How do I run my pool pump on solar power?

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. And you can still claim the solar rebate for these panels even though they are not connected to the grid!

Pros

• 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 panels can be mounted on a structure close to your pool - no need to take up valuable roof space.
• The pool pump will run less in winter and more in summer - which synchronises well with swimming season. 

Cons

• 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.

Pros

• 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. 

Cons

• On overcast days your pool pump may draw power from the grid.
• You will need a good sized solar power system to power your home and pump ( I recommend at least 6kW of solar)

My recommendation:

If possible, the best option is to simply power your pool pump from your home's regular supply. Just be sure you have a big enough solar system to power your pool pump as well as the rest of your house. This is the most efficient use of your solar power because all the solar power generated is either consumed or exported to the grid.

But there are 2 situations where an 'off grid' pool pump makes sense.

#1 If you can't get permission from your electricity network to install as many grid connected panels as you'd like, then you can take the 'off grid pool pump' route. The pool pump's panels will not be connected to the grid so no one can stop you adding those panels.

#2 If you can't get enough panels on your roof to power your home and your pool pump, then the pool pump's panels could be mounted on a structure close to the pool and directly connected to a DC pool pump.

The worst thing you can do:

The worst choice is to do nothing. Powering a pool pump with grid electricity at 30, 40 or 50c per kWh is madness. You need the pump to run during the day when the sun is shining, so take advantage of cheap solar that works out at less than 5c per kWh over the life of the system, and never worry about the expense of powering your pool pump again.