Cradle to grave environmental-economic analysis of tea life cycle in Iran

Tea as the second most consumed none-alcoholic beverage in the world next to the water is involved with considerable environmental impacts during its life cycle. Because of the high importance of the tea sector in northern Iran, the present study aimed to assess the environmental burdens of tea in life cycle, including green tea leaf production in the farm and its transportation to the factory, tea processing, tea packaging, processed tea transportation to the local shop and its preparation in private household in Guilan province, Iran. The hotspots of each stage were identified and then all of stages were combined and different alternatives were compared. For this purpose, Life cycle assessment (LCA) approach was used based on the ISO 14040 standard. CML-IA baseline method was applied for impact assessment. Also the economic performance was assessed for green tea leaf and packaged black tea by calculating ecoefficiency (EE) scores. Required input data were collected from 30 farms and 30 tea processing factories in Lahijan and Langroud regions. LCA results showed that machinery and diesel fuel were the most pollutant inputs in farm and factory, respectively. Tea green leaf production was identified as the major contributor (57%) to environmental burdens in comparison with other steps throughout tea life cycle. Two-layer packaging was found as the most pollutant scenario in comparison to other scenarios (onelayer, three-layer and polyethylene packages). Cooktop was found to be more environment-friendly than electric kettle. Low EE score for most impact categories indicated the necessity of reconsidering the patterns for tea leaf production. For packaging scenarios, three-layer packaging had the highest net income with lowest environmental impacts. Based on the modelled results, it is suggested that negative environmental consequences of tea life cycle can be reduced by optimization of agro-chemicals uses such as pesticides and chemical fertilizers in the farm, using natural gas instead of diesel fuel in tea processing factory, applying three-layer packages for packaging black tea and using cooktop for boiling water

The role of hydrogen in a net-zero emission economy under alternative policy scenarios

Low emission and green hydrogen as a carbon-free energy carrier has attracted worldwide attention in decarbonizing the energy system and meeting the Paris agreement target of limiting warming to 2 °C or below. This study investigates the contribution of different hydrogen pathways to the energy transition and sheds light on adopting different decarbonization scenarios for Quebec, Canada, while including biogenic emissions from forest-based biomass consumption. We assess various alternative policy scenarios using a TIMES model for North America (NATEM), a bottom-up techno-economic approach. This study examines the role of various hydrogen pathways in Quebec's energy transition by considering different net-zero policy scenarios and an additional set of “green” scenarios, which prohibit the use of fossil fuel-based hydrogen. The results show that varying the penetration of hydrogen provides a key trade-off between reliance on direct air capture, reliance on carbon storage, reliance on wind and solar buildout, the inter-sector allocation of residual emissions, and the overall cost of achieving emission targets. In particular, the use of hydrogen in the industrial sector, a sector known to be difficult to decarbonize, reduces industrial emissions and reliance on direct air capture (DAC). Clustering industrial plants to use captured CO2 as a feedstock for synthetic fuel production may not reduce industrial GHG emissions by 2050, but it offers the opportunity to use captured CO2 instead of sequestering it in deep saline aquifers. Even though increasing industrial green hydrogen penetration increases marginal GHG abatement costs in the green net-zero scenario by 2050, it further minimizes industrial GHG emissions and the need for DAC among all net-zero scenarios by 2050. Hydrogen plays a significant role in achieving ambitious net-zero emission target, especially where electrification is not feasible, or electricitystorage is required.</p