China

What i called a "standard-size 'nuclear plant" in the title is a 1000MW one(, or ~8.7TWh/year), some smaller ones only produce 300MV, the superPhoenix is a 1200MW, and the largest model is the EPR with 1600MW, or 12-13TWh/year, which means only one dam would produce as much as 25 EPR.
If i'm illustrating with solar panels instead, 1km^2^ of solar panels only produce ~1TWh/year(, which could rise to ~2TWh/year in the Sahara desert), so that's the equivalent of 300km^2^. We've only surpassed that installed area recently but it's growing exponentially, thanks once again to China b.t.w., so since 300TWh/year is equivalent to ~150-300GW depending on the sunshine, one dam is expected to produce as much as the world installed solar energy capacity in 2015, or twice the currently installed solar capacity in the u.s.

Relatively to energy generation(, and not energy consumption, which is ~4 times larger), that's the equivalent of the yearly production of the United Kingdom, or twice that of Norway or Argentina.

I hope that we(sterners) will ignore this achievement once it's done since, according to Radio Free Asia, and unlike the Hoover Dam, we wouldn't be able to avoid putting a negative spin on ~'the most' clean energy production.