Non-renewable Energy Demand Research Articles

Prospective life cycle assessment of an integrated biorefinery for production of lactic acid from dairy side streams

In Ireland, the world's first-of-a-kind integrated dairy biorefinery has been developed to address waste disposal challenges in the dairy industry by converting dairy side streams into high-value biochemicals, specifically lactic acid (LA). This study aims to assess the environmental impacts of this innovative technology at a commercial scale through a comprehensive life cycle assessment (LCA) study. Experimental data from a pilot-plant facility was scaled up to a production capacity of 20,000 tons of LA per year using SuperPro Designer®. This data was combined with information from upstream processes such as milk production, cheese production, and transport, using OpenLCA. The cradle-to-gate LCA revealed that milk production had the greatest overall impact across all categories. Enteric fermentation has the most significant impact on climate change, while fertilizer and concentrate feed production primarily contributed to non-renewable energy demand, ozone formation, human toxicity, water consumption and fossil depletion. Fertilizer application substantially influenced eutrophication, acidification and ecotoxicity indicators. However, scenario analysis showed that implementing strategies like substituting biorefinery byproducts with fossil-based products, increasing renewable energy penetration, and integrating dairy beef production could result in significant environmental savings across all impact categories. Moreover, the findings highlighted that the handling of co-products would determine the magnitude of the system's impact. This study concludes that combining process design analysis with accessible data at a higher Technology readiness level (TRL) 7 offers an opportunity to identify hotspots and recommend alternative strategies to improve the environmental sustainability of the whole system at the design stage. Additionally, this study provides valuable guidance for minimizing environmental impacts during the design phase, enabling informed investment decisions before construction. Ultimately, it plays a crucial role in establishing a circular bioeconomy within the dairy industry by effectively utilizing the side streams to produce sustainable biobased chemicals, specifically LA.

Energetic sustainability in the Amazon region: Exploring impacts, environmental solutions, and rebound effect analysis

The Amazon, a vital global ecosystem, renowned for biodiversity and climate regulation, faces unprecedented challenges due to escalating non-renewable energy consumption. This article sheds light on climate change's implications, exploring the intricate interplay in Amazon sustainability. The focus is on comprehending the impacts and exploring potential solutions to mitigate adverse effects. The research spans from 2002 to 2022, covering countries such as Brazil, Bolivia, Colombia, Peru, Venezuela, and Ecuador. This broad geographic and temporal scope provides valuable insights into the dynamic changes occurring in the Amazon region over the years. Employing a robust methodological approach, double log regression analysis is utilized as a powerful tool for a precise examination of the complex relationships between energy consumption, environmental preservation, and sustainable development. The study incorporates various estimators, including Non-Renewable Energy (EnR), Forest Area (FA), Forest Income (FI), Endangered Mammals (EM), Endangered Birds (EB), Endangered Fish (EF), Endangered Plants (EP), Freshwater Capitation (FC), Greenhouse Gases (GHG), Socioeconomic Factors (SF), Water Availability (WA). This comprehensive list enhances clarity and transparency, ensuring a thorough understanding of the research methods. The study uncovers the wide-ranging impact of growing non-renewable energy demand on Amazon biodiversity, forests, and species vulnerability, driven by direct rebound effects. It highlights both the backfire and super conservation effects, emphasizing the need for strategic, holistic approaches to energy and environmental management. Navigating this balance, the research informs decisions for a sustainable Amazon future, fostering awareness and inspiring action toward environmental stewardship and global conservation.

Are alpine floatovoltaics the way forward? Life-cycle environmental impacts and energy payback time of the worlds’ first high-altitude floating solar power plant

Floating photovoltaics (FPV) and high-altitude PV installations are increasingly gaining importance in the sustainable energy sector, each technology holding its own potential. A pioneering high-altitude FPV installation in Switzerland represents the first implementation of combining the two technologies. In order to determine the environmental performance of such an installation, the present study examines the life-cycle environmental impact of the world’s first high-altitude FPV system, using Life Cycle Assessment (LCA). Our results record life-cycle greenhouse gas emissions of 94 g of CO2–eq per kWh of electricity produced by the high-altitude FPV system. The non-renewable primary energy demand amounts to 10′810kWh oil-eq/kWp, which equals an energy payback time of 2.8 years. Environmental hotspots in the life cycle of the installation were found to be the production of the PV panels, due to the wafer production, and the mounting system, dominated by the production processes of the aluminium. Comparison to other PV installations identifies the mounting system as the main point of issue in the high-altitude FPV installation, due to a more intensive aluminium use. It was found that the high-altitude FPV installation can generally compete with alternative PV systems in the lowland, with its environmental impacts lying in the range of −45 % and + 15 %, while being largely outperformed by ground-mounted PV installations at high altitude. By implementing measures such as transitioning to renewable energies in the PV panel and mounting system supply chains, as well as reducing aluminium use for the mounting system, FPV systems hold great potential to help meet the increasingly growing demand of renewable energy sources.

External Wall Systems in Passive House Standard: Material, Thermal and Environmental LCA Analysis

The construction sector, a significant consumer of energy, possesses the potential to realize substantial environmental and economic advantages through the adoption of innovative technologies and design approaches. Notably, the Passive House standard, exemplified by energy-efficient single-family homes, emerges as a prominent solution. This study analyzes five external wall systems across multiple stages: (i) a literature review and examination of external wall techniques within the passive standard, utilizing the Passive House Database; (ii) a material and technological assessment of three wood-based and two masonry constructions; (iii) an in-depth thermal performance analysis of selected external partitions; and (iv) a Life Cycle Assessment (LCA) of the external wall systems. Our findings indicate that among the single-family homes built to the passive standard, 50.94% utilized timber constructions, while 34.21% employed masonry. Thermal analysis revealed that the masonry wall, EW-M-01, exhibited superior thermal efficiency with a heat transfer coefficient (U-value) of 0.0889 W/m2K. Meanwhile, the wooden wall, EW-T-01, led its category with a U-value of 0.1000 W/m2K. The LCA highlighted that the wooden wall EW-T-02 presented the lowest integrated non-renewable energy demand (PENTR) at 425.70 MJ/kg and the most favorable Global Warming Potential (GWP), with a reduction of 55.51 kg CO2e. Conversely, the masonry wall EW-M-01 recorded the highest energy demand and CO2e emissions, at 780.96 MJ/kg and 90.59 kg CO2e, respectively. Water consumption was lowest for the EW-T-02 wooden wall (0.08 m3) and highest for the EW-M-02 masonry wall (0.19 m3). Conclusively, our analysis of passive house external walls demonstrates that wood-based systems offer superior performance in terms of materials, thermal efficiency, and LCA indicators, positioning them as the preferred option for sustainable passive construction.

Buildings made of massive timber logs with a derogation from the application of technical conditions for traditional masonry technologies

Timber log walls are a unique form of construction - erected from solid material, they are both a building structure and a thermal barrier. Walls of wooden logs have numerous advantages, especially favourable physical and mechanical properties, including insulation and thermal capacity. The technical conditions, which are the Polish interpretation of the Nearly Zero Energy Building (nZEB) building, which a newly designed building must meet, must meet 2 conditions simultaneously: the value of the EP index, which determines the annual calculated demand for non-renewable primary energy for heating, ventilation, cooling and preparation of domestic hot water for the entire building, and adequate thermal insulation of the external walls. Calculating the thermal insulation of a wood partition, relying only on thermal conductivity coefficients without considering other properties of the material, does not reflect the true insulating properties of wood. The lack of research on the insulating properties of wood, and thus the lack of national technical and installation requirements for log houses seriously limits the development of this type of construction and forces to undertake reliable research and development work in this area. The proposed introduction in this type of building of the methodology of the so-called Integrated Energy Design (IED) allows to carry out multi-criteria analysis of design variants at the stage of the virtual model in the BIM standard, in terms of the final energy efficiency of the building. Conducting various types of variant analyses and simulations allows to achieve optimal energy efficiency and to verify and correct the adopted solutions. The high energy efficiency of the building demonstrated by such simulations can be the basis for a deviation from the current regulations, which will allow the implementation of newly designed buildings in massive log technology, without the need for additional thermal insulation. As a result, it will be possible to preserve the unique architectural expression of buildings erected with this technology, with visible massive timber logs both on the exterior facades and on the interior.

Energy-water-food security nexus in mung bean production in Iran: An LCA approach

Mung bean is a very important crop in Iran in both socio-economic and nutritional terms. However, although discussions on food and food security increasingly include sustainability issues, there are no precedents in academic literature that analyze in depth the nexus between energy, water use and food security in relation to this crop in Iran from an agri-food system approach. Therefore, our main objective is to assess the energy-water-food security (EWFs) nexus and the environmental impact of mung bean production in Iran from a “cradle to fork” approach using different nutritional units (1 kg of beans, 1 kg of proteins, and 1000 kcal) and load allocation criteria. In addition, an economic analysis of the farms is carried out. The results show that the on-farm production of mung beans is the phase where the largest environmental impacts are concentrated (between 40 % and 96 % of them, including those related to water and energy use), while cooking accounts for more than 50 % of the carbon footprint. The non-renewable cumulative energy demand (NR CED) and total water footprint (TWF) per kilogram of beans (“cradle to fork”) is estimated at 27.4 MJ and 1.55 m3 and the farm Net Margin (NM) is estimated at 3,677 USD per ha. The paper discusses whether mung bean is a low-impact option for protein production, especially when compared to animal products and the importance of using different functional units and load allocation criteria to address the issue of EWFs and sustainability. In this regard, further research is needed to improve the environmental efficiency of bean production, which is critical for promoting sustainable diets in line with food security goals.

To renovate or to reconstruct – A comparative life-cycle assessment study over an existing building in Fribourg, Switzerland

This study presents a simple and agile yet holistic comparative assessment of the impact, in terms of non-renewable cumulative energy demand (nrCED) and global warming potential (GWP), of two envisioned scenarios for the future of an existing administrative building located in Fribourg, Switzerland: its demolition and reconstruction versus its in-depth renovation. Based on our set of hypotheses, results show that over all life-cycle phases (construction and operation) and the building’s lifetime, the renovation scenario’s GWP is 540 kgCO2-eq/m2 lower than that of the reconstruction scenario, corresponding to a 50% savings. In terms of nrCED, the difference is of about 2 MWh/m2, a 45% savings in the renovation scenario. Both scenarios are found to comply with the SIA 2040 target values. These results, including findings on the most impactful elements, provide useful quantitative information for the decision-making and design team in their next steps toward defining the project.

Assessing the Impacts of Climate Change on Water Resources Carrying Capacity Using Venism

Purpose: Climate modification and population increase are threatening water supplies. The world's population have tripled ever since the turn of the century, nonrenewable energy demand has climbed by a ratio of 30, while occupational production had also risen by a ratio of 50.
 
 Theoretical Framework: Problem sizing and structure, model conceptualization, model implementation and testing, and scenarios analysis are the four phases of a conventional SD modeling framework.
 
 Methods: This indicates that as a result of occupational, agricultural, and urban usage, there is a rising demand for water and a diminishing supply of resources of sufficient quality. Due to the effects of climate change, unkind ocean smooth rose by 0.19 m among 1901 and 2010. Anthropogenic climate change is known to have impacted the incidence and magnitude of flooding. Globally, the recent identification of growing vogues in precipitation and large flows in specific basins suggests a larger impact.
 
 Results: This research article takes stock of the evaluation of the influences of climate change on water transport capacity, in particular using the Vensim model. In this research review, for the analysis or estimate of the impacts of climate change on the water transport capacity, Vensim was investigated using a system dynamics technique to simulate the basin slopes of the supply systems to study climatic effects.
 
 Conclusions: It was concluded that the combination of different adaptation strategies, such as desalination, the construction of dams and the promotion of water conservation, has the greatest effects in reducing the impacts of climate change.

Agroecology as a means to improve energy metabolism and economic management in smallholder cocoa farmers in the Ecuadorian Amazon

Cocoa is one of the most important crops in Ecuador, especially in the Ecuadorian Amazon, where >60,000 ha are dedicated to cocoa; 48,600 ha in production in 2021. Most of the cocoa area (82 %) is managed by smallholders with <10 ha under cultivation. Despite the socioeconomic and environmental importance of these systems, there are no previous studies that provide an integrated view of the energy metabolism and economic viability of different smallholder management styles. Consequently, the objective of this work is twofold: a) to estimate the aggregate energy and economic metabolism of small cocoa producers (< 10 ha) in the Ecuadorian Amazon and b) to investigate the existing differences in the technical-economic management styles of the crop. To this end, primary data were collected from a statistically representative sample of cocoa-growing areas distributed among 279 producers in 86 communities in the region, using the life cycle assessment (LCA) methodology and a cost-benefit analysis associated with management. Our data show that most smallholder farmers produce cocoa in low-input diversified agroforest system with a high share of unpaid family labor. At the Amazon level, smallholder farmers (< 10 ha) produced 16.9 million tons of food for the market with a non-renewable cumulative energy demand (NR CED) of 53.8 TJ (1343 MJ/ha), a carbon footprint (CF) of 8.16 Mt. CO2-eq. (203.9 kg CO2-eq/ha), and a net margin of 19.07 million $ (476.8 $/ha). On average, cocoa yields were estimated at 288 kg/ha, resulting in a NR CED and carbon footprint (CF) per kg of cocoa of 4.18 MJ and 0.98 kg CO2-eq. Despite its apparent homogeneity, three distinct styles of crop management were identified by a cluster analysis. The results suggest that farms with good organic/agroecological management can have a similar income generating capacity to the more intensive conventional farms evaluated, but with better environmental outcomes. Consequently, the paper finally discusses the need to promote public actions and policies that allow for the scaling up and improvement of successful agroecological management in the Ecuadorian Amazon.

Comparative Environmental Analysis for Using Waste Polyethylene and Steel Slag in Semi-dense Asphalt Pavements

Abstract This study presents a life cycle assessment (LCA) evaluating the use of virgin materials, waste polyethylene (PE), and electric arc furnace steel slag (EAFSS) in semi-dense asphalt (SDA) surface courses, which is primarily used for low-noise pavements. Three types of SDA mixtures with virgin materials, waste PE, and EAFSS were prepared and water sensitivity tests were conducted to determine the mechanical performance. The LCA defined three scenarios using system expansion, namely (1) the reference scenario using virgin materials in SDA and disposal of waste PE and EAFSS by municipal solid waste incineration (MSWI) and landfill, respectively; (2) the test scenario using waste PE and straight run binder in SDA, with landfilling of EAFSS; (3) the test scenario using EAFSS in SDA, with the disposal of waste PE by MSWI. The data from the experiments, Swiss industries, official reports, and standard databases were used for the inventory analysis. The results show that compared to the reference, the scenarios using waste PE and EAFSS in SDA would reduce 15 % and 36 % of greenhouse gases emissions, respectively. The reason for the improved environmental performance when waste PE is used in asphalt can be attributed to the use of straight run binder to replace polymer-modified binder and the avoided MSWI. For the EAFSS scenario, the improved environmental performance is attributable to the avoided landfilling. The results also indicate that the recycling of waste PE and EAFSS in SDA would not have benefits in nonrenewable cumulative energy demand.

Energy and greenhouse gases life cycle assessment of electric and hydrogen buses: A real-world case study in Bolzano Italy

The transportation sector plays an important role in the current effort towards the control of global warming. Against this backdrop, electrification is currently attracting attention as the life cycle environmental performance of different powertrain technologies is critically assessed. In this study, a life cycle analysis of the public transportation buses was performed. The scope of the analysis is to compare the energy and global warming performances of the different powertrain technologies in the city fleet: diesel, full electric and hydrogen buses. Real world monitored data were used in the analysis for the energy consumptions of the buses and to produce hydrogen in Bolzano. Compared to the traditional diesel buses, the electric vehicles showed a 43% reduction of the non-renewable primary energy demand and a 33% of the global warming potential even in the worst consequential scenario considered. The switch to hydrogen buses leads to very different environmental figures: from very positive if it contributes to a further penetration of renewable electricity, to hardly any difference if hydrogen from steam-methane reforming is used, to clearly negative ones (approximately doubling the impacts) if a predominantly fossil electricity mix is used in the electrolysis.

Electric arc furnace slag as aggregates in semi-dense asphalt

Electric Arc Furnace Slag (EAFS) is one of the primary by-products of the steel recycling industry, which comes out initially as large pieces, that can be further crushed and be used as aggregates in infrastructure materials. While being a waste product, the relatively high strength of the aggregates means that EAFS can provide favorable properties when used correctly. One possible destination for EAFS of higher value is semi-dense asphalt (SDA), a surface course used as low-noise pavement. Due to the relatively high percentage of air voids in SDA (10–18%), the mixture mechanical properties depend on strong interlocking of the aggregates. This study looks at the incorporation of EAFS fractions (2/4 and 0.125/2 mm) into SDA 4 mixtures at replacement of 13% by volume of the aggregates. These mixtures are compared to the control mixture with sandstone aggregates in terms of volumetrics, water sensitivity, stiffness modulus and fatigue by cyclic indirect tensile loading, along with permanent deformation by the cyclic compression test. The water sensitivity, rheological properties and fatigue resistance of the EAFS mixtures did not vary significantly from the control. The life cycles assessment (LCA) shows that compared to the reference SDA, the EAFS-modified SDA reduces the greenhouse gas emissions and ecological scarcity eco-points by 40% and 90%, respectively due to the avoidance of EAFS landfilling. However, the non-renewable cumulative energy demand is not improved by using EAFS in SDA, due to the additional consumption of bitumen.

Energy, Economic and Environmental Analysis of Alternative, High-Efficiency Sources of Heat and Energy for Multi-Family Residential Buildings in Order to Increase Energy Efficiency in Poland

The article presents energy, economic and environmental analyses of the possibilities of using alternative, high-efficiency sources of heat and energy for the multi-family residential building located in Wrocław, Poland, in the temperate climate zone characteristic of Central Europe. For conventional, alternative and hybrid heating systems based on renewable energy sources, comparative analyses of final energy demand, demand for non-renewable primary energy, CO2 emissions, investment costs and life cycle costs were carried out. The detailed comparative analyses of the research results led to the formulation of conclusions and recommendations which may serve as guidelines for designers of multi-family residential buildings and investors. The solutions of heating and hot water preparation systems recommended in the article will enable the design and construction of buildings with no negative impact on the environment. Taking into account the economic and environmental analyses, the optimal sources of heat and energy are alternative heating systems based on highly efficient heat pumps supplied from a photovoltaic installation. Such solutions, however, have both technical and legal limitations related to the possibility of their implementation and are generally associated with higher investment costs.

A symmetric impact of energy consumption on economic growth in South Africa: New evidence from disaggregated data

This paper aims to re-examine the impact of energy consumption on economic growth in South Africa over the period from 1981 to 2020. The study used a non-linear ARDL model and four proxies of energy consumption, which are largely from non-renewable sources, to examine this linkage. The proxies used in the study include electricity consumption, coal consumption, gas consumption and oil consumption. The study found that, in the short run, economic growth in South Africa is only affected by negative and positive shocks in electricity and oil consumption. However, in the long run, growth is affected by positive and negative shocks in oil consumption, positive shocks in electricity consumption, and negative shocks in both coal and gas consumption. Overall, the study found that in the short run, positive shocks in electricity and oil consumption affect economic growth positively, while negative shocks affect growth negatively. In the long run, the study found that 1) positive (negative) shocks in oil consumption affect economic growth positively (negatively); 2) positive shocks in electricity consumption affect economic growth positively; and 3) negative shocks in coal and gas consumption affect economic growth negatively. This implies that, even though South Africa may be one of the largest energy consumers in Africa, its economic growth in the short run is not entirely vulnerable to non-renewable energy demand shocks. This also implies that South Africa can still pursue energy conservation policies and renewable energy explorations in the short run without wholly compromising its comprehensive economic growth strategy. Policy implications are discussed.

Sustainability of food security in different cacao production systems: A land, labour, energy and food quality nexus approach

The present work analyses the sustainability of food security in cacao monocultures and agroforestry systems under organic and conventional management. Using a novel approach, we developed indicators to assess crucial dimensions of food security, including land and labour productivity, the nutritional quality of food, and their nexus with energy efficiency and consumption. Our ten-year data showed that monocultures, especially conventional ones, are more productive (in terms of land and labour) when only the main crop (cacao) is considered and energy consumption is not assessed. When all the crops produced and the demand for non-renewable energy are included, agroforestry systems are more productive (kg, kcal, proteins and fats and nutritional quality index) and more energy efficient than monocultures according to all the indicators analysed. Therefore, encouraging policies that take into consideration the positive externalities of agroforestry and organic management is crucial for the sustainability of food systems.

Doweled cross Laminated Timber (DCLT) Building Air Tightness and Energy Efficiency Measurements: Case Study in Poland

A contemporary challenge for the construction industry is to develop a technology based on natural building materials which at the same time provides high energy efficiency. This paper presents the results of an airtightness test and a thermal imaging study of a detached house built with technology using cross laminated dowelled timber panels. The thermal conductivity coefficients of the wood wool used to insulate the walls and ceiling of the building have also been measured, the linear heat transfer coefficients of the structural nodes have been numerically determined, and calculations have been made regarding the energy efficiency of the building. On the basis of the research, it was found that the air exchange rate in the analyzed building n50 is at the level of 4.77 h−1. Air leaks were also observed in the places of connection of longitudinal walls with the roof and at the junction of window frames with external walls. The experimentally determined thermal conductivity coefficient of the wood wool was ~10% higher than that declared by the manufacturer. Calculations for the energy performance certificate showed that an increase of ~10% in the thermal conductivity coefficient of the wood wool used to insulate the building results in a heating demand increase of 2.1%. It was also found that changing the value of the parameter n50 from 1.0 h−1 to 4.77 h−1 leads to a 40.1% increase in heat demand for heating the building. At the same time, the indicators for final energy demand EK and non-renewable primary energy demand EP increase by 18.1%.

Life Cycle Assessment of Innovative Asphalt Mixtures Made with Crumb Rubber for Impact-Absorbing Pavements

This study applies the life cycle assessment methodology to evaluate the environmental impacts of shock-absorbing pavements fabricated with recycled materials (crumb rubber and a colored pigment called ferrotone), employing the “cradle-to-grave” approach, in which the impacts of all life cycle phases (from materials’ acquisition to the end-of-life of the pavement) are included. The analysis compares the impacts of standard and innovative asphalt materials, considering cold and hot production processes. In addition, three different lifespans are simulated for the pavement structures: the reference service life until the first intervention is considered to be 5 years, and the following scenarios consider that the alternative asphalt materials may last 20% less (4 years) or 20% longer (6 years) than the reference service life. The analysis uses non-renewable cumulative energy demand (nr-CED) and global warming potential (GWP) as main indicators to determine the environmental impacts over a 45-year analysis period. The results show that adopting the “dry process” (consisting of adding the rubber as a partial substitution for aggregates) increases the overall impacts due to the need for higher contents of binder. However, if the alternative pavement structures last 20% longer than the reference, they would generate lower impacts in terms of nr-CED and GWP.

A Life-Cycle Approach to Investigate the Potential of Novel Biobased Construction Materials toward a Circular Built Environment

Conventional construction materials which rely on a fossil-based, nonrenewable extractive economy are typically associated with an entrenched linear economic approach to production. Current research indicates the clear interrelationships between the production and use of construction materials and anthropogenic climate change. This paper investigates the potential for emerging high-performance biobased construction materials, produced sustainably and/or using waste byproducts, to enable a more environmentally sustainable approach to the built environment. Life-cycle assessment (LCA) is employed to compare three wall assemblies using local biobased materials in Montreal (Canada), Nairobi (Kenya), and Accra (Ghana) vs. a traditional construction using gypsum boards and rockwool insulation. Global warming potential, nonrenewable cumulative energy demand, acidification potential, eutrophication potential, and freshwater consumption (FWC) are considered. Scenarios include options for design for disassembly (DfD), as well as potential future alternatives for electricity supply in Kenya and Ghana. Results indicate that all biobased alternatives have lower (often significantly so) life-cycle impacts per functional unit, compared to the traditional construction. DfD strategies are also shown to result in −10% to −50% impact reductions. The results for both African countries exhibit a large dependence on the electricity source used for manufacturing, with significant potential for future decarbonization, but also some associated tradeoffs in terms of acidification and eutrophication.

The impact of climate policy uncertainty on renewable and non-renewable energy demand in the United States

This paper evaluates the impact of climate policy uncertainty on renewable and non-renewable energy consumption in the United States over the quarterly data from 2000Q1 to 2021Q3. Economic growth and crude oil prices are added to the energy consumption functions as control variables. The paper considers several approaches to model both renewable and non-renewable energy demand. It is found that crude oil prices promote non-renewable energy demand and climate policy uncertainty reduces it. Surprisingly, the impact of economic growth on non-renewable energy consumption is positive but insignificant. It is also observed that economic growth promotes renewable energy demand, and crude oil prices reduce it. Furthermore, climate policy uncertainty positively affects renewable energy demand in the long run. Some policy implications are provided for reducing non-renewable energy consumption and promoting renewable energy use in the United States through climate policy implementation.

Evaluation of the environmental impacts of suckler calf-to-beef mixed crop-livestock farms in northern Italy: A farm-based study

The issue of the environmental impacts of beef production has been extensively debated in recent years. However, the research on this theme has mainly been based on farm-model studies with limited attention to contribution analysis of impact categories and aspects linked to cropping systems and feed self-sufficiency in mixed crop-livestock farms. This study evaluated the cradle-tofarm gate environmental impacts of mixed-crop livestock farms rearing the Piedmontese beef breed and suckler calf-to-beef operations in Northwest Italy. Data have been collected from detailed on-farm questionnaires, field books, and invoices of 11 farms over two years (2017-2018). The environmental impacts have been evaluated in terms of land occupation (LO, m2/year), global warming potential (GWP, kg CO2-eq), acidification potential (AP, g SO2-eq) and non-renewable cumulative energy demand (CED, MJ), using life cycle assessment methodology. The functional unit considered was one kilogram of live weight produced at the farm gate. The Piedmontese beef production system showed comparable average environmental impacts with those found in other studies, even though high variability was observed in the studied farms. The GWP averaged 15.7 kg of CO2 eq/kg LW and ranged from 12.1 to 17.6 kg of CO2 eq/kg LW. The CED, LO and AP were on average 62.4 MJ/kg LW, 18.5 m2/y/kg LW and 305 g SO2 eq/kg LW, respectively. Differences in environmental impacts and GWP contribution analysis were mainly due to differences in cropping system management strategies and the consequent levels of feed self-sufficiency. A positive effect of high fertility and animal productivity was observed on the GWP (r=0.62; P&lt;0.01), highlighting the importance of improving efficiency of these aspects for the reduction of emissions. From the contribution analysis of impact categories, the high cost of purchased feeds (in particular protein feeds), transport, and mineral fertilizers for feed production were highly relevant. However further research is needed to confirm these findings. Highlights - Study of 11 farms for two years. - High relevance of purchased feeds on environmental impacts. - Productive and reproductive performances are key points in reducing environmental impacts. - Importance of the valorisation of farm crop surfaces to satisfy animals’ needs.