Gather electricity data with meters to find opportunities and get your projects implemented
6 min readData is the key to your success.
Without data, you have a much more difficult task in front of you, if you want to reduce your electrical usage.
One of the biggest things you can do to drive sustainability efforts is purchase or lease a handheld electricity meter. First of all, electricity is most likely one of your biggest energy sources, and secondly, the data you will gather will help sell your business case for getting funding and support for future projects.
There are two main purposes of this electrical data:
- Estimate costs to run equipment
- Determine efficiency of equipment (power factor)
Estimating costs
In our experience, most people have NO idea how much electricity a piece of equipment or machine uses. I can use Kill A Watt plug-in meters on small appliances and devices, but for the big items, which have the biggest opportunities, you need something more.
Once you capture the KWH usage for a device, you can now make a business case for how to improve upon it. Maybe you can shut it off during breaks, because it doesn’t take much energy to start it up again. Maybe you can stagger the startup, because it takes a lot of energy when powered on. Perhaps the equipment uses twice the energy of a newer version, so you can show a quicker payback. Maybe you should run the equipment less frequently, when you have a full order, to save a considerable amount of energy. All these questions get brought up all the time, but without the data, they’re just questions. You need to turn the questions into answers!
Determining efficiency
The other benefit of electrical data is to determine the power factor of your equipment. I’m not an electrical engineer, so I won’t even try and explain it in much detail, but basically it is a measure of how efficient the equipment or device uses the electricity. Another way to put it, it measures how much of the current, provided by the electrical utility, is being used to produce useful work (run the equipment). It is a number from 0% to 100%, with 100% being ideal.
If the power factor is at 90%, then there is 10% of the electricity being wasted (as escaped heat into the environment). Most utilities do not charge directly for this amount, but you are paying for it somewhere in your electric bill, either in higher KWH rates, or as a power factor correction charge. I talk about this in my “Electricity metrics: Driving the wrong behavior!” post, if you’re interested. Improving the power factor will reduce your electricity needs and reduce your carbon emissions, but you may or may not see the savings on your bill (depends on your utility billing plan – which is an entirely different discussion).
You have a few options for increasing your power factor (Read more in this report from the US Dept of Energy – Reducing Power Factor Cost). The most popular one is a capacitor bank, which temporarily stores electricity, and balances out this difference. Another popular option is to use this data to help financially justify getting the more energy-efficient equipment you’ve been asking for.
Example
Let’s take a look at an example. We have an air compressor that supplies air to pneumatic tools and equipment. These typically use a lot of energy, so we want to quantify how much, to see whether it is worth our time and effort to focus on it.
We asked the electricians to hook up the power meter for one week, and I downloaded and plotted the data using Excel (click below to download a template for free!)
Here is the summary report that was created from the downloaded meter data.
You can see that the electricity usage is around 37 KWH throughout the entire week. This compressor runs all the time (24×7). We can take that information and turn it into a cost estimate, to predict how much money is being spent on electricity each year.
37 KWH per hour x 24 hours per day x 30 days per month = 26,640 KWH per year
If our utility costs are set at $0.08 per KWH (simple estimate), then we can estimate the total amount per year for this compressor.
26,640 KWH x $0.08/KWH = $2100 per year. There might be some opportunity here…
I also mentioned the power factor. If you look at the chart, it was a little over 80%, which means there is about 20% of the electricity not being utilized (wasted).
What that means is the utility company must provide more than 26,640 KWH to run this equipment. They need to provide an additional 20%, so that after the efficiency is lost, there is still enough power to run the compressor.
26,640 x 20% = 5238 additional KWH per year, to account for poor power factor level. If your utility charged you directly for this extra amount, it would cost 5238 x $0.08 = $420 per year in additional costs. Most do not charge extra to you directly, but it does show up somewhere “baked-in” to your bill.
Now we have the ammunition to confidently sell your improvement projects to management, and deliver them accurate savings predictions, so they trust what you give them. The last thing you want is to have leadership come ask you why the bill isn’t less this month, after you implemented one of your energy-saving ideas. Good luck getting another project approved. I highly recommend you capture savings on a project-by-project basis. With all the activity and weather impact on your electric bill each month, it is very difficult to clearly show electricity savings from a single project, unless you’re implementing something major.
Cost of data collection
This all makes sense I’m sure, but you’re probably worried about the cost to gather this data. Yes, there is an investment that you’ll need to make, especially if you don’t have a power meter already. Let’s look at some typical costs, just to give you an idea what to expect.
A really good power meter that measures KWH (instead of making you calculate it from amps and voltage readings, which is a lot of extra work) will run you around $3000-5000. You may save a little money if you contract out an electrician that already has one, but they’ll be more expensive. There are additional labor costs for the electrician to hookup the meter, then download the data into a useable format. Luckily, they don’t have to sit there while the data is being gathered, so you may need 1-2 hours of labor per equipment. There is also some cost in running reports and analyzing the data, which could be another 1-2 hours.
That may seem like a lot of money, when you’re trying to save money, but it will pay for itself quickly. One study from the Energy Cost Savings Council (can’t find a reference) estimated that meters and monitors have an average payback period of less than six months, and an average payback of 200%. From my personal experience, I completely agree with that number.
Bottom line: You’ll never be truly sustainable unless you have a good method of gathering electrical data. If you’re serious about saving electricity (like I know you are), then I guarantee after the first study, you will have the meter hooked up all the time, looking for new opportunities. It can be contagious gathering data to see how much energy everything uses!
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