Thursday, March 31, 2016

Analyzing Your Energy Consumption in Micro Increments, at a Macro Level

Energy consumption can be tricky to manage, even on a single building level.  Most utility bills don’t go into much detail, showing only what’s being drawn from the grid, not how much power your refrigerator or air conditioner consumes.  And even then, you find out how much in almost 30-day increments—how useful is that?  By taking advantage of your smart meter data, you can find a lot of information about the operational characteristics of your building.

This is a chart of hourly energy consumption over the course of 13 months for a small office.  It’s been averaged out over every hour of the day and separated out by day of the week, with the addition of holidays being its own day of the week.  As we can imagine, when the business is closed, you should be consuming less energy—the lights are off, the thermostat is set to a higher temperature, and far fewer people are in the building, reducing the energy load.  But what do you notice with the standard Monday through Friday?  Consumption slowly rises throughout the day, as more people arrive at work, turn on their computers and go about their day.  Around 7 at night, everything begins to slowly shut down.  We could, for this example, call that our baseline active usage.
How about weekend usage?  The light blue and orange lines represent the weekend days, and they’re pretty low—we could almost call that our baseline vacant usage. But look at the energy spike from 8pm to what looks like almost 10pm—it’s even greater than on the weekdays!  Remember, the usage is averaged from every weekend day out of the year, so if this was an anomaly, we would see maybe a little blip than a spike.
Now let’s look at the holiday usage.  Assuming that the office is closed, we’re seeing higher than expected usage from 9 to 8, compared to Saturday and Sunday usages.  Maybe the thermostat wasn’t turned off on the Thursday or Friday before the holiday.  Remembering to do so could bring in a lot of savings.
So after looking at this chart, we’ve noticed some more-than-likely quick and effective energy conservation measures—turning off the thermostat before holidays.  With a baseline vacant consumption day of around 2,000 kWh, this building could potentially save around 19,000 kWh per year, or $3,600 per year just by turning down the thermostat.  That’s some big savings just by reminding staff to turn down the thermostat before they leave!
If that weekend spike could be addressed too, that alone could potentially save 63,000 kWh per year, or about $12,000 per year.

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