As long as most of the wind-mill and solar components are manufactured in China, it's difficult to call it "sustainable".
You might call the dominance of the Chinese solar manufacturers a national security risk, but as long as we have the knowledge and resources to theoretically build them in the West (albeit more expensively), they are easier to replace than for example Saudi-Arabian oil or Russian natural gas.
It's the most dirty part to mine and is exclusively from China (95% of worldwide production).