Just eyeballing it there seems to be 1 square kilometer of panels total. At regular solar panel efficiency, output would be 1000-2000MW total. So the same order of magnitude as one nuclear reactor.
Closing a region gives you approximate area.
edit: There seems to be at least 35 sqkm.
It also says that it could produce 600MW by the end of January 2018, can produce 1400MW now, with 650MW more under construction. It also says 2000MW capacity being planned for by the end of 2019.
I'm not sure how much of the 53 km has active solar panels, but they'd only need 3.8% efficiency to hit 2000MW with that much area.