Berlin is the capital and largest city of Germany by both area and population. Its 3,748,148 inhabitants make it the second most populous city proper of the European Union after London; the city is one of Germany's 16 federal states. It is surrounded by the state of Brandenburg, contiguous with its capital, Potsdam; the two cities are at the center of the Berlin-Brandenburg capital region, which is, with about six million inhabitants and an area of more than 30,000 km², Germany's third-largest metropolitan region after the Rhine-Ruhr and Rhine-Main regions. Berlin straddles the banks of the River Spree, which flows into the River Havel in the western borough of Spandau. Among the city's main topographical features are the many lakes in the western and southeastern boroughs formed by the Spree and Dahme rivers. Due to its location in the European Plain, Berlin is influenced by a temperate seasonal climate. About one-third of the city's area is composed of forests, gardens, rivers and lakes; the city lies in the Central German dialect area, the Berlin dialect being a variant of the Lusatian-New Marchian dialects.
First documented in the 13th century and situated at the crossing of two important historic trade routes, Berlin became the capital of the Margraviate of Brandenburg, the Kingdom of Prussia, the German Empire, the Weimar Republic, the Third Reich. Berlin in the 1920s was the third largest municipality in the world. After World War II and its subsequent occupation by the victorious countries, the city was divided. East Berlin was declared capital of East Germany. Following German reunification in 1990, Berlin once again became the capital of all of Germany. Berlin is a world city of culture, politics and science, its economy is based on high-tech firms and the service sector, encompassing a diverse range of creative industries, research facilities, media corporations and convention venues. Berlin serves as a continental hub for air and rail traffic and has a complex public transportation network; the metropolis is a popular tourist destination. Significant industries include IT, biomedical engineering, clean tech, biotechnology and electronics.
Berlin is home to world-renowned universities, orchestras and entertainment venues, is host to many sporting events. Its Zoological Garden is one of the most popular worldwide. With the world's oldest large-scale movie studio complex, Berlin is an popular location for international film productions; the city is well known for its festivals, diverse architecture, contemporary arts and a high quality of living. Since the 2000s Berlin has seen the emergence of a cosmopolitan entrepreneurial scene. Berlin lies in northeastern Germany, east of the River Saale, that once constituted, together with the River Elbe, the eastern border of the Frankish Realm. While the Frankish Realm was inhabited by Germanic tribes like the Franks and the Saxons, the regions east of the border rivers were inhabited by Slavic tribes; this is why most of the villages in northeastern Germany bear Slavic-derived names. Typical Germanised place name suffixes of Slavic origin are -ow, -itz, -vitz, -witz, -itzsch and -in, prefixes are Windisch and Wendisch.
The name Berlin has its roots in the language of West Slavic inhabitants of the area of today's Berlin, may be related to the Old Polabian stem berl-/birl-. Since the Ber- at the beginning sounds like the German word Bär, a bear appears in the coat of arms of the city, it is therefore a canting arm. Of Berlin's twelve boroughs, five bear a Slavic-derived name: Pankow, Steglitz-Zehlendorf, Marzahn-Hellersdorf, Treptow-Köpenick and Spandau. Of its ninety-six neighborhoods, twenty-two bear a Slavic-derived name: Altglienicke, Alt-Treptow, Buch, Gatow, Kladow, Köpenick, Lankwitz, Lübars, Marzahn, Prenzlauer Berg, Schmöckwitz, Stadtrandsiedlung Malchow, Steglitz and Zehlendorf; the neighborhood of Moabit bears a French-derived name, Französisch Buchholz is named after the Huguenots. The earliest evidence of settlements in the area of today's Berlin are a wooden beam dated from 1192, remnants of a house foundation dated to 1174, found in excavations in Berlin Mitte; the first written records of towns in the area of present-day Berlin date from the late 12th century.
Spandau is first mentioned in 1197 and Köpenick in 1209, although these areas did not join Berlin until 1920. The central part of Berlin can be traced back to two towns. Cölln on the Fischerinsel is first mentioned in a 1237 document, Berlin, across the Spree in what is now called the Nikolaiviertel, is referenced in a document from 1244. 1237 is considered the founding date of the city. The two towns over time formed close economic and social ties, profited from the staple right on the two important trade routes Via Imperii and from Bruges to Novgorod. In 1307, they formed an alliance with a common external policy, their internal administrations still being separated. In 1415, Frederick I became the elector of the Margraviate of Brandenburg, which he ruled until 1440. During the 15th century, his successors established Berlin-Cölln as capital of the margraviate, subsequent members of the Hohenzol
Participatory democracy emphasizes the broad participation of constituents in the direction and operation of political systems. Etymological roots of democracy imply that the people are in power and thus that all democracies are participatory. However, participatory democracy tends to advocate more involved forms of citizen participation and greater political representation than traditional representative democracy. Participatory democracy strives to create opportunities for all members of a population to make meaningful contributions to decision-making, seeks to broaden the range of people who have access to such opportunities. Since so much information must be gathered for the overall decision-making process to succeed, technology may provide important forces leading to the type of empowerment needed for participatory models those technological tools that enable community narratives and correspond to the accretion of knowledge. Increasing the scale of participation, translating small but effective participation groups into small world networks, are areas being studied.
Other advocates have emphasized the importance of face to face meetings, warning that an overreliance on technology can be harmful. Some scholars argue for refocusing the term on community-based activity within the domain of civil society, based on the belief that a strong non-governmental public sphere is a precondition for the emergence of a strong liberal democracy; these scholars tend to stress the value of separation between the realm of civil society and the formal political realm. In 2011, considerable grassroots interest in participatory democracy was generated by the Occupy movement. Participation is defined as the act of taking part in some action.'Political participation', hence, is assumed as an act of taking part in'political' action. However, such definition varies in political science due to the ambiguities surrounding what can be conceived as'political' actions. Within this general definition, the perception of political participation varies by differing modes and qualities of participation.
From voting to directly influencing the implementation of public policies, the extent to which a political participation should be considered appropriate in political theory is, to this day, under debate. Participatory democracy is not a novel concept and has existed under various political designs since the Athenian democracy; the theory of participatory democracy was developed by Jean-Jacques Rousseau and promoted by J. S. Mill and G. D. H. Cole, who argued that political participation is indispensable for the realization of a just society; the sudden invigoration and popularity on this topic in the academic literature only began in mid-19th century. One conjecture is that the revival of political participation's significance was a natural progression from the growing assessment that representative models of democracy were in decline. Another, as argued by David Plotke, is that the proponents of participatory democracy were the critics of'minimal democracy', a theory popularly established by Joseph Schumpeter.
Plotke claims, "In the Cold War, nonCommunist left critics of minimal democracy tended to define their positions by reversing the claims. Given unappetizing menu, critics of minimal democracy advocated a sharp and sustained increase in political participation." Regardless of its origin, the recent resurgence of participatory democracy has led to various institutional reforms such as participatory budgeting challenging the traditionally predominant form of liberal democracy. The proponents of participatory democracy criticize liberal democracy and argue that representation is inherently deficient for democratic societies, leading to the fundamental debate on democratic ideology. Benjamin Barber, an advocate for'individual democracy', has denounced liberal democracy because "it alienates human beings from each other and, more important, because the epistemological basis on which liberalism stands is itself fundamentally flawed." Barber's notable significance is the return to the epistemological basis of politics and democracy, in that vein, Joel Wolfe reinforces his hypothesis: " strong democracy should be a form of government in which all people participate in decision-making and implementation.
While recognizing that the complexity of modern society imposes limits on direct democracy, participation by all is imperative because it creates shared interests, a common will, community action, all of which give legitimacy to politics." In 7th and 8th century Ancient Greece, the informal distributed power structure of the villages and minor towns began to be displaced with collectives of Oligarchs seizing power as the villages and towns coalesced into city states. This caused much hardship and discontent among the common people, with many having to sell their land due to debts, suffer from debt slavery. Around 600 BCE the Athenian leader Solon initiated some reforms to limit the power of Oligarchs and re-establish a partial form of participatory democracy with some decisions taken by a popular assembly composed of all free male citizens. About a century Solon's reforms were further enhanced for more direct involvement of regular citizens by Cleisthenes. Athenian democracy came to an end in 322 BC.
When democracy was revived as a political system about 2000 years decisions were made by representatives rather than by the people themselves. A minor exception to this
Critical thinking is the analysis of facts to form a judgment. The subject is complex, several different definitions exist, which include the rational, unbiased analysis, or evaluation of factual evidence. Critical thinking is self-directed, self-disciplined, self-monitored, self-corrective thinking, it presupposes assent to rigorous standards of mindful command of their use. It entails effective communication and problem-solving abilities as well as a commitment to overcome native egocentrism and sociocentrism; the earliest documentation of critical thinking are the teachings of Socrates recorded by Plato. Socrates established the fact that one cannot depend upon those in "authority" to have sound knowledge and insight, he demonstrated that persons may have power and high position and yet be confused and irrational. He established the importance of asking deep questions that probe profoundly into thinking before we accept ideas as worthy of belief, he established the importance of seeking evidence examining reasoning and assumptions, analyzing basic concepts, tracing out implications not only of what is said but of what is done as well.
His method of questioning is now known as "Socratic questioning" and is the best known critical thinking teaching strategy. In his mode of questioning, Socrates highlighted the need for thinking for clarity and logical consistency. Socrates asked people questions to reveal their irrational lack of reliable knowledge. Socrates demonstrated, he established the method of questioning beliefs inspecting assumptions and relying on evidence and sound rationale. Plato carried on the tradition of critical thinking. Aristotle and subsequent Greek skeptics refined Socrates' teachings, using systematic thinking and asking questions to ascertain the true nature of reality beyond the way things appear from a glance. Socrates set the agenda for the tradition of critical thinking, namely, to reflectively question common beliefs and explanations distinguishing beliefs that are reasonable and logical from those that—however appealing to our native egocentrism, however much they serve our vested interests, however comfortable or comforting they may be—lack adequate evidence or rational foundation to warrant belief.
Critical thinking was described by Richard W. Paul as a movement in two waves; the "first wave" of critical thinking is referred to as a'critical analysis', clear, rational thinking involving critique. Its details vary amongst those. According to Barry K. Beyer, critical thinking means making clear, reasoned judgments. During the process of critical thinking, ideas should be reasoned, well thought out, judged; the U. S. National Council for Excellence in Critical Thinking defines critical thinking as the "intellectually disciplined process of and skillfully conceptualizing, analyzing, synthesizing, or evaluating information gathered from, or generated by, experience, reasoning, or communication, as a guide to belief and action." In the term critical thinking, the word critical, derives from the word critic and implies a critique. The intellectual roots of critical thinking are as ancient as its etymology, traceable to the teaching practice and vision of Socrates 2,500 years ago who discovered by a method of probing questioning that people could not rationally justify their confident claims to knowledge.
Traditionally, critical thinking has been variously defined as follows: "The process of and skillfully conceptualizing, analyzing and evaluating information to reach an answer or conclusion" "Disciplined thinking, clear, open-minded, informed by evidence" "Purposeful, self-regulatory judgment which results in interpretation, analysis and inference, as well as explanation of the evidential, methodological, criteriological, or contextual considerations upon which that judgment is based" "Includes a commitment to using reason in the formulation of our beliefs" The skill and propensity to engage in an activity with reflective scepticism Thinking about one's thinking in a manner designed to organize and clarify, raise the efficiency of, recognize errors and biases in one's own thinking. Critical thinking is not'hard' thinking nor is it directed at solving problems. Critical thinking is inward-directed with the intent of maximizing the rationality of the thinker. One does not use critical thinking to solve problems—one uses critical thinking to improve one's process of thinking.
"An appraisal based on careful analytical evaluation"Contemporary critical thinking scholars have expanded these traditional definitions to include qualities and processes such as creativity, discovery, empathy, connecting knowing, feminist theory, subjectivity and inconclusiveness. Some definitions of critical thinking exclude these subjective practices; the ability to reason logically is a fundamental skill of rational agents, hence the study of the form of correct argumentation is relevant to the study of critical thinking. "First wave" logical thinking consisted of understanding the connections between two concepts or points in thought. It followed a philosophy where the thinker was removed from the train of thought and the connections and the analysis of the connect was devoid of any bias of the thinker. Kerry Walters describes this ideology in his ess
The Delphi method is a structured communication technique or method developed as a systematic, interactive forecasting method which relies on a panel of experts. The technique can be adapted for use in face-to-face meetings, is called mini-Delphi or Estimate-Talk-Estimate. Delphi has been used for business forecasting and has certain advantages over another structured forecasting approach, prediction markets. Delphi is based on the principle that forecasts from a structured group of individuals are more accurate than those from unstructured groups; the experts answer questionnaires in two or more rounds. After each round, a facilitator or change agent provides an anonymised summary of the experts' forecasts from the previous round as well as the reasons they provided for their judgments. Thus, experts are encouraged to revise their earlier answers in light of the replies of other members of their panel, it is believed that during this process the range of the answers will decrease and the group will converge towards the "correct" answer.
The process is stopped after a predefined stop criterion, the mean or median scores of the final rounds determine the results. The name "Delphi" derives from the Oracle of Delphi, although the authors of the method were unhappy with the oracular connotation of the name, "smacking a little of the occult"; the Delphi method is based on the assumption that group judgments are more valid than individual judgments. The Delphi method was developed at the beginning of the Cold War to forecast the impact of technology on warfare. In 1944, General Henry H. Arnold ordered the creation of the report for the U. S. Army Air Corps on the future technological capabilities that might be used by the military. Different approaches were tried, but the shortcomings of traditional forecasting methods, such as theoretical approach, quantitative models or trend extrapolation became apparent in areas where precise scientific laws have not been established yet. To combat these shortcomings, the Delphi method was developed by Project RAND during the 1950-1960s by Olaf Helmer, Norman Dalkey, Nicholas Rescher.
It has been used since, together with various modifications and reformulations, such as the Imen-Delphi procedure. Experts were asked to give their opinion on the probability and intensity of possible enemy attacks. Other experts could anonymously give feedback; this process was repeated several times. The following key characteristics of the Delphi method help the participants to focus on the issues at hand and separate Delphi from other methodologies: in this technique a panel of experts is drawn from both inside and outside the organisation; the panel consist of experts having knowledge of the area requiring decision making. Each expert is asked to make anonymous predictions. All participants remain anonymous, their identity is not revealed after the completion of the final report. This prevents the authority, personality, or reputation of some participants from dominating others in the process. Arguably, it frees participants from their personal biases, minimizes the "bandwagon effect" or "halo effect", allows free expression of opinions, encourages open critique, facilitates admission of errors when revising earlier judgments.
The initial contributions from the experts are collected in the form of answers to questionnaires and their comments to these answers. The panel director controls the interactions among the participants by processing the information and filtering out irrelevant content; this avoids the negative effects of face-to-face panel discussions and solves the usual problems of group dynamics. The Delphi Method allows participants to comment on the responses of others, the progress of the panel as a whole, to revise their own forecasts and opinions in real time; the person coordinating the Delphi method is known as a facilitator or Leader, facilitates the responses of their panel of experts, who are selected for a reason that they hold knowledge on an opinion or view. The facilitator sends out questionnaires, surveys etc. and if the panel of experts accept, they follow instructions and present their views. Responses are collected and analyzed common and conflicting viewpoints are identified. If consensus is not reached, the process continues through thesis and antithesis, to work towards synthesis, building consensus.
During the past decades, facilitators have used many different measures and thresholds to measure the degree of consensus or dissent. A comprehensive literature review and summary is compiled in an article by von der Gracht. First applications of the Delphi method were in the field of technology forecasting; the objective of the method was to combine expert opinions on likelihood and expected development time, of the particular technology, in a single indicator. One of the first such reports, prepared in 1964 by Gordon and Helmer, assessed the direction of long-term trends in science and technology development, covering such topics as scientific breakthroughs, population control, space progress, war prevention and weapon systems. Other forecasts of technology were dealing with vehicle-highway systems, industrial robots, intelligent internet, broadband connections, technology in education; the Delphi method was applied in other places those related to public policy issues, such as economic trends and education.
It was applied and with high accuracy in business forecasting. For example, in one case reported by Basu and Schroeder, the
The European Commission is an institution of the European Union, responsible for proposing legislation, implementing decisions, upholding the EU treaties and managing the day-to-day business of the EU. Commissioners swear an oath at the European Court of Justice in Luxembourg City, pledging to respect the treaties and to be independent in carrying out their duties during their mandate. Unlike in the Council of the European Union, where members are directly and indirectly elected, the European Parliament, where members are directly elected, the Commissioners are proposed by the Council of the European Union, on the basis of suggestions made by the national governments, appointed by the European Council after the approval of the European Parliament; the Commission operates with 28 members of the Commission. There is one member per member state, but members are bound by their oath of office to represent the general interest of the EU as a whole rather than their home state. One of the 28 is the Commission President proposed by the European Council and elected by the European Parliament.
The Council of the European Union nominates the other 27 members of the Commission in agreement with the nominated President, the 28 members as a single body are subject to a vote of approval by the European Parliament. The current Commission is the Juncker Commission, which took office in late 2014, following the European Parliament elections in May of the same year; the term Commission is variously used, either in the narrow sense of the 28-member College of Commissioners or to include the administrative body of about 32,000 European civil servants who are split into departments called directorates-general and services. The procedural languages of the Commission are English and German; the Members of the Commission and their "cabinets" are based in the Berlaymont building in Brussels. The European Commission derives from one of the five key institutions created in the supranational European Community system, following the proposal of Robert Schuman, French Foreign Minister, on 9 May 1950.
Originating in 1951 as the High Authority in the European Coal and Steel Community, the Commission has undergone numerous changes in power and composition under various presidents, involving three Communities. The first Commission originated in 1951 as the nine-member "High Authority" under President Jean Monnet; the High Authority was the supranational administrative executive of the new European Coal and Steel Community. It took office first on 10 August 1952 in Luxembourg City. In 1958, the Treaties of Rome had established two new communities alongside the ECSC: the European Economic Community and the European Atomic Energy Community; however their executives were called "Commissions" rather than "High Authorities". The reason for the change in name was the new relationship between the Council; some states, such as France, expressed reservations over the power of the High Authority, wished to limit it by giving more power to the Council rather than the new executives. Louis Armand led the first Commission of Euratom.
Walter Hallstein led the first Commission of the EEC, holding the first formal meeting on 16 January 1958 at the Château of Val-Duchesse. It achieved agreement on a contentious cereal price accord, as well as making a positive impression upon third countries when it made its international debut at the Kennedy Round of General Agreement on Tariffs and Trade negotiations. Hallstein notably began the consolidation of European law and started to have a notable impact on national legislation. Little heed was taken of his administration at first but, with help from the European Court of Justice, his Commission stamped its authority solidly enough to allow future Commissions to be taken more seriously. In 1965, accumulating differences between the French government of Charles de Gaulle and the other member states on various subjects triggered the "empty chair" crisis, ostensibly over proposals for the Common Agricultural Policy. Although the institutional crisis was solved the following year, it cost Etienne Hirsch his presidency of Euratom and Walter Hallstein the EEC presidency, despite his otherwise being viewed as the most'dynamic' leader until Jacques Delors.
The three bodies, collectively named the European Executives, co-existed until 1 July 1967 when, under the Merger Treaty, they were combined into a single administration under President Jean Rey. Owing to the merger, the Rey Commission saw a temporary increase to 14 members—although subsequent Commissions were reduced back to nine, following the formula of one member for small states and two for larger states; the Rey Commission completed the Community's customs union in 1968, campaigned for a more powerful, European Parliament. Despite Rey being the first President of the combined communities, Hallstein is seen as the first President of the modern Commission; the Malfatti and Mansholt Commissions followed with work on monetary co-operation and the first enlargement to the north in 1973. With that enlargement, the Commission's membership increased to thirteen under the Ortoli Commission, which dealt with the enlarged community during economic and international instability at that time; the external representation of the Community took a step forward when President Roy Jenkins, recruited to the presidency in January 1977 from his role as Home Secretary of the United Kingdom's Labour government, became the first President to att
Debate is a process that involves formal discussion on a particular topic. In a debate, opposing arguments are put forward to argue for opposing viewpoints. Debate occurs in public meetings, academic institutions, legislative assemblies, it is a formal type of discussion with a moderator and an audience, in addition to the debate participants. Logical consistency, factual accuracy and some degree of emotional appeal to the audience are elements in debating, where one side prevails over the other party by presenting a superior "context" or framework of the issue. In a formal debating contest, there are rules for participants to discuss and decide on differences, within a framework defining how they will do it. Debating is carried out in debating chambers and assemblies of various types to discuss matters and to make resolutions about action to be taken by voting. Deliberative bodies such as parliaments, legislative assemblies, meetings of all sorts engage in debates. In particular, in parliamentary democracies a legislature decides on new laws.
Formal debates between candidates for elected office, such as the leaders debates, are sometimes held in democracies. Debating is carried out for educational and recreational purposes associated with educational establishments and debating societies. Informal and forum debate is common, shown by TV shows such as the Australian talk show, Q&A; the outcome of a contest may be decided by audience vote, by judges, or by some combination of the two. Although debating in various forms has a long history and can be traced back to the philosophical and political debates of Ancient Greece, such as Athenian democracy, Shastrartha in Ancient India, modern forms of debating and the establishment of debating societies occurred during the Age of Enlightenment in the 18th century. Debating societies emerged in London in the early eighteenth century, soon became a prominent fixture of national life; the origins of these societies are not certain in many cases, although by the mid-18th century, London fostered an active debating society culture.
Debating topics covered a broad spectrum of topics while the debating societies allowed participants from both genders and all social backgrounds, making them an excellent example of the enlarged public sphere of the Age of Enlightenment. Debating societies were a phenomenon associated with the simultaneous rise of the public sphere, a sphere of discussion separate from traditional authorities and accessible to all people that acted as a platform for criticism and the development of new ideas and philosophy. John Henley, a clergyman, founded an Oratory in 1726 with the principal purpose of "reforming the manner in which such public presentations should be performed." He made extensive use of the print industry to advertise the events of his Oratory, making it an omnipresent part of the London public sphere. Henley was instrumental in constructing the space of the debating club: he added two platforms to his room in the Newport district of London to allow for the staging of debates, structured the entrances to allow for the collection of admission.
These changes were further implemented. The public was now willing to pay to be entertained, Henley exploited this increasing commercialization of British society. By the 1770s, debating societies were established in London society; the year 1785 was pivotal: The Morning Chronicle announced on March 27: The Rage for publick debate now shews itself in all quarters of the metropolis. Exclusive of the oratorical assemblies at Carlisle House, Free-mason's Hall, the Forum, Spring Gardens, the Cassino, the Mitre Tavern and other polite places of debating rendezvous, we hear that new Schools of Eloquence are preparing to be opened in St. Giles, Clare-Market, Hockley in the Hole, Rag-Fair, Duke's Place and the Back of the Borough. In 1780, 35 differently named societies advertised and hosted debates for anywhere between 650 and 1200 people; the question for debate was introduced by a president or moderator who proceeded to regulate the discussion. Speakers were given set amounts of time to argue their point of view, and, at the end of the debate, a vote was taken to determine a decision or adjourn the question for further debate.
Speakers were not permitted to slander or insult other speakers, or diverge from the topic at hand, again illustrating the value placed on politeness by late 18th century debaters. Princeton University in the future United States was home to a number of short-lived student debating societies throughout the mid-1700s, its influential American Whig Society was co-founded in 1769 by future revolutionary James Madison; the first of the post-revolutionary debating societies, the Dialectic and Philanthropic Societies, were formed at the University of North Carolina at Chapel Hill in 1795 and are still active. The first student debating society in Great Britain was the St Andrews Debating Society, formed in 1794 as the Literary Society; the Cambridge Union Society was founded in 1815, claims to be the oldest continually operating debating society in the World. This claim is arguably valid because Princeton's societies had been shut down during the American Revolutionary War, while the UNC societies' operations were suspended during the American Civil War.
Over the next few decades, similar societies emerged at several other prominent universities. Examples include the Yale Political Union and the Conférence Olivaint. Submitted by IIIT NUZVID In parliaments and other legislatures, members debate proposals regarding legislation, before voting on resolutions which become laws. Debates are conducted by proposing a law, or changes to a l
A power station referred to as a power plant or powerhouse and sometimes generating station or generating plant, is an industrial facility for the generation of electric power. Most power stations contain one or more generators, a rotating machine that converts mechanical power into electrical power; the relative motion between a magnetic field and a conductor creates an electrical current. The energy source harnessed to turn the generator varies widely. Most power stations in the world burn fossil fuels such as coal and natural gas to generate electricity. Others use nuclear power, but there is an increasing use of cleaner renewable sources such as solar, wind and hydroelectric. In 1878 a hydroelectric power station was built by Lord Armstrong at Cragside, England, it used water from lakes on his estate to power Siemens dynamos. The electricity supplied power to lights, produced hot water, ran an elevator as well as labor-saving devices and farm buildings. In the early 1870s Belgian inventor Zénobe Gramme invented a generator powerful enough to produce power on a commercial scale for industry.
In the autumn of 1882, a central station providing public power was built in England. It was proposed after the town failed to reach an agreement on the rate charged by the gas company, so the town council decided to use electricity, it used hydroelectric power for household lighting. The system was not the town reverted to gas. In 1882 the world's first coal-fired public power station, the Edison Electric Light Station, was built in London, a project of Thomas Edison organized by Edward Johnson. A Babcock & Wilcox boiler powered a 125-horsepower steam engine; this supplied electricity to premises in the area that could be reached through the culverts of the viaduct without digging up the road, the monopoly of the gas companies. The customers included the Old Bailey. Another important customer was the Telegraph Office of the General Post Office, but this could not be reached though the culverts. Johnson arranged for the supply cable to be run overhead, via Holborn Newgate. In September 1882 in New York, the Pearl Street Station was established by Edison to provide electric lighting in the lower Manhattan Island area.
The station ran until destroyed by fire in 1890. The station used reciprocating steam engines to turn direct-current generators; because of the DC distribution, the service area was small. In 1886 George Westinghouse began building an alternating current system that used a transformer to step up voltage for long-distance transmission and stepped it back down for indoor lighting, a more efficient and less expensive system, similar to modern system; the War of Currents resolved in favor of AC distribution and utilization, although some DC systems persisted to the end of the 20th century. DC systems with a service radius of a mile or so were smaller, less efficient of fuel consumption, more labor-intensive to operate than much larger central AC generating stations. AC systems used a wide range of frequencies depending on the type of load; the economics of central station generation improved when unified light and power systems, operating at a common frequency, were developed. The same generating plant that fed large industrial loads during the day, could feed commuter railway systems during rush hour and serve lighting load in the evening, thus improving the system load factor and reducing the cost of electrical energy overall.
Many exceptions existed, generating stations were dedicated to power or light by the choice of frequency, rotating frequency changers and rotating converters were common to feed electric railway systems from the general lighting and power network. Throughout the first few decades of the 20th century central stations became larger, using higher steam pressures to provide greater efficiency, relying on interconnections of multiple generating stations to improve reliability and cost. High-voltage AC transmission allowed hydroelectric power to be conveniently moved from distant waterfalls to city markets; the advent of the steam turbine in central station service, around 1906, allowed great expansion of generating capacity. Generators were no longer limited by the power transmission of belts or the slow speed of reciprocating engines, could grow to enormous sizes. For example, Sebastian Ziani de Ferranti planned what would have been the largest reciprocating steam engine built for a proposed new central station, but scrapped the plans when turbines became available in the necessary size.
Building power systems out of central stations required combinations of engineering skill and financial acumen in equal measure. Pioneers of central station generation include George Westinghouse and Samuel Insull in the United States and Charles Hesterman Merz in UK, many others. In thermal power stations, mechanical power is produced by a heat engine that transforms thermal energy from combustion of a fuel, into rotational energy. Most thermal power stations produce steam, so they are sometimes called steam power stations. Not all thermal energy can be transformed into mechanical power, according to the second law of thermodynamics. If this loss is employed as useful heat, for industrial processes or district heating, the power plant is referred to as a cogeneration power plant or CHP plant. In countries where district heating is common, there are dedicated he