The DER Solution
"We foresee a world of cleaner, smaller and more efficient units of power generation. We foresee more individual choice, more competition, and a closer approximation of a true market for energy in America. And we foresee increased reliability, increased supply, and lower prices.
"To achieve our vision of greater individual choice, our Plan embraces exploring the idea of distributed energy."
-- Energy Secretary Spencer Abraham, speaking about the Bush Administration's National Energy Plan, July 26, 2001
There are two problems at the root of the current power crunch. There is not always enough power generation available to meet peak demand, and existing transmission lines cannot carry all of the electricity needed by consumers. DER offers a solution to both of these problems.
Permitting and construction of large, central power plants takes years. To get more power on line as quickly as possible, many power providers are now adding smaller generating units throughout the electricity distribution grid. Some of these distributed generators can be brought on line in as little as a month from the time they are ordered. Electricity customers frustrated with power quality and reliability problems are also taking matters into their own hands, installing on-site generators to meet all or part of their electricity needs. Installing DER at or near a customer load can avoid the need to upgrade transmission and distribution lines to handle the extra power requirements.
Distributed energy resources are the power of choice for providing customers with reliable energy supplies.
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One application of DER is in minigrids -- a set of generators and load-reduction technologies that supply the entire electricity demand to a localized group of customers. By avoiding the cost of transmitting electricity from a distant central-station power plant, or transporting fuel from a distant supply source, a minigrid (sometimes called a "microgrid") can significantly improve the economics of meeting energy needs using DER.
Distributed generation involves adding modular electricity generators close to the point of consumption on a power grid. Minigrids typically use the same technologies employed by electric utilities in distributed power applications, but are not always connected to the central grid. In some cases, the generators and other distributed resources are installed to relieve utility constraints on the existing grid, with a view to possibly disconnecting these generators and their load from the grid at a later date. In other cases, an electrically isolated minigrid is created; this minigrid may then be integrated with the central grid if that option becomes attractive. The essential point is that the generators in a minigrid are capable of serving their load independently.
Using a mix of generating and demand-side-management technologies gives the power supplier the flexibility to meet a wider range of loads.
See the Block Island case study (PDF 210 KB) Download Acrobat Reader, for an example of a cost-effective application of DER using a combination of energy efficiency measures, cogeneration of electricity and hot water using fuels cells, and power generation using wind, PV, and backup diesel generators for emergencies.