Department of Energy Issues Low-cost Wireless Sub-Meter Challenge

May 02, 2013 by Jeff Shepard

Following the model of the U.S. Department of Energy's (DOE's) Better Buildings Alliance Rooftop Unit Challenge, DOE's Better Buildings Alliance Technology Solutions Team has issued its Low-cost Wireless Meter Challenge to industry to produce a cost-effective, wireless metering system capable of electrical energy measurement at various locations in a building and wireless communication to a remote data collection point within the building complex. The primary goal of the program is to catalyze the development of low cost panel-level metering solutions. Selected devices may, in some cases, also be applicable to a whole-building application, but that application is outside the scope of this challenge. In developing the specifications for this challenge, DOE considered input from federal agencies and members of the Better Buildings Alliance (BBA).

Some of the key performance specifications include: The sub-meter has to collect Watt-hour energy for a three-phase circuit. Data measurement, transmission and collection must be open protocol. The communications must be wireless, although there was no specification for the type of wireless. It cannot leverage the building’s other communication systems. The sub-meter must be self-contained. The power source has to come from within the power panel it connects to or the system being monitored. The $100 price tag has to include the device, sensor, any base station or repeater, and software, but does not have to include design or installation. No additional software should be required by the user, who is assumed to have internet access. Two-way communication is not required.

The oft-used adage "If you can't measure it, you can't manage it" is true in commercial buildings, where reducing energy can be enabled by the collection and use of data. While it is technically possible to get (near) real-time, granular energy use data for even the most complex building, many decision makers do not have that information, as the high cost of purchasing and installing additional meters is prohibitive. This is particularly critical in jurisdictions where metering of building energy use is required by law, such as the federal sector and a growing number of markets like New York City. The market is in need of reliable, cost-effective metering systems.

In order to take action to reduce energy usage, owners and operators need to know how energy is being used in their buildings. Metering data provides visibility to a building's energy use. Energy costs can be reduced by taking action to resolve problems identified by examining metered data. While metering systems do not directly improve energy efficiency, metering systems enable focused, energy efficient actions. It is estimated that using systems results in energy efficient actions that deliver electricity energy savings of at least 2%.

Today, the cost of building panel-level metering systems is typically the key hurdle to implementing these technologies. DOE has a proven track record through its Rooftop Unit Challenge of teaming up with industry to solve problems related to technology development. In this case, demand-side interest from commercial sector actors will form a compelling incentive to manufacturers to provide low cost, reliable metering devices. Manufacturers will see benefits from DOE raising awareness about the need for metering by working with BBA members and other stake holders to implement technologies. DOE will also provide technical assistance in the form of 3rd party verification and testing of the Challenge technologies. DOE can then drive the implementation of electric metering through lower pricing and a greater understanding of the performance of the technologies.