撒哈拉以南非洲的生物燃料潜力（英文版）_82页-5mb

Biofuel Potential in Sub-Saharan Africa: Raising Food Yields, Reducing Food Waste and Utilising Residues

Core Content

This report by IRENA (2017) explores the potential for bioenergy in Sub-Saharan Africa through three main approaches: sustainable collection of agricultural residues, sustainable intensification of agriculture to increase crop yields, and reducing food waste and losses in the food chain. These approaches aim to enhance biofuel production while ensuring that food security and environmental sustainability are not compromised.

Main Focus

The report estimates the biofuel potential from these approaches for five countries in Sub-Saharan Africa: Ghana, Mozambique, Nigeria, South Africa, and Uganda, which are considered representative of the region's diverse agricultural and economic conditions.

Key Information

1. Sustainable Collection of Agricultural Residues

• Residues from both harvest and processing of crops and forest products are available in large quantities.
• The fraction of residue that can be sustainably collected is estimated to be 25–50%.
• Energy content of agricultural residues is assumed to be 15 GJ per tonne.
• Global residue potential for 2050 is estimated at 79–128 EJ.
• Biofuel potential from these residues, assuming 40% conversion efficiency, could be 18–38 EJ.
• Residue for biofuel in the five countries (as of 2014) is shown in Tables S-1 and S-2, with the share of liquid fuel use also provided.

• If residues are used for biofuel, the biofuel potential could supply the entire projected transport fuel needs for the five countries collectively.

2. Sustainable Intensification of Agriculture (Higher Crop Yields)

• Yield increases are a major driver of food production and residue potential.
• 80% of the projected increase in food production is due to higher yields per hectare, while 10% comes from multiple cropping.
• Only 10% of the increase in food production is expected from expanding arable land.
• If yields are increased to close the global yield gap, 552 Mha of land could be freed up for biofuel crops.
• Biomass potential from this land is 83 EJ, which could be converted to 33 EJ of advanced biofuel at 40% efficiency.
• This could displace a significant portion of current liquid transport fuel use.

3. Land Freed by Reducing Food Waste and Losses

• Food waste and loss account for 36% of total food production in Sub-Saharan Africa.
• Eliminating losses and waste could free up 782 Mha of land globally by 2050.
• In the five countries, this corresponds to:

• If yields are increased to close the yield gap, 553 Mha of land is freed, leading to 83 EJ of biomass and 33 EJ of advanced biofuel.
• With global best practices in food waste reduction, roughly half of the biomass potential is achievable.

• The potential displacement of transport fuel by reduced food waste and losses is as follows:

Policy and Development Implications

• Technological readiness for advanced biofuels from lignocellulosic feedstocks is limited, but conventional biofuel technologies are well-established.
• Policy options include improving logistics for residue collection, promoting modern farming techniques, and enhancing agroforestry and supply chain efficiency.
• Reducing food waste through better harvesting, storage, and transportation infrastructure can free up significant land for bioenergy crops.
• Economic and logistical factors will influence the realization of biofuel potential.

Conclusion

IRENA highlights that Sub-Saharan Africa has considerable sustainable biofuel potential, which can be achieved through residue collection, yield improvements, and reducing food waste. With appropriate policy support and technological development, the region could displace a large portion of current transport fuel use and contribute significantly to energy security and sustainable development.