Pathway to a land-neutral expansion of Brazilian renewable fuel production

Abstract

Biofuels are currently the only available bulk renewable fuel. They have, however, limited expansion potential due to high land requirements and associated risks for biodiversity, food security, and land conflicts. We therefore propose to increase output from ethanol refineries in a land-neutral methanol pathway: surplus CO2-streams from fermentation are combined with H2 from renewably powered electrolysis to synthesize methanol. We illustrate this pathway with the Brazilian sugarcane ethanol industry using a spatio-temporal model. The fuel output of existing ethanol generation facilities can be increased by 43%–49% or ~100 TWh without using additional land. This amount is sufficient to cover projected growth in Brazilian biofuel demand in 2030. We identify a trade-off between renewable energy generation technologies: wind power requires the least amount of land whereas a mix of wind and solar costs the least. In the cheapest scenario, green methanol is competitive to fossil methanol at an average carbon price of 95€ tCO2−1.

Land-Use Requirements of Solar and Wind Power

“…In contrast to the aforementioned regions, South America, Australia & Oceania, and Africa are significantly less represented. LURs for South America were found in ten publications 12,14,31,39,[93][94][95][96][97][98] , eight of them provided data for solar PV LURs covering three countries with data on Brazil prevailing 12,14,[93][94][95][96][97][98] . Wind power LURs were provided in four publications for four countries 12,39,97,98 .…”

“…LURs for South America were found in ten publications 12,14,31,39,[93][94][95][96][97][98] , eight of them provided data for solar PV LURs covering three countries with data on Brazil prevailing 12,14,[93][94][95][96][97][98] . Wind power LURs were provided in four publications for four countries 12,39,97,98 . LURs for the CSP technology are only available for Chile 31 .…”

“…In the following discussion, we will explore key terms based on our systematic literature review and discuss crucial parameters that must be understood to interpret the associated LUR estimates correctly. We encountered 22 different terms for LURs across 55 publications 11,12,16,23,25,26,[28][29][30][32][33][34][35][36][38][39][40][41][41][42][43][44]46,49,50,[59][60][61][63][64][65][65][66][67][68]71,72,74,79,82,84,85,89,91,92,[96][97][98][102][103]…”

“…In the category others, we compiled terms reported only once -this was the case for 18% of publications. These terms include energy yields 108 , footprints 98 , and surface performance ratio 67 , among others (see table S3 in SI).…”

Land conservation and the renewable energy transition are simultaneously possible in Brazil

“…However, these long-term goals fail to provide guidance for spatial planning. By pushing new crops and pastures onto native lands [8], they risk worsening issues related to food security, land conflict, biodiversity [2,9] and deforestation, particularly in the Cerrado savanna and Amazon rainforest. Likewise, onshore wind farms have been leading to conflicts with local communities [10], while several parks have been deployed in priority areas for biodiversity conservation [11].…”