April 2010


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Putting the ‘M’ in EMS

Energy management from a management perspective

Andy McMillanAndy McMillan
President and CEO
Teletrol Systems Inc.

now a part of Phillips

BACnet International
Contributing Editor

Have you noticed lately how the term “Energy Management System” (or EMS) is popping up all over the place? In the trade press articles, in conference presentations and in product/service announcements everyone is talking about energy management. Companies with “System” in their name seem to want to stick “Energy Management” in front of it and companies that have “Energy” in their name want to stick “Management System” after it. I suppose all this could be driven by the billions of dollars in stimulus money focused on energy projects or maybe it’s a response to the growing building owner/operator focus on energy costs, sustainability and carbon footprints. Or, I guess it could just be that energy is the current “next big thing” much like “the web” was in the late nineties and biotech was a few years back. Whatever the reason, it seems more and more people are tying their wagons to the EMS star but not all of them fully appreciate what it means. In particular, I think a lot of people miss the point of the word “Management” in Energy Management System.

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There are lots of formal definitions of “Management” but in general I think we can say it includes three elements. To make it simple, let’s call them the “three I’s” – Information, Intelligence and Influence. To effectively manage anything we need information about the current situation and perhaps information about the past. We also need intelligence to interpret the information, balance competing objectives, consider alternate courses of action, assess the likely outcome of each action and make a decision. Finally, to effectively manage we need the ability to directly or indirectly influence the situation. So, let’s look at each of these in the context of energy management for commercial buildings.


Energy management in commercial buildings requires information on both energy efficiency and energy effectiveness. At a high level the first one is pretty clear. We need to know how much energy the building uses as conditions change and system parameters are adjusted. We can get this information through direct measurement. For example, we can measure the power consumption of the HVAC system in a building as the outdoor temperature varies and the internal temperature setpoints change. The second information component, energy effectiveness, is not so easy to measure directly. Effectiveness is a measure of how well we balance the use of energy with other building operation objectives such as occupant comfort, productivity and security. Since these are hard to measure it is important to work with a partner who has a strong base of experience to draw on. Otherwise we can easily sacrifice effectiveness in a misguided pursuit of efficiency.


The intelligence component of an energy management system can be provided by knowledgeable facility engineers and/or computer software that reflects many years of building operations experience. In either case the point of intelligence is to analyze the information available and decide on a course of action that will balance effectiveness and efficiency. The balance has to take into account the nature of the building and the characteristics of its usage. For example, in a retail store the optimum environment is a mission-critical issue since an uncomfortable shopper has many other choices of shopping venue. In an office building there may be more latitude on the comfort objective in pursuit of lower energy usage.


Influencing the use of energy is the third component of energy management and it relies on building automation and controls. Influence is exercised through changes in operating parameters such as temperature setpoints, fan operating modes and equipment schedules. This final link in energy management can be accomplished locally through user interfaces or remotely through a networked connection. Regardless of how it is handled, actually changing the system in response to intelligent analysis of relevant information is an essential component of energy management.

[an error occurred while processing this directive] With the “three I’s” in mind we can see that an energy efficiency project is not the same thing as an energy management project. Upgrading lighting, going to higher SEER systems and relocating thermostats may well improve energy efficiency, but these activities lack the information and intelligence aspects of true energy management.

Systems that collect data on power consumption and environmental variables and post them on a website are not really energy management systems, either. I suppose you could stretch a bit and presume someone will look at the website and on the basis of what they see make some decisions and change the building operating parameters accordingly. But, I think most people think of the Intelligence and Influence parts of the equation being a little more automated than that.

In the same way, a traditional building control system is not really an energy management system either. It has provisions for influencing the use of energy through its parameter setting mechanisms but it does not typically provide sufficient information not contain enough intelligence to qualify as an energy management system. Of course building automation can be a platform on which to build an energy management system.


The “M” in energy management is the hard part of the system. Building controls have been around for a long time and are not a significant challenge anymore. Databases, web interfaces and tools for turning lots of data in colorful charts are all pretty easy to manage, too. On the other hand, it takes real expertise to collect the right information, analyze it with building-specific insight and take effective action to influence the energy consumption going forward. These are the essence of the “M” in energy management and they are critical to getting long-term benefit from energy management systems. Settling for anything less than three I’s in your M is shortchanging yourself.

As always, the views expressed in this column are mine and do not necessarily reflect the position of BACnet International, Teletrol Systems, Philips, ASHRAE, or any other organization. If you want to send comments to me directly, feel free to email me at andysview@arborcoast.com .


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