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
The 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 Continue reading