May 19, 2022
What is Energy Use Intensity?
What is energy use intensity? Countries all over the world are gearing up to meet the Paris Accord emissions reduction goals, and commercial buildings are an important part of that process. For instance, smart buildings have been shown to potentially reduce annual emissions by almost 10%.
With all of the energy invested in limiting emissions, it’s also important to make a note of the real bottom-line benefits of better power management. Emission concerns are leading governments to create tax incentives for investing in energy efficiency as well as allocating funds to support people making those changes.
But that’s not all. By being conscious of your energy use and improving efficiency, you inherently save money on excess demand that is otherwise wasted. So what exactly is EUI?
EUI is a metric that describes a building’s energy efficiency based on the amount of space it takes up. To calculate EUI you simply take the annual energy consumed by a building in gigajoules (GJ) or British-thermal units (kBtu) over the area (m2 or ft2) of that building.
The only room for confusion comes from the two different ways to measure energy consumption, site energy and source energy.
Site energy takes the energy use reported by utility bills or advanced metering. It’s most commonly used when looking at EUI while designing buildings, as it reflects the realities of energy consumption that the average owner will face.
Source energy is calculated from the total energy used including all energy from producing and consuming assets, as well as the energy lost throughout the transportation process. This produces a much more accurate energy footprint that factors in the added intensity of different fuel sources based on type and distance to service. Buildings that plan to incorporate on-site renewables, batteries, and other supplementary energy systems should use this method in their calculations.
Some sites naturally have a higher EUI, like hospitals or data centers that run many high-intensity assets almost 24/7. Essentially, having more connected assets, greater energy demand per asset, and overall higher runtime are the main factors that increase EUI.