The integration of renewable rnergy sources (RESs) into the power grid involves operational challenges due to the inherent RES energy-production variability. Imbalances between actual power generation and scheduled production can lead to grid instability and revenue loss for RES operators and aggregators. To address this risk, in this paper, we introduce a mutually beneficial bilateral trading scheme between a RES and a DR aggregator to internally offset real-time energy imbalances before resorting to the flexibility market. We consider that the DR aggregator manages the energy demand of users, characterized by uncertainty in their participation in DR events and thus the actual provision of flexibility, subject to their offered monetary incentives. Given that the RES aggregator faces penalties according to dual pricing for positive or negative imbalances, we develop an optimization framework to achieve the required flexibility while addressing the trade-off between maximizing the profit of the RES and DR aggregators and appropriately incentivizing the users. By using appropriate parameterization of the solution, the achievable revenue for the imbalance offsetting can be shared between the RES and the DR aggregators while keeping users satisfied. Our analysis highlights the interdependencies of the demand–production energy imbalance on user characteristics and the RES and DR aggregator profits. Based on our results, we show that a win–win outcome (for the RES and DR aggregators and the users) is possible for a wide range of cases, and we provide guidelines so that such bilateral agreements between RES and DR aggregators could emerge in practical settings.

Federations of Infrastructure Service Providers (InfSPs) has emerged as a practice to successfully serve demanding applications in cloud- and edge-computing environments, by overcoming the limitations of each such provider (in terms of available resources, geographic coverage etc.). In this paper, we develop innovative effective mechanisms and policies for the decentralized management of InfSP federations, considering the needs both for resource allocation meeting service composition requirements and for performing a fair and efficient distribution of profits. Resource allocation is performed by means of a greedy algorithm that includes an opportunistic and an adjustment phase. For determining the payments of participating InfSPs, we introduce an innovative sealed-bid reverse auction that combines VCG and first-price auction mechanisms; these are coupled with a sophisticated federation wallet management mechanism serving as a sink for the federation revenues. This hybrid mechanism possesses several nice properties including efficiency, long-term budget balance, truthfulness and individual rationality. Moreover, we present how our solution can be implemented in a decentralized, privacy-preserving and trustworthy manner over a blockchain, achieving bid privacy, non-repudiation and public verifiability. Our approach is evaluated by means of extensive experiments, the results of which reveal that resource allocation is either optimal or very close thereto, while individual InfSP profits as well as total federation profits are maximized. Moreover, the results confirm that the VCG mechanism alone cannot guarantee budget balance, thus justifying the necessity for our hybrid sophisticated solution.

Transacting entities online may still become victims of fraud, cyber-threats, low quality or performance, privacy loss, unfair pricing, biases in matching offers to requests, among others. Blockchain and other decentralized technologies may provide remedy towards trustworthy online transactions. This paper proposes a blockchain-based market framework that enables trustworthy transactions. We first define the functionalities that such a market framework should combine, namely mechanisms for service discovery, decentralized reputation, price determination, self-sovereign identities and verifiable credentials, fair exchanges, anonymity, asset digitization, cryptocurrencies, invoicing, and more. Then, we describe blockchain-based solutions for addressing each one of these functionalities. Finally, we exemplify the operation of the market in three real-world use cases.