So I've discussed wind power and fossil fuel power before, now its time for solar power!
First I should mention this: ALL energy sources on this planet, including fossil fuels, nuclear energy and wind power are ultimately derived from solar power. The sun is the ultimate source of energy in the universe and scientists have predicted that an extremely advanced civilization will always end up harvesting energy from stars for this is such a greater source of power than any other source of energy (as far as we know of course).
Now, back to planet earth. What countries are already using solar energy? Germany is running at front, mainly because of a government incentive for solar energy, which guarantees that the government will buy electricity from people with solar panels at regular price rates. This feed-in tariff has caused a huge rise in solar energy production in Germany (from 100 MW in 2000 to 4000+ MW in 2008), and it was so successful that several countries have applied the feed-in tariffs as well. The downside is that this costs the government a lot of money. This can be countered with raising the electricity tariffs for consumers, moving the bill from the government to the people, but that makes electricity a lot more expensive. But hey, with depletion of fossil fuels resources as I pointed out in my previous story about Peak Oil, combined with global warming AND instable regimes in countries with a lot of oil and gas (Iran, Russia), we should not care about $100 more or less per year in your electricity costs.