The short answer is no. There is really no difference in the amount of energy used at night than during the day.
The most common pump houses a 2 HP motor and uses 0.12 cents per kilowatt hour.
A typical run schedule is 10 hours in the winter and 12 hours in the summer, so you are looking at a little over $2 per day.
It is crucial to run the pump during the hottest, sunniest time of the day so that you are circulating, filtering, and chlorinating when algae is most actively reproducing.
Why This Is Important: It’s important because people who run the pump during the night are leaving stagnant water in the pure sunlight and thus begging for algae.