<p>Data security is becoming a major issue with the rise of microgrids. Sensitive data on energy production and consumption must be protected. A high level of security is essential to ensuring the efficient operation of vital services supplied by renewable energies. Blockchain, through the smart contracts and consensus algorithms, offers an ideal security solution. However, this technology requires a lot of computing and energy resources. It is crucial to choose a consensus algorithm tailored to the specific needs of the microgrid in terms of security, performance and energy consumption. The high energy consumption of blockchain is seen by researchers as a major limitation to its use in many decentralized networks such as microgrids. This article proposes an optimal choice of consensus algorithm and type of blockchain, based on security, energy consumption and computing resources. To achieve this, a review of the consensus algorithms used in microgrids was carried out, and the data obtained was used to build a decision tree for their selection. The proposed model was evaluated for different sizes of local electricity networks, and this approach enabled a microgrid sizing workflow to be proposed that takes security requirements into account. The results will enable the design of microgrid architectures and components that are compatible with decentralized cybersecurity technologies without affecting their operation.</p>