A. Hunter Fanney
Senior Research Scientist, Energy and Environment Division
National Institute of Standards and Technology
The above plot (click image to see chart full-size) shows if the NZERTF was an exporter or importer of energy on a daily basis. Exports occur when the electrical energy produced by the solar photovoltaic array exceeds the energy consumed by the NZERTF. Imports occur when the energy consumed by the NZERTF exceeds the energy produced by the solar photovoltaic array. The blue line represents the cumulative electrical export. It is the sum of the energy exported minus the sum of the imported electrical energy over the entire time period depicted on the graph. Since the beginning of data collection (July 1, 2013) through June 30, 2014 the house has produced 491 kWh more energy than it has consumed while meeting all the needs of a typical family of four.