That was way back in 2008! Solar has been in China for a long time, but they were using it directly to warm the water, not via photovalic panels (which is why the results were so bad).
It’s hard to say. If they use photvalic instead of pure solar, they can top off a lack of sun with electricity from other sources to keep the hot water warm (outside of winter when it’s all natural gas based anyways). Ome would think they could do a better job with personal heat pumps.