Petroleum is a very complex compound with no plain formula, which consists mainly of hydrogen and carbon, and contains a small amount of nitrogen, oxygen and sulfur. Under normal conditions, it may exist gas, liquid and solid states. Liquid petroleum, which is referred to as raw petroleum in order to distinguish it from refined petroleum, is commercially the most important one. Read more »

Natural gas is a colorless and odorless gas which is lighter than air. Found in subterranean settings, and typically in close proximity to petroleum, it is extracted in the same way as petroleum, and later transmitted via large pipelines. Read more »

In 2007, total primary energy consumption of our country was 106 million tons equivalent of petroleum (TEP). In energy consumption, coal has a significant share of 28%. Read more »