To calculate energy usage for the pool pump motor, let's assume that it's a single phase motor operating at 80 percent efficiency. The energy usage, if the pump is operating at 100 percent capacity, is calculated as follows:
kW = HP x 0.746, divided by the motor efficiency
kW = 10 HP x 0.746/0.80 = 9.325 kW
If the pump runs for 720 hours in a month, the total energy usage will be 720 x 9.325 = 6,714 kWh
Note that that the pool pump may not run at 100 percent capacity. Just multiply the above number by the capacity to get the projected kWh usage. For example, if the pump motor operates at 75 percent capacity, the monthly energy usage would be 5,036 kWh.