You are right, I would classify companies into these categories:
1) NON-SCAM worth while investing: - I define non-scam by having NET profits and or verifiable patents. OR both!
== Solar3d has both. Seems to be a no brainer. Will it be a "one hit wonder"? or will it be continuously developing the cell. I've mentioned this before but JN hinted that they could use GaAS as material for the cell. This would increase the potential efficiency very much.
== Quantum Materials. Has impressive patents and is about to make a entrance into the quantum dots manufacturing segment. Quantum dots are extremely expensive and is the reason why they haven't been applied to TV's and cell phones. Quantum dots can be used to make solar panels. Multiple revenue streams lined up over here.
2) NON- SCAM but wait for the right moment.
== Mantra Venture Group. A fuel cell game changing inventor. Formic acid play, but seems too far from commercialization to consider seriously.
== Natcore Technologies. ehh beside solar3d one of the first solar stock companies I looked into. I'm not impressed with the fact that tey address the cost of manufacturing as the main reason why they favor relative to current technology. They make more power, but not enough to be "game changing". It's taking them much too much time to go commercial and I think that by the time they do it will be too late.
== Andalay Solar. Their approach to creating a kind of "snap-on" quick installation racking system to save time and avaoid installation costs is great. I do think that commercialization is taking much too much time. LG seems to have technology that could seriously compete.
== Clean Coal Technologies. Ive been "following" this company because I think that for my lifetime coal will be a major source of energy globally. I do think that it needs to be bettered and these guys have patented a method of making low grade coal into something "better" and cleaner-burning. I do own 2200 shares of this firm so im big time biased :P
== Neah Power Systems. Hard to figure out how exactly this company will do. They are making fuel cells, and have patents awarded. Their solution seems viable, however they have manufacturing hurdles that seem difficult to jump over. If they get the |Indian military to license their technology could be the icebreaker every OTC company is looking for.
There are other that I look at but I think that I will limit my post to companies that are listed on the OTC-QB. Pinkies are practically 100% scams.