28 research outputs found
Life cycle optimization of sustainable energy systems within planetary boundaries
Curbing carbon emissions in the power sector has become a priority to mitigate climate change, yet the sustainability implications of power generation decarbonization remain unclear. To shed light on whether current plans to decarbonize the electricity system would be enough to deliver sustainable energy, modeling frameworks able to achieve multi-criteria environmental analysis need to be developed.
Firstly, this thesis combines multi-objective optimization, life cycle impact assessment and multivariate regression based on elasticities to quantify the occurrence and severity of burden-shifting in energy systems due to carbon policies. Secondly, it integrates thousands of life cycle inventories into the optimization of energy systems using monetization. Thirdly, it downscales and integrates planetary boundaries into the optimization of energy systems. Finally, it evaluates and optimizes the planetary boundaries performance of the global power sector in 2100 using data obtained from Integrated Assessment Models (IAMs).
Results classify life cycle indicators into three categories: no burden-shifting, total burden-shifting and partial burden-shifting. Depending on the severity of the carbon target, burden-shifting to some life cycle indicators could take place. While meeting the Paris Agreement could generate indirect environmental savings, concurrently optimizing the direct and indirect costs of electricity generation would yield the highest environmental benefits. Few pathways developed via IAMs would operate within the planetary boundaries that all anthropogenic activities should share jointly in 2100, while all of them would exceed the share of budget allocated to the global power sector. Energy mixes in line with some carbon policies could transgress critical planetary boundaries, including those on climate change. Deploying bio-energy with carbon capture and storage hand-in-hand with renewables and nuclear plants is critical to minimizing the transgression of planetary boundaries while maintaining the gridâs reliability. This thesis, therefore, highlights the need to depart from carbon policies to multi-criteria environmental policies to power our development sustainably.Open Acces
Reply to the 'Comment on "Powering sustainable development within planetary boundaries"' by Y. Yang, Energy Environ. Sci., 2020, 13, DOI: 10.1039/C9EE01176E
In our recently published work, we incorporated planetary boundaries in the optimization of the United States (US) power sector in 2030. Yang claims there is a double-counting error in our results and encourages us to minimize direct emissions instead of life cycle emissions in our model. Here, we argue that Yang's main criticism based on the risk of double-counting emissions when multiple sectors are simultaneously optimized does not apply to our case study, in which only one sector â the power sector â is analyzed. To assess the implications of Yang's suggestion to minimize direct emissions, we repeated the calculations optimizing direct emissions instead of life cycle emissions. We found that this approach is unable to discriminate effectively between electricity production technologies and, consequently, leads to a suboptimal mix with impacts on climate change, ocean acidification and freshwater use 102, 33 and 1.5 times the limits, respectively, whereas our original solution meets all planetary boundaries concurrently. Our findings imply that Yang's suggestion of optimizing direct emissions in energy systems models might not the best way forward in single-sector studies like ours
Life cycle burden-shifting in energy systems designed to minimize greenhouse gas emissions: Novel analytical method and application to the United States
Energy systems are currently designed focusing only on minimizing their cost or, at most, including limits on greenhouse gas emissions. Unfortunately, electricity technologies performing well in global warming potential might not necessarily behave equally well across other sustainability criteria. Hence, policies focused solely on mitigating greenhouse gas emissions could potentially resolve one problem (i.e., climate change) by creating another, thereby leading to burden-shifting. Here, the occurrence and severity of burden-shifting in energy systems design are both investigated through the application of a novel approach integrating multi-objective optimization, life cycle assessment and multivariate regression based on elasticities. Environmental impacts are classified into three categories: no burden-shifting, total burden-shifting and partial burden-shifting, providing in turn for the latter two a measure of their severity. Due to inherent trade-offs in the life cycle performance of technologies, discussed in detail in this work, the Paris Agreement 2 ËC targets would lead to burden-shifting in the United States (total or partial) in up to eight environmental impacts. On the other hand, stringent carbon emissions reductions in line with the 1.5 ËC targets can lead to burden-shifting in three environmental impacts. Indeed, in both cases undesirable increases in some damage categories of up to 1.64% for every percentage increase in cost due to stringent reductions in greenhouse gas emissions compared to the least cost solution. Overall, this work aims to foster fruitful discussions on how to generate energy within the Earthâs ecological capacity by expanding the analysis beyond climate change
Quantifying the cost of leaving the Paris Agreement via the integration of life cycle assessment, energy systems modeling and monetization
Current energy systems models focus on cost minimization with a bound on some greenhouse gas emissions. This limited environmental scope can lead to mixes that are not consistent with our sustainable development. To circumvent this limitation, we here make use of the concept of monetization and life cycle assessment to quantify the indirect costs of electricity generation in the design of energy systems. Applying our approach to the United States, we found that the indirect costs of electricity generation could be reduced by as much as 63% by meeting the Paris Agreement. Consequently, the total opportunity cost (i.e., direct and indirect costs) of withdrawing from the Paris Agreement and continuing with the current mix would be as high as 1103 ± 206 billion USD2013 in 2030 (i.e., 6% of the United States gross domestic product in 2017). By optimizing the direct and indirect cost of electricity generation concurrently, we found an optimal ecological solution that attains total economic savings compared to the Paris Agreement mix of as much as 373 ± 164 billion USD2013 in 2030. Our work highlights the need to extend the environmental policies that govern energy systems beyond the direct greenhouse emissions to consider other critical environmental criteria
Reply to the âComment on âPowering sustainable development within planetary boundariesââ by Y. Yang, Energy Environ. Sci., 2020, 13, DOI: 10.1039/C9EE01176E
In our recently published work, we incorporated planetary boundaries in the optimization of the United States (US) power sector in 2030. Yang claims there is a double-counting error in our results and encourages us to minimize direct emissions instead of life cycle emissions in our model. Here, we argue that Yang's main criticism based on the risk of double-counting emissions when multiple sectors are simultaneously optimized does not apply to our case study, in which only one sector â the power sector â is analyzed. To assess the implications of Yang's suggestion to minimize direct emissions, we repeated the calculations optimizing direct emissions instead of life cycle emissions. We found that this approach is unable to discriminate effectively between electricity production technologies and, consequently, leads to a suboptimal mix with impacts on climate change, ocean acidification and freshwater use 102, 33 and 1.5 times the limits, respectively, whereas our original solution meets all planetary boundaries concurrently. Our findings imply that Yang's suggestion of optimizing direct emissions in energy systems models might not the best way forward in single-sector studies like ours.ISSN:1754-5692ISSN:1754-570
Correction: Powering sustainable development within planetary boundaries
Correction for âPowering sustainable development within planetary boundariesâ by Ibrahim M. Algunaibet et al., Energy Environ. Sci., 2019, 12, 1890â1900.ISSN:1754-5692ISSN:1754-570
Correction: powering sustainable development within planetary boundaries (vol 12, pg 1890, 2019)
Correction for âPowering sustainable development within planetary boundariesâ by Ibrahim M. Algunaibet et al., Energy Environ. Sci., 2019, 12, 1890â1900
Powering sustainable development within planetary boundaries
The concept of planetary boundaries identifies a safe space for humanity. Current energy systems are primarily designed with a focus on total cost minimization and bounds on greenhouse gas emissions. Omitting planetary boundaries in energy systems design can lead to energy mixes unable to power our sustainable development. To overcome this conceptual limitation, we here incorporate planetary boundaries into energy systems models, explicitly linking energy generation with the Earthâs ecological limits. Taking the United States as a testbed, we found that the least cost energy mix that would meet the Paris Agreement 2 degrees Celsius target, still transgresses five out of eight planetary boundaries. It is possible to meet seven out of eight planetary boundaries concurrently by incurring a doubling of the cost compared to the least cost energy mix solution (1.3% of the United States gross domestic product in 2017). Due to the stringent downscaled planetary boundary on biogeochemical nitrogen flow, there is no energy mix in the United States capable of satisfying all planetary boundaries concurrently. Our work highlights the importance of considering planetary boundaries in energy systems design and paves the way for further research on how to effectively accomplish such integration in energy related studies