On the Inadequacy of the CVR Factor for Active Schemes

Conservation Voltage Reduction (CVR) is a well-known technique to reduce energy consumption by reducing the supplied voltage within statutory limits. Historically, the efficacy of CVR schemes has been quantified using the CVR factor (CVRf) which relates, in a given period, voltage reduction to energy savings. This metric has proved useful in the past, where fixed voltage reductions were applied. However, this letter shows from a theoretical perspective and with a realistic case study that when used for active CVR schemes (voltages actively controlled throughout the day), the CVRf can be smaller than that for fixed voltage reductions despite the larger energy savings. This could be misleading for decision makers considering active CVR schemes as an energy efficiency measure. Consequently, it is recommended that comparisons among CVR schemes are carried out in terms of actual energy reductions.