© EYEWIRE & DIGITAL VISION, LTD.
|
This issue of IEEE Power & Energy Magazine includes articles that focus on different aspects of distributed resources and their impact on and interface with power systems. The topic of distributed resources most often conjures images of smallish generators installed and connected across the power system, with the strongest proponents envisioning a fuel cell or mircoturbine in every garage. The increase in natural gas prices from the historic lows seen in 2001 has moderated the more outrageous predictions for distributed generation market penetration, particularly with respect to those technologies using natural gas. However, in the same time frame several technologies have gained traction and market acceptance as a result of technological innovation, state and federal legislation, and favorable tax treatment. Photovoltaic technology has continued to advance and developers have narrowed their focus to projects fitting criteria that make economic justification more likely. Favorable tax treatment of wind generation in the United States spurred a large number of wind developments in recent years, although at the time of this writing the continuation of such treatment is in doubt, raising the bar for economic viability of future wind generation projects in the United States.
Interconnection of cogenerators and nonutility generators to both the transmission and distribution systems while maintaining reliability of supply and safety continues to be a challenge for utilities. The challenge is compounded since nearly all customers are aware of the potential of on-site generation as a result of the publicity surrounding distributed generation and high-profile system failures. Further, with tight budgets, slowing deregulation, and heavily loaded systems, demand-side management programs are getting renewed consideration at many utilities. In many respects, demand-side management is just a program administering distributed resources throughout the system.
This issue of IEEE Power & Energy Magazine focuses on several distributed resource topics relevant to distributed generator interconnection as well as broader distributed resource topics. In "Distributed Asset Insight," Sonderegger, Henderson, Bubb, and Steury discuss a data model and supporting analysis tools that allow utilities to more fully exploit distributed resources. The Distributed Asset Optimization (DAO) model presented by the authors allows utilities to estimate customer-level loads allowing more accurate planning for system expansions as well as demand-side management and distributed resource programs. The DAO model combines the features of transformer load management systems with data available from modern geographic information systems and clever analytical and visualization tools to provide users with information in a form that can be used across a variety of utility functions.
In "Don't Let the Sun Go Down on PV," Shahidehpour and Schwartz discuss one of the emerging renewable energy sources and the challenges faced by such new distributed resources. The authors introduce the subject with a short discussion of the history, physical operation varying geographical potential of photovoltaics (PVs). The article then provides a discussion of the economic factors involved with photovoltaics as well as operation and maintenance of photovoltaics. The authors wrap up the discussion by addressing the markets and interconnection issues facing PV generators. Although the article focuses on PV generation, many of the ideas presented are applicable to other types of distributed generation.
The third feature article in this issue, "Concerns Generated by Islanding," by Villeneuve, provides a review of practical issues that are faced with distributed generator interconnections. The article first provides a review of the different subsystems (e.g., governors and excitation systems) that are part of a distributed generation system. The article then discusses islanded and parallel operation of distributed generators and provides common configurations. The article closes with a discussion of interconnection agreements and additional considerations for islanded operation.
