Google's infamous company motto is "Don't be evil," but that's not really the same as "Do something good." Well, let's give Google a cheer for its just-announced, ambitious alternative energy project: The search engine giant wants not just to fund research into renewable energy sources, but to put those technologies into practice to power its own facilities. Its stated goal: To produce one gigawatt of renewable power that is cheaper than coal-fired juice.

Google already has several green initiatives underway, including a 1.6-megawatt solar array at its Mountain View headquarters.

Google co-founder Larry Page says that if Google can meet its new goal, the cost of solar power should fall by 25 to 50 percent, finally making it cost-competitive for general use instead of just something that only rich people can afford for their McMansions.

But solar isn't the only power source being investigated here: High-altitude wind power (generated by tapping into the gulf stream, high in the sky) is another big part of the equation, and some of the proposals Google is looking at are intriguing to say the least. Check out the mockups on this SF Gate story. Can you imagine having a "ladder mill" in your backyard?

Google has no timeline for when it hopes to achieve the dramatic cost reductions it wants, but it vaguely references years instead of decades. Good luck, Google guys!