In defense of the cumulative energy demand

1997 ◽  
Vol 2 (2) ◽  
pp. 61-61 ◽  
Author(s):  
Walter Klöpffer
2021 ◽  
Vol 13 (12) ◽  
pp. 6894
Author(s):  
Shakira R. Hobbs ◽  
Tyler M. Harris ◽  
William J. Barr ◽  
Amy E. Landis

The environmental impacts of five waste management scenarios for polylactic acid (PLA)-based bioplastics and food waste were quantified using life cycle assessment. Laboratory experiments have demonstrated the potential for a pretreatment process to accelerate the degradation of bioplastics and were modeled in two of the five scenarios assessed. The five scenarios analyzed in this study were: (1a) Anaerobic digestion (1b) Anaerobic digestion with pretreatment; (2a) Compost; (2a) Compost with pretreatment; (3) Landfill. Results suggested that food waste and pretreated bioplastics disposed of with an anaerobic digester offers life cycle and environmental net total benefits (environmental advantages/offsets) in several areas: ecotoxicity (−81.38 CTUe), eutrophication (0 kg N eq), cumulative energy demand (−1.79 MJ), global warming potential (0.19 kg CO2), and human health non-carcinogenic (−2.52 CTuh). Normalized results across all impact categories show that anaerobically digesting food waste and bioplastics offer the most offsets for ecotoxicity, eutrophication, cumulative energy demand and non-carcinogenic. Implications from this study can lead to nutrient and energy recovery from an anaerobic digester that can diversify the types of fertilizers and decrease landfill waste while decreasing dependency on non-renewable technologies. Thus, using anaerobic digestion to manage bioplastics and food waste should be further explored as a viable and sustainable solution for waste management.


Author(s):  
Alberto Tama Franco

Wind technology is considered to be among the most promising types of renewable energy sources, and due to high oil prices and growing concerns about climate change and energy security, it has been the subject of extensive considerations in recent years, including questions related to the relative sustainability of electricity production when the manufacturing, assembly, transportation and dismantling processes of these facilities are taken into account. The present article evaluates the environmental impacts, carbon emissions and water consumption, derived from the production of electric energy of the Villonaco wind farm, located in Loja-Ecuador, during its entire life cycle, using the Life Cycle Analysis method. Finally, it is concluded that wind energy has greater environmental advantages, since it has lower values of carbon and water footprints than other energy sources. Additionally, with the techniques Cumulative Energy Demand and Energy Return on Investment, sustainability in the production of electricity from wind power in Ecuador is demonstrated; and, that due to issues of vulnerability to climate change, the diversification of its energy mix is essential considering the inclusion of non-conventional renewable sources such as solar or wind, this being the only way to reduce both the carbon footprint and the water supply power.


Energies ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 252 ◽  
Author(s):  
Vincenzo Muteri ◽  
Maurizio Cellura ◽  
Domenico Curto ◽  
Vincenzo Franzitta ◽  
Sonia Longo ◽  
...  

The photovoltaic (PV) sector has undergone both major expansion and evolution over the last decades, and currently, the technologies already marketed or still in the laboratory/research phase are numerous and very different. Likewise, in order to assess the energy and environmental impacts of these devices, life cycle assessment (LCA) studies related to these systems are always increasing. The objective of this paper is to summarize and update the current literature of LCA applied to different types of grid-connected PV, as well as to critically analyze the results related to energy and environmental impacts generated during the life cycle of PV technologies, from 1st generation (traditional silicon based) up to the third generation (innovative non-silicon based). Most of the results regarded energy indices like energy payback time, cumulative energy demand, and primary energy demand, while environmental indices were variable based on different scopes and impact assessment methods. Moreover, the review work allowed to highlight and compare key parameters (PV type and system, geographical location, efficiency), methodological insights (functional unit, system boundaries, etc.), and energy/environmental hotspots of 39 LCA studies relating to different PV systems, in order to underline the importance of these aspects, and to provide information and a basis of comparison for future analyses.


Resources ◽  
2019 ◽  
Vol 8 (2) ◽  
pp. 110 ◽  
Author(s):  
Camilla Tua ◽  
Laura Biganzoli ◽  
Mario Grosso ◽  
Lucia Rigamonti

The European packaging market is forecast to grow 1.9% annually in the next years, with an increasing use of returnable packages. In this context, it is important to assess the real environmental effectiveness of the packaging re-use practice in terms of environmental impacts. This life cycle assessment aims to evaluate the environmental performances of reusable plastic crates (RPCs), which are used for the distribution of 36% of fruit and vegetables in Italy. RPCs can be re-used several times after a reconditioning process, i.e., inspection, washing, and sanitization with hot water and chemicals. The analysis was performed considering 12 impact categories, as well as the cumulative energy demand indicator and a tailor-made water consumption indicator. The results show that when the RPCs are used for less than 20 deliveries, the impacts of the life cycle are dominated by the manufacturing stage. By increasing the number of deliveries, the contribution of the reconditioning process increases, reaching 30–70% of the overall impacts for 125 uses. A minimum of three deliveries of the RPCs is required in order to perform better than an alternative system where crates of the same capacity (but 60% lighter) are single-use. The same modeling approach can be used to evaluate the environmental sustainability of other types of returnable packages, in order to have a complete overview for the Italian context and other European countries.


2000 ◽  
Vol 5 (6) ◽  
pp. 369-373 ◽  
Author(s):  
Michael Röhrlich ◽  
Mark Mistry ◽  
Per N. Martens ◽  
Stefan Buntenbach ◽  
Martin Ruhrberg ◽  
...  

Author(s):  
Ben Morelli ◽  
Sarah Cashman ◽  
Xin (Cissy) Ma ◽  
Jason Turgeon ◽  
Sam Arden ◽  
...  

Abstract The wastewater industry is undergoing a paradigm shift from focusing solely on treatment to incorporating concepts aimed at mitigating environmental impacts such as energy and nutrient recovery and water reuse. This study uses life cycle assessment and life cycle cost analysis to investigate the effect of expanding anaerobic digestion (AD) capacity and adding combined heat and power on environmental and cost indicators at a mid-sized wastewater treatment facility (WWTF) in Massachusetts, USA. Since 2014, Massachusetts has banned the disposal of organic waste from commercial organizations producing more than one ton of material per week. The WWTF's additional digester capacity allows the co-digestion of municipal solids with a food-based engineered bioslurry due to this ban. Study data were compiled for several AD feedstock quantity and performance scenarios, and compared to a baseline scenario representative of historic plant operations prior to co-digestion. Reductions in environmental impact are demonstrated for six of eight environmental impacts, including global climate change potential and cumulative energy demand. Eutrophication potential increases by 10 percent and 24 percent across assessed scenarios. Water use remains relatively constant across scenarios. Facility energy production increases dramatically with co-digestion, satisfying 100 percent of the WWTF's thermal energy requirement and producing surplus electricity assuming full AD capacity utilization.


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