REF - STULZ answers

Renewable Energy Factor (REF) represents the percentage of renewable energy (RE) in relation to the total energy in a data centre. In other words: It shows how a data centre's carbon footprint can be reduced in relation to its energy consumption.

REF is used by data centre managers to improve the energy procurement process of a data centre and to increase the diversity of the data centre’s energy dependency. In addition, customers can also use this KPI as a guideline when selecting a data centre (DC).

REF= E_{energy demand covered by renewable energy} / E_{energy demand DC}

The result of the above calculation is the total (annual) energy consumption of the DC in kWh. REF has a maximum value of 1.00, which means that 100% of the energy is renewable energy. In the case of on-site regeneration of renewable energy in excess of the DC's needs, the excess power generated is not taken into account for the REF.