Sharing Energy Information within the End Node
Sunday, November 15, 2009 at 08:44AM
Toby Considine in Smart Grid, Standards, Synergies, Zero Energy Buildings

Customers and/or their energy management systems require live energy usage information to help make decisions in response to grid-centric events such as DR, curtailment, and energy market events. Energy sales and purchases are the basic elements of transactional energy; a common shared understanding of each energy use proximate to the operating decisions that influence energy use is essential to collaborative energy on the smart grid.

The target of smart grid communications, particularly in collaborative energy space, should always be the microgrid. Some microgrids may contain a single home, or commercial building, or and industrial site—those are irrelevant details. Microgrids have a number of systems inside them that must work within the economic environment of that microgrid—and I am thinking of old economics, before the distinction of economics and ecosystem arose. Some microgrids may have a single entity inside, say a traditional siloed BAS (Building Automation System), but the unitary microgrid is merely an artifact of the way we have always done it. The energy services interface is the gateway to a microgrid.

Shared responsibility for balancing energy production and consumption requires shared access to information about energy markets and actual use. Shared information on energy use, especially live energy use, is essential to cooperation between the grid and its end nodes. Each end node may have multiple systems. Those systems may have multiple strategies and approaches to managing energy. Each strategy may have unanticipated effects on the other systems. These effects can occur quickly. Unambiguous feedback and continuous monitoring are essential to deliver results while providing services to the building occupants. The official recorder of market transactions is the electrical meter.

Energy use is more than net use for a period. Load shape matters. Multiple systems may each be operating efficiently, but in ways that their aggregate effect requires more energy use than anticipated. Systems within a building should be able to share their energy use, and their anticipated energy us with each other. Load shaping within a building is a critical pre-adaptation for site-based generation and energy storage. Load shaping is necessary for multiple systems to coexist within a minimal fixed energy budgets. The ability to function within a fixed energy budget reduces the risk and thereby increases the value of site based energy sources.

Microgrids contain collections of systems that may not share common technology. Some of these systems are small, self contained, and serve special purposes, such as appliances. Some are large and complex and span significant space, such as HVAC or an industrial line. Some look alike, are built from the same components, but have different missions; the laboratory fume hood and the air conditioning system are run for different purposes and have different constraints. Some may rely on different energy markets to do the same work; heat may come from electricity, gas, or solar thermal in the same building. Some systems may store generate energy used by other systems. All of these coexist in the ecosystem of the microgrid.

Shared energy usage information is essential to interactions between:

Any other interactions that will cause, use, or track energy transactions on smart grids.

Building revenue meters and intelligent systems in buildings should share their energy usage information in real time within the end node in a clear, accessible standard.

Article originally appeared on New Daedalus (http://www.newdaedalus.com/).
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