The event of cyber security in critical infrastructures has aroused the interest and the worry of energy utilities, government, regulatory agencies, and consumers as well as of the academic and research institutions. If on one hand it is prominent the vulnerability of the cyberspace, which augments the risk of attacks in the organizational environment, on the other hand, the research leading to alternatives for the governance and management of these critical structures are still too incipient. This study aims at building a theoretical-empirical model of cyber security governance and management and testing it along with academic experts and professionals from the energy sector. By using the Delphi method and statistics techniques for validation, an assessment instrument was developed based on both the constructs: governance and management; and nine dimensions with their respective variables that allowed for an analysis of the situation of the Brazilian energy utilities regarding the protection of their cyberspaces. The contribution of the article reaches two fronts: a conceptual and empirical one as it expands and systematizes the knowledge about aspects of the governance and management of cyberspaces; and a methodological one as it proposes measuring those dimensions in energy utilities.