I'll commence my response to this bold statement by saying I currently work in the energy technology sector.
Statements that solar or geothermal can provide the worlds energy needs are entirely theoretical and are usually made by the green armies that don't understand basic scientific and engineering principles. We currently have less than 0.1% of the worlds energy requirements coming from the two technologies that you provide as examples...think about that in the context of how we allocate our resources (in terms of raw materials and labour) and this is a task that nobody has ever attempted before...then consider that geothermal technologies are not "commercial" and that silicon based solar panels are only 15%-20% efficient (unless you want to spend millions like NASA do).
Then think about countries like China that are installing Australia's entire electricity generation capacity every 3 months with coal fired powerstations (they are also installing nukes and renewables on top of that).
So you begin to see, that the word "IMMEDIATELY" is not really helpful in moving forward and removing our reliance away from fossil fuels...
I'll commence my response by saying that whilst I'm not quite clever enough to understand energy technology sector science (doesn't Homer work in... never mind...) and perhaps I did use the word IMMEDIATELY (albeit correctly spelled and contextually cohesive) where 'in a bit' would have done, (and I have a PhD), can I call you a Luddite?
You quote NASA, true, NASA does spend a little more than my weekly shop on computer parts - but look where its 1960+ development got us..., software multitasking, virtual machines and paved the way for today's $99 iphone... Sure it costs a bit to start it all up, but once there...
And of course we only have noughtpointzip % of energy from my hippie sources - why should the big governments have to do any work when they can haul in tax dollars with the stuff they've got (untill it runs out - which it will... BTW, what
are current energy technology sector contingencies?)
Think about China - sure - but it's being sold technology from the West... of course it's going to be sold short... it's a business.
Sure I've worked through at least two recessions and know too well any R&D money is amongst the first to dry up... but one can't sit on ones arse and say it's unprecedented, that there's no infrastructure, no man power - hell, my old mate from the UK has a few pipes under his lawn and it supplies ALL his heating... if he can do that and we take inspiration from NASA who put a man on the moon (and paid a photographer to prove it), then maybe we can change the inertia of the proletariat.
No, the word "IMMEDIATELY" wasn't really helpful in moving forward and removing our reliance away from fossil fuels', but those few small brewers putting a panel on the roof or keeping chickens, are a starting to create the demand to change...