http://www.nrel.gov/docs/fy03osti/34715.pdfAugust 2003 NREL/SR-560-34715
Report on Distributed Generation Penetration Study
1.1 Background Discussion
Traditional nonutility-generated power sources, such as emergency and standby power systems, have minimal interaction with the electric power system (EPS). As distributed generation (DG) hardware becomes more reliable and economically feasible, there is an increasing trend to interconnect those DG units with existing utilities to meet various energy needs and offer more service possibilities to customers and the host EPS.
Among these possibilities are:
Standby/backup power to improve the availability and reliability of electric power
Peak load shaving
Combined heat and power
Sales of power back to utilities or other users
Renewable energy
Power quality, such as reactive power compensation and voltage support
Dynamic stability support.
This trend is fueled and accelerated by utility deregulation.
Safe and reliable operation of the power system will increasingly be influenced by distributed energy resources (DER). Penetration is a measure of the amount of DER compared with the total generation resource on a power system. In the broadest sense, this applies to the entire interconnected grid. However, the concept of local penetration is valuable, as well. A few megawatts of generation can represent a substantial penetration on a small system or the local portion of a large system. Further, penetration is not a static measure. A relatively small amount of installed DG might represent a high level of penetration when the system is at light load. A broad vision of DER includes widespread deployment of a range of new technologies. In that long-term view, the majority of attractive emerging DER technologies relies on power electronic inverters for connection to the power system. These technologies include fuel cells, photovoltaics, and microturbines. The first year of effort examining penetration focused on those technologies....