I completely agree with your comment (and disagree that someone marked it as "troll"). They're not using 100% renewable energy if they are hooked up to the grid receiving electricity that was generated by coal/gas/oil/etc. Like you said, if they gathered solar or wind energy during the day and stored it in batteries, that would be 100%.
Also, in a factory or manufacturing facility, having a continuous and steady flow of electricity is extremely important and not everyone can rely on variations of solar activity. If I had to make a guess, I would say their solar panels are not directed connected to the factory, but are instead configured like: solar panels-> inverters -> electric grid -> factory. Meaning they're relying on grid-sourced electricity and the solar panels exist solely to have net metering.
Finally, many manufacturers use exorbitant amounts of energy. Steel mills, car manufacturing, etc. It's not just a matter of putting a few solar panels on the roof.