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Dinorwig Power Station
The Dinorwig Power Station (; ), known locally as Electric Mountain, or Mynydd Gwefru, is a pumped-storage hydroelectric scheme, near Dinorwig, Llanberis in Snowdonia national park in Gwynedd, north Wales. The scheme can supply a maximum power of and has a storage capacity of around . Purpose The scheme was built at a time when responsibility for electricity generation in England and Wales was in the hands of the government's Central Electricity Generating Board (CEGB); with the purpose of providing peak capacity, very rapid response, energy storage and frequency control. Dinorwig's very rapid response capability significantly reduced the need to hold spinning reserve on part loaded thermal plant. When the plant was conceived the CEGB used low efficiency old coal and oil fired capacity to meet peaks in demand. More efficient 500 MW thermal sets were introduced in the 1960s, initially for baseload operation only. Dinorwig could store cheap energy produced at night by low ...
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Elidir Fawr
Elidir Fawr is a mountain in Snowdonia, north Wales, the northernmost peak in the Glyderau. Its name means 'Big Elidir', named after a legendary warrior king of the 6th century also known as Eliffer Gosgorddfawr (Elidir of the Great Army). To the north of the summit is a small lake, Marchlyn Mawr, which is the upper reservoir for Dinorwig power station, a pump-storage power station hidden inside the mountain. Water from this lake flows through huge tunnels into the lower reservoir Llyn Peris. From the north, Elidir Fawr is very prominent, and can appear to be higher than the higher mountains behind it. Slate quarries From Llanberis, the mountain is dominated by the former Dinorwic slate quarries and the waste they have left behind. Approach It is a reasonably short, but steep walk up to the summit, and this can be undertaken from the Deiniolen side or from Nant Peris. The Deiniolen walk provides views down to Llanberis, while the Nant Peris approach is short and quite steep. ...
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Imperial College London
Imperial College London (legally Imperial College of Science, Technology and Medicine) is a public research university in London, United Kingdom. Its history began with Prince Albert, consort of Queen Victoria, who developed his vision for a cultural area that included the Royal Albert Hall, Victoria & Albert Museum, Natural History Museum and royal colleges. In 1907, Imperial College was established by a royal charter, which unified the Royal College of Science, Royal School of Mines, and City and Guilds of London Institute. In 1988, the Imperial College School of Medicine was formed by merging with St Mary's Hospital Medical School. In 2004, Queen Elizabeth II opened the Imperial College Business School. Imperial focuses exclusively on science, technology, medicine, and business. The main campus is located in South Kensington, and there is an innovation campus in White City. Facilities also include teaching hospitals throughout London, and with Imperial College Healthcare ...
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General Electric Company
The General Electric Company (GEC) was a major British industrial conglomerate involved in consumer and defence electronics, communications, and engineering. The company was founded in 1886, was Britain's largest private employer with over 250,000 employees in the 1980s, and at its peak in the 1990s, made profits of over £1 billion a year. In June 1998, GEC sold its share of the joint venture GEC-Alsthom on the Paris stock exchange. In December 1999, GEC's defence arm, Marconi Electronic Systems, was sold to British Aerospace, forming BAE Systems. The rest of GEC, mainly telecommunications equipment manufacturing, continued as Marconi Communications. After buying several US telecoms manufacturers at the top of the market, losses following the bursting of the dot-com bubble in 2001 led to the restructuring in 2003 of Marconi plc into Marconi Corporation plc. In 2005, Ericsson acquired the bulk of that company. What was left of the business was renamed Telent. History ...
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Slate
Slate is a fine-grained, foliated, homogeneous metamorphic rock derived from an original shale-type sedimentary rock composed of clay or volcanic ash through low-grade regional metamorphism. It is the finest grained foliated metamorphic rock. Foliation may not correspond to the original sedimentary layering, but instead is in planes perpendicular to the direction of metamorphic compression. The foliation in slate is called "slaty cleavage". It is caused by strong compression causing fine grained clay flakes to regrow in planes perpendicular to the compression. When expertly "cut" by striking parallel to the foliation, with a specialized tool in the quarry, many slates will display a property called fissility, forming smooth flat sheets of stone which have long been used for roofing, floor tiles, and other purposes. Slate is frequently grey in color, especially when seen, en masse, covering roofs. However, slate occurs in a variety of colors even from a single locality; for ex ...
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Implenia
Implenia is a Swiss construction and construction services company. Implenia, with its headquarters in Opfikon near Zurich, employs more than 8,000 people in Europe and posted revenue of CHF 3.8 billion in 2021. History Implenia was created out of a series of mergers between Swiss regional construction companies. In mid-1997 ''Preiswerk Holding AG'' merged with ''Schweizerische Strassenbau- und Tiefbau-Unternehmung AG (Stuag) / Stuag Holding AG'' and ''Schmalz AG Bauunternehmung / Schmalz Holding AG'' to form Batigroup Holding, which was domiciled in Basel. Batigroup’s core competencies centred on traditional construction activities, including road building, poured asphalt, civil works, tunnelling and building construction. Zschokke Holding’s roots dated back to 1872 and the founding of ''Aktiengesellschaft Conrad Zschokke'' by Conrad Zschokke (1842–1918) in Aarau. In addition to building construction, Zschokke focused on general planning, general contracting and propert ...
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Alfred McAlpine
Alfred McAlpine plc was a British construction firm headquartered in Hooton, Cheshire. It was a major road builder, and constructed over 10% of Britain's motorways, including the M6 Toll (as part of the CAMBBA consortium). It was listed on the London Stock Exchange until it was acquired by Carillion in 2008. History Alfred McAlpine was one of the sons of 'Concrete' Bob McAlpine and he ran the operations of Sir Robert McAlpine in the north west of England. In 1935, following the death of Sir Robert and his eldest son, Alfred ran the north west independently, although the legal separation was not completed until 1940, when Sir Alfred McAlpine & Son was formed. Under a non-compete agreement with its former parent company, Sir Alfred McAlpine confined itself to civil engineering and to the north west of England. After the death of its founder, his son Jimmie McAlpine became chairman. The company was floated on the London Stock Exchange in 1958 under the name Marchwiel Holdings, ch ...
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Snowdonia National Park
Snowdonia or Eryri (), is a mountainous region in northwestern Wales and a national park of in area. It was the first to be designated of the three national parks in Wales, in 1951. Name and extent It was a commonly held belief that the name is derived from ("eagle"), and thus means "the abode/land of eagles", but recent evidence is that it means ''highlands'', and is related to the Latin (to rise) as leading Welsh scholar Sir proved. The term first appeared in a manuscript in the 9th-century , in an account of the downfall of the semi-legendary 5th-century king (Vortigern). In the Middle Ages, the title ''Prince of Wales and Lord of Snowdonia'' () was used by ; his grandfather used the title ''Prince of north Wales and Lord of Snowdonia.'' The name ''Snowdonia'' derives from '' Snowdon'', the highest mountain in the area and the highest mountain in Wales at . Before the boundaries of the national park were designated, "Snowdonia" was generally used to refer to a sm ...
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Utility Frequency
The utility frequency, (power) line frequency (American English) or mains frequency (British English) is the nominal frequency of the oscillations of alternating current (AC) in a wide area synchronous grid transmitted from a power station to the end-user. In large parts of the world this is 50  Hz, although in the Americas and parts of Asia it is typically 60 Hz. Current usage by country or region is given in the list of mains electricity by country. During the development of commercial electric power systems in the late-19th and early-20th centuries, many different frequencies (and voltages) had been used. Large investment in equipment at one frequency made standardization a slow process. However, as of the turn of the 21st century, places that now use the 50 Hz frequency tend to use 220–240  V, and those that now use 60 Hz tend to use 100–127 V. Both frequencies coexist today (Japan uses both) with no great technical reason to prefer one over ...
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Arbitrage
In economics and finance, arbitrage (, ) is the practice of taking advantage of a difference in prices in two or more markets; striking a combination of matching deals to capitalise on the difference, the profit being the difference between the market prices at which the unit is traded. When used by academics, an arbitrage is a transaction that involves no negative cash flow at any probabilistic or temporal state and a positive cash flow in at least one state; in simple terms, it is the possibility of a risk-free profit after transaction costs. For example, an arbitrage opportunity is present when there is the possibility to instantaneously buy something for a low price and sell it for a higher price. In principle and in academic use, an arbitrage is risk-free; in common use, as in statistical arbitrage, it may refer to ''expected'' profit, though losses may occur, and in practice, there are always risks in arbitrage, some minor (such as fluctuation of prices decreasing profit ...
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National Grid Reserve Service
To balance the supply and demand of electricity on short timescales, the UK National Grid has contracts in place with generators and large energy users to provide temporary extra power, or reduction in demand. These reserve services are needed if a power station fails for example, or if forecast demand differs from actual demand. National Grid has several classes of reserve services, which in descending order of response time are: Balancing Mechanism (BM) Start-Up, Short-Term Operating Reserve, Demand Management and Fast Reserve. National Grid Frequency Response This is a service that large power users such as steel works, cold stores, large water pumping stations, can offer to the UK National Grid. These contractors have frequency sensitive relays fitted to the incoming breakers, and these disconnect the load if the system frequency falls beyond a pre-set figure (49.7 Hz). These loads are shed for a contracted period of at least 30 minutes. Within this period Standing Res ...
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