Blockchain Papers

Ali Fırat Yazıcı, Ali Bahadır Olcay, Gökçen Arkalı Olcay

No abstract is available for this record.

Preetam Basu, Palash Deb, Akhilesh Singh

Purpose Businesses must now track the complicated supply chains of their products, which involve different manufacturers and suppliers. However, because supply chains are scattered across multiple countries and involve many institutions, it becomes an overwhelming practical challenge to ensure transparent recording and reporting of greenhouse gas emissions. The myriad issues necessitate a technological solution that will improve supply chain transparency, assist in managing carbon assets and allow all parties to obtain credible information on carbon output. As a potential solution, this study offers a unique architecture that effectively combines “blockchain technology” with the carbon supply chain of a multi-institution business network. Design/methodology/approach This research and proposed framework are based on publicly available reports on carbon emissions tracking, sustainability, carbon trade and emerging blockchain technologies. The authors also interviewed industry experts to obtain their input and feedback. Findings Businesses must support the pledges made by their respective governments towards meeting the objectives of the Paris Agreement. Although the emissions trading system encourages businesses to move in this direction, it can be challenging for them to efficiently manage their carbon assets owing to issues such as lack of standardised methods for tracking emissions across suppliers and manufacturers and the fragmentation of carbon markets. The carbon supply chain can maintain a record of the chronological flow of carbon emissions and eventually of all carbon assets by integrating a centralised ledger system based on blockchain technology. Originality/value Global warming, climate change and carbon emissions are among humanity’s pressing problems today. To achieve net zero emissions by the middle of the 21st century, emissions must be drastically reduced. Global supply chains have a crucial role to play in this context. This article provides a blockchain-based technology framework for carbon emissions visibility and tracking. The authors believe such a platform will provide critical visibility and tracking support to globally dispersed supply chains, moving a step closer towards carbon emissions control and net zero operations.

Mateen Ashraf, Cathal Heavey

The main objective of this article is to present a prototype that integrates blockchain and Internet-of-Things (IoT) devices to digitize information across a generic Supply Chain (SC). Blockchain bring many benefits to the operation of improving provenance and reliability, such as, digitizing the interaction among SC actors to allow implementation of smart contracts to support a secure and authenticated chain. In technical terms, blockchain is a decentralized database where information recording is secure and blockchain-based traceability in the SC can address shortcomings that exist in centralized solutions. Provenance could be achieved by implementing SC business logic within smart contracts using blockchains. This article presents an architecture of software that combines blockchain with IoT devices that allows traceability of a generic product from source to destination, through multi-echelon suppliers, logistics, manufacturers to the end-customer. The presented software architecture uses the Solana blockchain for the implementation of SC processes and business logic. This blockchain was selected from a review, reported in this article, of several widely used blockchain networks. It was selected mainly due to its speed and cost of transactions. Within the blockchain we store SC related data and events communicated over the internet and mobile application channels, in a Solana blockchain using Solana's native blockchain libraries. the IoT devices used are Sigfox cloud gateway, and Sensit that uses LPWAN (Low power wide area network) wireless telecommunication for data transfer. In our IoT device, the blockchain stores temperature, humidity, light, location, tilting, door opening, vibration, and magnetic field. The goal is to use existing technologies to develop a software architecture for a medium term objective of an implementable generic blockchain for SCs.

Emanuele Pagone, A. L. Hart, Konstantinos Salonitis

Cryptocurrencies are a digital form of money based on the blockchain technology. Their relatively recent raise in popularity and use, together with the energy-intensive nature of some of their algorithms, has raised environmental concerns about growing energy consumption (and associated carbon dioxide emissions). This paper aims at comparing the environmental impact of the most common cryptocurrency (i.e., Bitcoin) and fiat currencies (i.e. coins, banknotes, credit and debit card networks). Such comparison is carried out assessing and analyzing the life cycle main phases of each currency in terms of carbon dioxide equivalent emissions. Results show that Bitcoin has a carbon footprint almost 4 to 5 times greater than the sum of all forms of traditional currency together in one year. Furthermore, environmental impact “hotspots” of fiat currency including raw material production of coins, transportation of banknotes and electric energy consumption of ATMs are identified. Finally, considering future scenarios and the sensitivity of various parameters on the results, some solutions are proposed to reduce the environmental impact of currencies.

Juan Ignacio Ibañez, Francisco Ruiz

Blockchain technology and, more generally, distributed ledger technology (DLT) systems, face public scrutiny for their energy consumption levels. However, many point out that high energy consumption is a feature of (small block size) proof-of-work (PoW) DLTs, but not of proof-of-stake (PoS) DLTs. With the energy consumption of PoS systems being an under-researched area, we replicate, expand and update embryonary work modelling it and comparing different PoS-based DLTs with each other and with other non-PoS systems. In doing so, we suggest and implement a number of improvements to an existing PoS energy consumption model. We find that there may be significant differences in the energy consumption of PoS systems analysed and confirm that, regardless of these differences, their energy consumption is several orders of magnitude below that of Bitcoin Core.

Marcel Antal, Vlad Mihailescu, Tudor Cioara, Ionuț Anghel

The participation of prosumers in demand-response programs is essential for the success of demand-side management in renewable-powered energy grids. Unfortunately, the engagement is still low due to concerns related to the privacy of their energy data used in the prediction processes. In this paper, we propose a blockchain-based distributed federated learning (FL) technique for energy-demand prediction that combines FL with blockchain to provide data privacy and trust features for energy prosumers. The privacy-sensitive energy data are stored locally at edge prosumer nodes without revealing it to third parties, with only the learned local model weights being shared using a blockchain network. The global federated model is not centralized but distributed and replicated over the blockchain overlay, ensuring the model immutability and provenance of parameter updates. We had proposed smart contracts to deal with the integration of local machine-learning prediction models with the blockchain, defining functions for the model parameters’ scaling and reduction of blockchain overhead. The centralized, local-edge, and blockchain-integrated models are comparatively evaluated for prediction of energy demand 24 h ahead using a multi-layer perceptron model and the monitored energy data of several prosumers. The results show only a slight decrease in prediction accuracy in the case of blockchain-based distributed FL with reliable data privacy support compared with the centralized learning solution.

Ziyi Zhao, Jiliang Li, Zhou Su, Yuyi Wang

Smart contracts are programs running on Ethereum, whose deployment and use require gas. Gas measures the cost of performing specific operations as an index designed to quantify the computing power consumption. Existing unoptimized smart contracts make contract developers and users spend extra gas. To save gas and optimize smart contracts, this paper proposes a new tool named GaSaver for automatically detecting gas-expensive patterns based on Solidity source code. Specifically, we first identify 12 gas-expensive patterns in smart contracts and classify them into three categories: storage-related, judgment-related, and loop-related. Then, we deploy gas-expensive patterns and group them into three levels according to gas waste degree. By conducting extensive experiments on real data sets, we find that 89.68$\%$of the 1172 smart contracts suffer from gas-expensive patterns, 94.27$\%$of 1100 new smart contracts are gas-expensive, and 80.56$\%$of 72 widely used smart contracts are affected. Finally, the experiment results show that the proposed GaSaver can effectively optimize smart contracts. Besides, the proportion of gas-expensive cases in widely used smart contracts is lower than that in the newly released smart contracts.

Yutao Yang, Yuxuan Shi, Tianmei Wang

With the deepening application of blockchain technology, exaggerating its empowering effects has become common. In recent years, the rational assessment of the maturity of blockchain technology applications in digital projects in different fields has been the focus of attention and identified as the key to improving the implementation effect of various digital projects. Although some studies have obtained substantial research results on technology maturity and its derivative applications, which can be used to predict the overall trend of a technology or guide the implementation of the technology on the ground, few studies have evaluated the maturity of blockchain technology in combination with different application scenarios. Our study combines application scenarios and the technical characteristics of blockchain technology and proposes an evaluation system for blockchain technology application maturity consisting of five primary indicators, that is, key application requirements, data security, process complexity, application ecological completeness, and technical performance requirements, and their corresponding secondary indicators. In addition, we take digital government public service projects as application scenarios and use the analytic hierarchy process (AHP) entropy method and expert scoring method to determine the weights corresponding to each index in the assessment system and construct a blockchain technology application maturity assessment model. Moreover, we apply the model to ten typical digital government public service projects to conduct a comprehensive assessment and analysis. By comparing the indicator scores of the different projects, we analyze the project characteristics influencing blockchain technology application maturity and provide suggestions for applying “blockchain + digital government public services”.

Deqing Ma, Hanqing Qin, Jinsong Hu

No abstract is available for this record.

Ashish Rajendra Sai, Harald Vranken

There is a growing interest in understanding the energy and environmental footprint of digital currencies, specifically in cryptocurrencies such as Bitcoin and Ethereum. These cryptocurrencies are operated by a geographically distributed network of computing nodes, making it hard to accurately estimate their energy consumption. Existing studies, both in academia and industry, attempt to model the cryptocurrencies energy consumption often based on a number of assumptions for instance about the hardware in use or geographic distribution of the computing nodes. A number of these studies has already been widely criticized for their design choices and subsequent over or under-estimation of the energy use. In this study, we evaluate the reliability of prior models and estimates by leveraging existing scientific literature from fields cognizant of blockchain such as social energy sciences and information systems. We first design a quality assessment framework based on existing research, we then conduct a systematic literature review examining scientific and non-academic literature demonstrating common issues and potential avenues of addressing these issues. Our goal with this article is to to advance the field by promoting scientific rigor in studies focusing on Blockchain's energy footprint. To that end, we provide a novel set of codes of conduct for the five most widely used research methodologies: quantitative energy modeling, literature reviews, data analysis \& statistics, case studies, and experiments. We envision that these codes of conduct would assist in standardizing the design and assessment of studies focusing on blockchain-based systems' energy and environmental footprint.

Aditya Pappu, Gerwin Hoogsteen, Johann L. Hurink

This paper presents a method to implement cooperative Demand Side Management (DSM) approaches over a distributed communication network. Our method combines a decentralized DSM approach called Profile Steering with two distributed consensus mechanisms Proof of Work (PoW) and Proof of Stake (PoS). We make use of a network manager to moderate the network and a distributed ledger system to store the power profiles from each planning period.We evaluate our approach using publicly-available real data from 25 houses. We successfully implemented our distributed approach in Python using JSON files as blocks and performed time-performance evaluations of this implementation. We show that, distributed DSM for day-ahead planning using blockchain concepts is possible and adds an overhead of only 0.98 seconds and 3.99 seconds in the case of PoW and PoS respectively.

Douglas Dias, Fumio Machida, Ermeson Andrade

Blockchain platforms have gained popularity in recent years and integrated with other digital technologies like Internet of Things (IoT) and Artificial Intelligence (AI) for multiple-business purposes. Software aging is a common issue in many long-running software systems, but little has been experienced in the context of blockchain platforms. To narrow this gap, this work aims to characterize potential software aging issues in the Cardano blockchain platform that is considered the largest cryptocurrency adopting proof-of-stake. By performing statistical analysis on the measurement data of the Cardano blockchain deployed in two environments with different configurations, we found a symptom of software aging through memory degradation that was confirmed by the Mann-Kendall test. By analyzing the running processes, we identify the cardano-node (the main process of the platform) as the process possibly responsible for such degradation.

Matthias Babel, Vincent Gramlich, Marc-Fabian Körner, Johannes Sedlmeir · 6 authors

Abstract In the energy transition, there is an urgent need for decreasing overall carbon emissions. Against this background, the purposeful and verifiable tracing of emissions in the energy system is a crucial key element for promoting the deep decarbonization towards a net zero emission economy with a market-based approach. Such an effective tracing system requires end-to-end information flows that link carbon sources and sinks while keeping end consumers’ and businesses’ sensitive data confidential. In this paper, we illustrate how non-fungible tokens with fractional ownership can help to enable such a system, and how zero-knowledge proofs can address the related privacy issues associated with the fine-granular recording of stakeholders’ emission data. Thus, we contribute to designing a carbon emission tracing system that satisfies verifiability, distinguishability, fractional ownership, and privacy requirements. We implement a proof-of-concept for our approach and discuss its advantages compared to alternative centralized or decentralized architectures that have been proposed in the past. Based on a technical, data privacy, and economic analysis, we conclude that our approach is a more suitable technical backbone for end-to-end digital carbon emission tracing than previously suggested solutions.

Chunhua Ju, Zhonghua Shen, Fuguang Bao, Pengtong Weng · 6 authors

To achieve the goal of carbon neutrality, many countries have established regional carbon emission trading markets and tried to build a low-carbon economic system. At present, the implementation of carbon emission trading and low-carbon economic systems faces many challenges such as manipulation, corruption, opacity, lack of trust, and lack of data tracking means. The application of blockchain technology can perfectly solve the above problems. However, the data recorded on a blockchain are often multi-type and heterogeneous, and users at different levels such as regulators, enterprises, and consumers have different requirements for data types and granularity. This requires a quick and trustworthy method for monitoring the carbon footprint of enterprises and products. In this paper, the carbon footprint traceability of enterprises and products is taken as an application scenario, and the distributed traceability concept of "traceability off the chain and verification on the chain" is adopted. By reconstructing the pointer of the file structure of the distributed storage, an interactive traceability structure supporting type filtering is constructed, which enables fast retrieval and locating of carbon emission data in the mixed data on the chain. The experimental results show that using the interactive traceability structure that supports type filtering for traceability not only releases the computing power of full nodes but also greatly improves the traceability efficiency of the long-span transaction chain. The proposed carbon footprint traceability system can rapidly trace and track data on an enterprise's and a product's carbon footprint, as well as meet the needs of users at all levels for traceability. It also offers more advantages when handling large amounts of data requests.

Moritz Platt, Stephen Ojeka, Andreea-Elena Drăgnoiu, Oserere Ejemen Ibelegbu · 7 authors

Abstract Decentralized cryptocurrency networks, notably those with high energy demand, have faced significant criticism and subsequent regulatory scrutiny. Despite these concerns, policy interventions targeting cryptocurrency operations in the pursuit of sustainability have largely been ineffective. Some were abandoned for fear of jeopardizing innovation, whereas others failed due to the highly globalized nature of blockchain systems. In search of a more effective angle for energy policy measures, this study adopts a consumer-centric perspective, examining the sentiments of Nigerian cryptocurrency users ($n=158$) toward Bitcoin’s sustainability, a representative cryptocurrency known for its high electricity demand. Three main findings emerged: 1) Even among those self-identifying as highly knowledgeable, most considerably underestimated Bitcoin’s electricity consumption. 2) Participants with a more accurate understanding of Bitcoin’s energy demand were more inclined to support sustainability measures. 3) Most of this supportive cohort viewed private entities as the primary stakeholders for implementing such measures. Given these findings, we suggest that consumer education should be at the forefront of policy initiatives aimed at cryptocurrency sustainability.

Zhixiang Zhou, Yuanfei Ma, Yinghao Pan, Yangguang Zhu

No abstract is available for this record.

Amin Shokri, Ali Shokri, Dean White, Richard Gelski · 7 authors

The capacity of the greenhouse gas recycling mechanism in nature has long reached its limit, resulting in a sharply increasing trend in the marginal cost of recycling one unit of human-produced carbon and other greenhouse gas emissions. Externalities associated with the marginal cost of greenhouse gas emissions affect health, climate, and the economy, which have urged global authorities and governments to request urgent actions to slow down the production of such pollutants. Nonetheless, without public awareness and a holistic mechanism to monetise the impact of pollutants, a universal strategy to reduce greenhouse gas emissions is condemned to failure. This paper presents an overview of emerging technologies that can come together to offer an innovative solution for monetising, incentivising and realising the reduction of greenhouse gas emissions. Through a brief review of the literature, an innovative ecosystem is proposed for the first time, accounting for a unified platform for carbon verification, validation and monetisation, which can be adopted as a business model to validate and monetise the amount of incentivising businesses and people for carbon saving on a decentralised blockchain platform.

Amanda Ahl, Mika Goto, Masaru Yarime, Kenji Tanaka · 5 authors

No abstract is available for this record.

Hongming Yang, Zefeng Yang, Sheng Xiang, Huan Zhao · 5 authors

With the rapid development of distributed energy, traditional power consumers have been transformed into prosumers who both produce and consume power, and are able to conduct flexible peer-to-peer transactions. Blockchain is a distributed ledger technology suitable for peer-to-peer transactions. However, the single-chain blockchain cannot simultaneously support the network security check and decentralized power transactions. Therefore, a double-chain blockchain and the corresponding peer-to-peer transaction model are proposed with the reorganization of the transaction chain and power chain. The peer-to-peer independent decision-making transactions are achieved through the transaction chain (public chain) to maximize the prosumer's economic interests. The security check and adjusted transaction scheme are achieved through the power chain (alliance chain) with the power network constraint. Based on the Ethereum blockchain development platform, simulations of peer-to-peer transactions in the IEEE 14-node distribution network are implemented. The simulation results show that the designed double-chain blockchain has higher transaction processing efficiency than the single-chain blockchain. The secure and autonomous peer-to-peer transaction of prosumers can be well supported by the proposed method.

Jinyoung Kim, Misoo Kim, Eunseok Lee

With the introduction of smart contacts, Ethereum has become one of the most popular blockchain networks. In the wake of its popularity, an increasing number of Ethereum-based software have been developed. However, the carbon emissions resulting from these software has been pointed out as a global issue. It is necessary to reduce the energy consumed by these software to reduce carbon emissions. Recently, most studies have focused on smart contracts and proposed energy-efficient methods for the development of carbon friendly Ethereum networks. However, in addition to smart contracts, the energy used by client software in Ethereum networks should also be reviewed. This is because the client software performs all functions occurring in the Ethereum network, including smart contracts. Therefore, energy bugs that waste energy in Ethereum client software should be investigated and solved. The first task to enable this is to build an energy bug benchmark of Ethereum client software. This study introduces ECench, an energy bug benchmark of Ethereum client software. ECench includes 507 energy buggy commits from 7 series of client software that are officially operated in the Ethereum network. We carefully collected and manually reviewed them for cleaner commits. A key strength of our benchmark is that it provides eight energy wastage categories, which can serve as a cornerstone for researchers to identify energy waste codes. ECench can provide a valuable starting point for studies on energy reduction and carbon reduction in Ethereum.

Anna Vacca, Michele Fredella, Andrea Di Sorbo, Corrado Aaron Visaggio · 5 authors

Blockchain technology is becoming increasingly popular, and smart contracts (i.e., programs that run on top of the blockchain) represent a crucial element of this technology. In particular, smart contracts running on Ethereum (i.e., one of the most popular blockchain platforms) are often developed with Solidity, and their deployment and execution consume gas (i.e., a fee compensating the computing resources required). Smart contract development frequently involves code reuse, but poor readable smart contracts could hinder their reuse. However, writing readable smart contracts is challenging, since practices for improving the readability could also be in contrast with optimization strategies for reducing gas consumption. This paper aims at better understanding (i) the readability aspects for which traditional software and smart contracts differ, and (ii) the specific smart contract readability features exhibiting significant relationships with gas consumption. We leverage a set of metrics that previous research has proven correlated with code readability. In particular, we first compare the values of these metrics obtained for both Solidity smart contracts and traditional software systems (written in Java). Then, we investigate the correlations occurring between these metrics and gas consumption and between each pair of metrics. The results of our study highlight that smart contracts usually exhibit lower readability than traditional software for what concerns the number of parentheses, inline comments, and blank lines used. In addition, we found some readability metrics (such as the average length of identifiers and the average number of keywords) that significantly correlate with gas consumption.

Evgenia Kapassa, Marinos Themistocleous

Energy management in the Internet of Vehicles (IoV) is becoming more prevalent as the usage of distributed Electric Vehicles (EV) grows. As a result, Demand Response (DR) management has been introduced to achieve efficient energy management in IoV. Through DR management, EV drivers are allowed to adjust their energy consumption and generation based on a variety of parameters, such as cost, driving patterns and driving routes. Nonetheless, research in IoV DR management is still in its early stages, and the implementation of DR schemes faces a number of significant hurdles. Blockchain is used to solve some of them (e.g., incentivization, privacy and security issues, lack of interoperability and high mobility). For instance, blockchain enables the introduction of safe, reliable and decentralized Peer-to-Peer (P2P) energy trading. The combination of blockchain and IoV is a new promising approach to further improve/overcome the aforementioned limitations. However, there is limited literature in Demand Response Management (DRM) schemes designed for IoV. Therefore, there is a need for a systematic literature review (SLR) to collect and critically analyze the existing relevant literature, in an attempt to highlight open issues. Thus, in this article, we conduct a SLR, investigating how blockchain technology assists the area of DRM in IoV. We contribute to the body of knowledge by offering a set of observations and research challenges on blockchain-based DRM in IoV. In doing so, we allow other researchers to focus their work on them, and further contribute to this area.

Abderahman Rejeb, Karim Rejeb, John G. Keogh, Suhaiza Zailani

Blockchain can help to fundamentally alter aspects of circular economy (CE) activities and overcome pressing sustainability issues. Nevertheless, limited studies have investigated the barriers to blockchain adoption in the CE. This study aims to close the knowledge gap by providing a comprehensive review of the barriers hampering the adoption and integration of blockchain technology in the CE. An integrated approach based on fuzzy Delphi and best-worst methods has been applied to analyze and rank the barriers. Sixteen barriers to blockchain adoption in the CE were identified from the academic literature and validated by a panel of experts. The findings from the fuzzy Delphi technique identified ten significant barriers for further analysis. Then, using the best-worst method, the optimal weights were determined based on the experts’ judgment to recognize the importance of each barrier. The findings from this method showed that a lack of knowledge and management support, reluctance to change and technological immaturity are the most significant barriers. In contrast, the least significant barriers are investment costs, security risks, and scalability issues. Theoretically, this study is the first to apply an integrated approach combining fuzzy Delphi and best-worst techniques to prioritze the barriers to blockchain adoption in the CE. It also provides valuable insights for managers and decision-makers that can be used to optimize blockchain implementations in the CE.

Varun Kohli, Sombuddha Chakravarty, Vinay Chamola, Kuldip Singh Sangwan · 5 authors

There is an urgent need to control global warming caused by humans to achieve a sustainable future. CO2 levels are rising steadily, and while countries worldwide are actively moving toward the sustainability goals proposed during the Paris Agreement in 2015, we are still a long way to go from achieving a sustainable mode of global operation. The increased popularity of cryptocurrencies since the introduction of Bitcoin in 2009 has been accompanied by an increasing trend in greenhouse gas emissions and high electrical energy consumption. Popular energy tracking studies (e.g., Digiconomist and the Cambridge Bitcoin Energy Consumption Index (CBECI)) have estimated energy consumption ranges from 29.96 ​TWh to 135.12 ​TWh and 26.41 ​TWh to 176.98 ​TWh, respectively for Bitcoin as of July 2021, which are equivalent to the energy consumption of countries such as Sweden and Thailand. The latest estimate by Digiconomist on carbon footprints shows a 64.18 MtCO2 emission by Bitcoin as of July 2021, close to the emissions by Greece and Oman. This review compiles estimates made by various studies from 2018 to 2021. We compare the energy consumption and carbon footprints of these cryptocurrencies with countries around the world and centralized transaction methods such as Visa. We identify the problems associated with cryptocurrencies and propose solutions that can help reduce their energy consumption and carbon footprints. Finally, we present case studies on cryptocurrency networks, namely, Ethereum 2.0 and Pi Network, with a discussion on how they can solve some of the challenges we have identified.