Here's something really revolutionary:
* good insulation in homes
* Energy Use literacy
The only problem is mass ignorance, which means the gov-endorsed Solar Scams are allowed to exist, and not only exist, but flourish while everyone gets told to bend over whenever they see their bill & their hidden taxes being used to subsidise the thieving Energy Cartels.
Solar panels should be cheap enough for at least 50% of the earth's population to have some sort of self-sufficiency. But too many are ignorant of energy use and the regulations make it hard for them to break free - by design. Which brings me to the political parasites: it's not a tech problem we have, really. And today it's not really a prohibitively expensive cost problem. It's making small changes to the way we live by being conscious of our energy usage and then making changes to severely reduce it using tech we have now.
This is 99.9% of the 'real' problem now, in my estimation.