New Insights into Biomass and Biofuels in Rapidly Changing Energy Scenario

1. Introduction

The energy sector is going through considerable upheavals due to a combination of factors such as climate change, environmental pressure, the need for urgent decarbonization, and the Russia–Ukraine war. The times when little used to happen are gone. These ongoing changes are unparalleled. The energy sector is generally very volatile, particularly oil and gas; volatility is rife with increasing market dislocation. We are in a serious crossroad. Surging energy prices will curb demand, at least in the short term. Worse, they will increase the use of fossil fuels as there are no immediate viable alternatives.

For many decades, few significant changes took place in the energy sector, with fossil fuels being the king. This is particularly the case in transport. Biomass-based fuels have had many ups-and-downs but have never managed to become mainstream in the modern energy sector, except in some niche markets, e.g., ethanol in Brazil and the USA. Recently, a fundamental paradigm shift has begun, with huge implications.

Although fossil fuels will continue to dominate for a few decades to come, their role will gradually be eroded due to the above-stated reasons, compounded by social and political pressures. New emerging technological alternatives, e.g., biofuels, hydrogen, electric vehicles, and solar energy, are springing up. Environmental sustainability and bioeconomy are becoming key players.

The current climate is, therefore, clouded with huge uncertainties driven by unprecedented radical changes, a scenario in which nobody seems to have any clear idea of what the future may hold. Uncertainty is nothing new, but the present situation is unparalleled in many ways. This is because, although many alternatives are emerging, none appear as a clear winner. Hence, it is almost impossible to forecast what may come in the future with any degree of certainty, except to say the energy sector will be less monopolistic, fragmented, and diverse. An additional huge challenge is how to address increasing energy demand, particularly in less developed countries; economic sustainability; social equality; and even greater, climate change.

However, this unprecedented situation is forcing great minds to focus on finding solutions. The current situation is unsustainable, and even the most recalcitrant defenders of fossil fuels now accept that the business- as- usual scenario (BAUS) is simply unrealistic. As a result, huge investments are pouring into alternative sustainable energy sources.

In this rapidly emerging scenario, what could possibly be the role of biomass-based fuels in the short-term and what possible role can these sources play in future energy scenarios? Solid biomass has been around for centuries and liquid biofuels for transport have been around for decades.

This Special Issue of Energies tried to answer some of these questions by examining key areas, e.g., biomass for electricity and heat, biofuels for transport, and environmentally sustainable feedstocks, and by trying to identify the potential future role of such fuels and current research gaps.

2. Comments on Articles of the Special Issue

This section summarizes the main points of each published article. It tries to identify the major possibilities and obstacles of each one.

“Thermochemical Properties of Lignocellulosic Biomass from Energy Crops” by Soriano et al. [1] is an excellent analysis of various Populus clones for energy crops. The authors analysed all fundamental properties in detail. Short rotation coppice (SRC) already plays an important role in some countries, e.g., Sweden. Many studies have been carried out to analyse their potential for electricity and heat generation. A few decades ago, plantations were considered by some as a partial solution to biomass-based fuels. Currently, this option is viewed as unrealistic, primarily due to the perceived competition with food production and from an economic, social, environmental, and climate change perspective. Thus, this option has serious limitations.

As this study demonstrated, despite its potential, SRC is very site-specific, and what works for one site does not necessarily work for another. The emphasis must be on residual (agroforestry residues) and other woody biomass because large plantations for the purpose of generating energy are unrealistic while residues are far more abundant and more acceptable under an environmental, social, and political viewpoint.

The authors have identified various gaps that need further research. These include more feasibility studies and technical analyses (e.g., combustion, gasification, pyrolysis, etc.) to determine the real potential and conversion of different biomasses to generate electricity and heat. This will require large-scale use of SRC, which severely limits this option.

Although hydrogen and electricity can be obtained from biomass, the gradual phasing out of fossil fuels and the diversification of potential emerging alternatives prompted this Special Issue to identify two other most pressing and promising alternatives as new commercial uses of biomass:

-

Aviation fuels (one paper);

-

Maritime transport (two papers).

The research article “Spatially Explicit Assessment of the Feasibility of Sustainable Aviation Fuels Production in Brazil: Results of Three Case Studies” by Walter et al. [2] investigated the feasibility of the use of sustainable aviation fuels (SAFs). This work presented the results of an assessment of the feasibility of the production of SAF in Brazil, considering three certified routes, based on the dedicated production of eucalyptus, soy, sugarcane, and corn. Why Brazil? Because this country is a world pioneer in this field.

About a decade or so ago, the academic community and a few of the major airlines began to show interest in SAF partly because of the monopolistic structure posed by kerosene, rather than for environmental reasons. It was a wakeup call in a very tricky situation. Currently, all major airlines are scrambling to find SAFs, driven primarily by environmental considerations, but continue to be constrained by costs.

Both IATA (2021) [3] and ICAO (2022) [4] have introduced specific policies to reduce emissions. Within a few years, the vision and attitudes of air travel have shifted significantly in favour of achieving carbon neutrality. For example, IATA’s [3] Annual Report indicates that SAF has the capability to reduce emissions by 80% in certain conditions. Despite high costs, SAF is increasing significantly, e.g., in 2021, production and use were estimated between 100 to 150 million litres (m/L), a 50% increase over the previous year. By 2025 about 5 billion litres (B/L) of SAF could be available, capable of meeting 2% of the global demand, and the 2030 projections will cover at least 5% of the global demand [3].

The authors carried out a critical and detailed assessment of the feasibility of SAF, including conversion technologies/processes, biomass availability, costs, etc.

Technologies that convert biomass into alternative aviation fuels rely heavily on the characteristics of the feedstock, a key cost component of the fuel, representing between 60 and 80%, depending on the specific circumstances. The result of this study demonstrated that the production of SAF in Brazil is cheaper than in other countries due to the availability of local resources. There remain considerable doubts as to the feasibility of energy plantations due to large distances and costs and because this will require large plantation areas, which, as indicated above, is not the best alternative.

From the results presented in this study, it is clear that, besides the crucial production of biomass and intermediates at low costs, it is also necessary to reduce transportation and industrial costs. This point indicates that coordination and planning will be fundamental in creating adequate conditions for SAF production. Logistics still remain a major challenge.

The results presented in this paper are valid for Brazil and may not be possible to replicate in other parts of the world. Consequently, generalisation of the conclusions cannot be made without caution. It is clear that the conditions prevailing in Brazil for the large-scale production of biomass do not exist in many countries. This viability also depends, crucially, on the existing transport and industrial infrastructure.

Unquestionably, the use of biomass to produce SAF has a long road ahead. Aviation requires a very high fuel quality standard. Even in Brazil, where the conditions are much better that most countries, the availability, and cost of biomass remain a considerable obstacle. Therefore, important gaps remain, e.g., ensuring the sustainability of the feedstock, technical processes, logistics, and high costs of biomass; ensuring there is a positive trade- off between carbon footprints and gaining consumers’ confidence; etc.

Maritime transport system (MTS) is a growing sector fundamental to world trade. It is estimated that four-fifths of trade (8 billion tons, out of 9.84 billion) is transported by sea [5]. This is why this Special Issue includes two publications on this topic. The first focuses on the wider international dimensions of using biomass energy, and the second examines the potential in Brazil.

The MTS is undertaking a major global effort to reduce emissions of greenhouse gases (GHG), e.g., sulphur oxides, nitrogen oxides, and the concentration of particulates in suspension. Substantial investment is necessary to develop alternative sustainable fuels, engines, and fuel modifications. Unlike other transport sectors, MTS is lagging far behind when it comes to pollution control. A considerable difference between aviation and maritime transport is that fuel quality requirements of the MTS is far lower.

The research paper entitled “Biofuels for Maritime Transportation: A Spatial, Techno-Economic, and Logistic Analysis in Brazil, Europe, South Africa, and the USA” by Carvalho et al. [6] assessed potential localities for maritime biofuel (biobunkers) production in Brazil, Europe, South Africa, and the United States, considering geographical, logistic, and economic aspects. It presents a broad view of major world potential regions.

That study sought to identify potential areas for biobunker fuel production from agriculture and forestry, considering geographical, logistic, and economic aspects, on the above areas. The combination of a georeferenced analysis, logistic integration, seasonality, and a techno-economic analysis represents an innovative methodology for assessing regional capabilities that could make some regions potential biobunker fuel suppliers, according to the authors.

There are of course many aspects that need further investigation, since as the study indicates, there are some limitations that should be addressed in future work, including the following:

-

Feedstock availability assessment of the study has not considered biomass use in other hard-to-decarbonize sectors, such as aviation and industry.

-

The economic analysis was partial. This tends to underestimate capital costs, construction, and commissioning times and overestimate fuel production yields compared with pioneer plants.

-

The fuel transport mode choice was based on the proximity to infrastructure and not to main transport stations, which could increase fuel transportation costs, which constitute an important part of the overall costs.

-

Integrated assessments to capture CO₂ are required in much greater detail.

-

The overall impacts in energy and land use by replacing conventional maritime fuels with biofuels require further investigation.

This paper has shed considerable light onto this problem, but its complexity means that considerably more work is still needed.

Finally, the research paper “Perspective Use of Fast Pyrolysis Bio-Oil (FPBO) in Maritime Transport: The Case of Brazil” by Cortez et al. [7] focuses on Brazil. Brazil has basically three markets for MTS: long-distance international maritime, coastal maritime, and fluvial transportation. It is a major growing market.

The alternative fuels considered include liquified natural gas, nuclear energy, hydrogen, electricity, and biofuels. However, the main focus of this paper is biomass-based fuels. Particular emphasis is given to fast pyrolysis bio-oil (FPBO), a serious partial alternative contender for MTS.

The key issues investigated include FPBO, the production and end use of feedstocks, the most promising alternatives, thermal conversion technologies, potential applications of FPBO in Brazil, sustainability, biofuel properties, fuels under consideration in MTS, and challenges and opportunities in a rapidly changing maritime fuel sector. Although the focus is on Brazil, the findings of this paper can be replicated in many other parts of the world.

The use of biofuels in light and heavy vehicles required some engine modifications. The MTS has important similarities, but unlike aviation and road transport, the requirements surrounding the quality of the fuel are much lower. It is also important to keep in mind that we are dealing with big engines in which the associated logistics play a much greater role. Replacing current heavy fuels with biofuels, be it partially, will require important R&D efforts, particularly in fuel quality, diesel engine adaptation/modifications, etc.

Given the stage of R&D of biofuels in Brazil, its potential, and its accumulated historical experience, the country should play a leading role in this paradigm shift. There is, nonetheless, a considerable road ahead, ranging from feedstock availability and sustainability, engine modifications, land use, and environmental issues.

The future use of biofuel in the marine sector will depend on a combination of political, feedstock availability, environmental, technological, and socio-economic considerations, and choices.

3. Main Conclusions

What we can learn from these papers is that there are many untapped opportunities for biomass-based fuels, given the right conditions. It also indicates that there is a bumpy road ahead. However, given the exponential advances in science and technology, such potential is not a chimera but a real opportunity.

Despite the many obstacles, there is room for optimism. Human ingenuity has almost no limits. We are currently facing huge problems, but never in history have so many researchers and resources been dedicated to finding a solution. In fact, we are witnessing a golden era of scientific research. True, the benefits are unequally distributed, and this scientific and technological explosion is not without its drawbacks, e.g., a huge amount of data is being generated and can be unreliable and biased. The huge amount of information is not necessarily useful; in fact, it can be conflicting as it can easily be manipulated.

The scientific community is forced to be very specific and to focus on specialised research, in the detriment of the wider implications. The man on the street is unable to understand this rapid change and is confused by this flood of often contradictory data. In other words, science and technology is advancing far more quickly that our human capacity to grasp the implications.

New technologies and innovations are advancing exponentially. A clear example has been the search for the COVID-19 vaccines, which in normal times would have taken years to develop but, in reality, took only months. Another example is UN COP26 in Glasgow. Despite huge difficulties, it was possible to reach some fundamental agreements.

These examples demonstrate that, when Homo Sapiens confront a serious problem, they can find solutions. However, we cannot ignore human stupidity, and its enormous capacity for self-destruction. The energy sector could also experience the same self-destruction. After all, the most complex thing we know in our universe is the “human brain”. A simple, immediate, and cheap solution for all of us (those who consume a lot and waste even more) without negatively affecting our living standards, is to use less energy. We all can make choices, and many small choices amount to a big one. As Gandhi, said: “There is enough for everybody’s need but not everyone’s greed.” The new reality requires bold decision-making and political brinkmanship!