To convert watt-hours per gallon to watts, it's essential to understand the difference between energy (watt-hours) and power (watts). One gallon of gasoline contains approximately 33.3 kilowatt-hours of energy, which is equivalent to about 120 million BTU. The relationship between miles per gallon (mpg), miles per hour (mph), and gallons per hour can help determine power in watts. By converting gallons into watt-hours, one can derive the power output in watts. Understanding these conversions clarifies the calculation process for determining power from fuel consumption.