Energy Review, Vol 5. Issue 05. 2023
The world is currently facing a critical challenge: the urgent need to transition to a new energy matrix that is free from fossil fuels. With the ever-increasing demand for energy and the undeniable reality of climate change, finding sustainable and renewable energy sources has become imperative.
In recent years, we have witnessed significant growth in wind and solar photovoltaic sources. These renewable energy technologies have made remarkable progress and are becoming more cost-effective. However, they also bring to light a major concern, which is the intermittency of supply. Unlike traditional fossil fuels, wind and solar power are dependent on weather conditions, making their output inconsistent and unreliable for meeting the demands of industrial production and other energy-intensive sectors.
To address this challenge, it is crucial to explore energy sources that are not only renewable but also dispatchable, meaning they can be controlled and supplied on demand. This is where bioenergy derived from biomass enters. Biomass refers to organic matter from plants and animals that can be used as a source of energy.
Brazil, with its favorable soil and climate conditions, has abundant biomass resources that can be utilized for energy purposes while ensuring the preservation of native forests and environmental protection. The country has traditionally utilised biomass sources such as wood, sugarcane bagasse, and rice husks through combustion. Additionally, Brazil has successfully harnessed biofuels like ethanol from sugarcane and biodiesel from soybeans, contributing to its renewable energy supply.
Currently, renewable sources account for approximately 30 percent of Brazil's domestic energy supply. However, there is still tremendous potential to further expand the use of biomass for energy production. Some biomasses, including sisal and macauba, have attracted interest from international energy companies due to their promising characteristics and availability in Brazil.
Sisal, a fiber obtained from the Agave plant, is a prime example. Brazil is the largest global producer of sisal fiber, generating around 236,000 tons annually. However, the fiber production process utilises only a small fraction of the plant, leaving the majority as biomass with untapped energy potential. Sisal biomass can be used as a raw material to produce bioenergy, particularly methane and ethanol 1G and 2G. By leveraging sisal's potential, Brazil could utilise 230,000 tons of biomass annually for environmentally, economically, and socially beneficial bioenergy production.
Another valuable biomass resource is macauba, a palm tree species well-suited to the arid soil and intense sun found in Brazil's northeast region. Macauba offers multiple oil sources, including oil extracted from its pulp and almond, which can be utilised to produce biodiesel, renewable diesel, and sustainable aviation fuel. Studies indicate that macauba has the potential to produce up to eight tons of pulp oil per hectare, along with 1.2 tons of almond oil. Furthermore, macauba biomass residues, such as endocarp, pulp, and almond residue, can be used for various purposes, such as charcoal production and animal feed.
By cultivating sisal and macauba on a larger scale, Brazil could potentially revolutionise its energy matrix. For example, sisal's bioenergy production could replace the need for sugarcane-based alcohol production, occupying significantly less fertile land and requiring less water. Moreover, Brazil has vast areas, approximately 108 million hectares, suitable for agave cultivation. Similarly, by dedicating degraded land to macauba plantations, Brazil could potentially produce up to 1 billion liters of oil annually, contributing to the replacement of fossil fuels and reducing greenhouse gas emissions.
However, realising the full potential of sisal and macauba as bioenergy sources requires overcoming technological limitations and modernising existing production chains. In the case of sisal, the cultivation and fiber production processes still heavily rely on manual labor, posing challenges to attracting young people to the industry. A modernisation effort, similar to what was achieved in Brazil in the 1970s with the introduction of ethanol fuel, is needed to streamline sisal production. For macauba, the current lack of technologies and predominantly extractive practices hinders its full exploitation. Establishing sustainable cultivation systems, offering cultivars, and providing recommendations for fertilisation, planting, irrigation, and crop management are key challenges to overcome.
In conclusion, harnessing the bioenergy potential of Agave sisalana and macauba palm trees holds the key to transforming Brazil's energy matrix and replacing fossil fuels with renewable alternatives. By producing ethanol, biogas, and biodiesel from these biomass sources, Brazil can significantly reduce greenhouse gas emissions while realising economic, environmental, and social benefits. Utilising the abundant biomass resources available in Brazil, particularly sisal and macauba, represents a sustainable path towards a greener and more sustainable energy future.
(Dr.Luciano Hocevaris is a Professor at the Energy Engineering department, UFRB / CETENS - Center for Science and Technology in Energy and Sustainability, in Bahia, Brazil. Dr. Carine Tondo Alves is a participating Professor at the Graduate Program in Industrial Engineering (PEI) at the Federal University of Bahia, and at the Graduate Program in Energy and Environment (CIENAM) at UFBA, Brazil.) ■□■