If it were actually cheaper to use solar and wind than coal then the power industry would have already switched from coal to those sources to cut their costs and increase their profits.
That's what's been happening, but it has been a gradual process, not an instantaneous one.
This comment is like someone a century ago asking what was so great about horseless carriages when large numbers of people continue to use horses.
That's not what's been happening. What's been happening is that wind and solar producers have been massively subsidised and protected from the reality that they cost more. And as the article in the OP points out, the result has been massive rises in electricity prices, where these have been widely adopted.
Electricity is a service, not a commodity - what people are prepared to pay for is electricity
when they want or need it. What the big wind and solar producing nations now have is a situation where people are made to buy electricity
when the producers have it to sell. Whether they need it or not. And then they also have to pay for the standby generation - usually gas - that has to be there for the big gaps when wind and solar produce nothing.
Even if we magically replaced the gas backups with some kind of miraculously adequate storage solution, the cost of that solution still must be worn by the consumers, and it's just poor accounting not to include that cost when considering whether intermittent renewables are cost effective.
There are only three serious contenders for making electricity without carbon dioxide emissions. Wind, Solar, and Nuclear. France, Sweden and Ontario have gone with nuclear; Germany and Denmark with wind. Nobody has yet gone far into solar, but California is starting to do so.
We can compare the results fairly easily. And doing so, we find that the nuclear nations have far lower carbon dioxide emissions, and far lower electricity bills, than the wind nations; And the fledgling solar adopters are going the same way as the wind power people.
Of course, the very powerful lobby in favour of wind and solar make it easy to imagine that this is not the case, by presenting irrelevant facts (eg 'Denmark runs for three days on wind power alone' - sure, but three days is meaningless. Wake me up when they run for a year on more than 90% renewables).
But an honest review of the bottom line - actual carbon dioxide emissions over a year; actual power prices averaged over all consumers for a year - shows the real story. Compare France and Sweden with Denmark and Germany in the video below. Then try to tell me, with a straight face, how effective Germany or Denmark have been at reducing carbon dioxide emissions.
Solar power has a capacity factor of around 30% in the tropics, dropping off dramatically at high latitudes. Wind has a capacity factor of between 30 and 55%, most sites at the lower end of that range. Nuclear power plants have a capacity factor of over 90%, and unlike wind or solar, the timing of the unproductive periods is flexible and can be planned to coincide with low demand, or to avoid coinciding with downtime at other nearby facilities.
Intermittent renewables are very cheap and clean. Sometimes. But the majority of the time, they are actually coal or gas. Which costs nearly as much with wind and solar as it would without.
[YOUTUBE]http://www.youtube.com/watch?v=G6EOoC_kKI0[/YOUTUBE]
Olduvai theory, that our industrial civilization will have a lifetime limited by availability of convenient fossil-fuel deposits. That means that it will end at most a century after the present, and likely earlier.