Guardian: A novel drill that is inspired by a jet engine and uses super-heated water to carve through rock could help harness to make clean energy from underground rocks more economically viable, according to its backers at Google. Potter Drilling is part-funded by Google.org – the internet search giant’s philanthropic arm – and wants to use its technology to develop geothermal energy, which involves tapping the energy from hot rocks deep in the Earth. Geothermal energy is seen by …