Introduction

Abstract

Global energy sources are classified into two groups fossil and renewable. Primary energy sources can be divided into non-renewables and renewables. Non-renewable energy resources include coal, petrol, gas, gas hydrate and fissile material, while renewable energy sources are biomass, hydro, geothermal, solar and wind energy.Methane hydrates are the world’s largest source of fossil fuel. Large fields of methane hydrates are scattered throughout the world’s oceans and are thought to contain about as much energy as all other forms of fossil fuel combined. This unconventional hydrocarbon energy source has remained untapped, however, because traditional sources are still plentiful and less expensive to develop. Nevertheless, scientists have recently been taking a closer look at hydrates, and not only as a possible energy source. A widely quoted US Geological Survey estimate predicts that there is twice as much organic carbon in gas hydrate than in all recoverable and unrecoverable conventional fossil fuel resources, including natural gas, coal and oil.The renewable energy refers to primary energies that are continuously generated by the energy sources solar energy, geothermal energy and tidal energy. The energy produced within the sun is responsible for a multitude of other renewable energies (such as wind and hydropower) as well as renewable energy carries (such as solid or liquid biofuels). Main renewable energy sources are biomass, hydropower, geothermal, solar, wind and marine energies. The renewables are the primary, domestic and clean or inexhaustible energy resources.