# A Blockchain-Based Real-Time Power Balancing Service for Trustless Renewable Energy Grids
###### Abstract  
We face a decentralized renewable energy production scenario, where a large number of small energy producers, i.e., prosumers, contribute to a common distributor entity, who resells energy directly to end-users. A major challenge for the distributor is to ensure power stability, constantly balancing produced vs consumed energy flows. In this context, being able to provide quick restore actions in response to unpredictable unbalancing events is a must, as fluctuations are the norm for renewable energy sources. To this aim, the high scalability and diversity of sources are crucial requirements for the said balancing to be actually manageable. In this study, we explored the challenges and benefits of adopting a blockchain-based software architecture as a scalable, trustless interaction platform between prosumers' smart energy meters and the distributor. Our developed prototype accomplishes the energy load balancing service via smart contracts deployed in a real blockchain network with an increasing number of simulated prosumers. We show that the blockchain-based application managed to react in a timely manner to energy unbalances for up to a few hundred prosumers. blockchain; smart contract; green energy; power modulation +
Footnote †: journal: _Future Internet_  
fully decentralized system to work and trust between parties to hold, without requiring any previous agreement on a common trust authority to guarantee that no one will tamper with the recorded data and computations. Blockchain-based solutions have, thus, been widely applied in the literature for the design of the next generation of distributed applications in a variety of different application domains, all sharing the common requirement of enabling Internet users or IoT devices to safely trade information and resources across untrusted environments and networks [4; 5; 6; 7]. On the other hand, while blockchains and smart contracts are a powerful tool to automatically enforce the rules governing the interaction amongst mutually untrusted parties, their expressive power in terms of coordination ability, while rapidly evolving, is still limited [8]. As a consequence, it becomes quite difficult to confidently prefigure at design time the actual validity, or to assess the efficiency and scalability, of any complex blockchain distributed application without actually implementing and testing it. In principle, a blockchain-based distributed ledger can support the implementation of all the aggregator management tasks, such as the negotiation and signing of contractual agreements, the energy profiling of prosumers, the handling of billing and payments, and the issuance of power modulation commands to the controlled energy sources. However, a legitimate question that has not yet been explored, and which we specifically addressed in this work, is whether a blockchain platform can actually support the scaling and timing requirements specific to time-critical services, i.e., the quick power modulation actions that an aggregator is expected to implement in response to any unpredictable power unbalancing events occurring in the grid. In this paper, to answer this question, we evaluated the feasibility and performance of a blockchain-based implementation of the aggregate power modulation service of an aggregator's virtual power plant. This has been carried out by creating a prototype application, complete with front-end and back-end system components, which operates on a real blockchain and sends the modulation commands to the prosumer's devices. Nevertheless, the aggregator monitors the prosumer's smart meters directly and in real time, to gather the readings of the prosumer-generated power and continuously assess the ability of the prosumers to follow the requested operational mode, while avoiding any impact due to the blockchain. The main contribution of the paper is in the way the commands handling the modulation of production are exchanged.