What is bad about solar energy?

Nothing

Silicon panels produce STC in production which can be fully recycled creating a closed-loop system. Therefore it produces no bad by-product.

Cadmium Indium Gallium Selenide or CIGS had some concerned that harmful chemicals would be released if the panels were caught in a fire but extensive fire testing found they burning of the cells actually encapsulated the harmful material within the other materials in the array releasing less than even slightly harmful amounts of the material. In addition, such manufacturers as First Solar have created escrow accounts for a forced recycling program meaning all the panels when no longer working will be picked up by the company and recycled. Reusing 90+% of the panels material and removing any harmful possibilities.

Solar array's of course need no fuel and produce no waste simply converting the sun's energy directly into DC energy.

Traditional silicon solar panels when they are recycled either because they are being replaced or have become damaged can be almost fully recycled as well as the valuable materials which are basically silicon, aluminum, steel, copper, and glass all of which can be recycled.

The other harmful chemicals present of course are lead, cadmium, selenium, tetrachloride, and indium. However, between modern sealed landfills, the trace amount of these materials and the economic incentive from recovering the materials in panels these are not a significant or even minor threat to the environment.