With several technologies available, including the production of bioenergy with carbon capture and storage, experts discuss the role and the future of biomass for the reduction of emissions

The “Bioenergy: Advanced Technologies and Sustainability Issues” workshop brought together Brazilian and foreign experts in the auditorium of the Energy and Environment Institute of the University of São Paulo (IEE-USP) last August 1. They discussed the future of bioenergy in the global context of reducing carbon emissions and of the technological trends for using biomass for generating power. The meeting was organized by Professor Suani Coelho, leader of Project 27 of the FAPESP Shell Research Centre for Gas Innovation (RCGI), and it also marked the prelaunch of the book Technologies for Producing and Using Biogas and Biomethane (Tecnologias de Produção e Uso de Biogás e Biometano, RCGI/USP/Synergia series, 2018), which she and her research team organized.

Professor Júlio Meneghini, RCGI’s Scientific Director, took part in the opening panel of the event, which was opened by Professor Coelho and closed by Professor José Goldemberg, President of the São Paulo Research Foundation (FAPESP). Prof. Coelho gave an overall presentation regarding the use of renewable energy sources, worldwide, including biomass: the “modern” renewable fuels that were responsible for merely 10.4% of the final total energy consumption in 2016. According to her, traditional forms of biomass (wood, coal) were responsible for 7.8%, during that period.

These figures come from the report Renewables 2018 – Global Status Report (https://bit.ly/2KmhGoK).

“There are still traditional forms of biomass, which we no longer want but, unfortunately, we have. It is used mainly in stoves, emits pollutants, and impacts human health. On the other hand, we also have what we call ‘modern’ biomass, which uses current technologies to convert organic material into solid, liquid, and gaseous states that can more efficiently substitute fossil fuels,” she explained

Among the organic materials that can be used to generate power by applying modern technologies are damp organic residues (from waste water treatment plants), animal wastes, and liquid organic run-off; and the organic fraction of solid urban waste. There are also waste materials from agri-business, agriculture, and forestry, as well as plant species that are cultivated for generating energy, including such food crops as corn, wheat, and sugar. And non-food crops, such as grasses and trees, like short-rotation willow and eucalyptus. There are also plants that contain oil and vegetable oils produced from palm heart, canola seeds, and other raw materials.

Emissions reduction – The backdrop of the discussions was the nationally determined contributions (NDC) assumed by Brazil in the Paris Agreement, in 2015, and the need to cut emissions. Brazil committed to cutting its greenhouse gas (GHG) emissions 37%, by 2025, and 43%, by 2030, with 2005 being the base year. “There is a global need to cut emissions, and modern bioenergy can help. Bioenergy is a component of this equation for reducing emissions,” said Luiz Cortez, of the Interdisciplinary Center for Energy Planning (NIPE) of the State University of Campinas (Unicamp). According to him, there will be a radical change in the ways energy is produced and it is necessary to pay attention to the role of bioenergy – and, in the case of Brazil, especially ethanol, with the introduction of electric cars to the market.

In the opinion of Cortez, we must find a new model for ethanol production in Brazil.

“Brazilian production has stagnated. Sugar is the main market for the sugarcane mills, but people will not eat more sugar, just because it is cheap. Brazilian ethanol needs a more flexible coproduct,” he stated, as he presented the case of the Americans. “Ethanol from American corn has a coproduct called Dried Distillery Grain (DDG). It is used as cattle feed. It could play an important role, here, if it is integrated with the sugarcane of flex mills.”

Although there is a variety of technologies and the benefits of bioenergy have significant impacts, there are technological challenges to be overcome, as was shown by Professor Charles Kinoshita, Director of the Western Insular Pacific Sun Grant Subcenter, of the University of Hawaii, in Manoa. “The ratio between the energy input and output of biofuels is not often impressive, and plants have a relatively low efficiency level in converting solar energy into power and usable products. Furthermore, there is a conflict regarding whether or not to use land for producing energy or for producing foodstuffs, and a potential impact on the environment when we plant a monoculture to produce energy,” he stated.

Kinoshita classified biofuels as first, second, third, and fourth generations.

“Those of the first generation are produced from crops on arable land and are criticized for marginally producing environmental benefits, and for competing with the planting of foodstuffs. The second are produced from lignocellulosic biomass, agricultural waste, or plant residues, and are cultivated on land not destined for growing food, neither consuming large quantities of water nor fertilizers. Those of the third generation are made from specially planned energy sources, like algae. Algae do not compete with food production, and do not require farm land or fresh water. Finally, the fourth generation produces sustainable energy, while sequestering CO2, and posts negative carbon emissions, instead of being carbon neutral.”

BECCS, which is the technology of bioenergy with CCS (Carbon Capture and Storage), was the subject of Eric Larson, who coordinates the Energy Systems Analysis Group at the Andlinger Center for Energy and the Environment of Princeton University, in the U.S. “If CO2 is captured and stored underground during the production of biomass and its energy usage, the result will be a removal of CO2 from the atmosphere. BECCS can be an important option for stabilizing or reducing the concentration of CO2 in the atmosphere. According to him, BECCS is the transition point between the biologically negative emissions systems and those that are created by engineering techniques. “It has gotten attention, recently, because, in the first place, it has a relatively lower cost and a high accumulative potential. But we still must understand the storage of carbon underground. Much work has been done and there are projects underway, worldwide. We are learning with them.”

Costs and Opportunities – José Goldemberg sees the need to pay close attention to the perspectives for renewable energy sources. “They are highly desirable, but merely desiring them is not enough. Because if you need technology, you need to think about costs. Within the current worldwide energy system, 85% comes from fossil fuels. And 70% of the world’s electricity is generated from fossil fuels.” He says that the per capita energy consumption is slowly growing, due to the influence of the developing countries, but that the per capita consumption of electricity is growing at a highly rapid rate. Therefore, wind, solar, and hydric are becoming dominant energy sources.

“Today, we are very aware of the dynamics of petroleum. It is much cheaper to produce petroleum, but international prices are not linked to costs. The Organization of the Petroleum Exporting Countries (OPEC) needs a minimum price to support the development of the Emirates, which is about US$ 70 per barrel. But there are other producers, who are also consumers, and attempt to lower the price, resulting in a constant battle. And regarding the renewable sources, the idea that petroleum could rise to US$ 150 – 200 per barrel – and that this would benefit the renewable sources – is not happening.”

As he sees it, the “new renewable sources” represent a very small part of the energy consumed in the world, which is about 4%, but it has attracted heavy investments. “Three hundred billion dollars per year are invested in the so-called ‘renewable sources’. That is more than has been invested in fossil fuels, which is explainable, because the petroleum industry has been investing for over one hundred years. Investments in renewable sources have been taking place for only 20 years, at most. This leads us to the subject of energy efficiency.”

Goldemberg states that it is in the transportation sector that biofuels will have their greatest importance. “The transportation sector has been the one that invested the least in energy efficiency, in recent years. But it is one of the keys to resolving the problem. Bioenergy and CCS are important within that scenario.”

The event was also attended by José Luz Silveira and Carlos Frederico de Oliveira Graef of São Paulo State University (UNESP), and Gilberto Carlotti Jr., USP’s Post-Graduate Dean, as well as Alexandre Breda, the Technical-Scientific Coordinator for Shell in the RCGI.

This Workshop was made possible by the São Paulo School of advanced Science on Renewable Energy, funded by FAPESP, which was responsible for the coming of these speakers of excellence.