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Energy the nexus of everything: October 2009 Archives

On a recent trip to Brazil to understand water-resources management with respect to biofuel crop and other agriculture, I learnt much more about Brazilian energy policy. While in some cases, water-resource management is in its infant stages, in many others reductions of water usage have made great strides.

The total water flow in a sugar-cane-ethanol distillery is approximately 22 m3 per tonne of sugar cane processed, but new plants can be designed to withdraw only 1 m3 per tonne of cane. Most distilleries withdraw less than 5 m3 per tonne. Additionally, Dedini (the Brazilian vertically integrated company that sells industrial components and turn-key sugar-cane processing plants) has a plant design that can take green sugar cane, harvested by machine and without burning, and actually produce clean, fresh water instead of requiring it as an input.

Speaking of machine harvesting, the state of Sao Paulo, where more than 50% of cane is grown, has mandated that all sugar cane is harvested mechanically (i.e. by tractor) by 2014. The reason is to improve air quality during harvest season when the cane would otherwise be burnt before manual harvest. The cane is burnt to remove the leaves and "trash" from the stalk of the sugar-cane stalk and this leaves the main stalk with the sucrose and fiber. So much cane was being produced and harvested in a relatively small region that air quality was becoming unsafe for residents.

This practices of using mechanical harvesters for harvest was actually used as one of the criteria guiding the designation of Agriecological Zones for future sugar-cane agriculture. To prevent any perception of "food v fuel" argumetns for sugar cane in Brazil, the goverment has now set up the zones where sugar cane should be expanded. A sugar-cane developer cannot recieve goverment support via low-cost loans unless exapnding into these agricultural zones, and agriculture is generally too expensive without this government support. So, because mechanical harvesting is assumed not possible on lands with slopes greater than 12°, that slope limit was used as the criterion number. The other two criteria for determining the agricultural zones were climate (rainfall, temperature profile, etc.) and soil quality. The vast majority of sugar cane in the south and central parts of Brazil requires no irrigation except for possibly some during initial planting, and those areas in the new zones are anticipated to require little irrigation (˜200–300 mm/yr) if any at all, and it is not clear if the economic payoff will induce the investment in irrigation infrastructure.

Another, more social, aspect of Brazilian energy policy is the promotion of small farmers throughout Brazil for growing various crops for vegetable oils for biodiesel. The "pro-alcohol" programme was seen to leave out the small farmer as it is a large-scale industrial crop. Because sugar cane to ethanol is estimated to have a much higher energy return on energy invested than many oils to biodiesel, it is not apparent if people expect to make monetary returns similar to the industrial scale ethanol industry. Nontheless, there is an attempt to include more rural communities and farmers into Brazilian energy policy – for better or for worse.

Thus, from air quality to soil quality, Brazilian energy policy is promoting its cash crop of sugar cane. As the current land area used for Brazilian sugar cane is approximately 8–9 million ha, and the land used for cattle pasture is 180–200 million ha, we don't have to worry about Brazilian biofuel development as a specific driver for removal of the Amazon rainforest. The Amazon is clearly restricted via the agriecological zoning for sugar cane. On the other hand, increasing pressure for beef may have a part to play as policing such as vast area is difficult to impossible. But there is a push for increasing the density of cattle on land in Brazil to prevent expanded land clearing for pasture.

In summary, there is sufficient land zoned for sugar cane for Brazil to produce approximately 4–5 times as much ethanol than is produced today (˜6.2 billion gallons in 2008). There is also generally a better climate (rain and temperature) and soils for first-generation and possibly second-generation biofuels feedstocks than in North America or Europe. Thus, it is important that the developed world understand its own agricultural practices for energy-related biomass and determine whether domestic water and soil resources are better preserved by importing and investing in Brazil or investing at home. But then perhaps this brings up a new set of domestic social sustainability questions ...