Innovations in Comfort, Efficiency, and Safety Solutions.
Thomas Hartman, P.E.
As the stimulus package works its way into reality and funding is allocated for smart grid programs throughout the US, there is already a long line forming of product and service providers clamoring for their piece of the stimulus pie. To me, the developments so far are disappointing for this reason. Active members of our industry – you and I – have a unique understanding of the nature of the major loads served by these electric grids - buildings. But so far, I see very little appreciation or desire for effectively employing that special understanding into smart grid concepts that are likely to really work.
One of the big challenges in smart grid development
is the effect the shift to renewable energy will have on electric grids. As
renewable sources of electric power such as wind or solar begin to climb in
percent of total power into the grid, the predictability of the overall power
applied into grids will fall. Wind speed and solar insolation are hard to
predict hours ahead, and even if we learn to do so, it will still leave us with
those natural variances that will be difficult to manage.
This is a great challenge, but it is one that many of us who have worked in building energy system design and operations have special insight to resolve. And our solutions are likely to be much more economical and effective than what I am hearing being proposed. Instead of starting by installing specialized energy storage devices throughout the grid, would be developers of smart grids should look to the buildings themselves as the primary dynamic that can keep available power and loads balanced. As we enter this era of increased variability and reduced predictability of power sources, buildings themselves when properly configured and controlled can provide the needed balancing flexibility. From my perspective, there are two critical elements of the building energy system that can be exploited for smart grid applications without the need for any new systems. And there is a big additional benefit to starting here to develop truly smart grids:
1. Off-hour Standby Operation: It has been shown over a number of tests, that in many modern commercial buildings, less energy is used if the building is switched into a “standby” mode when unoccupied instead of shut down entirely and then restarted before the start of next occupancy. As building envelopes become more efficient, this will soon be true for nearly all buildings, both commercial and residential. In such operating schemes, energy use is very flexible, especially during standby hours and load characteristics can easily be changed to suit the variability requirements of the electric grid.
2. Building Thermal Inertia: Years ago I participated in a study to find what could be done to solve a developing electric peaking capacity shortfall in the business district of a major US city. We determined that by adding networked HVAC and Lighting control capabilities to major buildings in that area we could reduce total peak electric demand at any time by at least 30% for short periods of time without any noticeable effect on the building occupants. The thermal inertia property of buildings is quite well known among many in our industry. It was a key component of control strategies my firm and others used for many years in the early days of digital controls. This field needs to be reopened since it provides a far more economical and useful approach to managing the modern electric supply/demand equation than many of the other energy storage systems being considered.
But there is another enormous benefit achieved by
focusing first on buildings as a means to balance electrical demand with
available power. That is the substantial reduction in overall energy use that
can accompany such a focus. It has been shown very clearly in many applications
that the same smart building controls capable of off-hour standby modes and
“whole building” demand control can also greatly reduce overall building energy
use during the rest of the building operations hours. Many of us in the building
industry know that capturing this energy could have a dramatic added effect in
reducing the greenhouse gas emissions that are at the core of the motivation
toward smart grids. We know why many of the programs aimed at capturing those
savings to date have performed so poorly and we could be part of the solution to
correcting such failures in the future.
There are many reasons the building industry is largely bypassed in conversations about developing smart electric grids. But already having a plethora of smart ideas does not seem to me to be one of them. It’s time for all of us to speak up and be heard. Developing smart electric grids requires smart ideas and our industry can be a valuable contributor in developing them!
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