Natural sources of geothermal energy are becoming costly to exploit. So, current efforts focus on man-made geysers, or "enhanced" geothermal. The idea is to locate hot rocks beneath the ground, fracture those rocks and pass water through the fractures.
The rocks are very, very hot. And, when water passes through fractures it turns to steam, which can turn generators to make electricity. If a company is fracturing its own hot rock beneath the ground it needs to know something about the fractures it is making and it needs the information from a mile or two beneath the Earth.
But, mapping and measuring fractures far down is challenging and expensive. One solution could be nanoparticles, thousands of times narrower than human hair.
Professor Roland Horne of Stanford and doctoral candidate Mohammad Alaskar put some typical geothermal rock into a chamber. They injected a fluid of silicon-based nanospheres into one side. Using pressure they drove the particles through solid rock, out the other side, and counted and measured them, proving for the first time that this could be done.
"Nanotechnology has found a tremendously varied number of uses," said Horne. "And, this occurred to us to be one of them. By passing the nanoparticles through the fractures we have a way of determining how big they are and potentially other things, such as their temperature, perhaps pressure, chemistry, all of those things."
Not only is the nano method potentially the cheapest way to analyze rock, but in his words, "It's kind of amazing that you could pass one solid particle through another, just through the little spaces that are within it."
So now, renewable energy is not rocket science. It is rock science.