A review of life cycle assessments of renewable energy systems

A review of life cycle assessments (LCAs) of wind energy published in the past few years are presented in this paper. The aim is to identify the differences of the developed methodologies, in particular, the factors such as methods used, energy performance and influence of uncertainty. Each of the factors is addressed to highlight the shortcomings and strengths of various approaches. Potential issues were identified regarding the way LCA is used for assessing environmental impact and energy performance of wind energy. It is found that the potential of incorporating the quantification of uncertainty in the manufacturing phase has not been studied elaborately. A framework methodology has been proposed in this paper to address this issue

A hybrid Data Quality Indicator and statistical method for improving uncertainty analysis in LCA of a small off-grid wind turbine

In Life Cycle Assessment (LCA) uncertainty analysis has been recommended when choosing sustainable products. Both Data Quality Indicator and statistical methods are used to estimate data uncertainties in LCA. Neither of these alone is however adequate enough to address the challenges in LCA of a complex system due to data scarcity and large quantity of material types. This paper applies a hybrid stochastic method, combining the statistical and Data Quality Indicator methods by using a pre-screening process based on Monte Carlo rank-order correlation sensitivity analysis, to improve the uncertainty estimate in wind turbine LCA with data limitations. In the presented case study which performed the stochastic estimation of CO2 emissions, similar results from the hybrid method were observed compared to the pure Data Quality Indicator method. Summarily, the presented hybrid method can be used as a possible alternative for evaluating deterministic LCA results like CO2 emissions, when results that are more reliable are desired with limited availability of data

Sustainability Assessment of Wind Turbine Design Variations: An Analysis of the Current Situation and Potential Technology Improvement Opportunities

Over the last couple of decades, there has been increased interest in environmentally friendly technologies. One of the renewable energy sources that has experienced huge growth over the years is wind power with the introduction of new wind farms all over the world, and advances in wind power technology that have made this source more efficient. This recognition, together with an increased drive towards ensuring the sustainability of wind energy systems, has led many to forecast the drivers for future performance. This study aims to identify the most sustainable wind turbine design option for future grid electricity within the context of sustainable development. As such, a methodology for sustainability assessment of different wind turbine design options has been developed taking into account environmental, data uncertainty propagation and economic aspects. The environmental impacts have been estimated using life cycle assessment, data uncertainty has been quantified using a hybrid DQI-statistical method, and the economic assessment considered payback times. The methodology has been applied to a 1.5 MW wind turbine for an assessment of the current situation and potential technology improvement opportunities. The results of this research show that overall, the design option with the single-stage/permanent magnet generator is the most sustainable. More specifically, the baseline turbine performs best in terms of embodied carbon and embodied energy savings. On the other hand, the design option with the single-stage/permanent magnet generator performs best in terms of wind farm life cycle environmental impacts and payback time compared to the baseline turbine. With respect to the design options with increased tower height, it is estimated that both designs are the least preferred options given their payback times. Therefore, the choice of the most sustainable design option depends crucially on the importance placed on different sustainability indicators which should be acknowledged in decision making and policy

Improving uncertainty analysis of embodied energy and embodied carbon in wind turbine design

In this paper, a method for improving uncertainty estimates of embodied carbon and embodied energy is presented and discussed. Embodied energy and embodied carbon results are the focus of this analysis due to the fact that, at the conceptual design stage, these two are the most important quantities for decision making in life cycle assessment (LCA) studies. The use of renewable and new energy sources and the development of cleaner and more efficient energy technologies will play a major role in the sustainable development of a future energy strategy. Environmental protection,economic and social cohesion and diversification and security of energy supply are highlighted by the International Energy Agency as a high priority for the development of cleaner and more efficient energy systems and promotion of renewable energy sources. In the case studies presented,better results for the baseline turbine were observed compared to turbines with the proposed technology improvement opportunities. Embodied energy and embodied carbon results for the baseline turbine show an about 50 % probability that the turbine manufacturer may have lost the chance to reduce carbon emissions and 85 % probability that the turbine manufacturer may have lost the chance to reduce the primary energy consumed during its manufacture. The proposed approach is therefore a feasible alternative when more reliable results are desired for LCA-based design decision making

A hybrid Stochastic Approach for Improving Uncertainty Analysis in the Design and Development of a Wind Turbine

This paper presents an analysis of potential technological advancements for a 1.5 MW wind turbine using a hybrid stochastic method to improve uncertainty estimates of embodied energy and embodied carbon. The analysis is specifically aimed at embodied energy and embodied carbon results due to the fact that life cycle assessment (LCA) based design decision making is most important at the concept design stage. The development of efficient and cleaner energy technologies and the use of renewable and new energy sources will play a significant role in the sustainable development of a future energy strategy. Thus, it is highlighted in International Energy Agency that the development of cleaner and more efficient energy systems and promotion of renewable energy sources are a high priority for (i) economic and social cohesion, (ii) diversification and security of energy supply, and (iii) environmental protection. Electricity generation using wind turbines is generally regarded as key in addressing some of the resource and environmental concerns of today. In the presented case studies, better results for the baseline turbine were observed compared to turbines with the proposed technological advancements. Embodied carbon and embodied energy results for the baseline turbine show an about 85% probability that the turbine manufacturer may have lost the chance to reduce carbon emissions, and 50% probability that the turbine manufacturer may have lost the chance to reduce the primary energy consumed during its manufacture. Conclusively, the presented approach is a feasible alternative when more reliable results are desired for decision making in LCA

Hydrothermal treatment of waste plastics : an environmental impact study

This paper presents the attributional life cycle assessment results of a study of plastic recycling using hydrothermal treatment (HTT), a chemical recycling technology. HTT was investigated due to its potential to address current gaps in the plastic recycling system, largely due to several plastic packaging materials and formats that are currently not processed by traditional mechanical recycling technologies. As society transitions towards a net-zero-based circular economy, assessments should be conducted with a futuristic outlook, preventing costly mistakes by employing the right technologies in the right areas. The results using ReCiPe 2016 impact assessment methodology shows HTT with a GWP of 478 kg CO2 eq. per tonne can generate up to 80% reduction in climate change impacts when compared with comparable end-of-life treatment technologies whilst conserving material with the system. Additionally, the GWP could be reduced by up to 57% by changing how electricity is generated for on-site consumption. This represents a new understanding of the chemical recycling of polymers by establishing a prospective life cycle assessment study that looks to introduce a step-change in the recycling system and highlights the benefits of introducing this technology as opposed to the current model of disposal through incineration or landfill

Comparative LCA technology improvement opportunities for a 1.5 MW wind turbine in the context of an offshore wind farm

Wind energy is playing an increasingly important role in the development of cleaner and more efficient energy technologies leading to projections in reliability and performance of future wind turbine designs. This paper presents life cycle assessment (LCA) results of design variations for a 1.5 MW wind turbine due to the potential for advances in technology to improve the performance of a 1.5 MW wind turbine. Five LCAs have been conducted for design variants of a 1.5 MW wind turbine. The objective is to evaluate potential environmental impacts per kilowatt hour of electricity generated for a 114 MW onshore wind farm. Results for the baseline turbine show that higher contributions to impacts were obtained in the categories Ozone Depletion Potential, Marine Aquatic Eco-toxicity Potential, Human Toxicity Potential and Terrestrial Eco-toxicity Potential compared to Technology Improvement Opportunities (TIOs) 1 to 4. Compared to the baseline turbine, TIO 1 showed increased impact contributions to Abiotic Depletion Potential, Acidification Potential, Eutrophication Potential, Global Warming Potential and Photochemical Ozone Creation Potential, and TIO 2 showed an increase in contributions to Abiotic Depletion Potential, Acidification Potential and Global Warming Potential. Additionally, lower contributions to all the environmental categories were observed for TIO 3 while increased contributions towards Abiotic Depletion Potential and Global Warming Potential were noted for TIO 4. A comparative LCA study of wind turbine design variations for a particular power rating has not been explored in the literature. This study presents new insight into the environmental implications related with projected wind turbine design advancements

Analysis of Technology Improvement Opportunities for a 1.5MW Wind Turbine using a Hybrid Stochastic Approach in Life Cycle Assessment

This paper presents an analysis of potential technological advancements for a 1.5 MW wind turbine using a hybrid stochastic method to improve uncertainty estimates of embodied energy and embodied carbon. The analysis is specifically aimed at these two quantities due to the fact that LCA based design decision making is of utmost importance at the concept design stage. In the presented case studies, better results for the baseline turbine were observed compared to turbines with the proposed technological advancements. Embodied carbon and embodied energy results for the baseline turbine show that there is about 85% probability that the turbine manufacturers may have lost the chance to reduce carbon emissions, and 50% probability that they may have lost the chance to reduce the primary energy consumed during its manufacture. The paper also highlights that the adopted methodology can be used to support design decision making and hence is more feasible for LCA studies

A Review of Life Cycle Assessment of Renewable Energy Systems

A review of life cycle assessments (LCAs) of wind energy published in the past few years are presented in this paper. The aim is to identify the differences of the developed methodologies, in particular, the factors such as methods used, energy performance and influence of uncertainty. Each of the factors is addressed to highlight the shortcomings and strengths of various approaches. Potential issues were identified regarding the way LCA is used for assessing environmental impact and energy performance of wind energy. It is found that the potential of incorporating the quantification of uncertainty in the manufacturing phase has not been studied elaborately. A framework methodology has been proposed in this paper to address this issue

Hydrothermal treatment of waste plastics : an environmental impact study

This paper presents the attributional life cycle assessment results of a study of plastic recycling using hydrothermal treatment (HTT), a chemical recycling technology. HTT was investigated due to its potential to address current gaps in the plastic recycling system, largely due to several plastic packaging materials and formats that are currently not processed by traditional mechanical recycling technologies. As society transitions towards a net-zero-based circular economy, assessments should be conducted with a futuristic outlook, preventing costly mistakes by employing the right technologies in the right areas. The results using ReCiPe 2016 impact assessment methodology shows HTT with a GWP of 478 kg CO2 eq. per tonne can generate up to 80% reduction in climate change impacts when compared with comparable end-of-life treatment technologies whilst conserving material with the system. Additionally, the GWP could be reduced by up to 57% by changing how electricity is generated for on-site consumption. This represents a new understanding of the chemical recycling of polymers by establishing a prospective life cycle assessment study that looks to introduce a step-change in the recycling system and highlights the benefits of introducing this technology as opposed to the current model of disposal through incineration or landfill