The Smart Grid Concept
The smart grid has been described as a cyber-physical entity, which reflects the emergence of an increasing interdependence between the ‘‘hard’’ and ‘‘soft’’ infrastructure it is made up of [3, 4]. A striking contrast between electricity net- works of the past and present is the rapid rise of data availability from a wider range of sensing technologies. Notwithstanding the advancements in network and generation processes, these are driving the rapid reformation of the modern electricity industry. Tighter integration with market, service, and consumer domains is being enabled but extension of the scope of the smart grid to other energy prime movers such as gas and possibly water is conceivable in future. Management of the smart grid is challenged by the increase in data volume and the requirement for interoperability. For example, some 50 million electricity and gas smart meters are to be installed in the UK alone in the next 7 years. The smart grid requires a guiding intelligence that extends from domestic to transmission voltages across generation to service provider domains. Its reflexive nature, supported by Information and Communications Technology (ICT) systems, is undisputed [5].
Electricity transmission networks are already smart but with the addition of renewable and Variable Energy Resources (VERs), Distributed Energy Resources (DERs), and Advanced Metering Infrastructures (AMIs) a holistic approach to conceptualization of the smart grid is necessary, covering not only the domain of transmission but also distribution, storage, generation, markets, service providers, and customers [6]. To establish the role and importance of the CIM and associated standards in the information networks that support operation of the physical electricity networks, it is necessary to frame them within the smart grid concept. In practical terms, this understanding is also essential to making the business cases necessary to justify investment in the changes to power utility information architecture and infrastructure. In responding to the greater flexibility and responsiveness called for in smart grid capabilities these business cases acknowledge the need to manage and leverage the value of the increasing amounts of available data that will not be possible without an established standards framework relating to generally agreed conceptual models of what the emerging smart grid actually is [7].
The origins of the smart grid concept have been described in [8] and the US Department of Energy (DoE) initiating research and development [9], with out- comes such as the Electric Power Research Institute (EPRI) Intelligrid programme. The strategic prerogatives for sustainable energy and security, functionality, and management of electricity networks have formed the basis of smart grid devel- opment initiatives around the world [10–13]. In [14] the European Commission (EC) views the smart grid as having an essential role in achieving the ‘‘20/20/20 Targets’’ set for the European Union (EU) countries. EC mandate M/490 is the umbrella directive for smart grid development coordination and has driven the formation of the Joint Working Group (JWG), also known as the ‘‘Smart Grids Coordination Group’’ (SC-CG), comprising CEN, CENELEC, and ETSI standards
development organizations. Previous EU mandates already existed for the devel- opment of open smart metering standards (M/441) and electric vehicle charging standards (M/468). These initiatives lead us to a broad functional definition of a smart grid having at least the following characteristics:
• Maintains and enhances security of supply (self-healing).
• Facilitates connection to low carbon generating plant.
• Enables innovative demand-side technologies and strategies.
• Facilitates further consumer choice over energy management by providing tariff-based choices.
• Features a holistic communications system providing greater clarity of the grid state and allows it to operate in a way coherent with its decarbonization pri- orities (reflexive).
• Allows optimization of cost and carbon impacts upon networks.
Given its broad scope, which effects millions of stakeholders and draws upon massive investment to realise, it is imperative that the conceptual models drawn from different viewpoints of the smart grid are widely accepted and established as reference architectural standards. Reed et al. highlight this point by indicating, while different players define the smart grid according to their particular per- spectives, it will be difficult to arrive at consensus on gaps in standards and technologies without a standard definition [15]. Two models are continuing to converge and form the dominant standard for high-level smart grid conceptual reference architectures however. These are the National Institute of Standards and Technology (NIST) ‘‘Conceptual Architectural Framework’’ [16] and the EU SG-CG ‘‘Smart Grid Reference Architecture’’ [17]. The NIST framework is based upon seven interoperating domains comprising, ‘‘Bulk Generation, Transmission, Distribution, Customer, Operations, Markets and Service Provider.’’ The SG-CG architecture, or Smart Grid Architecture Model (SGAM), generally corresponds to the NIST reference architecture but has extended it with the addition of an eighth domain for ‘‘Distributed Energy Resources.’’ Its three-dimensional presentation reflects the flexibility of the smart grid in a range of manifestations from centralized to noncentralized, as well as accommodating forward-looking local area energy systems such as micro-grids.