I have a stake, as you know, in a renewable energy future. As one of the co-owners of Semington A which contributes in a modest way to the grid's attempts to keep the lights on, I keep an eye on prices and subsidies and watch renewables hugely increase their contribution to world electricity generation – whilst remaining a pathetically small part of overall production. And two graphs in this week's Economist are enough to sober up anyone drunk on the hope of a quick achievement of carbon-free electricity.
The article A world turned upside down explored the problems of the success of the growth in renewable use. Currently, non-hydro renewables contribute 7% of global electricity with our old friends coal and oil contributing the most. It was ~2% in 2005 which shows the recent rate of growth.
Here's a hint of the problem:
"In 2014 the International Energy Agency (IEA), a semi-official forecaster, predicted that decarbonising the global electricity grid will require almost $20trn in investment in the 20 years to 2035, at which point the process will still be far from finished. But an electricity industry that does not produce reliable revenues is not one that people will invest in."
... and the Economist explains in detail why reliable revenue production is now so difficult. When revenue production proves unreliable, so surely will electricity generation.