Yes, solar panels that are attached to your home are covered by your home or landlord insurance policy. You'll just need to ensure that your sum insured is enough to rebuild your home, including these solar panels.
If your solar panels aren't attached to your home, then these are covered by our contents insurance policies. You'll need to make sure that your contents sum insured is enough to replace all of your belongings, including your solar panels.
You can find further details about what you're covered for in your policy document, under the section 'What you are covered for', under 'What the words 'your home' mean'.