As the technology involved in solar power improves and costs come down, it will be an increasingly viable energy source. (dotearth.blogs.nytimes.com)
However, purifying biological products to usable levels raises production costs beyond what most people will pay for, but with a new molecular control system, researchers expect to engineer more robust microbes and increase biofuel yields, making living organisms a more viable energy source. (scientificamerican.com)
Similarly, while I doubt that nuclear power is ever going to prove an economically viable energy source, even in the presence of high carbon taxes, I have no problem with mining and exporting uranium, subject to the usual environmental safeguards needed for mining operations in general. (johnquiggin.com)