Sugar

Goldemberg J. (2007). Ethanol for a sustainable energy future. Science, Vol. 315. no. 5813, pp. 808–810

This study looks at the various renewable energy options, focusing particularly on ethanol produced from sugar cane in Brazil. It argues that sugar-derived ethanol is fully competitive with motor gasoline and appropriate for replication in many countries. It also says that competition for land use between food and fuel in Brazil has not been substantial: sugarcane covers 10% of total cultivated land and 1% of total land available for agriculture in the country. It argues that expanding the Brazilian ethanol program by a factor of 10 (i.e. an additional 30 million hectares of sugarcanein Brazil and in other countries) would supply enough ethanol to replace 10% of the gasoline used in the world and that this would take up only a small fraction of the land available.

See here for a link to the article (free to Science subscribers).

Renouf M A and Wegener M K (2007) Environmental life cycle assessment (LCA) of sugarcane production and processing in Australia. Proceedings of the Australian Society of Sugar Cane Technologists, Vol. 29, 2007

This paper reports the results of a detailed life cycle assessment (LCA)sugarcane production and processing in Queensland. The results presented show the life-cycle impact of producing a tonne of raw cane sugar in Queensland, for a range of environmental impact categories: energy input, greenhouse gas emissions, eutrophication and water use. Results are presented for three scenarios: the ‘State average’ farming system and two fairly distinct cane growing regions, the Burdekin and the Wet Tropics. These results highlight the significant aspects associated with sugar production in Australia as well as the range in variation present in the industry due to different growing conditions. To put the environmental impact of cane sugar production into perspective, sugarcane is compared with other starch and sugar-bearing crops, sugar beet and corn. Cane sugar is shown to have distinct advantages in relation to energy input, greenhouse gas emissions, and land utilisation, but does not rate as well in relation to other the impacts assessed (eutrophication and water use). Three factors were found to have the strongest influence on the outcome: agricultural yield, nitrogen emissions, and the environmental credits attributed to co-products. The paper provides further insight into the environmental impacts of cane-sugar production in Australia, and suggests opportunities for improving the environmental profile of the cane industry in this country. These include maximising the environmental credits from co-products, optimising nitrogen inputs, mitigating nitrogen losses, and continuing with water efficiency efforts.

See here for the abstract. The full paper is available only to ASSCT members or for purchase.

The findings are presented in very similar form in: Renouf MA, Wegeneer MK and Nielsen LK (2008). An environmental life cycle assessment comparing Australian sugarcane with US corn and UK sugar beet as producers of sugars for fermentation Biomass and Bioenergy, Volume 32, Issue 12 Pages 1144-1155

Ramjeawon T (2004). Life Cycle Assessment of Cane-Sugar on the Island of Mauritius

The goal of this case study was to identify and review the significant areas of potential environmental impacts across the whole life cycle of cane sugar on the island of Mauritius. The functional unit was one tonne of exported raw sugar from the island. The life cycle investigated includes the stage of cane cultivation and harvest, cane burning, transport, fertilizer and herbicide manufacture, cane sugar manufacture and electricity generation from bagasse. Data was gathered from companies, factories, sugar statistics, databases and literature. Energy depletion, climate change, acidification, oxidant formation, nutrification, aquatic ecotoxicity and human toxicity were assessed. The inventory of the current sugar production system revealed that the production of one tonne of sugar requires, on average, a land area of 0.12 ha, the application of 0.84 kg of herbicides and 16.5 kg of N-fertilizer, use of 553 tons of water and 170 tonne-km of transport services.

With regard to greenhouse gas emissions, 160 kg of CO2 per tonne of sugar is released from fossil fuel energy use and the net avoided emissions of CO2 on the island due to the use of bagasse as an energy source is 932,000 tonnes. Agriculture (cane cultivation, and fertilizer and herbicide manufacture) contributed to about 80% of GHG emissions. Options for improvements across all environmental impacta areas include: better irrigation systems, precision farming, optimal use of herbicides, centralisation of sugar factories, implementation of co-generation projects and pollution control during manufacturing and bagasse burning are measures that would considerably decrease resource use and environmental impacts.

British sugar carbon reduction activities and carbon footprint

British Sugar is investing £20m in energy reduction projects over the next 3 years. They vary from small projects such as more efficient lighting, to investment in heat recovery, energy recapture and the use of biogas as an alternative fuel. Between 2006 and 2009 the company is working to reduce its use of energy by 19%.

British Sugar has also worked with the Carbon Trust to calculate its carbon footprint and finds that a 1kg bag of its sugar produces 0.5 kg of CO2e.

See here and here for more information.

Impacts of Changes in Key EU Policies on Trade and Production Displacement of Sugar and Soy

This study, by Annie Dufey, David Baldock & Martin Farmer (commissioned by WWF for IIED, with the collaboration of IEEP) while not specifically climate change related, is interesting from a land use perspective. It looks at how .EU agricultural and trade policies and agreements impact on the way key commodities, notably sugar and soy, are produced in the rest of the world.

For more information see here.