In a fight between solar and fossil fuels, the latter has always had a killer question up its sleeve: "What about supercritical steam?" That's the method by which the most advanced power stations generate electricity, superheating water until it instantly becomes steam, a feat that's only possible (and affordable) by burning coal or gas. Or, at least it was. Australia's Commonwealth Scientific and Industrial Research Organization has managed to use solar energy to the same effect, boiling liquid to temperatures of 570 degrees Celsius in a test chamber. What does this mean for all of us? "Power plants of the future could instead be using the free, zero-emission energy of the sun," explains Dr. Alex Wonhas.

Theoretically, future power stations could be covered in solar panels, but that energy is only directed towards heating the water necessary to drive a steam turbine. That system may be long-winded, but it's significantly cheaper than installing photovoltaic systems on the roofs of every home in the world, and could use existing infrastructure, too. Naturally, we're still in the early stages of the system, but even the most ardent fossil-fuel enthusiast can't disagree that swapping out coal for solar in this method would be cheaper than paying to dig carbon out of the ground.