Distributed Power Demands Safe, Reliable Controls

In the wake of the recent power outage in the Northeastern U.S. comes a fresh reminder of how we take uninterrupted supply of electricity for granted. The need to protect and make power supplies more reliable likewise comes to the forefront. One element along the route to reliability is a nascent trend toward smaller-scale, modular distributed power systems. Distributed power (DP) locates small electric generating systems close to users and their facilities-in contrast to large central power generating plants. Typical size of DP sources ranges widely from 1 kW to 10 MW (or more). DP is implemented in several modes: On-site generation, in parallel with the utility power grid, or fed wholly into the grid. Distributed power has particular appeal to users in remote locations. With current higher costs for distributed power and slow adoption of all new technologies, the DP trend is just starting to emerge. However, substantial generation projects are in place, involving microturbines, fuel cells, wind powered generators, battery-storage systems, smaller power plants, and others. (Find more about alternative power sources in an Online Extra to this article at www.controleng.com.) Also included under DP are standby generators that can be tapped during peak demand periods to defray utility costs at some sites. And the trend is growing. Industry experts say 10-30% of new power will come from distributed generation by 2010. An Electric Power Research Institute (EPRI) study indicates that 25% of new generation facilities will be distributed by then.