Yeah this is totally normal, and how my employer does it, but it does also have a significant early adopter advantage. It's pretty easy and cheap for the first 3rd of companies to go all-renewable because they can put a big pile of solar into the grid and draw out the same amount and ta-fucking-da, net-zero. Even if that does mean you are providing solar to someone else during the day and using "their" dirty coal power at night.
On the one hand, this is great. Amazon invested billions in clean power and we should totally applaud that. On the other, perhaps they should be held to a higher standard because they can surely afford it - the next step needs to be getting to net-zero on an hourly basis by investing in storage, or maybe getting all the diesel vans off the road and brining on more electric ones.