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AbstractSustainable alternatives to fossil fuels are urgently needed to avoid severe climate impacts and further environmental degradation. Microalgae are one of the most productive crops globally and do not need to compete for arable land or freshwater resources. Hence, they may become a promising, more sustainable cultivation alternative for the large‐scale production of biofuels provided that substantial reductions are achieved in their production costs. In this study, we identify the most suitable areas globally for siting microalgal farms for biodiesel production that maximize profitability and minimize direct competition with food production and direct impacts on biodiversity, based on a spatially explicit multiple‐criteria decision analysis. We further explore the relationships between microalgal production, agricultural value, and biodiversity, and propose several solutions for siting microalgal production farms, based on current and future targets in energy production using integer linear programming. If using seawater for microalgal cultivation, biodiesel production could reach 5.85 × 1011 L/year based on top suitable lands (i.e., between 13% and 16% of total transport energy demands in 2030) without directly competing with food production and areas of high biodiversity value. These areas are particularly abundant in the dry coasts of North and East Africa, the Middle East, and western South America. This is the first global analysis that incorporates economic and environmental feasibility for microalgal production sites. Our results can guide the selection of best locations for biofuel production using microalgae while minimizing conflicts with food production and biodiversity conservation.

AbstractSustainable alternatives to fossil fuels are urgently needed to avoid severe climate impacts and further environmental degradation. Microalgae are one of the most productive crops globally and do not need to compete for arable land or freshwater resources. Hence, they may become a promising, more sustainable cultivation alternative for the large‐scale production of biofuels provided that substantial reductions are achieved in their production costs. In this study, we identify the most suitable areas globally for siting microalgal farms for biodiesel production that maximize profitability and minimize direct competition with food production and direct impacts on biodiversity, based on a spatially explicit multiple‐criteria decision analysis. We further explore the relationships between microalgal production, agricultural value, and biodiversity, and propose several solutions for siting microalgal production farms, based on current and future targets in energy production using integer linear programming. If using seawater for microalgal cultivation, biodiesel production could reach 5.85 × 1011 L/year based on top suitable lands (i.e., between 13% and 16% of total transport energy demands in 2030) without directly competing with food production and areas of high biodiversity value. These areas are particularly abundant in the dry coasts of North and East Africa, the Middle East, and western South America. This is the first global analysis that incorporates economic and environmental feasibility for microalgal production sites. Our results can guide the selection of best locations for biofuel production using microalgae while minimizing conflicts with food production and biodiversity conservation.

Microalgae are a promising alternative for future biofuel production. Compared to first- and second-generation biofuels, microalgal production systems offer higher biofuel productivities per unit area and do not necessarily depend on fertile soils or freshwater. However, little is known about how microalgal biofuel production on a scale large enough to meet a nation’s domestic transport energy targets might conflict with agricultural lands and biodiversity in the context of energy independence. Here, we use estimates of lipid productivity, resource availability, and accessibility to identify the most cost-effective areas for fulfilling 30% of each country’s transport energy demands in 2016 and 2050 while avoiding areas of high agricultural and biodiversity value. To fulfill this target, microalgal cultivation would need less than 1.1% of global land area, mainly in drier low-latitude areas or drier lowlands within each country. The most promising countries for microalgal biofuel production are mainly located in North and East Africa, the Middle East, western South America, the Caribbean, and Oceania. In countries with either high energy demands or without available human-transformed dry lands, decreasing targets in microalgal biofuel production or shifting production to countries where impacts are lower, could further reduce potential conflicts with food production and biodiversity.

Microalgae are a promising alternative for future biofuel production. Compared to first- and second-generation biofuels, microalgal production systems offer higher biofuel productivities per unit area and do not necessarily depend on fertile soils or freshwater. However, little is known about how microalgal biofuel production on a scale large enough to meet a nation’s domestic transport energy targets might conflict with agricultural lands and biodiversity in the context of energy independence. Here, we use estimates of lipid productivity, resource availability, and accessibility to identify the most cost-effective areas for fulfilling 30% of each country’s transport energy demands in 2016 and 2050 while avoiding areas of high agricultural and biodiversity value. To fulfill this target, microalgal cultivation would need less than 1.1% of global land area, mainly in drier low-latitude areas or drier lowlands within each country. The most promising countries for microalgal biofuel production are mainly located in North and East Africa, the Middle East, western South America, the Caribbean, and Oceania. In countries with either high energy demands or without available human-transformed dry lands, decreasing targets in microalgal biofuel production or shifting production to countries where impacts are lower, could further reduce potential conflicts with food production and biodiversity.