The growth in behind-the-meter distributed energy resources (BTM DER) has been a key feature of the NEM over recent years. BTM solar has grown from ~1-2% of total energy supplied five years ago to ~6% this year. In fact, looking within the day, the percentage of supply being provided by rooftop solar has been as high as 20-30% in the middle of the day when solar output is at its highest.
Increased rooftop solar penetration has the practical effect of reducing grid level demand or operational demand. This trend underpins the “duck curve” phenomenon most pronounced in South Australia but spreading to other NEM regions.