An experimental grid-scale battery system releases 15 MWh15\text{ MWh}15 MWh of energy as it discharges fully. What is the mass equivalent of this energy (the decrease in the mass of the battery system)?
1.7×10−10 kg1.7 \times 10^{-10}\text{ kg}1.7×10−10 kg
6.0×10−10 kg6.0 \times 10^{-10}\text{ kg}6.0×10−10 kg
1.7×10−7 kg1.7 \times 10^{-7}\text{ kg}1.7×10−7 kg
6.0×10−7 kg6.0 \times 10^{-7}\text{ kg}6.0×10−7 kg
