The Future of Clean Energy Is Arriving...

I agree with the premise that the clean energy revolution appears to finally be starting up, and that we do see some rays of sunshine over the horizon, but I don't want to encourage any complacency. We really have a long way to go - the world is still accelerating the use of fossil fuels:

Fossil Fuels to Dominate World Energy Use Through 2040 | Climate Central

I think that renewables are going to grow strongly this century, I have almost no doubt about it. But in most projections, renewables only supplement fossil fuels as global energy demands grow to meet the needs of billions more people, rising developing nations, and growing economies worldwide. Still, a majority of that growing energy need will have to be met with fossil fuels, that is disastrous for climate change. Unless of course, global governments make some kind of worldwide agreement to reduce carbon emissions and actually stick to it (I wouldn't hold my breath). Or, fossil fuel companies worldwide agree to go against their own business plans and phase out fossil fuels (ha!). Or, one more scenario, the world's conservatives and climate change deniers finally come to reason and start helping us (I wouldn't hold my breath on that either). So in reality, we are exactly where we started: climate change is not going to be something that's solved by somebody else, it's going to be solved by you and me. We'll be the ones that have to build the future, but I'm heartened that we have guys like Elon on our side. There are plenty of people that want to help out in this endeavor, so let's get to work.

Agree with @tigerade on this. The big issue is that we have invested in a huge capital stock of fossil-fired generation plant. These plants have economic lives of 30-60 years, so they aren't going to go away any time soon without a substantial change in policy. Although wind and solar are getting cheaper, it's still more expensive to build new wind turbines (on a lifetime $/MWh basis) than to operate existing fossil-fired plants. So, even if 100% of all new generation installed is renewable, the vast majority of power will be fossil-sourced until those old plants retire.

It's the same problem that we have with EVs: even if 100% of all new cars are EVs, there are a lot of gas- and diesel-fueled cars that people will hold onto for many years.

There's a flaw in the article @SCW-Greg posted, in that the cost of wind and solar depends dramatically upon where you install it. Solar in Seattle has lousy economics, and many of the best sites for wind in the eastern US are now taken. Wind is also a very diffuse power source, so it requires a much heavier build-out of transmission, which is expensive and unpopular.