DER Basics           

Distributed energy resources (DER) refers to a variety of small, modular power-generating technologies that can be combined with energy management and storage systems and used to improve the operation of the electricity delivery system, whether or not those technologies are connected to an electricity grid.

Implementing DER can be as simple as installing a small electricity generator to provide backup power at an electricity consumer's site. Or it can be a more complex system, highly integrated with the electricity grid and consisting of electricity generation, energy storage, and power management systems.

DER systems range in size and capacity from a few kilowatts up to 50 MW. They comprise a portfolio of technologies, both supply-side and demand-side, that can be located at or near the location where the energy is used.

DER devices provide opportunities for greater local control of electricity delivery and consumption. They also enable more efficient utilization of waste heat in combined heat and power (CHP) applications boosting efficiency and lowering emissions. CHP systems provide electricity, hot water, heat for industrial processes, space heating and cooling, refrigeration, and humidity control to improve indoor air quality and comfort.

DER technologies are playing an increasingly important role in the nation's energy portfolio. They can be used to meet baseload power, peaking power, backup power, remote power, power quality, as well as cooling and heating needs.

Customers usually own the small-scale, on-site power generators, or they may be owned and operated by a third party. If the distributed generator doesn't provide 100% of the customer's energy needs at all times, it can be used in conjunction with a distributed energy storage device or a connection to the local grid for backup power.

Distributed energy resources support and strengthen the central-station model of electricity generation, transmission, and distribution. The diagram below shows how the grid looks after the addition of distributed resources to the power grid. While the central generating plant continues to provide most of the power to the grid, the distributed resources meet the peak demands of local distribution feeder lines or major customers. Computerized control systems, typically operating over telephone lines, make it possible to operate the distributed generators as dispatchable resources, generating electricity as needed.

In grid-connected applications, DER involves using small electricity generators throughout the distribution grid (at points indicated by arrows) to augment the electricity supplied by a large, central-station power plant. This is often referred to as "distributed power" (DP) or "distributed generation" (DG). Energy storage devices and load reduction measures are sometimes also used in combination with generators. "Distributed energy" is the collective term for all of these approaches to reducing demands on the power grid.

From Mainframes to Networks

The growing popularity of DER is analogous to the historical evolution of computer systems. Whereas we once relied solely on mainframe computers with outlying workstations that had no processing power of their own, we now rely primarily on a small number of powerful servers networked with a larger number of desktop personal computers, all of which help to meet the information processing demands of the end users.

And just as the smaller size and lower cost of computers has enabled individuals to buy and run their own computing power, so the same trend in generating technologies is enabling individual business and residential consumers to purchase and run their own electrical power systems.

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Project Financing & Partnering

This part of the DER Web site is still in development. When completed, it will provide information on the following topics:

State & Local Information

This part of the DER Web site is still in development. When completed, it will consolidate geographically related information from other parts of the DER Web site, including information on:

About the DER Office

The Office of Distributed Energy Resources (DER), created in October 2000, had its origins in an earlier DER Taskforce. Formed in March 2000, the Taskforce combined DER-related programs of the Office of Energy Efficiency and Renewable Energy (EERE) into one office to enhance the effectiveness of research, development, demonstration, education, and implementation activities.


The DER Office has a vision that by 2020, the United States will have a flexible, secure, efficient, and reliable energy infrastructure by optimizing the use of distributed energy resources. At the heart of this vision is the goal of meeting 20% of the nation's generating capacity additions with DER by the year 2010.

Relationship to National Energy Policy (NEP)

The Distributed Energy Resources Program directly supports the Administration's Reliable, Affordable, and Environmentally Sound Energy For America's Future: Report of the National Energy Policy (NEP) Development Group in the areas of Transmission, Combined Heat and Power, and Alternative Energy. The program supports regional efforts as recognized in Chapter Two: "The NEPD Group recommends the President recognize unique regional energy concerns by working with the National Governor associations to determine how to better serve the needs of diverse areas of the country". In the area of Transmission, the program is supporting a National Grid Study as recommended in Chapter Seven: "Direct the Secretary of Energy, by December 31, 2001, to examine the benefits of establishing a national grid, identifying transmission bottlenecks, and identify measures to remove transmission bottlenecks". Under Combined Heat and Power (CHP), the Program is supporting EPA in the elimination of barriers to installing CHP and developing advanced integrated energy systems that provide power, heating, cooling and improves indoor air quality as discussed in Chapter Six. Distributed Energy Resources is referred to as Alternative Energy in Chapter Six, and the Program is responding to the recommendation "that the Secretary of Energy develop the next-generation technology including hydrogen and fusion". Under this recommendation, the Program is developing advanced microturbines, reciprocating engines and fuel cells with a vision towards the integrated energy systems.

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