Much like natural gas, solar power is getting easier to store, and at a much lower price. The total solar energy hitting Earth each year is equivalent to 12.2 trillion watt-hours, so why isn't solar energy used more?
Currently, photovoltaic solar panels produce only 0.7 percent of the energy the world uses. The U.S. Department of Energy estimates the average cost per megawatt-hour for solar is $156.90, compared to $99.60 per MW/h in coal, and between $65.50-$132 per MW/h of natural gas.
While the cost may defer some, the financial and technology problems that solar faces is closer to being solved.
"If the trend stays on track for another eight to ten years, solar generated electricity in the U.S. will descend to a level of $120 per MW/h by 2020, or even 2015 for the sunniest parts of America. If prices continue to fall over the next 20 years, solar costs will be half that of coal (and have the added benefits of zero carbon emissions, zero mining costs, and zero scarcity)."
There have also been big advances in thermal storage that continues to be developed by scientists. The combination of lowered costs and better storage capacity would mean plenty of solar energy production and widespread falling energy costs.
Source: The Week