Bioenergy strategies and the global carbon cycle. / Stratégies bioénergétiques et cycle global du carbone

Bioenergy strategies are seen as effective options to reduce net CO₂ emissions to the atmosphere. Carbon emissions from fossil fuel burning can be avoided if biomass is used as an energy carrier instead, because in a bioenergy system CO₂ is taken up by the plants and released to the atmosphere again when biomass is burned for energy. However, a carbon balance of bioenergy also needs to take into account the associated changes of С stored in the biosphere, i.e. in the vegetation, in plant litter and soils. For example, a net reduction of the С content in the biosphere leads to an increase of the atmosphere's С content by the same amount, and vice versa. Bioenergy is often produced along with other goods such as wood products. In such cases the carbon balance has to include the effect of С storage in biomass products and the substitution of other, energy consuming materials like steel or concrete with biomass. GORCAM (Graz -Oak Ridge -Carbon Accounting Model) is a spreadsheet model that has been developed to calculate the carbon balance of land management and biomass utilization strategies in forestry and agriculture. Input parameters describe the management régime (rotation length, harvesting intensity, growth rate...), previous land use, soil and litter carbon dynamics, fate of the harvest (biomass for energy, biomass products with varying lifetimes), fossil fuel substitution and its efficiency (bioenergy instead of fossil energy ; biomass products instead of products from other, more energy intensive materials), fossil fuel requirements for land management and biomass conversion. Model results reveal that the carbon balance of land management and biomass utilization strongly depends on the initial С storage on the site, the growth rate, the efficiency with which the harvest is used, and the time period of consideration. For high growth rates and efficient use of the harvest, the dominant component of the С balance is seen to be fossil fuel substitution. Some strategies result in a significant net reduction of carbon emissions from their very beginning {e.g. short-rotation forestry on previously agricultural land). Harvest of existing forests for biofuels and wood products can lead to a net source or sink at the beginning, depending on the efficiency of harvest use. In the case of a net initial source, the С balance can return to positive values as the forest regrows, the «payback period» being determined by the forest growth rate and other factors mentioned above.Stratégies bioénergétiques et cycle global du carbone Les stratégies bioénergétiques sont perçues comme des options utiles à la réduction des émissions de CO₂ dans l'atmosphère. Les émissions de carbone issues de la combustion de fuels fossiles peuvent être évitées si la biomasse est considérée comme un réservoir d'énergie, puisque dans un système bioénergétique le CO₂ est absorbé par les plantes puis relâché lors de la combustion. Cependant, le bilan carboné bioénergétique doit aussi tenir compte des modifications induites des quantités de carbone stockées dans la végétation, la litière des plantes et les sols. Par exemple, une réduction du contenu net de carbone bioterrestre conduit à une augmentation de la même quantité dans l'atmosphère, et vice versa. La bioénergie est souvent produite en association avec d'autres biens, comme les produits en bois. Dès lors, le bilan carboné doit tenir compte du carbone stocké dans les produits de la biomasse, et des effets de substitution de la biomasse à d'autres matériaux coûteux en énergie comme l'acier ou le béton. GORCAM (Graz -Oak Ridge -Carbon Accounting Model) est un modèle développé sur logiciel tableur qui a pour but de calculer le bilan carboné en fonction de la gestion des terres et des stratégies d'utilisation de la biomasse en sylviculture et en agriculture. Parmi les paramètres d'entrée du modèle, il est tenu compte des caractéristiques du mode de gestion (durées de rotations, intensité des coupes, taux de croissances...), de l'occupation antérieure des terres, de la dynamique du carbone dans le sol et la litière, du devenir des récoltes (bioénergie, durée de vie variée de la biomasse selon son utilisation). Il est également tenu compte de la substitution des combustibles fossiles par la bioénergie, du rendement énergétique de la biomasse, et de la production de biens à partir de la biomasse en remplacement d'autres matériaux plus coûteux en énergie. La consommation de combustible fossile nécessaire à la gestion du milieu et à la conversion de la biomasse est aussi prise en compte. Les résultats du modèle révèlent que le bilan carboné résultant d'une nouvelle gestion des terres et de l'utilisation de la biomasse dépend fortement de la quantité initiale de carbone sur le site, du taux de croissance, de l'efficacité de l'utilisation des récoltes, et de l'échelle de temps considérée. Pour des taux de croissance élevés et une utilisation efficace des récoltes, la principale composante du bilan carboné s'avère être la substitution des combustibles fossiles. Certaines stratégies débouchent sur une diminution significative des émissions nettes de carbone dès leur début (e.g. rotation forestière rapide sur d'anciens terrains agricoles). La coupe de forêts existantes mène au début à un dégagement ou à un stockage de carbone, selon l'efficacité d'utilisation de la récolte. Dans le cas d'une source initiale nette, le bilan carboné peut revenir à nouveau vers des valeurs positives (puits) lors de la repousse de la forêt au terme d'une période fonction du taux de croissance de la forêt et des autres facteurs mentionnés ci-dessus.Schlamadinger Bernhard, Canella Lorenza, Marland Gregg, Spitzer Josef. Bioenergy strategies and the global carbon cycle. / Stratégies bioénergétiques et cycle global du carbone. In: Sciences Géologiques. Bulletin, tome 50, n°1-4, 1997. The global carbon cycle in the terrestrial biosphere, sous la direction de Gérard Dedieu et Jean-Luc Probst. pp. 157-182

Life-cycle Based Environmental Effects of 1.3 Mio. Electric Vehicles on the Road in 35 Countries - Facts & Figures from the IEA Technology Collaboration Program on Hybrid & Electric Vehicles

There is an international consensus that the environmental effect of electric vehicles can only be assessed with life cycle assessment (LCA) including production, operation and end of life treatment. A group of international experts working since 2011 on the LCA of Electric Vehicles in the Technical Collaboration Program on “Hybrid and Electric Vehicles of the International Energy Agency (IEA), estimated the environmental effects of the current worldwide electric vehicle fleet of about 1.3 million in 35 countries. The environmental effects assessed for electric vehicles are greenhouse gas emissions, acidification, ozone formation, particle matter emissions and primary energy consumption, which were compared to conventional internal combustion engine vehicles

LCA Based Estimation of Environmental Effects of the Global Electric Vehicles Fleet - Facts&Figures from the IEA Technology Collaboration Program on Hybrid&Electric Vehicles

There is an international consensus that the environmental effect of electric vehicles can only be assessed with life cycle assessment (LCA) including production, operation and end of life treatment. Since 2011 a group of international experts working on the LCA of Electric Vehicles in the Technical Collaboration Program on “Hybrid&Electric Vehicles of the International Energy Agency (IEA), continuously estimates the environmental effects of the growing worldwide electric vehicle fleet (BEV, PHEV), currently of about 1.3 million in 35 countries. The environmental effects assessed for electric vehicles are greenhouse gas emissions, acidification, ozone formation, particle matter emissions and primary energy consumption compared to the substituted conventional internal combustion engine vehicles. The global assessment shows substantial environmental improvements, e.g. 25% to 30%GHG-reduction, 40% to 50% PM reduction, 50% to 60% ozone reduction, 15% to 20% total primary energy reduction. The broad estimated range of environmental effects are mainly due to variation in the emissions of national electricity production, the electricity consumption of the EV fleet in daily real driving conditions, and the fuel consumption of substituted conventional ICEs

Evaluation of the Environmental Benefits of The Global EV-Fleet in 40 Countries – A LCA Based Estimation in IEA HEV

The environmental effect of electric vehicles can only be assessed based on life cycle assessment (LCA) covering production, operation and end of life treatment. Since 2014 in the Technical Collaboration Program on “Hybrid&Electric Vehicles” (HEV) of the International Energy Agency (IEA) an expert group developed and applied the LCA to estimate the environmental effects of the increasing EV fleet globally. In 2018 about 5 million EVs were on the road in 40 countries by substituting fossil fuels ICEs. The environmental effects assessed are greenhouse gas emissions, acidification, ozone formation, particle matter emissions and primary energy consumption. Depending on the country specific electricity mix the environmental benefits are different but in total there is a significant growing improvement (2014 – 2017) on the environmental effects due to the strong increasing number of EVs globally

An environmental assessment of biorefining of rubber dandelion to rubber and bioplastic

‘DRIVE4EU - Dandelion Rubber and Inulin Valorization and Exploitation for Europe’, a demonstration project, aims at the development of a value chain for natural rubber and inulin from Rubber dandelions. The objective of the project is to set up a new European chain for the production and processing of natural rubber. This will enable the EU to become less dependent on the import of natural rubber and at the same time to respond to the threat of a global rubber shortage. The viability of using Rubber dandelions for rubber and inulin for bioplastics (PEF – Polyethylene Furanoate) production depends on the sustainability of this new value chain. Within the project an environmental assessment using the methodology of Life Cycle Assessment (LCA) is performed. The aim is to identify, quantify and assess the most important environmental impacts and benefits of rubber and inulin from Rubber dandelion based on the whole value chain. Within the LCA scientific environmental indicators (e.g. global warming potential, cumulated primary energy demand, land use, water use, and acidification) will be used to guide the development of the DRIVE4EU value chain to realize the highest possible sustainability in comparison to a substituted reference system (natural rubber from Hevea tree and PET from fossil resources). The combination of natural rubber and inulin makes Rubber dandelion very interesting as a production platform

An environmental assessment of biorefining of rubber dandelion to rubber and bioplastic

‘DRIVE4EU - Dandelion Rubber and Inulin Valorization and Exploitation for Europe’, a demonstration project, aims at the development of a value chain for natural rubber and inulin from Rubber dandelions. The objective of the project is to set up a new European chain for the production and processing of natural rubber. This will enable the EU to become less dependent on the import of natural rubber and at the same time to respond to the threat of a global rubber shortage. The viability of using Rubber dandelions for rubber and inulin for bioplastics (PEF – Polyethylene Furanoate) production depends on the sustainability of this new value chain. Within the project an environmental assessment using the methodology of Life Cycle Assessment (LCA) is performed. The aim is to identify, quantify and assess the most important environmental impacts and benefits of rubber and inulin from Rubber dandelion based on the whole value chain. Within the LCA scientific environmental indicators (e.g. global warming potential, cumulated primary energy demand, land use, water use, and acidification) will be used to guide the development of the DRIVE4EU value chain to realize the highest possible sustainability in comparison to a substituted reference system (natural rubber from Hevea tree and PET from fossil resources). The combination of natural rubber and inulin makes Rubber dandelion very interesting as a production platform