Author : Holmgren David
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Biomass Fuels from Sustainable Land Use : A permaculture perspective by David Holmgren. Nov. 2003. The increasing interest, research and promotion of renewable energy, driven by the Greenhouse imperative has included a vigorous debate over the role of biomass fuels in a more sustainable future. Imminent global oil peak and consequent rises in global energy prices are likely to accelerate the action and the debate on biomass options. Biomass energy sources include industrial use of wood and charcoal fuels, methanol production from wood and ethanol production from agricultural crops such as sugar cane as well as oil seed crops such as canola for “biodiesel”. The permaculture concept lends substantial support to the concept of plants as sources of sustainable energy. In many ways nature has already optimised the harvesting of solar energy, we just need to develop the most productive land use systems to use that abundance within nature’s limits. However, many of the proposals and projects to produce biomass fuels have had less than ideal environmental consequences. Twenty years ago, the Solar Energy Council of Victoria (predecessor to SEAV) produced a plan for 20% of Victoria’s liquid fuel needs from biomass by 2000. The centre piece of the plan was a root crop Jerusalem artichoke to be grown in the northern Victorian irrigation district for ethanol production from industrial scale regional plants. In a detailed submission to the draft plan I commended the choice of Jerusalem artichoke as probably superior to Sugar beet but questioned the sustainability of the scheme, and the claimed net energy yield ratio of 10:1. The proposed irrigation districts already suffered from salinity and compaction under dairy farming. A shift to broadacre root cropping would have been disastrous. Because the mash by product of ethanol is potential animal feed, dairy production in the region could have been maintained but it would have required cows in large feedlots clustered around the ethanol plants as well as longer distance transport of manure back to the artichoke crops. This suit of adverse environmental impacts was capped by doubts about the net energy yield figures. A similar proposal in NZ (using Sugar beet ) had been evaluated in 19791 to have an embodied energy yield ratio of 0.9:1 ( in other word a marginal net loss). The Solar Energy Council never replied to my questions and 20 years of cheap oil has made sure the scheme never came to fruition. ...