ASHRAE Journal - November 2009 - B9

Residential Microgrid With Rooftop Solar and Backup Generation Microgrids Can Be Self-Sustaining And Taken Off the Main Grid Campus Microgrid Clean Coal With Local Renewables, Energy Storage and Back-up Generation Nuclear Tomorrow’s Smart Grid Efficient Grid, Integrated Renewables and Storage, and a Healthy Electricity Marketplace Urban Core Urban Density Requires External Power Generation District Microgrid With Generation and Storage Commercial Industrial Residential Large Renewables Hydro, Wind Renewables are intermittent power sources that require storage or demand elasticity for large-scale integration. Figure 2: Tomorrow’s Smart Grid with integrated microgrids, central and distributed generation, renewables, and storage, and a price-driven marketplace that drives new products and technology. Smart Grid a pipeline connecting central generation facilities to end use customers into a system that is more distributed and robust (see “What’s New About Smart Grid”). This scenario contrasts significantly with the current system shown in Figure 1. The typical customer uses electricity with no indication of the real-time value, and pays a monthly bill. Except for a few customers subject to peak demand charges or participating in existing demand response (DR) programs, there is little incentive to use less energy at peak demand times, or more at night when the real market price is low. In effect, a market exists at the utility level, but not at the consumer level. November 2009 Today’s system of regulated utilities offering flat-price sole-source contracts has developed, in part, because there was no way to communicate to the customer the dynamic value of electricity and no way for the customer to actively respond to that dynamic value. Instead, an artificial market was put in place that has resulted in a frequently under-utilized grid, non-competitive utilities, confused rate structures, under-development of infrastructure, and an inability to effectively integrate renewable energy sources. Because we need a more efficient and more robust grid with successful integration of distributed renewables, the system must be transformed. Commercial building load responsiveness is one of the key elements to enabling this transformation. Figure 2 shows the future, smarter grid. As we build more efficient buildings and install local generation, the net energy coming into a building, campus, or neighborhood is reduced. As some buildings approach net zero energy consumption there is no longer a need for a big pipe, but rather the utility becomes a back-up power supply. With the addition of storage, a micro-grid may be able to produce and manage its own power needs independently of the grid. However, in many places population density demands power density that renewables cannot currently supply, so central generation will continue to serve a vital role. The promise of a smart grid is cleaner and better quality power with a more efficient electricity distribution system. The B A C n e t ® To d a y | A S u p p l e m e n t t o A S H R A E J o u r n a l

ASHRAE Journal - November 2009

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