Oil shale industry

The oil shale industry is an industry of mining and processing of oil shale—a fine-grained sedimentary rock, containing significant amounts of kerogen (a solid mixture of organic chemical compounds), from which liquid hydrocarbons can be manufactured. The industry has developed in Brazil, China, Estonia and to some extent in Germany and Russia. Several other countries are currently conducting research on their oil shale reserves and production methods to improve efficiency and recovery. Estonia accounted for about 70% of the world's oil shale production in a study published in 2005. Oil shale has been used for industrial purposes since the early 17th century, when it was mined for its minerals. Since the late 19th century, shale oil has also been used for its oil content and as a low grade fuel for power generation. However, barring countries having significant oil shale deposits, its use for power generation is not particularly widespread. Similarly, oil shale is a source for production of synthetic crude oil and it is seen as a solution towards increasing domestic production of oil in countries that are reliant on imports.

History

Oil shale has been used since ancient times. Modern industrial oil shale mining began in 1837 at the Autun mines in France, followed by Britain, Germany and several other countries. The oil shale industry started growing just before World War I because of the mass production of automobiles and trucks and the supposed shortage of gasoline for transportation needs. In 1924, the Tallinn Power Plant was the first power plant in the world to switch to oil shale firing. Following the end of World War II, the oil shale industry declined due to the discovery of large supplies of easily accessible and cheaper crude oil. Oil shale production however, continued to grow in Estonia, Russia and China. Following the 1973 oil crisis, the oil shale industry was restarted in several countries, but in the 1980s, when oil prices fell, many industries faced closure. The global oil shale industry has grown again from the mid-1990s. In 2003, the oil shale development program was initiated in the United States, and in 2005, the commercial leasing program for oil shale and tar sands was introduced. As of May 2007, Estonia is actively engaged in exploitation of oil shale on a significant scale and accounts for 70% of the world's processed oil shale. Estonia is unique in that its oil shale deposit account for just 17% of total deposits in European Union but it generates 90% of its power from oil shale. Oil shale industry in Estonia employs 7,500 people, which is about 1% of national employment, accounting for 4% of its gross domestic product.

Mining Oil shale is mined either by traditional underground mining or surface mining techniques. There are several mining methods available, but the common aim of all these methods is to fragment the oil shale deposits in order to enable the transport of shale fragments to a power plant or retorting facility. The main methods of surface mining are open pit mining and strip mining. An important method of sub-surface mining is the room-and-pillar method. In this method, the material is extracted across a horizontal plane while leaving "pillars" of untouched material to support the roof. These pillars reduce the likelihood of a collapse. Oil shale can also be obtained as a by-product of coal mining. The largest oil shale mine in the world is the Estonia Mine, operated by Enefit Kaevandused. In 2005, Estonia mined 14.8 million tonnes of oil shale. During the same period, mining permits were issued for almost 24 million tonnes, with applications being received for mining an additional 26 million tonnes. In 2008, the Estonian Parliament approved the "National Development Plan for the Use of Oil Shale 2008-2015", which limits the annual extraction of oil shale to 20 million tonnes.

Power generation

Oil shale can be used as a fuel in thermal power plants, wherein oil shale is burnt like coal to drive the steam turbines. As of 2012, there are oil shale-fired power plants in Estonia with a generating capacity of 2,967 megawatts (MW), China, and Germany. Also Israel, Romania and Russia have run oil shale-fired power plants, but have shut them down or switched to other fuels like natural gas. Jordan and Egypt have announced their plans to construct oil shale-fired power plants, while Canada and Turkey plan to burn oil shale at the power plants along with coal. Thermal power plants which use oil shale as a fuel mostly employ two types of combustion methods. The traditional method is Pulverized combustion (PC) which is used in the older units of oil shale-fired power plants in Estonia, while the more advanced method is Fluidized bed combustion (FBC), which is used in the Holcim cement factory in Dotternhausen, Germany, and was used in the Mishor Rotem power plant in Israel. The main FBC technologies are Bubbling fluidized bed combustion (BFBC) and Circulating fluidized bed combustion (CFBC). There are more than 60 power plants around the world, which are using CFBC technology for combustion of coal and lignite, but only two new units at Narva Power Plants in Estonia, and one at Huadian Power Plant in China use CFBC technology for combustion of oil shale. The most advanced and efficient oil shale combustion technology is Pressurized fluidized-bed combustion (PFBC). However, this technology is still premature and is in its nascent stage.

Oil extraction

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