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Plug Load Nuggets

  1. Plug Loads: The Overlooked Energy Hog
  2. Plug Loads: Low Hanging Fruit for Reducing Building Energy
  3. The Power of Power Management
  4. Night Time is the Right Time (to Power Down Your Office Equipment)
  5. Installing Timer Plug Strips to Save Energy (and Money)
  6. The Energy Lowdown on Laptops
  7. What Gets Measured Gets Managed: Metering Your Plug Loads

 

Plug Load Nuggets

      1. Plug Loads: The Overlooked Energy Hog

        Plug loads refer to energy used by equipment that is plugged into an outlet. In an office, key plug loads include computer and monitors, printers, and copiers. Plug loads can average approximately 30% of electricity use in office settings.

        Plug loads as a share of overall building energy use is higher in energy efficient buildings. In minimally code-compliant office buildings, plug loads may account for up to 25% of total energy consumption. But in high efficiency buildings, plug loads may account for more than 50% of the total energy consumption.

        Minimizing plug loads is a key challenge in the operation of an energy-efficient building. For example, California’s office plug loads consume more than 3,000 gigawatt hours annually, costing more than $400 million each year. The associated carbon dioxide emissions of these plug loads is more than 700,000 metric tons annually—equivalent to the carbon dioxide emissions of 140,000 cars during one year.

        You can reduce plug loads by up to 50% at your facility by implementing simple, no cost and low cost strategies including power management and powering down equipment that is not in use. Federal facilities’ electricity use varies widely, depending on their size and the nature of their operations, but the average federal office facility spends $1.32 per square foot on electricity annually. If we assume plug loads account for 25%-35% of electricity use for federal facilities, than the average facility could save $0.17 - $0.23 per square foot annually by managing plug loads. This translates into savings of roughly $40,000 - $60,000 over five years for a facility of 50,000 square feet, or $200,000 to $300,000 over five years for a facility of 250,000 square feet.

      2. Plug Loads: Low Hanging Fruit for Reducing Building Energy

        Plug loads refer to energy used by equipment that is plugged into an outlet. In an office, key plug loads include computer and monitors, printers, and copiers. Plug loads as a share of overall building energy use is higher in energy efficient buildings. In minimally code-compliant office buildings, plug loads may account for up to 25% of total energy consumption. But in high efficiency buildings, plug loads may account for more than 50% of the total energy consumption.

        Plug loads are a key challenge in operating an energy efficient building. They are also a promising opportunity for cost-effective energy reduction. You can reduce plug loads by up to 50% at your facility by implementing simple, no cost and low cost strategies including power management and powering down equipment that is not in use. Investing in these no cost and low cost strategies can forestall or minimize the need to invest in renewable energy sources to meet net zero energy targets for federal facilities.

        Federal facilities’ electricity use varies widely, depending on their size and the nature of their operations, but the average federal office facility spends $1.32 per square foot on electricity annually. If we assume plug loads account for 25%-35% of electricity use for federal facilities, than the average facility could save $0.17 - $0.23 per square foot annually by managing plug loads. This translates into savings of roughly $40,000 - $60,000 over five years for a facility of 50,000 square feet, or $200,000 to $300,000 over five years for a facility of 250,000 square feet. Follow the checklist for implementing your plug load plan.

      3. The Power of Power Management

        Energy Star computers have factory installed power management features, but they are often disabled by administrators and users. Computers in particular are often left in active mode even when they are not in use. 

        By enabling the power management features, you can reduce computer energy use during non-business hours by 60% at no cost. The average desktop computer without power management enabled uses nearly 500 kWh annually. Applying the average electricity rate paid by the federal government, in a federal facility with 500 computers, this reduction in computer energy use during non-business hours would save $7,500 annually or $37,500 over five years. Because using power management is a no-cost strategy, these savings pay for themselves immediately. Power management features are important to enable in other office equipment as well. Enabling power management in copiers can save up to 90% of energy use in non-business hours, and up to 90% for laser printers.

      4. Night Time is the Right Time (to Power Down Your Office Equipment)

        While offices and buildings are becoming more energy-efficient in general, the trend in powering down office equipment is going in the wrong direction. Computers and other devices are less likely to be powered down when not in use now than they were a few years ago.

        Monitors, printers, and copiers should always be turned off at night. In addition, facility managers should work with their IT departments to allow and encourage occupants to power down their computers at night. By powering down office equipment, a federal facility with 500 workstations could save $25,000 annually or $125,000 over five years.

        The Energy Star program offers free technical assistance to federal facilities and IT departments to overcome any technical barriers to powering down (such as scheduling software updates and other maintenance during nighttime hours).

      5. Installing Timer Plug Strips to Save Energy (and Money)

        Plug strips can save energy from computers and other office equipment by automatically powering down devices when not in use. However, not all plug strips are equal. As a general rule, to maximize energy savings, you should buy timer plug strips (i.e., plug strips that operate on a pre-set schedule) rather than other types of plug strips.

        Timer plug strips pay for themselves through energy savings in about 3.5 years. While they cost more initially than other plug strips, the savings over time mean they are a good value in terms of lifecycle cost. Occupancy and load-sensing plug strips can also save energy, but their payback period is much longer.

        You can find plug strips with energy saving features through multiple GSA Schedules and on GSAAdvantage!

      6. The Energy Lowdown on Laptops

        Laptops outperform desktops from an energy use perspective. Laptops use 78% less energy than desktops on average. Also, users are more likely to keep power management features enabled on laptops than on desktops.

        The average laptop use 58 kWh per year compared to 266 kWh for the average desktop. Applying the average electricity rate paid by the federal government, each laptop used by the federal government saves about $20[DL1] per year. This means that if your facility purchases 200 new personal computers this year, you can save $4,000 in energy costs in one year from buying 200 laptops instead of desktops, and $20,000 over 5 years.

        Be sure to specify Energy Star products when purchasing laptops.

      7. What Gets Measured Gets Managed: Metering Your Plug Loads


        Plug loads (energy used by equipment that is plugged into an outlet) can average approximately 30% of electricity use in office settings. To understand a facility’s plug loads and develop effective energy management strategies, managers must first obtain accurate energy use data. Proper metering is the key to getting this data.

        The first step is to choose the right meter. To measure plug loads properly, a meter should be able to measure data sampled every 30 seconds. It should also be designed for the specific circuit type present (e.g., 120 Volt), and able to measure loads of up to 1,800 Watts.

        Once you have selected an appropriate meter, the steps to measure plug loads are:
        1.  Identify the equipment and a sample of workstations to meter. 
        2. Set up and install the meters, using a sampling interval of 30 seconds. 
        3. Collect energy data for one week, using office equipment as normal. 
        4. Use the data to calculate the average load during work and non-work hours.

Strategies to reduce plug loads can save about $0.17 - $0.23 per square foot for an office building. This translates into savings of roughly $40,000 - $60,000 over five years for a facility of 50,000 square feet. Metering plug loads is a necessary first step to realizing these savings.

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CONTACTS

Michael Bloom
(312) 353-0729


Plug Load Nuggets