Nanogrids: An ultimate solution for creative energy aware buildings

Nanogrids are small microgrids, typically serving a single building or a single load. Navigant Research has developed its own definition of a nanogrid as being 100 kW for grid-tied systems and 5 kW for remote systems not interconnected with a utility grid. Nanogrids mimic the innovation that is rising up from the bottom of the pyramid and capturing the imagination of growing numbers of technology vendors and investment capital, particularly in the smart building and smart transportation spaces, says Navigant. In other ways, nanogrids are more conventional than microgrids since they do not directly challenge utilities in the same way. Nanogrids are restricted to a single building or a single load, and therefore do not bump up against regulations prohibiting the transfer or sharing of power across a public right-of-way. From a technology point of view, perhaps the most radical idea behind nanogrids is a clear preference for direct current (DC) solutions, whether these systems are connected to the grid or operate as standalone systems, according to Navigant. building is often only as intelligent as the electrical distribution network it connects with. That's why smart buildings are often seen as an extension of the smart grid. Meters, building controls, intelligent lighting and HVAC systems, distributed energy systems and the software layered on top are indeed valuable for controlling localized energy use within a building. But in many cases, the building relies on the utility or regional electricity grid to value those services. Some analysts define these technologies as the "enterprise smart grid" because of their interaction with the electricity network. But what if there were no supporting centralized grid? How would buildings be designed then? In today's grid-centric framework, the building works for the benefit of the larger grid. But Nordman thinks there's a future where the opposite is true. And that future is the nanogrid. A nanogrid is different from a microgrid, according to the authors. Although some microgrids can be developed for single buildings, they mostly interface with the utility. Some aren't even fully islandable. A nanogrid, however, would be "indifferent to whether a utility grid is present." Rather, it would be a mostly autonomous DC-based system that would digitally connect individual devices to one other, as well as to power generation and storage within the building. Nordman and Christensen describe it this way: "A nanogrid is a single domain of power -- for voltage, capacity, reliability, administration, and price. Nanogrids include storage internally; local generation operates as a special type of nanogrid. A building-scale microgrid can be as simple as a network of nanogrids, without any central entity." The nanogrid is conceptually similar to an automobile or aircraft, which both house their own isolated grid networks powered by batteries that can support electronics, lighting and internet communications. Uninterruptible power supplies also perform a similar function in buildings during grid disturbances. Here's a simple diagram illustrating how a nanogrid -- based on the concept of "local power distribution" -- would function. Essentially, it would allow most devices to plug into power sockets and connect to the nanogrid, which could balance supply with demand from those individual loads.