Biomethane has the smallest carbon footprint among various available energy sources

In a workshop organized by the RCGI and the ICDK, Brazilian and Danish experts discuss technologies for obtaining fuel in Brazil, whose production potential is 80 million m³ per day

Brazil’s potential production of biomethane is 80 million m³ per day, according to the Brazilian Association of Biogas and Biomethane (Abiogás). If it is feasible, the use of this gas would be the equivalent of 24% of the country’s total demand for electrical power and 44% of the total demand for diesel oil. These figures were presented during the workshop “Dialogues between Brazil and Denmark regarding the benefits of producing biogas/biomethane, and their applications”, coordinated by Professor Suani Teixeira Coelho, of the Energy and Environment Institute (IEE) and researcher for the FAPESP Shell Research Centre for Gas Innovation (RCGI). Organized by the RCGI in a partnership with the Innovation Centre Denmark (ICDK) and with the Innovation Network For Biomass (INBIOM), the event brought together experts from the two countries in the IEE auditorium, on the 24th.

“We believe that biogas from biomass has enormous potential. It is an area that is still developing. In Denmark, we have 40 years of experience in producing biogas from biomass. We hope to be able to share experiences and collaborate in stepping up the debate on the subject in Brazil,” stated Stina Nordsborg, Director of the Innovation Centre Denmark, which is linked to Denmark’s Ministry of Foreign Affairs.

In that country, biogas is used mainly for generating electricity and for heating. “Denmark will probably be the first country in the world to definitively ban the use of fossil fuels. And biomass is the major driver of renewable energy in the next ten years,” said Jens Bo Holm-Nielsen, the University of Aalborg.

According to him, most of the biogas used in his country (65%) comes from agriculture, with sugar beets being the main origin of the energy source. Another 53% come from effluents from sewage treatment plants, 28% from sanitary landfills, and 6% from industry. “Brazil’s potential for generating biogas from biomass is enormous, because you are huge agricultural producers.” Just to get an idea of that potential, Brazil annually produces 150 million tons of sugarcane straw, which could be used to produce biogas. That does not count the food production sector.

Sources of biomass – In Brazil, the biggest potential for producing biogas is in the sugarcane industry (56 million m³/day). That is followed by the food processing industry (17 million m³/day) and, finally, the sanitation sector (7 million m³/day). “São Paulo has the largest potential for producing biogas and biomethane from the sugarcane industry, especially from vinasse, waste left from the production of ethanol. Based on the 2015/2016 harvest, it would be possible to produce biogas at the rate of 302,848 m3/h and biomethane at 151.424 m3/h, with the potential of generating 4,133 GWh/year,” calculated Suani Coelho, who coordinates a project at the RCGI for the purpose of mapping the potential production of biogas and biomethane in the State of São Paulo.

As the Undersecretary for Renewable Energies of São Paulo, Antonio Celso de Abreu Júnior, sees it, biogas and biomethane can help maintain the renewable profile of the State’s energy matrix. “In São Paulo, 58% of the energy matrix is renewable. Today, we have an estimated volume of biogas production that could supply 20% of our demand for electrical power. Therefore, the State is highly interested in having biogas in its energy matrix.”

Suani Coelho emphasized that this is a propitious moment for discussing biomethane; in fact, policies are being established for injecting this energy source in the lines of the natural gas system. Furthermore, there is now greater dialogue between academe, the productive sector, and the government. “We have been involved with bioenergy for 20 years. And at first, we were fearful of dealing with the companies, and they with us. Now things are changing: we talk with the companies and with the governments. There is a whole network of players that are thinking with us, there is collaboration.”

Regulations – The result of these joint efforts is more vigorous, in terms of the norms generated for the sector. In June, the National Petroleum, Natural Gas, and Biofuels Agency (ANP) finally set long-awaited regulations for controlling the quality and specifications of biomethane originating from sanitary landfills and sewage treatment plants for vehicular, residential, industrial, and commercial use.

In São Paulo, at the end of July, The State Sanitation and Energy Regulatory Agency (ARSESP) decided to regulate the conditions for distributing biomethane in the natural gas system of the State of São Paulo (Decision no. 744/2017). This measure establishes the rules for inserting biomethane supplied by producers in the public natural gas pipeline system. In the coming weeks, the State of São Paulo will define and publish the percentage of biogas that should be injected in its network. “We are preparing a bill that makes it mandatory to have a percentage of biogas in the State system. This will probably be done by phases, beginning in 2020 with X% and increasing every four years,” Abreu Júnior explained.

Carbon footprint – The Scientific Director of RCGI, Julio Meneghini, stressed the possibilities for cooperation between Brazilian and Danish researchers for a prime objective. “I believe it is possible to share research objectives and that the collaboration between the two countries can help us do our best to reduce carbon emissions.”

Alessandro Gardemann, President of Abiogás and Director of Geoenergética, reminded that the carbon footprint of biomethane is one of the smallest among the know energy sources. “I am certain that we have one of the lowest carbon footprints among the available fuels. When analyzing the carbon footprint of the life cycle of several energy sources, we conclude that, while diesel emits more than 100 gCO2eq/MJ and vehicular natural gas more than 80 gCO2eq/MJ, biomethane presents a negative emission factor: something around-20 gCO2eq/MJ.” The comparison includes diesel, vehicular natural gas, electricity generated by natural gas, biodiesel, and electricity generated by the sun and by the wind.

He emphasized the importance of biomethane in reducing greenhouse gas (GHG) emissions. “The substitution of biomethane for 47% of the diesel burned in 2015 would have reduced the emissions from the burning of diesel, during that year, by 74%. That corresponds to 17% of Brazil’s emissions reduction goals.”

Integrated biorefineries – Jin Mi Trioli, of the University of Southern Denmark, pointed out that biogas can be produced from the bagasse of any type of crop. “We have identified 92 types of biomass from plants that have the potential for generating methane. But that potential diminishes during storage: after ten months, the potential for generating methane is reduced by 19%.”

She also presented the concept of integrated biorefineries. “We are proposing integrated mills, with zero emissions, which could be very useful for Brazil, where the production of ethanol has the emissions footprint of methane and the use of vinasse as a fertilizer emits NO2.” The idea of integrated mills has to do with the sequential production of biofuels and biofertilizers, thus reducing GHG emissions. “An integrated biorefinery would avoid the emissions from ethanol production,” Trioli stated.

The event, which ended with the presentation of a number of case studies, also had lectures by Rikke Lybeak, of the University of Roskilde; Pietro Sampaio Mendes, of the National Petroleum, Natural Gas, and Biofuels Agency (ANP); Claudio Oller, one of the Directors of the Physicochemical program of RCGI; Gilberto Martins, of the Federal University of the ABC District (UFABC); Bruno Carmo, Vice Scientific Director of RCGI; Alastair James Ward, of the University of Aarhus; Samuel Melegari, of UNIOESTE; Pedro Paixão, Manager of Applications of Cabot Brasil; Michael Støckler, of the Agro Business Park; Aurélio de Souza, of Usinazul; and Felipe Souza Marques, of CiBiogas.