The Kendal Company manufactures automobile engine parts. Running the manufacturing operations requires 12 watts (units of electricity per hour). The amount of electricity required to run the manufacturing operations and lighting the facility is given by y = 12x + 24, where x is the number of hours of manufacturing and y is the amount of electricity expended. How much electricity is used on a day when no parts are manufactured? (x 0, y 0)

you say running the plant uses 12 watts

how many hours per day does the plant run?
The energy used is watts * hours