2 main disadvantages to solar energy are that it is an intermittent energy source and that it requires a lot of land to be effective.
Solar energy is intermittent because the sun doesn't always shine. This can be a problem for two reasons. First, if the sun isn't shining, you can't produce electricity from solar panels. Second, even when the sun is shining, solar panels may not be producing electricity if they're not pointed in the right direction or if there's too much cloud cover.
Solar energy also requires a lot of land to be effective. This is especially true if you want to generate enough electricity to power your whole house or business. The good news is that technology is getting better and better,