Smart grids and smart homes (smart appliances, gateways etc.) and smart meters (electricity, gas, water) are key elements of the smart energy ecosystem. Smart home appliances are typically those devices consumers interact with daily. By enabling these devices to talk to each other and be controllable by the consumer, a whole new dimension of convenience is added (Figure 2). There are several products (smart thermostats, smart switches, smart refrigerator, and more), which are available today that offer some level of intelligence and wireless connectivity. Some of the more advanced appliances include built-in Web servers to interact with other devices in the connected home. Smart meters are the gateways into these homes (and offices) and collect and measure resource usage before sharing some or all of this information with the smart grid. The grid, in turn, acts upon this information by taking necessary steps such as load adjustment, peak curtailment, and even demand-side management.
Smart energy devices, apart from performing their standard functions, must be able to communicate with other smart energy devices within the local network and be able to send and receive relevant information (pricing, usage, alerts, etc.). The exchange of data not only improves the overall efficiency and fault tolerance but optimizes the consumption of energy. Smart meters collect and transmit usage data to the energy providers and allow consumers the ability to monitor and manage their own energy consumption. In other words, usage data flows from the consumer to the energy provider and, at the same time, pricing data flows from the energy provider to the consumer. This bi-directional flow of information allows consumers to make decisions to manage consumption. This two-way, real-time communication enables energy providers to improve planning and improve energy distribution.
Standardizing smart energy design
As multiple manufacturers design smart energy systems, it is becoming increasingly clear that all devices interoperate in a network. The ZigBee Alliance is working on a specification called the Smart Energy Profile 2.0 (SEP 2.0) to help formalize the requirements for many aspects of the smart energy ecosystem including device communication, connectivity and information sharing requirements.
SEP 2.0 provides the guidelines in which the devices should communicate with one another. It defines various device properties that can be manipulated. These properties (also known as “resources”) work together in logical groups to implement SEP 2.0 functionalities (called the “function sets”). A metering system, or pricing system, is an example of an application-specific function set. Devices like smart meters implement one or more function sets to provide value-added services such as usage statistics and trends. These pricing statistics and trends can then be used by either the energy provider or the consumer to further manage services or usage, respectively.
Function sets and their resources on a device are accessed through HTTP URLs. These devices dynamically discover relevant services on the network using technologies like mDNS and DNS-SD and register themselves to further access resources to implement SEP 2.0 functionality. To provide for a truly interoperable ecosystem of interconnected smart energy devices, use of TCP/UDP and IP-based networking is necessary. Support for security features within a device is critical because of vulnerabilities from exposure to a broader network, and more importantly, the access a device provides to the energy grid. Since many smart devices serve up continuous, reliable, and real-time data, they must be "Always-ON" and "Connected" which necessitates that all smart energy devices be power efficient themselves. Lastly, they must also support both wired and wireless networking capabilities.
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