Within the next decade, it’s predicted an average home could contain more than 500 smart devices and appliances performing a wide range of functions, including the basic tasks of heating and cooling, water heating, lighting, and vehicle charging.

One building energy expert, PNNL’s Nora Wang, believes the most effective approach for optimizing the value of these many devices may exist in two emerging disciplines: Transactive Control and Coordination (TCC) and Transactive Energy Networks (TENs). The Nature Energy journal recently published Wang’s futuristic paper on the topic, “Transactive Control for Connected Homes and Neighborhoods.”

Traditional Approach Poses Challenges

In the paper, Wang describes the traditional energy management method known as direct load control, in which utilities are granted, by homeowners, limited control over smart thermostats and other household devices, which enables balancing of electricity use across the energy system. For instance, when electricity demand is high, the utility can drop home thermostats by a degree or two for a certain time period or perhaps turn off the water heater.

This approach, as described, has not caught on, as it doesn’t offer sufficient energy savings or appealing incentives to homeowners and, in many cases, is perceived as intrusive. As a result, there hasn’t been widespread acceptance among consumers for broad implementation.

TCC and TENs Communicate with Energy Market

Wang goes on to outline a different—and perhaps more appealing—potential solution that employs TCC and TENs. Under TCC, individual smart devices in a home are essentially capable of direct negotiations with the energy market—that is, if the utility’s electronic price signal for electricity is too high, the device, perhaps a heating system, can determine whether it really wants to purchase the electricity and provide heat, or maybe delay operation until the price drops. The decision ultimately would be based on the device honoring homeowner preferences (for example, whether heating, water heating, or clothes drying is more important at a given time). A group of connected devices operating in this manner would effectively form an in-home TEN.

This same series of decisions, Wang proposes, could take place at a neighborhood level, automatically and simultaneously, with devices within homes “talking” with each other, with other homes, and with the power grid. The neighborhood TEN effectively identifies the best times and rates for energy consumption across all homes and subsequently delivers a wide range of benefits, including:

Maximum comfort and convenience with minimal cost for homeowners, who as a result might more willingly embrace connected devices

A resilient grid that can adapt to changes on both the demand side (distributed generation, electric vehicles, extreme weather, etc.) and the supply side (integration of solar and wind energy and reduced greenhouse gas emissions).

“TCC and TENs are not without challenges, and further research is needed to understand the hurdles and opportunities for more rapid and widespread deployment. But these methods offer the possibility of converting homes from passive energy consumers into intelligent, active energy storage and service providers for the future grid,” Wang notes.

“And beyond energy-related uses, it’s possible the methods could enable other solutions and applications driven by consumer desires on a wide range of fronts,” she adds.

PNNL is working in multiple areas to advance transactive control concepts and methods, including Connected Homes research. Additionally, PNNL led the Olympic Peninsula Gridwise Demonstration, and participated in the Pacific Northwest Smart Grid Demonstration Project, which was led by Battelle, operator of PNNL.