DOE DEPARTMENT OF ENERGY
DG DISTRIBUTED GENERATION
DER 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. New money and programs promise a growth spurt for those contractors who recognize the opportunity. Here is an update based on DOE public information.
The DOE Program supports the development of technologies and policies that enable distributed generation (e.g., photovoltaic, wind, fuel cells and microturbines), storage and direct load control technologies to be integrated into the electric system. Development is pushing all technologies into more competitive price ranges, and state regulations are opening up new markets. DER technologies provide site-specific benefits to end-use customers and electric utilities, such as high power quality, improved reliability and low-cost power delivery.
DER’s benefits are evident in the following examples:
• A bank in Omaha installed a fuel cell generation system to avoid power disturbances that were shutting down its computer systems. The bank was able to purchase an on-site generation system for about the cost of a one-hour outage.
• A large grocery store chain operating in the Northeast estimates that an on-site generation system at a Portland, Maine, store saves $50,000 to $80,000 every day during a power outage when the store can remain open and the competition closes.
• A McDonald’s restaurant in Chicago gets most of its electricity from a natural gas-fired microturbine, cutting $1,500 from its monthly power bill while improving power reliability.
• A police station in New York’s Central Park recently bought a fuel cell to run its electronic crime-fighting equipment, saving $200,000 over the cost of a line upgrade.
• The city of San Francisco is sponsoring installation of 15,000 solar roofs that will generate 50MW of power independent of utility controls.
DER systems range from a few kilowatts up to 50 MW. They comprise a portfolio of technologies that can be located at or near where the energy is used. DER devices provide opportunities for greater local control of electricity delivery and consumption.
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 percent 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. DER technologies support and strengthen the central-station model of electricity generation, transmission and distribution.
While the central generating plant continues to provide most of the power to the grid, the distributed resources meet the special 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.
For all of their advantages, a number of significant technical, economic and institutional barriers still hinder the deployment of distributed power technologies. The DER program is addressing these barriers:
• Interconnection with the grid—Current interconnection requirements for distributed generation differ from utility to utility and from state to state. Customers attempting to install these technologies may also have to pay for costly engineering studies. The typical lack of a single utility point of contact or defined process for distributed generation interconnection and the absence of simple standardized applications and agreements delay and discourage customer-owned projects.
• Utility pricing practices and tariff structures—Utility tariffs and rate design usually do not price distribution services to account for benefits of distributed generation. More appropriately designed tariffs can provide for utility standby and back-up power services without incurring prohibitive charges.
• Siting, permitting and environmental regulation—Zoning, air permitting, water use permits, comprehensive environmental plan approval and other regulatory processes can both delay and increase the costs of DER implementation. National building, electrical and safety codes need revision to cover these technologies. Local code and zoning officials are typically not familiar with them either, and environmental regulations do not give credit for their overall pollution reduction effects. The IEEE Standards Coordinating Committee 21 is now working to develop IEEE P1547, Standard for Distributed Resources Interconnected with Electric Power Systems. The consensus standard will contain specific requirements related to performance, operation, testing, safety and maintenance of interconnections between distributed resources and other electric power systems.
Current business models and practices—Existing business practice and business models often reflect the vertically integrated utilities and central station power plants. New ones are needed to capture the values of nonutility-owned distributed power in delaying or avoiding transmission and distribution system upgrades, the use of distributed power for ancillary services and for improving system reliability, power quality and reducing line losses.
The DOE Office of Distributed Energy Resources has provided comprehensive information on its Internet site (www.eren.doe. gov/EE/power_distributed_generation.html). Its sections include the following:
• The DER solution: to learn about the benefits of DER, current applications, barriers to large-scale adoption of DER technologies and ways to improve the electricity grid’s functioning.
• DER technologies: to learn about the technologies used for power generation, energy storage, load reduction, connecting to the grid and load control.
• Installing DER: to learn about the issues that should be addressed when installing a distributed power system. EC
TAGLIAFERRE is proprietor of C-E-C Group. He may be contacted at 703.321.9268 and e-mail email@example.com.