Development of a Quantitative Exergy-Based Measure of Sustainability

可持续发展已迅速成长为变革的关键关注点和驱动力，但可持续到底意味着什么？像“减少、再利用、再循环”这样的原则有助于指导我们的思维，但它们并没有提供一种量化的、普遍适用的衡量标准，可以用来理性地做出艰难的决定。同样，目前量化可持续性的方法，包括碳足迹和排放量，往往只关注可持续性的一个特定方面，如气候变化，而忽视了与环境退化有关的众多问题。例如，当比较燃煤发电和核电的碳足迹时，核电很容易获胜；然而，这种评估忽略了围绕核废料的明显环境问题。与这些狭隘的衡量标准不同，经济成本可以为量化可持续性提供一个普遍的基础；然而，经济成本受到其他可以人为操纵的因素的影响(例如，通过投机或政府补贴)，并不总是准确地反映资源的真实价值及其使用对环境的影响。火用是一种资源中的可用能源，它提供了可持续发展的一般、严格的热力学衡量标准。火用已被广泛用于表征工业过程(如发电和化工制造)、环境工程、城市规划和生态系统的可持续性。至关重要的是，(火用)可用于量化过程中的低效、比较技术途径、量化对生态系统造成的损害以及估计生态系统恢复的成本。尽管有其优点，但它没有考虑许多重要的实际因素，如时间的价值，以及利用特定资源所需技术的可用性、效率和成本。该项目将开发一种新的可持续发展的量化衡量标准，其基础是扩展火用的概念，将这些实际因素包括在内。最初的工作是将改进的(火用)分析与标准方法进行比较，如热经济分析和夹点技术，用于完善的工程过程。然后，它将转移到更当前的问题，例如生物质有价化中的原料和产品选择。该项目将提供一个有效的工具，指导政策制定者、公司和个人做出决策，更好地利用我们非常有限的资源。

Sustainable development has rapidly grown to become a key concern and driver for change, but what does it truly mean to be sustainable? Principles like "reduce, reuse, recycle" help to guide our thinking, but they do not provide a quantitative, generally applicable measure that can be used to rationally make difficult decisions. Similarly, current methods of quantifying sustainability, including carbon footprints and emissions, tend to only focus on one particular aspect of sustainability, such as climate change, and neglect the multitude of problematic issues with environmental degradation. For example, when comparing the carbon footprints of coal-generated power to nuclear power, nuclear power easily wins; however, this assessment neglects the obvious environmental issues surrounding nuclear waste. Unlike these narrowly focused measures, economic cost can provide a universal basis to quantify sustainability; however, it is influenced by other factors that can be artificially manipulated (e.g., through speculation or government subsidies) and does not always accurately reflect the true value of resources and environmental impact of their use. Exergy, the usable energy within a resource, provides a general, rigorous thermodynamic measure of sustainability. Exergy has been used extensively to characterize sustainability in industrial processes (e.g., power generation and chemical manufacture) environmental engineering, city planning, and ecosystems. Crucially, exergy can be used to quantify inefficiency within processes, compare technological pathways, quantify the damage inflicted on an ecosystem and estimate the costs of ecosystem restoration. Despite its merits, it does not consider many important practical factors, such the value of time, and the availability, efficiency and cost of the technology required to utilize a given resource. This project will develop a novel quantitative measure of sustainability, based on extending the concept of exergy to include these practical factors. The initial work will compare the modified exergy analysis to standard methods, such as thermoeconomic analysis and pinch technology, for well-established engineering processes. It will then move to more current problems, such as feedstock and product selection in biomass valorisation. The project will provide an effective tool to guide policy makers, companies, and individuals to make decisions to make better use of our very limited resources.