The goal of the UI project is to quantify the material requirements and dependencies, especially in terms of critical materials, of planned low-carbon infrastructure deployments.
To design a truly adaptable, sustainable, low-carbon infrastructure and deliver it without bottlenecks caused by materials scarcity and waste management, we need to be able to model:
the flow of materials into and out of infrastructure;
the stocks of materials contained within infrastructure, during operation and demolition;
the location and properties of these materials and the components they are a part of;
the criticality of key materials, in terms of substitutability and supply risks;
the interactions between these factors.
We propose to achieve this by expanding the usual single-element Stocks and Flows modelling paradigm and rebuilding it as a parallel, multi-element planning tool encompassing resource demand projections (and hence potential vulnerabilities) and material properties information (for effective re-use strategies). This will require S&F to be complemented with three new levels of information, detailed below.
Quality, Property and Location of stocks
Most S&F models have as a outcome the total stock of material in the system. In this model, we want to know more about the stocks than their total quantity. We want to know enough about the state of the materials to deliver a useful prognosis in terms of potential for re-use or recycling in different applications, as well as continued performance in its intended application. This requires a higher level of detail. We need this information for two distinct purposes: to analyse how changes in the ‘quality’ of the structural or functional materials in the system affect its vulnerability. As part of carbon mitigation efforts, the properties required of infrastructure materials can be expected to change (for example low carbon concrete). Such changes can be expected to have knock-on effects on infrastructure vulnerability. The second purpose is to estimate the potential for infrastructure ‘mining’. This is done by reducing the impact of infrastructure disposal through reuse and recycling, and by designing new infrastructure to optimise resource recovery at end of life. In both cases, we need detailed information regarding the material-containing components that enter the stocks, in terms of their composition and the recycle-ability thereof (alloys), physical properties of structural elements, including modified lifetimes and other associated issues.
The goal here is to quantify, in various ways, the risk posed by critical material supply disruption to continued operation of existing infrastructure, or the proposed introduction of new infrastructure. Embedding new technology within infrastructure introduces a reliance on materials at risk of supply chain disruption and with limitations on substitutability. These materials are often not extracted in the EU, introducing trade dependencies. They are largely absent from existing infrastructure, and thus cannot be supplied through waste processing. Their introduction in to infrastructure can have a knock-on effect owing to its sheer scale; similarly, previously apparently abundant materials may become critical. As other countries introduce similar technologies, resource competition will increase. Our methodology will estimate the (large) scale demand for such new materials required by new infrastructure plans and compare it with current supply. By combining individual indices, we will determine the overall vulnerability of systems.
The modelling and analysis in this project is dynamic in several ways. As a basis, we use a variety of scenarios for the deployment of low carbon infrastructure, enabling us to investigate diverse future options. In addition to these scenarios, the time-resolved properties of the infrastructure and its components are included, in the form of appropriate lifetimes and lifetime functions. Additional information on the degradation or dissipation of the materials and components over time will be tracked in the infrastructure properties. This will enable us to predict where and when vulnerabilities are likely to occur; and plan appropriate prophylactic measures. Moreover, the robustness of the results to uncertainties in various technical parameters will be tested, which is are not common practice in current S&F models, but crucial for policy uptake.
Application: case studies
This methodology will be tested on three case studies to refine the initial approach and demonstrate its applicability to the challenge described in this proposal. The case studies will include:
- Some simple, proof-of-concept physical infrastructure systems (such as a bridge);
- More detailed of a system; for example a power station; and
- A system of systems; a place that interacts with a number of different infrastructure systems (for example a neighbourhood or city).
The case studies will be analysed to identify existing stocks, assess the vulnerability of ‘replacement’ infrastructures and identify new proposals and solutions for alternative approaches. We recognise that the boundaries of the systems and flows may be difficult to define in this project. However, we consider that it would be more important to demonstrate the approach than to define the boundaries absolutely. This demonstration will help us to understand how this approach could be used by policy makers and decision makers and inform more detailed studies in the future.
As an analysis tool, the methodology will be used to assess the vulnerability of e.g. a city or infrastructure system and target appropriate remedial strategies. As a design tool, it will be used to compare the vulnerability of design options (e.g. for a low-carbon infrastructure component) to material scarcity. As a policy tool, it will enhance assessment of the impact of decisions that affect national infrastructure systems.
This will help us to ensure that low-carbon solutions do not lead to decreased resilience requiring unpredictable, carbon-costly remedial measures in the future. It will allow us to design increasingly resilient solutions by identifying and ‘designing out’ pinch-points in materials supply; and it will provide a robust intellectual and practical framework for analysis of complex interconnected infrastructure systems.