HONOLULU (HawaiiNewsNow) - Puna Geothermal stores lots of pentane on-site and plans to move it in case the lava moves northeast from where it is now. But what IS pentane? Like pentagram and Pentagon, the name refers to FIVE. It's 12 hydrogen atoms held together by 5 atoms of carbon. Pentane is used as a solvent, and in high-octane fuels, and it's a blowing agent in making styrofoam. And it's widely-used as a working medium in geothermal plants, which pump fluids into deep holes to make steam, which drives turbines. Pentane vaporizes at a relatively low temperature, less than 100 degrees. Under an open flame it can quickly oxidize to form carbon dioxide and water.