Buildings as Networks: Danger, Opportunity, and Guiding Principles for Energy Efficiency

07/04/2010 by David Slade.

Summary
The coming twenty years will see a dramatic transformation in the patterns of energy consumption in buildings. Each year an increasing proportion of both devices and end uses in buildings will be influenced or dominated by controls that are defined by digital networks. Some of these networks will be established specifically to save energy but more often the controls and networks will be installed for other reasons, and can just as easily increase rather than reduce consumption. The efficiency community needs to be a lead actor in defining these networks’ creation and evolution, to assure that efficiency is a primary goal in their design and deployment. The alternative is to forever try to tame the energy consumption of networked products and technologies after they have been designed and installed.

The past twenty years of increasing networking of electronics shows the danger of a lack of attention to energy minimisation. Apart from niche wireless devices, energy has not often been a concern of the electronics industry in the myriad ways that devices are networked with each other. Consumption of electronics has risen dramatically in this time, partly due to increases in the stock of devices and services delivered, but a significant amount is wasted from lack of considering energy in network design. We should expect a similar outcome for other energy end uses.

Engaging with the industries that create the products — and the standards they will rely on to operate — will require significant investment by the efficiency community. However, in most cases there will be no incremental cost for manufacturing or deploying the more efficient products. Furthermore, there are likely to be few available projects for industrialized countries that rival efficient networks as an energy efficiency resource in terms of size and cost-effectiveness. The most effective and least costly time to address this issue is now.

Background
The electricity delivery system is a vast and extraordinarily complex network — one we have had for over a century. Information networks are also not new; for example the telegraph network arose over 150 years ago. Traditional light switches and thermostats are very simple network examples. The telephone system is also quite old, though originally — and still partially — analogue rather than digital. Computer networks emerged as entirely digital from the beginning. Consumer electronic devices have long been networked — until recently almost entirely through analog connections, though they are now undergoing a rapid shift to digital.

The digital nature of current network developments is the key to their power and potential for energy efficiency. Computer networks, in particular the Internet, were not designed with energy use or efficiency in mind. The number of network nodes was small, and consequently, so was the aggregate direct consumption of network hardware; also, the fact of being networked did not change the consumption of devices on the network. So, the lack of attention to energy use was completely understandable. When power management was introduced into personal computers, network connectivity was not considered in its design; it was simply lost when going to sleep. When connectivity was acknowledged, with the introduction of “Wake On LAN”, the energy efficiency community was not involved (while Wake On LAN “works”, it is not widely used and so saves only a modest amount of energy). Meanwhile, most energy used by desktop PCs occurs when no one is present. There is an enormous infrastructure of hardware, software, protocols, applications, users, expectations, and the like which do not support energy efficiency of networked PCs in allowing them to go to sleep without compromising a basic — and often desired — capability to stay connected to the network. Fixing this problem after the fact is possible, but much more difficult and expensive than doing so when the network technologies were originally developed.
For consumer electronics (CE), people have long been accustomed to powering on and off televisions and devices connected to them with remote controls, and manually with power buttons. For devices other than the TV display, this is an annoyance (if consumers are even aware that other devices are on), with the result that devices are often left powered on during times of non-use. As CE devices become cheaper, and can be more easily networked with others (that may be in different rooms), the likelihood of devices being on when not in active use is rising.
TV set-top boxes are typically on continuously, to provide connectivity both upstream and downstream. As with computers, those concerned with energy use and efficiency have not been involved in developing the standards for inter-device control.
Manufacturers who do so are more focused on simply making things work at all, content protection, and with features which appeal to consumers — rather than to any focused effort on power controls (which is unlikely to increase sales).

In both cases, there has been additional confusion sown by poorly-designed and inconsistent user interfaces around power controls. Industry did not address this topic, but energy efficiency motivated work did (IEEE 1621) and has had success in rectifying this problem.
While there is little about networked electronics to indicate that energy efficiency will be a cost burden, the reality is that without specific attention to energy efficiency, it usually doesn’t happen. The only entities likely to bring this specific focus are those whose primary concern is efficiency; however these organizations struggles to deal with the highly technical nature of integrating power management into networks.

The Traditional End Uses Energy use in buildings is largely a matter of assembling and operating many individual and isolated components, with most of these are largely static. Products put into buildings are generally independent of each other in that the efficiency of one won’t affect the consumption of another (aside from internal loads affecting space conditioning). By contrast, digital networks make behavior of one product a factor in the energy consumption of others on the network, possibly driving it up or down.

The Default Future
As with the introduction of electronics, and most high-tech building controls to date, the forces driving building networking will be to improve the quality of the space for the benefit of the occupant, not saving energy. Other lessons from electronics will also likely apply in the absence of efforts to the contrary:

• Promoters of specific technologies will ignore or resist opportunities for interoperability, as they try to gain maximum market share for their unique technologies.

• Efficiency will be an afterthought, with other features driving the process (trade publications and trade shows provide overwhelming evidence for this).

• Standards will be critical to facilitate some degree of interoperability, but aspects of these standards that could aid energy efficiency will generally be absent or ill-formed. Clear opportunities for harmonization across standards (e.g. in terminology) will not be taken.

• User interfaces will be neglected, with individual manufacturers seeing this as an opportunity to differentiate their products, at the expense of users and of energy efficiency.

• Little or no coordination will occur across domains. In electronics this manifests itself as the “IT” and “CE” domains, with different physical, application, and device infrastructure. For buildings, this is the end-use domains such as space conditioning, lighting, security, electronics, and others.

Achieving a Better Future
To arrive at a future in which digital networks optimally support energy efficiency, we should place ourselves into that long-run future — perhaps a ten year look ahead — and identify those features of network architecture not widely present that are most important for energy efficiency. We can then begin to describe key details of these features, how to develop them further as ideas, and how to market them to industry (many), standards organizations, and energy policy organizations.

Guiding Principles
Energy efficiency efforts around building-related networks need some “guiding principles” that can be used to evaluate existing and proposed network technologies. These need further development, but an initial list of Guiding Principles are as follows:

A. The existence of one device on a network should not cause another device to stay awake when it might otherwise go to sleep.

B. The network should be designed such that a legacy or incompatible device will not prevent the rest of the network from effectively using power management.

C. Devices should expose their own power state to the rest of the network and be able to report estimated or actual power use levels.

D. Product interfaces — for people or other products — should follow (international) standard principles and designs.

E. Products or devices that influence energy consumption should adhere to (international) standards for behavior and communication appropriate to their function.

F. Products and connections should have the ability to modulate energy use in response to the amount of service required.

G. Energy efficiency efforts should not favor any particular hardware — or even software — technology. All network technologies must be the target for efficiency efforts. Future buildings will include many different technologies; those in any particular building will be diverse, and always changing.

H. Harmonization of basic principles underlying efficient design for networked devices should cross all end uses and be global.

Conclusions
For the past two decades, we have seen an inexorable increase in the degree and sophistication of digital networking across electronics (both information technology and consumer electronics). This has greatly increased the services they provide, but spawned the creation of devices whose only function is to provide connectivity, increased the power levels drawn by these devices, and critically, driven up the time spent fully on for many of them. Electronic networks have been designed and implemented with little regard for energy consumption, and without the involvement of the energy efficiency community, so the resulting large increases in consumption are no surprise. Many aspects of set-top box energy consumption will apply to emerging networks in appliances and equipment.

Appliances and equipment in buildings are just beginning this transformation, a path which will lead to them becoming highly networked and controllable, across the major traditional end uses such as space conditioning, lighting, and security. As in the past, for the most part this will be done for reasons other than saving energy, such as greater comfort, control, security, productivity, and entertainment. A likely outcome is increased energy use, even aside from the energy needed to power the network itself.

This future is not inevitable. Action now can lay a strong foundation for devices to be interoperable with each other and with people in ways that facilitate maximum energy efficiency. This action will require careful attention from an efficiency perspective to many diverse standards that accomplish this interoperability — a few of these already exist but can be amended; many others are yet to be developed.

The efficiency community is not generally literate or involved in network standards development.

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