Bird spikes are unlikely to protect your home when pigeons invading your solar panels. The needle-like rods are commonly used on street lights, ledges and commercial signs in order to prevent birds landing or roosting, designed to deter birds without harming or killing them. We have seen bird spikes being used in an attempt to stop pigeons or other bird pests from entering or nesting underneath solar panels but this has not worked.
The pigeons and will still find space to land on the roof tiles and due to their intelligent nature, pigeons will soon find a way to push their way through the rods unharmed. Otherwise should you put them around your panels are a deterrent solution, they are unlikely to make any difference at all.
The only way bird spikes would to deter pigeons from your solar panels work but would be to put bird spikes all over the entirety of your roof as this will prevent birds from landing on your roof all together. However, unless you were to put them over the entirety of your roof, they are unlikely to make any difference at all.