Is EUI GJ/Sqft the Best Performance Metric for Building to Grid?
Energy Use Intensity (EUI) has long been used by various standards to measure building performance and for benchmarking of individual buildings in comparison with the average buildings of a similar type and size. It is a great and simple metric to measure a buildings efficiency. However as more building go all electric and utilities and ISOs deploy more programs that incentivize flexible operation of building and #DER technologies is EUI still the right metric?
Several examples come to mind that can benefit both the building owner and the grid simultaneously but would would be missed if EUI is the only metric applied. Take load shifting or energy storage dispatch to avoid demand charges and/or participate in utility DR programs to alleviate grid constraints, the building owner has bill savings and payments from utility DR programs and the grid benefits from reduced load impact and potential avoided infrastructure costs. Yet with EUI the result would likely remain the same with or without this flexible load operation. Similarly as buildings are increasingly looking to use #DG to reduce electricity bills and provide resiliency the EUI metric may not capture the associated benefits if DG is not factored in the calculation or even if it is factored may produce strange looking results that could be considered as error or outlier and subsequently ignored, such as very low EUI or even negative EUI.
To conclude new metrics need to be considered as #buildingtogrid becomes more important. For example, separate metrics for energy consumed and energy generated per sqft and metrics that provide a measure of building load to grid peak load such as coincidence factors.
Founder of LovEnergy