Energy crops: current status and future prospects

Abstract

Energy crops currently contribute a relatively small proportion to the total energy produced from biomass each year, but the proportion is set to grow over the next few decades. This paper reviews the current status of energy crops and their conversion technologies, assesses their potential to contribute to global energy demand and climate mitigation over the next few decades, and examines the future prospects. Previous estimates have suggested a technical potential for energy crops of $ 400 EJ yr À1 by 2050. In a new analysis based on energy crop areas for each of the IPCC SRES scenarios in 2025 (as projected by the IMAGE 2.2 integrated assessment model), more conservative dry matter and energy yield estimates and an assessment of the impact on non-CO 2 greenhouse gases were used to estimate the realistically achievable potential for energy crops by 2025 to be between 2 and 22 EJ yr À1 , which will offset $ 100-2070 Mt CO 2 -eq. yr À1 . These results suggest that additional production of energy crops alone is not sufficient to reduce emissions to meet a 550 lmol mol À1 atmospheric CO 2 stabilization trajectory, but is sufficient to form an important component in a portfolio of climate mitigation measures, as well as to provide a significant sustainable energy resource to displace fossil fuel resources. Realizing the potential of energy crops will necessitate optimizing the dry matter and energy yield of these crops per area of land through the latest biotechnological routes, with or without the need for genetic modification. In future, the co-benefits of bioenergy production will need to be optimized and methods will need to be developed to extract and refine high-value products from the feedstock before it is used for energy production.

Resistance and Resilience of A Stream Salamander To Supraseasonal Drought

“…Various studies have arrived at differing figures for the potential contribution of biomass to future global energy supplies, ranging from below 100 EJ/yr to above 400 EJ/yr in 2050 (Hoogwijk, 2004;Hoogwijk et al, 2005;Sims et al, 2006). Smeets et al (2007) indicate that the ultimate technical potential for energy cropping on current agricultural land, with projected technological progress in agriculture and livestock, could deliver over 800 EJ/ yr without jeopardising the world's food supply.…”

Bioenergy from “surplus” land: environmental and socio-economic implications

“…Bioenergy crops can be important constituents in a portfolio of climate mitigation measures (Sims et al 2006). This option however depends on the C debt of a biofuel cropping system which is partly determined by the land use it is replacing (e.g.…”

Sectoral approaches to improve regional carbon budgets

“…Ethanol fuel can be considered to have no net CO 2 "Fossil" C intensity is the measure relevant to greenhouse gas, and by this measure wood from renewable harvest and re-growth of trees is zero in C intensity emissions if the ethanol is produced from corn or sugar cane, but significant amounts of fossil fuels are generally used for the agricultural and conversion processes (Kheshgi et al 2000;Sims et al 2006). Sectoral budgets should also include loss of C to aquatic systems.…”