The Hidden Energy Cost of Networked Devices

July 17, 2014 | 23:19
The Hidden Energy Cost of Networked Devices
The Hidden Energy Cost of Networked Devices
Maintaining a network connection can account for up to 80% of a device's energy demand. Revolutionizing standby could reduce energy consumption of the world's rapidly growing fleet of connected devices by up to 65%, according to a new publication of the International Energy Agency.

In 2013 approximately 14 billion networked-enabled devices were in use worldwide consuming an estimated 616 TWh. By 2020 their number is expected to rise to 50 billion. And even though many of the future devices to come online will be low-power Internet of Things applications, by 2025 the estimated energy demand for ICT technologies is 1.140 TWh. That's 6% of the current total final electricity consumption.

These numbers are published in the report More Data, Less Energy put together by the International Energy Agency (IEA) which serves as a call-to-action for manufacturers, software developers, policy makers and end users to reduce electricity waste.

The report offers several systematic approaches on how to make network technology more energy efficient by combining energy management and power scaling. Energy management applies mostly to devices at the edge of networks like TVs and computers which are used intermittently. These devices should power down to a low energy state more quickly and more often. In the case of network equipment like servers sleep mode generally isn't possible because of its functions, however power scaling would ensure that the device's energy consumption matches the work being performed.

The difficulty with online devices is the - unlike stand-alone units which can power off whenever they're not in use - necessity to respond to messages send over the network. Networks are chatty things, devices keep pinging each other to create a situational overview of the network as a whole. When devices fail to respond because they are sleeping, they'll be marked as offline and excluded from network communication. This is one of the reasons why connected devices spend so much more energy when not performing their primary functions compared to stand-alone units.

According to the IEA a multi-pronged approach is necessary to address this problem on the levels of protocols, networks, and software. The thousands of protocols that have been established since the emergence of the Internet have in most cases not been designed with energy efficiency as a priority. As such, “most protocols require devices to remain awake and ready to respond to signals within a short time frame. This makes it difficult or, in some cases, impossible for the devices to power down to low power modes. Poor interoperability continues to hinder energy savings from power management. Router protocols, for example, can impede a network‐enabled television from powering down as designed”, says the report.

As energy efficiency becomes more important new protocols are being developed to serve that purpose such as the recently announced wireless standard Thread for low-power Internet of Things devices. In the many cases connected devices have to deal with power-hungry legacy protocols, work-arounds can be a solution. For instance, edge devices can trick the network into thinking its awake by delegating the task of responding to the network to a small subsystem. If the subsystem gets a legitimate request for the primary system, it sends a wake-up call.

The network devices and infrastructure are an extremely heterogeneous bunch, the IEA points out. There is no single solution to advance energy efficiency and a host disparate actors need to rally behind the cause. But despite its impressive conquest it is likely today's Internet will appear puny compared to its future self two, three decades from now. Making energy savings an integral part of todays designs will make a huge difference.
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