Calculate the total energy released if exactly $1.50 \text{ grams}$ of matter is completely converted to energy, and express your answer in megawatt-hours ($\text{MWh}$). (Use Einstein's mass-energy equivalence $E = mc^2$, where $c \approx 2.99792 \times 10^8 \text{ m/s}$ and $1 \text{ Watt} = 1 \text{ Joule per second}$)