Moving the system boundaries in decarbonization of large islands

The bacterial chemotaxis in a one-dimensional system with a repellent has been considered. The process of bacterial redistribution in the system is analyzed, and a corresponding phenomenological model is proposed, which makes allowance for the diffusion of bacteria and their motion caused by the repellent gradient. The repellent injection into the system is governed by boundary conditions. In the framework of this model, the chemotaxis sensitivity function, a numerical characteristic, which describes the nonuniformity in the bacterial distribution, is calculated. A dependence of the chemotaxis sensitivity function on the repellent concentration at the system boundaries is obtained. A relation between the bacterial distribution and the parameters of repellent distribution is found.

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An Eco-Industrial Park-Based Method for Net Zero Community Creation

10.1115/detc2021-71440 ◽

2021 ◽

Author(s):

Garrett Hairston ◽

Astrid Layton

Keyword(s):

Case Studies ◽

System Structure ◽

Industrial Park ◽

System Boundaries ◽

Design Work ◽

Sustainable Living ◽

Systems Research ◽

Use Of Resources ◽

Net Zero ◽

Human Networks

Abstract Much emphasis is placed on the role of Net Zero Communities (NZCs) in achieving a sustainable future. Systems research on the topic, including the application of bio-inspired techniques already used on other human networks, is currently hindered by the lack of case studies documenting the structure and quantity of energy, water, and waste flows within realistic NZCs. This work proposes and preliminarily tests a method of generating a database of hypothetical-realistic NZCs by expanding the system boundaries for well-documented Eco-industrial Park (EIP) networks. The expansion includes residential and commercial actors from the community surrounding the EIP. Past studies using Ecological Network Analysis (ENA) to improve the environmental and economic performance of these EIPs have resulted in a quantitative database of case studies. Combining these industrial hubs to nearby residential, commercial, agricultural, etc. actors can generate potential multi-use networks on which similar design work can be conducted. Three EIP to NZC cases are generated and analyzed focusing on their system structure. Cyclicity, an ENA metric used to quantify the presence and complexity of cyclic pathways in a network, has been shown to promote the efficient use of resources in both biological and human networks. Cyclicity values for the original EIP networks, the community additions, and the potential NZC case studies reveals that there are many meaningful interactions that occur between actors that are only visible once the system boundaries are expanded to the NZC level. This offers a glimpse into the potential benefits of approaching the NZ problem, and sustainable living more generally, on a system scale — an analysis that will be further enabled by the generation of an NZC database initiated by this work.

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Powering a Sustainable and Circular Economy—An Engineering Approach to Estimating Renewable Energy Potentials within Earth System Boundaries

Energies ◽

10.3390/en12244723 ◽

2019 ◽

Vol 12 (24) ◽

pp. 4723 ◽

Cited By ~ 7

Author(s):

Harald Desing ◽

Rolf Widmer ◽

Didier Beloin-Saint-Pierre ◽

Roland Hischier ◽

Patrick Wäger

Keyword(s):

Renewable Energy ◽

Energy Demand ◽

Great Distance ◽

World Population ◽

Earth System ◽

Energy Access ◽

Renewable Energy Resources ◽

System Boundaries ◽

Energy Mix ◽

Engineering Approach

This study proposes a method to estimate the appropriability of renewable energy resources at the global scale, when Earth system boundaries/needs and the human demand for chemical energy are respected. The method is based on an engineering approach, i.e., uncertainties of parameters and models are considered and potentials calculated with 99 % confidence. We used literature data to test our method and provide initial results for global appropriable technical potentials (ATP) that sum up to 71 TW , which is significantly larger than the current global energy demand. Consequently, there is sufficient renewable energy potentially available to increase energy access for a growing world population as well as for a development towards increasingly closed material cycles within the technosphere. Solar energy collected on the built environment ( 29 % ) and in desert areas ( 69 % ) represent the dominant part of this potential, followed in great distance by hydro ( 0.6 % ), terrestrial heat ( 0.4 % ), wind ( 0.35 % ), and biomass ( 0.2 % ). Furthermore, we propose indicators to evaluate an energy mix on different levels, from an energy mix in single products to the mix used by the global economy, against the estimated RE potentials, which allow an evaluation and consideration in the design of sustainable–circular products and systems.

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Determination of the carbon budget of a pasture: effect of system boundaries and flux uncertainties

Biogeosciences ◽

10.5194/bg-13-2959-2016 ◽

2016 ◽

Vol 13 (10) ◽

pp. 2959-2969 ◽

Cited By ~ 18

Author(s):

Raphael Felber ◽

Daniel Bretscher ◽

Andreas Münger ◽

Albrecht Neftel ◽

Christof Ammann

Keyword(s):

Carbon Budget ◽

Agricultural Sector ◽

Ghg Emissions ◽

C Sequestration ◽

Co2 Exchange ◽

System Boundaries ◽

Simultaneous Application ◽

Soil C ◽

Ecosystem Carbon ◽

Eddy Covariance Measurements

Abstract. Carbon (C) sequestration in the soil is considered as a potential important mechanism to mitigate greenhouse gas (GHG) emissions of the agricultural sector. It can be quantified by the net ecosystem carbon budget (NECB) describing the change of soil C as the sum of all relevant import and export fluxes. NECB was investigated here in detail for an intensively grazed dairy pasture in Switzerland. Two budget approaches with different system boundaries were applied: NECBtot for system boundaries including the grazing cows and NECBpast for system boundaries excluding the cows. CO2 and CH4 exchange induced by soil/vegetation processes as well as direct emissions by the animals were derived from eddy covariance measurements. Other C fluxes were either measured (milk yield, concentrate feeding) or derived based on animal performance data (intake, excreta). For the investigated year, both approaches resulted in a small near-neutral C budget: NECBtot −27 ± 62 and NECBpast 23 ± 76 g C m−2 yr−1. The considerable uncertainties, depending on the approach, were mainly due to errors in the CO2 exchange or in the animal-related fluxes. The comparison of the NECB results with the annual exchange of other GHG revealed CH4 emissions from the cows to be the major contributor in terms of CO2 equivalents, but with much lower uncertainty compared to NECB. Although only 1 year of data limit the representativeness of the carbon budget results, they demonstrate the important contribution of the non-CO2 fluxes depending on the chosen system boundaries and the effect of their propagated uncertainty in an exemplary way. The simultaneous application and comparison of both NECB approaches provides a useful consistency check for the carbon budget determination and can help to identify and eliminate systematic errors.

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