© 2014 John Wiley & Sons Ltd
Edited By: Steve Long
Impact Factor: 4.714
ISI Journal Citation Reports © Ranking: 2012: 2/78 (Agronomy); 8/81 (Energy & Fuels)
Online ISSN: 1757-1707
Associated Title(s): Global Change Biology
Woody Crop Energy and Greenhouse Gas Emissions
Dedicated short rotation woody crops such as poplar and willow are promising candidate bioenergy crops. One advantage of woody crops is that they can be grown on abandoned and/or contaminated land. Thus, production does not necessarily have to compete with food crops for the most fertile soils and their management is usually less energy intensive than for food crops
For the production of any bioenergy crop to be ecologically and energetically viable, the energy gain must outweigh the energy used for the production, transport, and conversion to bio-electricity. In addition, their production must significantly reduce impacts on the environment. There is currently a lack of consensus regarding the energy and greenhouse gas balance of bioenergy production from short rotation woody crops.
Njakou Djomo and coauthors reviewed and synthesized 26 studies on energy balance and environmental impacts of bioenergy production from poplar and willow. Their goals were to summarize information regarding the energy and greenhouse gas balance, identify the mechanisms that frequently lead to conflicting results, and highlight the shortcomings in environmental impact analysis.
The authors concluded that short rotation woody crops can play an important role in mitigating greenhouse gas emissions. Although energy ratios and greenhouse gas emission estimations varied widely, they found a general consensus on two points: short rotation woody crops yielded 36 times more energy than coal per unit of fossil energy input, and GHG emissions were 24 times lower than those of coal.
Nonetheless, some uncertainties that pose the major challenges to accurately evaluating greenhouse gas emissions remain. The authors conclude that effort should be made to develop a widely accepted framework toward a reliable analysis of energy efficiency of bioenergy production systems.
Njakou Djomo S, El Kasmioui O, Ceulemans R (2011) Energy and greenhouse gas balance of bioenergy production from poplar and willow: A review. GCB Bioenergy. DOI: 10.1111/j.1757-1707.2010.01073.x