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The increasing production of bio-based plastics calls for thorough environmental assessments. Using life cycle assessment, this study compares European supply of fully bio-based high-density polyethylene and partially bio-based polyethylene terephthalate from Brazilian and Indian sugarcane ethanol with production of their petrochemical counterparts in Europe. Bio-based polyethylene results in greenhouse gas emissions of around −0.75 kg CO 2eq /kg polyethylene , i.e. 140% lower than petrochemical polyethylene; savings on non-renewable energy use are approximately 65%. Greenhouse gas emissions of partially bio-based polyethylene terephthalate are similar to petrochemical production (±10%) and non-renewable energy use is lower by up to 10%, partly due to the low bio-based content of the polymer. Assuming that process energy is provided by combined heat and power reduces the greenhouse gas emissions of partially bio-based polyethylene terephthalate production to a range from −4% (higher) to 15% (lower) compared to petrochemical polyethylene terephthalate depending on the methodological choices made. Production from Brazilian ethanol leads to slightly higher impacts than production from Indian ethanol due to dampening effects of allocation on Indian ethanol produced from sugarcane molasses, different sugarcane pre-harvesting practices and inter-continental transport of Brazilian ethanol to India. Internal technical improvements such as fuel switch, new plants and best available technology offer savings up to 30% in greenhouse gas emissions compared to current production of petrochemical polyethylene terephthalate. The combination of some of these measures and the use of biomass for the supply of process steam can reduce the greenhouse gas emissions even further. In human health and ecosystem quality, the impact of the bio-based polymers is up to 2 orders of magnitude higher, primarily due to pesticide use, pre-harvesting burning practices in Brazil and land occupation. When improvements are assumed across the supply chain, such as pesticide control and elimination of burning practices, the impact of the bio-based polymers can be significantly reduced. Realising such improvements will minimise the greenhouse gas and other emissions and resource use associated with bio-based polyethylene terephthalate and will allow to alleviate further pressure on fragile ecosystems. [ABSTRACT FROM AUTHOR]

Management strategies for loblolly pine ( Pinus taeda ) plantations in the Southeastern USA can be adapted to fulfill both the demand for wood products and for bioenergy. This study quantifies the impact of plantation management choices on the cumulative carbon balance and the net present value of loblolly pine plantations at the stand level, as well as the wood supply cost for bioenergy production for these different management strategies. The strategies assessed (conventional, additional thinning and short rotation) are characterised by planting density, thinning age and rotation period, each with and without collection and utilization of slash residues for bioenergy. The total wood supply costs for bioenergy include the cultivation, harvesting and transport costs for small diameter trees and slash. The results show that the carbon balance after 100 years is 205 (247), 214 (268) and 149 (195) Mg ha −1 for the conventional, additional thinning, and short rotation loblolly pine plantation management strategies (within parentheses: same strategies with slash utilization). The conventional strategy has the lowest wood supply costs for bioenergy, 47 (46) $ Mg −1 pulpwood, followed by the additional thinning strategy, 50 (49) $ Mg −1 pulpwood, and 54 (52) $ Mg −1 pulpwood for the short rotation management strategy. In conclusion, switching from the current conventional strategy without the utilization of slash for bioenergy to an additional thinning strategy with the use of slash increases the overall carbon accumulation by about 31%, at marginally higher wood supply cost. Adapting plantation management strategies can have a positive effect on the economic performance and on the carbon balance of loblolly pine plantations. Integration of wood supply for bioenergy and traditional forestry sectors can lead to co-benefits in terms of cost reduction and carbon accumulation. [ABSTRACT FROM AUTHOR]

The expansion of the ethanol industry in Brazil faces two important challenges: to reduce total ethanol production costs and to limit the greenhouse gas (GHG) emission intensity of the ethanol produced. The objective of this study is to economically optimize the scale and location of ethanol production plants given the expected expansion of biomass supply regions. A linear optimization model is utilized to determine the optimal location and scale of sugarcane and eucalyptus industrial processing plants given the projected spatial distribution of the expansion of biomass production in the state of Goiás between 2012 and 2030. Three expansion approaches evaluated the impact on ethanol production costs of expanding an existing industry in one time step (one-step), or multiple time steps (multi-step), or constructing a newly emerging ethanol industry in Goiás (greenfield). In addition, the GHG emission intensity of the optimized ethanol supply chains are calculated. Under the three expansion approaches, the total ethanol production costs of sugarcane ethanol decrease from 894 US$/m 3 ethanol in 2015 to 752, 715, and 710 US$/m 3 ethanol in 2030 for the multi-step, one step and greenfield expansion respectively. For eucalyptus, ethanol production costs decrease from 635 US$/m 3 in 2015 to 560 and 543 US$/m 3 in 2030 for the multi-step and one-step approach. A general trend is the use of large scale industrial processing plants, especially towards 2030 due to increased biomass supply. We conclude that a system-wide optimization as a marginal impact on overall production costs. Utilizing all the predefined sugarcane and eucalyptus supply regions up to 2030, the results showed that on average the GHG emission intensity of sugarcane cultivation and processing is −80 kg CO 2 /m 3 , while eucalyptus GHG emission intensity is 1290 kg CO 2 /m 3 . This is due to the high proportion of forest land that is expected to be converted to eucalyptus plantations. Future optimization studies may address further economic or GHG emission improvement potential by optimizing the GHG emission intensity or perform a multi-objective optimization procedure. [ABSTRACT FROM AUTHOR]