Blockchain-based Design for Performant Peer-to-Peer Energy Trading Systems
Creators: Fan, Caixiang
Publisher: name: University of Alberta Library
Year: 2023

<p>With the emergence of renewable energy resources, such as solar panels, wind turbines and plugin electric vehicles, there is an increasing need for peer-to-peer energy trading (P2P-ET) among small-scale energy producers, known as prosumers. Many recent studies have suggested blockchain for P2P-ET to provide many advantages over centralized solutions. These include but are not limited to, improved security, privacy, fast payment settlement and better fault tolerance. However, to leverage blockchain at scale, its well-known limitations, i.e., scalability and performance, should be adequately analyzed and addressed. Even though many promising consensus mechanisms have been proposed to tackle the blockchain performance issue, their performance has not been sufficiently<br>
evaluated and mathematically analyzed in production environments. Thus, in this proposed Ph.D. research, blockchain-based solutions for P2P-ET are investigated, with their performance being carefully evaluated, to show their feasibility and efficiency in energy trading applications.</p>

<p>First, we conducted a systematic survey on blockchain performance evaluation by categorizing all reviewed solutions into two main categories: empirical analysis and analytical modelling. The current empirical analysis methodologies include benchmarking, monitoring, experimental analysis and simulation. The analytical techniques include the Markov chains, queueing theory, and stochastic Petri nets. Through contrasting, comparing and grouping different methods, we extracted important criteria used to select the most suitable evaluation technique. We also identified a list of performance bottlenecks in various blockchain systems.</p>

<p>Then, we rigorously studied the performance of two promising and performant blockchain solutions: the DAG ledger IOTA and Hyperledger Besu, to examine their applicability for P2PET. In the IOTA performance study, we first extended a DAG simulator to support realistic IOTA simulations and investigated the impact of different design parameters on IOTA’s performance. Then, we proposed a layered model to investigate the optimal waiting time to resend a previously submitted but not yet confirmed transaction. Our findings reveal the impact of the transaction arrival rate, tip selection algorithms (TSAs), weighted TSA randomness, and network delay on the throughput. Using the proposed layered model, we shed some light on the distribution of the confirmed transactions on different layers. The distribution is leveraged to calculate the optimal time for resending an unconfirmed transaction to the distributed ledger. To study the performance of Hyperledger Besu, we designed and automated a benchmarking framework with an Nginx load<br>
balancer and judiciously selected a set of test parameters, including transaction send rate, network size, node flavour, load balancing, consensus, and block time. Then, we set up private blockchain networks to thoroughly test the impact of these parameters on the metrics such as transaction throughput, latency, scalability and resource utilization using the Hyperledger Caliper benchmark tool. Further performance data and log analyses reveal some interesting findings which shed some light on further performance improvement of Hyperledger Besu and building performant enterprise applications.</p>

<p>At last, we proposed and developed a unified Blockchain-based framework for P2P-ET called BPET, which combines blockchain with microservice architecture to achieve better reliability. Our proposed framework adopts a modular smart contract design, which enables P2P-ET at both the distribution level and end-user level by implementing different market rules. In particular, four smart contracts are developed: Registry for recording the registration information, EnergyToken for providing a stablecoin payment method, Market for defining all market rules, and Payment for processing the payment settlement step. We also developed a decentralized application (DApp) prototype on top of a private Hyperledger Besu blockchain network deployed on the cloud. A case study of P2P-ET in the Alberta electricity wholesale market was conducted with real data set from the Alberta Electric System Operator (AESO) to demonstrate the feasibility and efficiency of the proposed BPET system. The system evaluation results indicate that the implemented system can effectively and efficiently process energy trading transactions in the Alberta electricity wholesale market.</p>