This chart comes from a CleanTechnica article about how solar is soon going to make shale oil and gas redundant because it is getting so cheap. It is a telling and compelling picture. Note that it is drawn on a log scale (although that means that the x-axis can't be at zero as labelled--they must mean 20, I'd guess) Now, because it is a log scale, a constant slope ( a straight line) represents a constant rate of decline or a constant annual percentage decline. If you assume that recent rates of decline/percentage declines will continue, then all you have to do is extend the green (solar) line downwards in a straight line. And if you do that, solar, which already cheaper than retail electricity in the US, will cross crude oil this year and natural gas next. That doesn't mean that electricity generation will switch to solar in the next year or two, because there are all sorts of issues to be settled, including legal issues, grid stability, etc.
But if solar keeps on falling in price, then the logic for switching wherever possible will be irresistible. And as battery costs fall, the 'wherever possible' will expand exponentially. And the beauty of this is that it doesn't matter what the climate change denialists say, the world will switch to clean energy, not because they care (though I think they do, as it has become obvious that global warming is real and potentially disastrous) but because it makes economic and financial sense.
[click on chart to see it full sized]
Disclaimer. After nearly 40 years managing money for some of the largest life offices and investment managers in the world, I think I have something to offer. But I can't by law give you advice, and I do make mistakes. Remember: the unexpected sometimes happens. Oddly enough, the expected does too, but all too often it takes longer than you thought it would, or on the other hand happens more quickly than you expected. The Goddess of Markets punishes (eventually) greed, folly, laziness and arrogance. No matter how many years you've served Her. Take care. Be humble. And don't blame me.
BTW, clicking on most charts will produce the original-sized, i.e., bigger version.