Early history It is often reported that 18th-century naturalist and explorer
Johann Anton Güldenstädt had mentioned a discovery of a "burning rock" near
Jõhvi in 1725, but his published travel notes mention neither oil shale nor Estonia. It is also often reported that the earliest documented record of oil shale in Estonia, authored by the
Baltic German publicist and linguist
August Wilhelm Hupel, dates to 1777. However, this is based on a misinterpretation of the German word
Steinöhl (meaning: stone oil), which was used by Hupel but which most likely did not mean oil shale in the context of his publication. The first scientific research into the rock's oil yield, using samples from the village of
Vanamõisa of the Kohala Manor, was published by Georgi at the
Russian Academy of Sciences in 1791. In 1838 he made a thorough experiment to distil oil from the Vanamõisa oil shale deposit. During the 1850s, large-scale works were undertaken in Estonia to transform excessively wet land into land suitable for agriculture; this included the digging of drainage ditches. In the process, previously unknown layers of oil shale were discovered in several locations. In the years 1850–1857, the territory of Estonia was explored by the Baltic German geologist Carl Friedrich Schmidt who studied these findings of oil shale. Russian chemist Aleksandr Shamarin, who at the end of the 1860s had studied the composition and properties of oil shale originating from the Kukruse area, concluded it made sense to use oil shale for the production of gas and as a solid fuel. However, he considered shale oil production unprofitable. For example, in the 1870s, Robert von Toll, landlord of the Kukruse Manor, started to use oil shale as a fuel for the manor's distillery. There were failed attempts to use graptolitic argillite as fertilizer in the 19th century. In the beginning of the 20th century, geologist and engineer Carl August von Mickwitz studied self-ignition of graptolitic argillite near
Paldiski. At the
University of Tartu oil shale geology and chemistry analyses were conducted during the 19th century by Georg Paul Alexander Petzholdt, Alexander Gustav von Schrenk, and
Carl Ernst Heinrich Schmidt, among others. These events marking the beginning of the Estonian oil shale industry In February 1918, the area surrounding the oil shale basin in northeast Estonia was
occupied by German troops. During this occupation, mining activities were carried out at Pavandu by the German company Internationales Baukonsortium (), including sending oil shale to Germany for research and experimentation. This work used a
retort constructed by
Julius Pintsch AG, known as a Pintsch generator. In late 1918, German forces left Estonia, by which time no more than a single trainload of oil shale had been mined and sent to Germany.
Developments in interwar Estonia , 1937. Photo by
Carl Sarap) , 1931) After
Estonia gained independence, the state owned oil shale enterprise, Riigi Põlevkivitööstus (), was established as a department of the Ministry for Trade and Industry on 24 November 1918. The enterprise, later named
Esimene Eesti Põlevkivitööstus (), was the predecessor of
Viru Keemia Grupp, one of the current shale oil producers in Estonia. It took over the existing Pavandu open-pit mine, and opened new mines at Vanamõisa (1919), Kukruse (1920), and Käva (1924). Initially, oil shale was used primarily in the cement industry, but also for firing
locomotive furnaces and as a household fuel. The first major industrial consumers of oil shale were
cement factories in
Kunda and
Aseri. By 1925, all locomotives in Estonia were powered by oil shale. Shale oil production started in Estonia in 1921 when Riigi Põlevkivitööstus built 14 experimental oil shale processing retorts in
Kohtla-Järve. These vertical retorts used the method developed by Julius Pintsch AG that would later evolve into the current
Kiviter processing technology. The German-owned company
Eesti Kiviõli (, , predecessor of Kiviõli Keemiatööstus), affiliated with G. Scheel & Co. and
Mendelssohn & Co., was established in 1922. By the end of the 1930s, it had become the largest shale oil producer in Estonia. Around the company's mine and oil plant, the Kiviõli settlement (now town) was formed in the same way as the Küttejõu settlement (now district of Kiviõli) formed around the mine owned by Eesti Küttejõud. In 1924, the British investor-owned Estonian Oil Development Syndicate Ltd. (later Vanamõisa Oilfields Ltd.) purchased an open-pit mine in Vanamõisa and opened a shale oil extraction plant that was abandoned in 1931 due to technical problems. The Swedish–Norwegian consortium
Eestimaa Õlikonsortsium (, ), controlled by
Marcus Wallenberg, was founded in
Sillamäe in 1926.
New Consolidated Gold Fields Ltd. of the
United Kingdom built a shale oil extraction plant at
Kohtla-Nõmme in 1931. Since 1935, Estonian shale oil has been supplied to the German
Kriegsmarine as a ship fuel. In 1938, 45% of Estonian shale oil was exported, accounting for 8% of Estonia's total exports. In 1937, the Geological Committee under the Ministry of Economic Affairs, and the Institute of Natural Resources, an independent academic institution, were established. A department of mining was established at Tallinn Technical University in 1938. Estonian oil shale industries conducted tests of oil shale samples from
Australia,
Bulgaria, Germany and
South Africa.
Developments in German-occupied Estonia Soon after the
Soviet occupation in 1940, the entire oil shale industry was
nationalised and subordinated to the Mining Office and later to the General Directorate of Mining and Fuel Industry of the Peoples' Commissariat for Light Industry.
Germany invaded the Soviet Union in 1941 and the industry's infrastructure was largely destroyed by retreating Soviet forces. This entity was subordinated to
Kontinentale Öl, a company that had exclusive rights to oil production in
German-occupied territories. On 21 June 1943,
Reichsführer Heinrich Himmler issued an order to send as many male Jews as possible to the oil shale mining. Baltische Öl consisted of five units (Kiviõli, Küttejõu, Kohtla-Järve, Sillamäe, and Kohtla), all of which were partially restored, previously existing industries. In addition, Baltische Öl started construction of a new mining and shale oil extraction complex in
Ahtme, but it never became operational. Prisoners of war and
forced labour made up about two-thirds of the work force in these units. Existing oil shale-fired power stations were also destroyed. Statistical Office of Estonia; Estonian Oil Shale Industry Yearbook 2019) Shale oil extraction, except the Kiviõli and Kohtla-Nõmme plants, was merged into the Kohtla-Järve shale oil combinate (, now Viru Keemia Grupp) under the General Directorate of Synthetic Liquid Fuel and Gas of the USSR (
Glavgaztopprom). Both organisations were directed from Moscow. New mines were opened in
Ahtme (1948), Jõhvi (No. 2, 1949),
Sompa (1949),
Tammiku (1951), and in the area between Käva and Sompa (No. 4, 1953). The Ubja mine was closed in 1959. The industry declined during the subsequent two decades. Demand for electric power generated from oil shale decreased following construction of nuclear power stations in the
Russian SFSR, particularly the
Leningrad Nuclear Power Station. The shale oil industry at Kohtla-Järve and Kiviõli was redeveloped. In 1945, the first tunnel kiln was restored, and by the end of the 1940s four tunnel kilns located in Kiviõli and Kohtla-Nõmme had been restored. German prisoners of war contributed most of the labour. Between 1946 and 1963, 13 Kiviter-type retorts were built in Kohtla-Järve and eight in Kiviõli. The first Galoter-type commercial-scale pilot retorts were built at Kiviõli in 1953 and 1963 with capacities of 200 and 500 tonnes of oil shale per day, respectively. The first of these retorts closed in 1963 and the second in 1981. The
Narva Oil Plant, annexed to the Eesti Power Station and operating two Galoter-type 3,000-tonnes-per day retorts, was commissioned in 1980. In 1948 an oil shale gas plant in Kohtla-Järve became operational, and for several decades the oil shale gas was used as a substitute for natural gas in Saint Petersburg (then known as Leningrad) and in northern Estonian cities. It was the first time in history that synthetic gas from oil shale was used in households. To enable delivery of the gas, a pipeline from Kohtla-Järve to Saint Peterburg was built, followed by a pipeline from Kohtla-Järve to Tallinn. In 1962 and 1963, the conversion of oil shale gas into
ammonium was tested; however, for industrial production, oil shale gas was replaced with natural gas. Although this gas had become uneconomical by 1958, production continued and was even expanded. After peaking in 1976 at , oil shale gas production ceased in 1987. In 1988 Moscow-based authorities planned a third oil shale-fired power station in Narva with a capacity of 2,500 MW, together with a new mine at
Kuremäe. The plan, disclosed at the time of the
Phosphorite War and the
Singing Revolution, met with strong local opposition and was never implemented. Between 1946 and 1952,
uranium compounds were extracted from locally mined graptolitic argillite at the Sillamäe Processing Plant (now:
Silmet). More than 60 tonnes of uranium compounds (corresponding to 22.5 tonnes of elemental uranium) were produced. Preliminary research into oil shale-based chemical production began the same year, exploring the potential for the use of oil shale in
bitumen, synthetic construction materials,
detergents,
synthetic leathers,
synthetic fibres,
plastics,
paints,
soaps,
glues, and
pesticides. Between 1959 and 1985, of
mineral wool were produced from
oil shale coke, a solid residue of oil shale. In 1968, a branch of the
Skochinsky Institute of Mining was established in Kohtla-Järve, In 1995, state-owned shale oil producers in Kohtla-Järve and Kiviõli were merged into the single company named RAS Kiviter. In 1997, Kiviter was privatized and a year later it declared insolvency. Its factories in Kohtla-Järve and Kiviõli were sold separately and new oil producers – Viru Keemia Grupp and Kiviõli Keemiatööstus – emerged. The proposed deal with NRG Energy met a strong public and political opposition and was cancelled after NRG Energy failed the deadline to secure financing for the project. Consequently, the Government transferred its remained shares in Eesti Põlevkivi to a state-owned company Eesti Energia, a parent company of the Narva Power Stations, and Eesti Põlevkivi became a fully owned subsidiary of Eesti Energia. Oil shale production started to increase again in the beginning of the 21st century. In 2000, the open-pit mines at Viivikonna, Sirgala and Narva were merged into the single Narva open-pit mine. Since 2003, several new mines were opened: the Põhja-Kiviõli open-pit mine in 2003, the Ubja open-pit mine in 2005, and the Ojamaa underground mine in 2010. The exhausted Aidu open-pit mine was closed in 2012, followed a year later by the Viru underground mine. In 2004, two power units with
circulating fluidised bed combustion boilers were put into operation at the Narva Power Stations. Construction of the Auvere Power Station, located next to the existing Eesti Power Station, began in 2012. In the end of 2012, the Ahtme Power Station was closed. In 2008, Eesti Energia established a joint venture, Enefit Outotec Technology, with the Finnish technology company
Outotec. The venture sought to develop and commercialise a modified Galoter process–the Enefit process–that would enhance the existing technology by using circulating
fluidised beds. In 2013, Enefit Outotec Technology opened an Enefit testing plant in
Frankfurt. Kiviõli Keemiatööstus began to test two Galoter-type retorts in 2006. VKG Oil opened three new Galoter-type oil plants called Petroter correspondingly in December 2009, in October 2014, and in November 2015. In 2020, Eesti Energia announced a plan to build additional oil plant by 2023. At the same time, it cancelled a shale oil pre-refinery project developed jointly with Viru Keemia Grupp. In spring 2021, the government coalition of
Estonian Reform Party and
Estonian Centre Party put a political target in their coalition agreement to stop oil shale power generation by 2035 and using oil shale in the entire energy sector by 2040 at the latest. Shortly after, Eesti Energia announced it will stop burning oil shale for electricity generation by 2025 and burning oil shale gas by 2030. It will close older type shale oil plants by 2040 while in newer generation shale oil plants oil shale will be replaced with waste plastics. Estonia is negotiating with the
European Commission to receive €340 million support from the
Just Transition Fund to mitigate the impact of the oil shale industry transition. ==Economic impact==