Implementation of Interoperability in the “Real World” of the Smart Grid (SG)

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Dom Geraghty


U.S. energy policy initiatives are changing the structure of the physical power system and power system markets. While achieving policy goals, they also create undesirable side-effects for service reliability and power costs. Smart Grid (SG) applications can mitigate these side effects. However, the SG can only work if its applications are interoperable because objects in the power grid network are inter-dependent.  In the “real world”, interoperability comes in many forms. Whatever form it takes, it is a prerequisite for the implementation of SG applications, which in turn are required to ameliorate the undesirable and/or unintended side-effects of salutary and broadly-supported energy policy initiatives.

Situation – Structural Changes in the Power Sector

Today, there are two primary structural changes occurring in the U.S. power grid: (1) physical (ongoing) and (2) power markets (early phases). These changes are being driven by the following energy policy initiatives:

  • Renewable Portfolio Standards (RPS) mandate which introduces increasing amounts of intermittent/variable power production
  • Promotion of, and subsidies for, distributed energy resources (DERs), micro-grids, virtual power plants (VPPs)
  • Promotion of electric vehicles (EVs)
  • Availability of demand response (DR)/load dispatch programs
  • Availability of increased end-use customer choice/energy management options such as smart thermostats, “Green Button”, home automation systems, building automation systems, dynamic rates
  • Integration of wholesale and retail markets, and integration of physical and power market operations

Side-Effects of Energy Policies – There Is a Disturbance in the Force

The above structural changes resulting from energy policy changes have some undesirable side-effects that impact service reliability and create challenges for grid operators.

The operations-related side effects of policy-related structural changes in the grid include:

  • More volatile operations as a result of intermittent resources
  • Events/actuations happen faster – machine-to-machine (M2M), some automation – create a need to manage system security/protection and system stability more tightly
  • Un-designed-for operation of traditional distribution systems, e.g., two-way flows in distribution systems, high-gain feedback loops due to price-responsive demand management programs
  • Visualization of the instantaneous “state of the grid” becomes more challenging
  • The power dispatcher’s job becomes more complex in terms of matching supply and demand on a quasi-real-time basis, e.g., load-following is more demanding
  • Forecasting the “net” load curve is more uncertain
  • More reserves are required to maintain service reliability targets

Two-t-lines-56-mauve-New-Image1-e1355772451904-150x150The side-effects occur because the electricity grid is an interconnected network. Energy policies can affect service reliability negatively because an undesigned-for change in one part of the grid’s operation affects other parts of the grid to an unknown extent, e.g., Lorenz’s “butterfly effect” -- the sensitive dependency on initial conditions in which a small change at one place in a deterministic nonlinear system can result in large differences in a later state. Everything in the electricity grid is interdependent – everything is connected to everything else.

Examples of this interconnectedness in action in the electric power grid include:

  • The November 2006 European grid collapse into three separate domains as phase angles sharply separated between the north, south and east due to insufficient inter-transmission service operator coordination and non-fulfilment of an N-1 criterion
  • The proven ability of a 120V wall socket in a University of Austin building to sense disturbances in the ERCOT grid over 350 miles away

Other, More Generic, Undesirable/Unintended Side-Effects of New Energy Policies

The policy-created structural changes in the power sector can also create other undesirable side-effects:

  • Increased costs because the “first cost” of SG-related equipment is almost always higher than existing (less-smart) equipment
  • Reductions  in system load factor

Bottom Line – Undesirable Side-Effects Need to Be Addressed

If unmitigated, the implementation of the above broadly-supported policy initiatives creates undesirable reliability, cost and asset utilization side-effects under business-as-usual power grid operations -- enter the SG with solutions to mitigate or even eliminate some of these side-effects.

A Brief Digression - Definition of the SG as an Intelligent Network

Before discussing how SG applications can mitigate or eliminate undesirable side-effects of new energy policies, it is important to define the SG.

The ultimate SG is a network of physical objects related to the generation, delivery, and utilization of electricity -- the objects are provided with unique identifiers and the ability to transfer data over the network without requiring human-to-human or human-to-computer interaction. All individual objects in the SG have network connectivity, allowing them to send and receive data.

Final Smart Grid Onion Value Chain of 1.0 to 2.0The objects contain embedded technology to interact with internal states or the external environment. In the smart grid, each part of the electricity grid network knows what is happening in all the other parts and the network can adjust dynamically to changing conditions.

This SG is enabled by the convergence of wireless technologies, micro-electromechanical systems (MEMS), and standardized communications protocols, just like the Internet of Things (IoT) is evolving based on the TCP (Transmission Control Protocol)/IP (Internet Protocol) standard.

Now, having defined the SG, let’s get back to our primary theme: addressing the undesired impacts of new energy policies on the power grid.

SG Applications Can Mitigate and Even Eliminate Undesired Side Effects of Energy Policies

The timing of the arrival of the SG could not be better. SG applications can mitigate and eliminate the undesirable side-effects of the new policies cited above. Implementing the SG provides:

  • More accurate sensing/situational awareness (especially for distribution systems)
  • Real-time state information (“big data”)/ more instantaneous visibility of the state of the grid
  • Intelligence at the edge with smart sensors and embedded analytics, integrated with centralized intelligence
  • High-speed control, automation, and optimization
  • Integration of industrial control systems (ICS) and enterprise IT systems, i.e., integrating the physical, customer, financial, and market aspects of operations
  • Ability to operate closer to power infrastructure design margins
  • Better load and capacity forecasting
  • Ability to incorporate intrusion detection and blocking systems

Combined, the above functionalities can be used to improve service reliability, reduce operating costs, improve the utilization of existing assets, thus reducing capital requirements. That is, they can provide solutions to address the undesired side-effects of the new policies discussed above.

What role does interoperability play in realizing these solutions?

It is a prerequisite.

We can’t have the SG without interoperability.

The Smart Grid (SG) and Interoperability Are Symbiotic

DSC_1253-150x150By definition, the SG is an interoperable network. It would be a contradiction in terms if SG applications were not interoperable. Interoperability is a prerequisite to the realization of the concept of the SG and the derivation of the benefits of SG applications – all parts of the grid need to work harmoniously together, to interoperate, since everything affects everything else in the grid to a greater or lesser extent.

Bottom line: for it to realize and deliver its potential value, the SG needs to be interoperable.

In the “Real World”, Interoperability Encompasses Much More Than Just Standards

It is important to note that the concept of interoperability is far broader than the concept of standardization – in fact, there is an interoperability “continuum” in the “real-world” (see the diagram below).

Standards are not always available. When they are, standards are dynamic, not static. Vendors’ new equipment may or may not be compliant with the latest version of a standard. Proprietary legacy systems will continue to exist and age for decades to come.

Compounding the normal flux in the standards’ world, U.S. utilities have chosen for the most part to operate in a multi-vendor environment which exacerbates integration challenges – the differing equipment uses a mix of different standards and proprietary protocols. This is a contrast to European utilities that often choose a single systems vendor -- the vendor can consequently provide a fully-standardized system across the utility’s power grid without having to worry about interoperability with other vendors’ systems.

So, standards are not a panacea, nor should they be the only solution for achieving interoperability. The ongoing SGIP’s Implementation Methods Committee (IMC) utility case study program of “real world” implementation of SG applications amply demonstrates the wide variety of choices available to achieve interoperability.

10. DSC_1334-150x150In the “real world” of the power grid, legacy systems are almost always involved – if we are to integrate them into the SG network, we need to develop Application Programming Interfaces (APIs) to bridge the “gap” between incompatible systems.

In the “real world”, the general approach for implementing SG applications is “one project at a time”, despite the inherent inefficiency in not taking a more holistic approach. There are two main reasons for this:

  • First: single, isolated/independent SG projects can be implemented faster with less organizational disruption. Examples of this approach are provided by the IMC’s utility case studies on the implementation of interoperability, e.g.,  the DTE/Common Information Model (CIM) IMC case study, the Public Service Company of New Mexico (PNM) IMC case study, the Saint Bernard Electric Cooperative (SBEC)/NRECA IMC case study.  The SGIP IMC case studies provide “real world” examples of this approach and “lessons learned” in implementing customized interoperability – this is the way interoperability is actually happening. In this approach, the SG edifice is built one block at a time, with the mortar between blocks connoting interoperability. Just as we throw several pebbles in different parts of a pool (“the grid”), the ripples will begin to overlap and, over time, will be integrated, gradually building the SG in a manner similar to the layers of an onion, from the inside outwards
  • Second: in the “real world”, utilities are often reluctant to implement enterprise-wide standards because they require the organization to take on “a new way of living” – in fact, the organizational process and culture issues can be more challenging than the technical challenges. An example of this is the extensive organizational change requirements associated with the implementation of IEC 61850

As a consequence, utilities need an internal capability to write APIs or they need to arrange to have vendors or consultants develop the APIs for them in order to achieve interoperability as they deploy the SG. Since standards will continue to be developed, tested, and improved, this need will never fully disappear.

The Interoperability Continuum

Let’s summarize the mixture of approaches that will be used to implement interoperability as the power industry transitions to the SG.

To date, interoperability between applications or systems has been achieved by using standards developed by Standards Development Organizations (SDOs) or by purpose-built Application Programming Interfaces (APIs). It is actually a little more complicated than that, however. The graphic below presents the “Interoperability Continuum”. The left-hand side represents a situation where no standard exists for a proposed interface/integration. On the right-hand side, a mature standard exists which can be used for the interface. Moving from left to right denotes increased general interoperability.

A more detailed discussion of the Interoperability Continuum is provided here.

SG Applications Will be Phased-In Using a Hybrid API/Standards Interoperability Approach

The SG is not ready for prime time -- not all SG applications are commercial, and some are still in the R&D stage. The SG will be phased in over the next 25 – 30 years, project by project, locality by locality, utility by utility, and region by region.


Realistically, in the “real world”, the transition to the SG will be gradual because the following essential SG functions are in various states of readiness, or in some cases, not available/not developed, not ready/in development, not economical, not commercial, or not mature. These critical SG functions are, in increasing order of complexity/intelligence:

  • Sensing
  • In-situ diagnostics
  • Monitoring/communications
  • Controlling
  • Automation
  • Optimization

7. DSC_0150-150x150Deployment will be driven by the near-term grid operators’ needs for service reliability and cost-saving solutions, e.g., remediating negative reliability trends, achieving least cost (or zero-cost) SG deployment using the 80/20 rule, reducing business/operating costs by releasing latent capacity, managing the Load Duration Curve (LDC), and reducing losses and inefficiencies.

In addition, as sensing, diagnostics, monitoring and communicating functions become more ubiquitous in the SG, they can also be used to provide a solution for another critical issue facing the power industry: intelligent replacement of aging infrastructure.


The SG is coming…….for it to work, interoperability is a prerequisite – you can’t have the SG without it – the ultimate SG is a “plug-and-play” networked machine, ultimately like the Internet of Things (IoT) – actually, it is the Internet of Smart Grid Things (SG IoT).

Without the SG, reliability decreases and costs go up more.

Without interoperability, we don’t have the SG.

The work of the SGIP’s Implementation Methods Committee (SGIMC) is about “real world” implementation of interoperability – the way it is actually happening. The SGIMC’s utility case study series is creating a knowledge-base of “lessons learned” by pioneering utilities that can provide valuable interoperability implementation pointers for other utilities as they deploy SG applications and equipment.

By mid-century perhaps, the ultimate, interoperable, plug-and-play SG will create an electricity services commodity market with automated delivery, pricing and purchasing in real-time, at customer-specified reliability levels, i.e., akin to “The Feed” in Neal Stephenson’s intriguing book.

As always, comments are welcome and appreciated.

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