Power Usage Effectiveness, or PUE, was developed by a consortium called the Green Grid. PUE is a ratio that measures the total power required for a facility divided by the power consumed by the IT equipment. A hypothetical value of 1.0 is perfection and unattainable. According to Josh Krischer Associates, less than 10% of data centers worldwide have a PUE below 1.5 and on average data centers have PUEs of between 2-3. This means that the total data center demand, on average, is 2-3X the demand for IT equipment.