Many alternative energy stocks were run up to absurd speculative levels during the oil price surge in 2007-2008. In most cases the "values" of these shares were totally disconnected from any fundamentals and were not sustainable. What followed was less a "collapse" than a return to realistic valuations.

There's certainly a future in alternative/renewable energy, but many of the companies in the field have a minimal track record and it's still way too early to determine what direction that future will take and which companies will be the main beneficiaries. Unless you have some serious technical expertise it's a sector to be cautious with: lots of hype flying around and you need to be able to sort the hype from the reality.

Chinese stocks... don't get me started. There may be some good companies there, but given the standard of reporting it will be difficult to find them.