Seite - 77 - in Water, Energy, and Environment - A Primer

of animalwastes from livestockproduction andmunicipalwaste in landfills. Naturalgasburnsmorecleanly thancoaloroil– lessNOxand particulate emissions, and minimal SO2 emissions – and it releases, per unit of energy produced by its combustion, 43% lessCO2 than coal and 30% lessCO2 than oil. As a greenhouse gas in its own right, CH4 is about 20 timesmore powerful than CO2 as a driver of globalwarming,As a result, leakage ofCH4 from the infrastructure surrounding natural gas production and use is a serious concern. (Note: CH4’s half-life in the atmosphere ismuch less than that ofCO2.) It is most commonly used to produce electricity and heat for industrial processes and buildings. A small amount of compressed natural gas is used for transportation – for example, in bus fleets. It also serves as a feedstock for the production of fertilizers, paints, and plastics. It is usually transported by pipeline, but increasingly it is being transported internationally in ships as cooled and liquefied natural gas (LNG). 6.3.1 Methanehydrates For thosewho followenergy issues closely, apersistent question has been: are methane hydrates a realistically large potential energy resource?The answer is yes. Several decades ago the information available to answer that question was not available. Today the literature on methane hydrates (also known as methane clathrates, methane ice, and fire ice) is extensive andgrowing. What are clathrates and hydrates? Clathrate is a general term that describes solids inwhich gases are trappedwithin any kind of chemical cage, while hydrate is the specific term usedwhen that cage is made of water molecules. In methane hydrates the trapped gas is CH4. CO2 and other gas hydrates are also possible and are speculated to exist onMars, other planets and Fossil fuels 77