From the article, it looks like they are installing 20 GWp of solar cells. ("peak power" that is only achieved when the sun is right above the solar cells with no atmosphere in between). The plan seems to be to store 36-42 GWh, and to deliver 2 GW max.

That makes for a 20h energy storage at full power, and a big enough power reserve to recharge that storage during the day while delivering at full power. Likely a reserve for morning/evening/clouds. Easy to add more storage.

So, it's a 2 GW power link, not a 20 GW power link. It's a 20 GWp site, and that's impressive too. At 200 Wp (STC) per sq m, that is 100M m², or a 6 mile square not counting any access roads. Huge, but if five of these is all it takes to power Singapore, then I guess we're looking at a bright future.