You have 2 options for powering your pool pump with solar electricity:
1) Take your pool pump off grid.
You can buy a 'DC pool pump' and dedicate 4-6 solar panels to powering it. The solar panels are wired directly in to the pool pump (via some power electronics) and when the sun is shining your pool pump will run.
Your pool pump is not connected to the grid so you will never pay for grid electricity to power it.
The solar panels connected to the pump are not connected to the grid so you don't need the grid's permission to install them. Further the panels connected to the pool pump do not count towards the maximum number grid connected solar panels that you can install.
The pool pump will run less in winter and more in summer - which synchronises well with swimming season.
You need to replace your pool pump.
If you are producing more solar energy than your pool pump needs to maintain the water - it goes to waste because the panels are not shared with the rest of the house.
If your panels are not producing enough energy to power the pool pump for long enough then you need to add more panels - the grid cannot top up the energy.
2) Power your pool pump with your grid connected solar system.
If you buy a decent sized solar system for your home (6kW+), then that will be able to easily power your pool pump except on really overcast days. Simply install regular solar and set your pool pump timer to run as close to midday as possible. For example you may run it from 11am-1pm over winter and 10am-3pm over summer.
No need to change your pool pump, or run wires from the panels to your pool pump.
All your solar from your panels gets used. Either by your pool pump, or your other appliances or if you still have excess solar - it get's exported to the grid for a Feed In Tariff.
On overcast days your pool pump will draw power from the grid.