Fuelling the Future with Gas Hydrates as a Perpetual Energy Source

Abstract

Introduction Gas hydrates are crystalline compounds that form when water (or ice) contacts small molecules (called hydrate guests) under certain pressure and temperature conditions. The correct chemical name should be gas clathrate hydrates, with a clathrate being a compound formed by the inclusion of molecules of one kind in the crystal lattice of another (water in this case). In practice, these compounds are commonly referred to as gas hydrates, clathrate hydrates, or just hydrates. While specific to the particular hydrate guest, gas hydrates are stable typically at high pressures and low temperatures. A wide range of molecules have been shown to form gas hydrates. Those of the most practical interest are light hydrocarbons such as methane, ethane, and propane. Carbon dioxide and hydrogen sulfide also form hydrates and are of particular interest. When hydrates form, water crystallizes to create a lattice of molecular-sized cages that trap guest molecules without chemical bonding between the host water and the guest molecules.