If you had to pick a modern equivalent to Iron Man's Tony Stark, I don't think you could do better than Tesla founder Elon Musk. Musk used his success in PayPal to create his own electric car company Tesla Motors, a space company SpaceX, and is involved in a new revolutionary new highspeed train project. Essentially if there's something technological that should be done but nobody dares to do it, you can can bet that Musk is up to the challenge.
Musk has stated that one of his goals is to make human life multi-planetary. This has led to him start SpaceX and create revolutionary rocket systems cheaper and better than anyone else. People said electric cars couldn't be done so he started Tesla. Others said solar would never be economical, so he helped start SolarCity. If anything could be profitable, then Musk was going to find a way to do it.
Despite all these great achievements, Musk will never realize human life on another planet, nor a completely fossil fuel free economy unless he can find his own version of an arc reactor. It will take an extremely long time until solar becomes economically viable on a country scale (let along global scale) to complete with coal & natural gas prices. You would need fairly high carbon taxes or other subsidies to make fossil fuel based power competitive with renewables. This is why I believe, we can't have a bright future without a significant increase in nuclear power.
I know nuclear scares a lot of people, but bear in mind that we've been using primarily first generation 1960's nuclear reactor designs up until now, and those were the ones that have caused all the problems we've seen in nuclear. Now, all these 1st gen plants are reaching their end of life, and it really would be a lost opportunity if we replaced it with the same thing with the same sets of problems. What we really need is a nuclear renaissance in the development of next generation nuclear reactors.
It wasn't until recently when I discovered a forgotten type of nuclear reactor that was radically different from the light water reactors (LWR) we see today. It's known as the liquid fluoride thorium reactor (LFTR, pronounced like "lifter") and it's design may be the key to safe, cheap, low waste, proliferation resistant power. In this design, the nuclear fuel is an element known as thorium instead of uranium, and it is formed into a fluoride salt and melted into a liquid in the reactor. In typical solid fueled reactors, the nuclear decay and fission products build up inside the fuel pellets. This contamination, prevents all the energy in the pellet from being released. In fact, at most about 3% of the energy in the fuel pellet gets used before it is replaced. In LFTR, the liquid fuel can be chemically separated, allowing the thorium to be burned up completely as energy. This drastically reduces the waste generated and managing waste is a significant portion of the cost of nuclear. Additionally, since the fuel is designed to be in the melted state, there is no worries about nuclear meltdown (its already, and should be melted).
Thorium, itself is pretty interesting. Apparently, mining companies and countries around the world are desperate for a source of rare earth elements (REE) used in high tech equipment. A large subset of these REE's (the more expensive heavy ones) exist predominately in a type of rock known as monazite which we get as a byproduct of mining for other elements like iron, titanium, etc, and this monazite often has thorium in it. Unfortunately, in the 50's, thorium was classified as a nuclear source material which made handling, storing, transporting, and disposal of it so much of a burden that thorium rich byproducts were being dumped back into the ground from which they were mined. That meant that the production of REE's was drastically reduced as only very low thorium bearing byproducts would be processed for REE extraction.
China, on the other hand, did not fear the thorium content and eventually became the sole supplier of the heaviest REE's for the world, purely by refining their byproducts of iron mining. Today, companies that depend on a stable supply of certain REE's must relocate their manufacturing to China. China has even stated that they do not wish to be the sole provider of the world's REE and may begin severely limiting or even eliminating its exports.
A thorium fueled, reactor would create not only a demand for thorium, but an escape from the environmental and legal burdens that come with processing thorium and REE rich byproducts. A nice win-win solution.
What Musk needs, is a cheap, clean energy solution. And wouldn't it be great bonus if you could load it on a spaceship and use it on another planet? Amazingly, the LFTR design, with its passive safety, would weigh much less than a typical reactor. Thorium too can be found on the moon and Mars and satellites can easily scan the surface for rich deposits. So Elon, what are you waiting for?