Buildings someday could play an integral role within the power distribution network. Through microgrids that are separate from the central utility plant, buildings would be able to assume a role in the power network that personal computers, tablets, and smartphones play in the data network, according to the EMerge Alliance, an open industry association developing standards leading to the rapid adoption of DC power distribution in commercial buildings. Microgrids would serve as distributed notes that may require input but also can produce output and operate while on or off the power network, in an "Internet of energy" known as the "Enernet."
For this Enernet to be reality, it will require the ability to harvest multiple and diverse forms of energy that currently are being wasted or are too impractical to couple into today's highly synchronized AC infrastructure. The fact that electrical energy use is outpacing consumption of all other energy forms by more than 2:1 also needs to be addressed.
"Utility experts maintain that today's national grids only can accept 15 percent of its power from distributed sources, which means we have a significant unsolved problem — so-called 'smart grid" notwithstanding," says EMerge Alliance president Brian Patterson. "Combined information and computer technology devices will nearly equal the total load of lighting homes and businesses in terms of raw power consumption by the end of this decade."
Existing power grids simply cannot generate and distribute the amount of power needed to meet the world's growing demand without significant help, Patterson says.
For the electrical power generation industry and its consumers, change is necessary, as the number of electrical devices continues to grow. But how do we power all of these devices — from computers and smart phones to electric cars to all of the components in building operating systems — with clean, sustainable sources of electricity rather than traditional ways?
Buildings today take the centrally supplied electricity from utility grids and pass it through to electric devices (loads) located in and around the facilities. These electronic devices use a different kind of power than what comes from the grid. Their internal chips need direct current (DC) — the kind of power that comes from batteries or other big chips, like solar panels.
While some electronics in buildings are there to conserve energy — dimmers, occupancy sensors, speed controls — building electrical distribution systems have somewhat the opposite effect. They simply aren't set up for direct current, so just about every device must convert the grid-supplied alternating current (AC) over to DC, rather than use it directly. These mismatched power requirements can lead to lost energy, because converting from AC to DC wastes energy.
"You get losses every time you have an AC conversion," says Dennis Symanski, senior project manager at the Electric Power Research Institute (EPRI).
With this long-standing challenge hindering efficiency efforts, it's time for a change, experts note.
"Buildings need to take over the majority role of generating and/or harvesting their own power, particularly their own electricity," Patterson notes. "It's much like how personal computers and other highly distributed data devices have taken over the vast majority of data that is collected and re-distributed in the Internet."
Even buildings that have started down the path of self-generation still largely have been designed to convert locally generated power from DC back to AC.
"We are past the tipping point of DC versus AC need," Patterson says. "Instead of having to include AC-to-DC power conversion in every device in a building, the building itself needs to take on the role of providing DC power directly to its devices."
Developing Enernet Foresees Buildings Playing Integral Role Within Power Distribution Network
Future Building Needs Include Connecting Directly To Utility’s AC Power
Enernet’s Success Will Mean Buildings Must Easily Generate Their Own Clean Energy