Green Tech

Solar power: $80/kilowatt. Wind turbines: $120/ kilowatt. Ocean tide rechargers: $150/ kilowatt. Coal: $5/ kilowatt.

The goal of green tech? Make the cool, non-polluting energy sources at least somewhat close to the costs of coal, the least green of all energy technologies.

Coal pollutes; wind turbines just kill a few birds here and there. If you're ever wondering about why this area of investing is so important, check out a really skinny polar bear some time and then just...get sad. Then go figure out how to make these other technologies cheap and easy to proliferate. And the world will thank you.