Distributed energy management technologies include energy storage devices and various methods for reducing overall electrical load.
Energy storage technologies are essential for meeting the levels of power quality and reliability required by high-tech industries. Storage can provide emergency power and peak-shaving benefits. Energy storage is important for other distributed energy devices by giving them more load-following capability, and also supports renewable technologies such as wind and solar electricity by making them dispatchable.
Read more about energy storage technologies.
When the supply of electricity is constrained and prices rise, both utilities and their customers have an incentive to reduce the amount of electricity being consumed. Load reduction benefits utilities because they can avoid or postpone the construction of new generating plants, and energy consumers benefit through avoided energy costs.
Reducing electrical load can be accomplished by improving the efficiency of end-use equipment and devices, or by switching an electrical load to an alternative energy source — heating water or building interiors with heat from the earth or sun, for example.
Following are some examples of commercially available technologies for reducing electricity consumption.
Energy efficiency — Involves improving energy-dependent equipment and systems to get the same output while using less energy input. Energy efficiency includes a broad spectrum of measures and applications. Some can be simple and fairly inexpensive, such as caulking and weather-stripping windows in a home. Others can be more complicated and more expensive, such as installing LED (light emitting diode) traffic signals throughout an entire community.
Geothermal heat pumps — Geothermal, or ground-source, heat pumps use the constant temperature a few yards below the surface of the earth to provide space conditioning: heating, cooling, and humidity control. They may also provide water heating, either to supplement or replace conventional water heaters. Read more about geothermal heat pumps.
Passive solar building design — Uses a structure's windows, walls, and floors to collect, store, and distribute the sun's heat in the winter and reject solar heat in the summer. It can also maximize the use of sunlight for interior illumination ("daylighting"). Unlike active solar heating systems, it doesn't involve the use of mechanical and electrical devices — such as pumps, fans, or electrical controls — to circulate the solar heat. Buildings designed for passive solar incorporate large south-facing windows and construction materials that absorb and slowly release the sun's heat. They typically incorporate natural ventilation and roof overhangs to block the sun's strongest rays during the summer season. Read more about passive solar design.
Solar hot water systems — Use the sun's energy to heat water and are almost always used along with conventional water heaters. They use the sun's energy either to heat water directly or to heat a fluid such as antifreeze that indirectly heats the water through a heat exchanger. Solar-heated water is then stored for use as needed. A conventional water heater provides any additional heating that might be necessary. Read more about solar hot water systems.
Transpired air collectors — Dark, perforated metal plates installed over a building's south-facing wall to capture the sun's heat to warm buildings. An air space is created between the old wall and the new facade. The dark outer facade absorbs solar energy and rapidly heats up on sunny days, even when the outside air is cold. A fan or blower draws ventilation air into the building through hundreds of tiny holes in the collectors and up through the air space between the collectors and the south wall. The solar energy absorbed by the collectors warms the air flowing through them by as much as 40° F. Read more about transpired air collectors on the Conserval Web site. Conserval developed this space-heating technology by drawing on the expertise of researchers at NREL.