Calculate mass of hydrogen needed to operate PEM FC at an average of 18 kW for a period of 3 hours. Assume the utilization of hydrogen is 0.98 and that each cell is operating at 0.7 V. Roughly18 kW power is needed to sustainably power a passenger vehicle on the highway. Compare the mass of hydrogen calculated with the mass of gasoline that would be needed. If helpful, you may assume that the average speed for the 3-hour period is 90 kmph