Digital Twins: The Link Towards Sustainability

Abstract
In this case study, we analyze the potential of emerging technologies involved in the development and design of Digital Twins (DT) for the tracking and monitoring of physical assets through virtual representations. First mentioned by Michael Grieves, an engineer from the University of Michigan, Digital Twins are virtual representations of particular products, assets, portfolios, or entire environments. Currently, DTs are employed in supply chains to monitor, predict, and simulate scenarios in order to future-proof the practices within a company. Prominent use cases disclosed in this study are Singapore's Virtual Town, a DT mounted on Build Information Modeling (BIM) that prepares virtual recalibrations of the city's variables for better multi-tracking and monitoring; and 3M's PACEsetter, a proprietary DT that processes data for real-time analysis of their manufacturing assembly lines. While describing the benefits provided by DTs in these use cases, we also present a comprehensive examination of its downsides and possible challenges for implementation, such as issues with data accuracy and investment costs. In addition, we provide an in-depth review of Everledger's initiative of creating a DT of each diamond in the conflict stones industry in Africa as a secure and permanent digital record containing precise information of their characteristics and ownership, thus facilitating tracking, compliance, trustworthiness, and accountability. We append to this case study with a review of the European Green Deal's landmark action called Destination Earth, an information framework intended to create an Earth's digital replica to help the world shift from energy-intensive practices to approach zero waste and zero contamination. Finally, we also explore DT's contributions to sustainability and potential obstacles it may face in the future, including the overall business adoption and the creation of policies and regulations to forward its employment.

What happens to supply chains if we digitally replicate all physical objects within its entire ecosystem? What is more, what if we create a digital replica of the whole world? One that can trace and monitor global activity in real-time and simulate events before they even happen?

Creating a Sustainable Economy

Throughout time, humanity has transferred its observations of the planet Earth into static representations to keep track of what we can see but not corporally record in detail in our minds, such as maps, paintings, photographs, numbers, or simple sketches. These static representations never stopped evolving, as well as our interest in registering and monitoring how the tools we invent behave in the environment we inhabit.

With the rapid development and introduction of innovative emerging technologies, the process of documenting virtual representations of physical assets evolved too. Together with getting closer to understanding how entire ecosystems behave with the help of Satellite Image Processing (SIP), improved insights about more significant issues such as the climate crisis, the amount of CO2 emissions released by industries, land-use management, and natural resource scarcity came along too.

The images harnessed by satellites are often static, and to acquire more comprehensive views of the Earth's variables, data scientists need to collect other types of information to complement their studies. Yet, the data they harness is not always accountable. As shown by recent research released by CDP, just 57% of global suppliers report their emission reduction activities, a mere 37% have structured a carbon-reducing goal, and only 3% of their goals align with scientific projects to act sustainably.

To add more concerns to these staggering numbers, as a curious fact, a study published in Nature revealed that carbon emissions from supply chain multinationals' decreased considerably between 2011 and 2016. Some researchers argued that these numbers were a result of higher investment in making industries more carbon efficient, but what the study really showed was that plenty of assets and suppliers were outsourced to developing countries instead of concentrating CO2 emissions in developed nations. For instance, the emissions generated between 2011 and 2016 through investments from the US to India increased from 43.5 million tons to 70.7 million tons. According to Dr. Zengkai Zhang from Tianjin University, the lead author of the study,

In December 2019 The European Union drafted a strategy for the planet to become climate neutral by 2050, known as the European Green Deal. In order to bring about a green transition, the policies received €1 trillion investment to back-up developments in carbon-neutral fuels, the production of sustainable energy, and a shift from energy-intensive industries to reach zero waste and zero pollution.

A crucial element of this initiative is to transform Europe into a digital central hub for informed decision-making with open and available data. The initiative identified two actions with great expectation to support information systems:

• GreenData4All: A European approach designed to manage and explore geospatial information.

• Destination Earth: A highly accurate 'digital twin' to monitor and predict environmental changes and human impact on ecosystems by combining recent advances in Machine Learning Data Analytics and extensive data sources of Earth's observations.

The Destination Earth landmark action is at the early stages of research, but the concept dates back to the 1960s with NASA's pairing technology, a tool used to run simulation models of physical entities to virtually test space mission scenarios. Decades later, this tool became what is commonly called as Digital Twin (DT), a virtual replica of physical assets. To shed light on its specifications, we dedicate the following section to a comprehensive analysis of DTs' development, design, and recent use cases.

The Development and Design of Digital Twins

First mentioned by Michael Grieves, an engineer from the University of Michigan, Digital Twins are virtual representations containing data about a particular product, asset, portfolio, or environment. Grieves describes the interactions between physical assets and virtual representations as a twinning concept, in which data from physical entities feed virtual layers that process back to the physical.

The virtual space where physical and digital interact consists of, according to Grieves, an unprecise number of sub-spaces that allow virtual operations for testing, optimization, and modeling. The design brought by Michael Grieves is still the foundation for further development and creation of current use cases of DTs worldwide.

According to Grieves' design, the virtual and physical assets are not meant to be a static representation of each other; the link between the two parties is what represents the lifecycle of the system itself, whereas the connected system only takes place when both the physical and the virtual are retrofeeding themselves.

There are three types of Digital Twins: Digital Twin Prototype (DTP), Digital Twin Instance (DTI), and Digital Twin Aggregate (DTA), in which all are operated on a Digital Twin Environment (DTE).

• Digital Twin Prototype (DTP): informational sets containing all necessary data to describe and produce a prototypical physical version of the data that virtually duplicates a physical artifact. This type of DT does not describe real-time alterations performed on the physical asset; to include modifications on the physical asset to the digital replica, a new DTP shall be designed.

• Digital Twin Instance (DTI): informational sets that remain interlinked to a physical artifact throughout the lifecycle of that physical artifact without the need to creating a new DT of the physical asset, unlike DTP. The dataset added to the DTI includes the geometry of the physical instance and its components, a list of current components and all past components, a list including the operations performed in creating the physical instance, descriptions of past services performed and components replaced, and finally, real-time data captured from sensors, used to feed the virtual replica with precise information regarding the physical asset.

• Digital Twin Aggregate (DTA): informational sets that aggregate all the datasets added to the DTI. The data components added to the DTA receive and process all the data captured by sensors and later analyze it against contextual data.

The Digital Twin Environment (DTE) is the virtual representation of the environments where the physical asset exists. The DTE is the application space for operating simulation, modeling, and evaluation of DTs for a variety of purposes.

Prominent Use Cases

Virtual Singapore

The most popular use case of DTs is the virtual town of Singapore, a digital replica that can run pilots of the city variables and test scenarios before implementing actions. Singapore's virtual town is part of the Integrated Digital Delivery (IDD), a project developed by Singapore's Building and Construction Authority that aims to integrate operation methods and consolidate networks between stakeholders to work on the same project throughout the development and construction lifecycle of the city. This digital initiative holds the promise to backup Singapore's government and lawmakers in visualizing the city's variables for better multi-tracking and monitoring, thus acting as the backbone for decision-making.

The IDD is mounted on Building Information Modeling (BIM), which enables stakeholders to prepare recalibrations on the physical assets while digitally modifying them in real-time, including design, fabrication, and assembly on-site. All new physical elements added to the plan are verified against a digital 3D model, allowing site managers to trace and analyze the work being done and prevent possible malfunctionings. The IDD project enables specialists to monitor the city's variables such as the ambient temperature, the interactions between new constructions and already existing installations, as well as analyzing the amount of sunlight harvested by solar rooftops installed on top of the buildings.

Recent developments of Singapore's Virtual Town include a tool available to all citizens that incorporate precise virtual representations of the physical landscape. The platform allows access to information such as the closest bus stop, cycling routes, and barrier-free pathways for the disabled. This open-source platform is expected to serve as an accountability tool where citizens can keep track of the urban planning developments performed by authorities, thus enabling transparency and better communication between parties.

3M's Digital Transformation

DTs are impacting the manufacturing sector too. The Film and Material Research Division (FMRD) of 3M, one of the world's largest manufacturing corporations, responsible for producing about 60,000 patented products worldwide, has recently started a digital transformation of its production processes. The multinational company, after reporting data intermittency problems on their former digital platform system that works as a traditional midpoint for sharing and transferring information, decided to implement an innovative solution called PACESetter, a proprietary DT that processes data for real-time analysis and spatial monitoring.

PACESetter is expected to improve real-time feedback on changes of orders and records, increase security and transparency in data transfers, automate processes, and provide a sustainable approach to their manufacturing standards by predicting possible malfunctionings on resource allocation and extending the life of existing equipment.

These methodological frameworks in which DTs are applied offer great opportunities for businesses to simulate scenarios for parameter optimization. Yet, if physical assets in the supply chain are poorly replicated in the Digital Twin Environment, the resulting virtual simulations may lead to problems too, such as inaccurate simulations that do not correspond to the physical reality. It is key to fine-tune the physical asset simulations before relying on the DT, which could be solved by implementing more precise sensors throughout the supply chain or constantly reviewing the contextual data.

Another concern for the implementation of DTs along the supply chain is affordability. The investments for adopting this digital framework are considerably high, even though the outcomes may pay off implementation costs. For example, Robert Sentz, a manufacturing technology engineer at 3M, reported that after implementing their proprietary DT, it helped increase production volumes and extend equipment lifetime, which balanced the investments placed on this digital transformation. Even if promising, implementation costs can also lead to a considerable gap in terms of access between multinationals and small businesses, which in the short-term may benefit only those companies with more capital liquidity.

However, some future developments are expected to resolve this problem. Recreating a digital replica of the whole planet and sharing this information through an accessible and open platform could be advantageous for small-sized businesses and possibly minimize the costs of their investments. In addition, beyond improving internal planning and communication practices, DTs also hold immense promise in enhancing transparency among customers and producers. In the following section, we disclose recent developments in DTs architecture that are shifting years-old conflicts along the supply chain in terms of worker rights and environmental impacts.

Digital Twinning Every Single Blood Drop Spit

In 2019, the blockchain company Everledger launched a 2.0 version of their blockchain platform with the aim to increase transparency across intricate and poorly regulated diamond supply chains. Their initiative attracted the attention of many companies, including the US-based retailer Fred Meyer Jewelers and Alrosa, the world's largest diamond company. To propel a blockchain-powered program to track the diamond supply chain, the platform provides informed data on all procedures the diamonds pass through, such as the transfer of diamonds from the mines to the refinery, the places where they are torqued, the distributor, and the reselling channel.

In the past decades, African countries such as Angola, Liberia, Sierra Leone, the Republic of Congo, Côte d'Ivoire, the Central African Republic, and the Democratic Republic of Congo, have undergone civil conflicts caused by the exploitation of diamonds. In fact, in the Central African Republic, a civil war erupted in 2013 due to an arms race to source local diamonds. So far, the wars fuelled by diamonds have taken the lives of about 3.7 million people. This industry was coined as the 'blood diamond' or 'conflict diamond' industry, mainly because the disputes financed by rebel militias and local armies subsequently led to slave labor in diamond mines and illicit profit from arcane diamond provenance.

Everledger's program aims to create a whole ecology of networked transactions that deliver collaborative, transparent, and reliable sources to track diamonds and check their origins. By creating a Digital Twin of each diamond and placing it in the blockchain distributed ledger as a secure and permanent digital record containing precise information of their characteristics and ownership, it facilitates tracking and compliance. With the help of Nano Thermal Sensors, embedded within mines to monitor working conditions, GPS tracking data devices, and Low-Orbit Satellites that trail and examine in high-resolution the activities taking place in the mine's refineries, the platform can deliver a formal provenance record that corroborates the information being shared.

The certification method is emitted through Blockchain Asset Tracking which in turn issues a Blockchain Certificate, ensuring the diamonds being bought comply with sustainable practices. This also enables auditing, where users can have a closer look where the data does not necessarily line up, thus helping to identify and investigate possible frauds. In addition, this blockchain solution is ISO27001-certified, which means that the highest level of trust in security and data protection is being followed suit.

Blockchain asset tracking ecology

This tailored and highly secured solution for the diamond industry provides unprecedented collaboration between customers, manufacturers, retailers, and most importantly, miners, which can consequently add value throughout the supply chain and be applied to other industries too. By establishing a link to each node of the history of a precious stone, this solution is evidence that more holistic approaches can significantly improve sustainable practices.

What if IoT networks expand to the point of registering accurately all Earth's movements? To better grasp how constant monitoring can underpin sustainability, we have created a dedicated section covering current developments and possible future implications.

DT Contributions to Sustainability and Future Implications

The UK government has recently announced that large companies and financial institutions will be required to promulgate a mandatory climate risk report to keep track of their sustainable investments and practices. Other projects such as the Canada Infrastructure Bank's (CIB) Growth Plan and the European Green Deal are pursuing a recovery plan to require value chain actors to put the climate at the center of any economic decision, therefore, to act more sustainably.

From an economic point of view, a green transition with a stronger focus on their workers' well-being and environmentally-sound practices is no easy task to accomplish. However, recent research found that attention to Environmental, Social, and corporate Governance (ESG) earns rewards: for most of 2020, the value of companies with ESG principles outperformed other players in the market. This means that investments with a higher focus on sustainability are expected to thrive during significant crises such as the COVID-19 pandemic.

Likewise, the concept of an Earth's digital twin designed by Destination Earth is anticipated to require substantial infrastructure changes —as well as economic investments— before implementation.

In terms of possible benefits, beyond assisting in weather forecasting, the model will enable a direct approach to creating a realistic replica of profoundly nonlinear systems with myriad degrees of detail. Many of the physical aspects of the Earth's climate system are incredibly complex to describe mathematically and, therefore, to predict its variations accurately. Variables such as the composition of the atmosphere, the behavior of natural heat sources, and the gradients of pressure, gravity, and temperature at each location and time, are just some of countless Earth's nonlinear systems that oscillate constantly. Unfortunately, current DTs applied for climate forecasting can not register all variables from the environment, and many display unresolved issues in terms of approximations for spatial observations that objectively affect the success of a higher-quality simulation model.

With the project being expected to start working in 2021, Destination Earth aims to improve spatial observation models with a more robust focus on prediction and climate crisis adaptation framework to solve current issues in error traceability and quality data. The architecture of the Earth DT is a game-changer in DTs processing design because it combines spatial observations and simulations at a much greater spatial scale by including both km and hm from globally to regionally scales to increase physical realism. It will also enhance the prediction and monitoring of multimodal data from natural and human activities, such as unpredictable climate disasters as well as land-use management and greenhouse gas emissions.

This information framework, opposed to current monitoring tools that register human activity on Earth, has a remarkable feature that includes the laws of physics within its parameters. The simulation model is expected to become a consistent integrator of observational information in harmonization to physical-based dynamics (e.g., speed of light, gravity, etc.), which can provide more detailed versions of planet Earth. But for this to happen, it is of foremost importance to include a federated program that builds infrastructure to both data production, collection, access, and development. This will have the potential to accelerate the quantification of different types of scenarios, such as testing what-if circumstances for farmers to evaluate the impact of agriculture policies that can produce consequences on a global scale (e.g., calculating the exact portion of required fertilizer and the possible outcomes to the environment). This could also allow improved assessment systems to analyze weather disasters and to leverage human activities that can have dramatic changes on ecosystems, thus alleviating adaptation measures in, for instance, infrastructure planning based on local impacts caused by inundations or heatwaves.

In addition, this initiative holds the promise to address solutions for the lack of access small producers have in terms of technological developments. By enrolling global projects that aim to provide full and open access to the population, DTs that were initially reserved to multinational companies that can scale significant portions of investment, this framework will give non-experts full access to data analytics through a scalable cloud-based infrastructure.

However, the resulting Earth system will not take place alone without the help of other information instruments. To cover highly detailed data from the planet, tools such as Nano Satellites, individual mobile phones, as well as monitoring methods such as Drone Monitoring integrated through advanced communication protocols such as 5G Network will be able to expand the limits of data modeling to continuous real-time monitoring, simulation, and prediction systems with more realistic and reliable results.

The implementation of these emerging technologies to achieve an Earth DT will convert the classical, linear value chain based on traditional supply chain flows of consumers, distributors, manufacturers, and suppliers, into a holistic circular infrastructure that includes the environment at the center of logistics management, as the basis of sustainable development. The process of estimating each unit's response and calculating the consequences of the activities taking place everywhere enables the possibility of recreating and even exploring new possible futures. By testing well-observed scenarios, the Earth DT can prove to become an indispensable tool for public administrations in decision-making. In addition, considering Earth's DT nature of creating an open and accessible tool, at a local level, it can also help communities determine new policies and business models that are fittest to their contexts, giving them independence from centralized information systems.

Still, reinforcing sustainable practices may not be a priority from a business viewpoint. Many companies will likely raise red flags and record objections in the face of such comprehensive monitoring initiatives, which will expectably impose hurdles to the implementation process. A global action intended to force an elicit publicly visible and verifiable compliance will severely disrupt the supply chain and even take ethical choices and practices beyond suspicion or guesswork. As showcased in 3M's proprietary DT, or even Everledger's initiative to fight conflict stones, DTs can be the spine for sustainable supply chain lines.

It comes as no surprise that with every solution, many challenges tend to arise, and the same could be said to DTs implementation. However, this digital solution can establish a trusted network among customers, workers, manufacturers, stakeholders, law-makers, governments, and retailers to make better-informed decisions and probably put the environment at the core of their concerns. It is a long road ahead, one which needs the backup of policies and regulations to forward its employment, but the end is already set.

For generations, humanity documented representations of reality, and DTs are only a cutting-edge version that, on the other hand, works not only as a register but the spring for innovation.