic characteristics of ethanol biofuels compared to petrol, and the significant CO emissions reduction that it offers, we may say that biofuels are indeed the way forward. However, CO2 is still being released, right? which means that an amount of CO2 must still be offset during the production process of the biofuel itself. However, with the cleaner burning of ethanol compared to petrol, this offsetting doesn't necessarily need to happen in such an intense manner to reach net-zero emissions for the overall production/consumption system of the biofuel. This means that ethanol provides a theoretically easier path to net-negative carbon emissions for overall system, and with continued R&D into the field, barriers such as energy balance inefficiencies* and lower energy density issues, can progressively be eliminated, resulting in a higher yielding source of energy overall.

* Energy Balance Inefficiencies: 1st gen bio-ethanol production processes often have low net energy gain due to the intense energy input required for the cultivation, processing and transportation of resources and feedstocks. This intense energy input then negatively offsets the eventual energy saving capability of the end fuel. Because of this, inefficiencies must be reduced throughout the whole system, not just within the engine that burns the fuel.

Although numerous factors exert influence on the sustainability of biofuels, it can be posited that on a commercial scale, with notable inefficiency reductions, biofuels represent a more sustainable and environmentally conscientious way to provide energy via combustion. It is imperative to note though, that this statement is subjective to whether the biofuels used belong to the 1st, 2nd or 3rd generation, the compatibility of engines with this new fuel architype, and the specific cultivation and production modalities that are used throughout the continuum.

The Path Forward!

Given the intense competition between many different facets of this argument, it is hard to come to a definitive conclusion as to whether biofuels should be the fuel of the future, or not, and with significant research under way, it is currently unclear to see whether they will be the next big thing, or a total flop. But based on my awareness of the field, here is the conclusion I have come to.

Due to the infrastructure similarities between the oil and gas sector, and the biofuels sector, (ie, pipelines and combustion engines), it seems possible to me that liquid and gaseous biofuels could come into play on the global stage within a shorter timeframe than many people might expect. Because rather than having to build new processing plants and pipelines to support a biofuel economy, I suspect that the possibility of being able to retrofit current infrastructure, to harmonise it with liquid biofuels, will mean biofuels can be commercially undertaken with less resistance. But, when thinking about this, a questioning juxtaposition arises in my mind, and that has to do with the "big oil" companies of today. On the one hand, "big oil" is in control of an immensely sophisticated level of oil and gas infrastructure which, in my eyes, with suitable retrofit, could play a staple role in a potential biofuel economy, this is positive. On the other hand however, big oil is often vehemently opposed to the notion of a new revolutionary energy source, over fear of losing market share and profit, which is bad and could hinder a transition. So, in light of this juxtaposition, I propose an idea which states that: one of the most influential factors in the future success of biofuels, is whether we can get "big oil" onboard with this technology in good time or not. By, "getting them on board", I mean devoting more than just 1-2% of their profits to the cause. I am not all pessimistic about this though, as I do believe this can be possible if current research projects can provide a proof of concept for this technology, which the oil and gas industry, theoretically, can use as evidence that biofuels are in fact a profitable energy source to devote time, money and resources towards. To me it seems that creating a harmonisation, rather than a conflict, of interest between the oil and gas industry, and the environmentalists, through the means of attractive profit, is a great starting point on the road to commercialisation for any new energy source. This is because commercialisation requires economies of scale, which more often than not requires huge upfront investment, and what we can guarantee is that that money needs to come from somewhere doesn't it?

My belief also lies in the fact that with increased experimental research into new feedstock and processing methods, such as genetic engineering, and trans and inter esterification, a more efficient 3rd generation biofuel source may not be so far around the corner, and this is promising, although only time will tell.

So to answer the question, "Are Biofuels the Way Forward?", I would say no, they are not THE way forward, but rather they are, A way forward, as they are not perfect as it stands, and other energy sources such as electric power and hydrogen propulsion are also notable to look out for in the coming future.

Because it's not possible to cover all bases in this argument in as much depth as they deserve, in an article as short as this, I suppose the least I can do is offer up some questions for anyone reading to have a think about. These are questions that I asked myself whilst writing and researching, and would love to have answered for me:

Can biofuels become a perfect energy source, or are they more suitable as a stepping-stone towards a perfect solution?

Is it possible to juggle earth's land area in a manner which provides both enough food and enough biofuel for our demanding economy?

To what extent is current oil and gas infrastructure compatible with liquid and gaseous biofuels?

Can the cost of biofuels be bought down enough to become economically viable?