Amonix

Amonix, Inc. is a solar power system developer based in Seal Beach, California. The company manufactures concentrator photovoltaic (CPV) products designed for installation in sunny and dry climates. CPV products convert sunlight into electrical energy in the same way that conventional solar photovoltaic technology does, except that they use optics to focus the solar radiation before the light is absorbed by solar cells. According to a comparative study of energy production of solar technologies, CPV systems require no water for energy production and produce more energy per megawatt (MW) installed than traditional PV systems. Amonix has nearly 70 megawatts (direct current) of CPV solar power systems deployed globally, including Southwestern U.S. and Spain. In May 2012, the Alamosa Solar Generating project, owned and operated by Cogentrix Energy, began commercial operation. This is the largest CPV power plant in the world and is expected to produce enough clean renewable energy per year to power more than 6,500 homes and will avoid the emissions of over 43,000 metric tons of carbon dioxide per year. The Alamosa Solar Generating Project is supported by a power purchase agreement (PPA), which is a long-term agreement to sell the power it will generate. Under the project's PPA, the Public Service Company of Colorado will buy the power generated by the solar facility for the next 20 years. In July 2012, Amonix set the world record for photovoltaic module efficiency at 33.5% (full regression analysis) under nominal operating conditions, verified by the National Renewable Energy Laboratory. In April 2013, Amonix broke the record set in July 2012, demonstrating photovoltaic module efficiency at 34.9% (full regression analysis) under normal concentrator standard operating conditions, also verified by the National Renewable Energy Laboratory. In August 2013, Amonix announced it had achieved a 35.9% photovoltaic module efficiency rating under concentrator standard test conditions (CSTC) as calculated by NREL. In June, 2014, the assets of Amonix were acquired by Arzon Solar, LLC for the purpose of continued development of CPV technology and products.
History.
Amonix was founded in 1989 by CPV solar technology developer, Vahan Garboushian, its current chief executive officer and chairman of the board of directors. Sewang Yoon who developed high efficiency silicon back junction solar cell for HCPV application was co-founder of Amonix. The company began research and development of large-scale CPV solar power systems for the electric utility industry in 1990. Since then Amonix has developed seven generations of progressively advancing CPV solar power systems.
In 1994, the company won R&D Magazine's R&D 100 award for silicon solar cell performance with record conversion efficiency. According to the Department of Energy, Amonix developed the world's most efficient silicon solar cell in 2005, achieving a sunlight-to electricity conversion efficiency of 27.6 percent, which still holds the world record for efficiency of an augmented multi-sun silicon cell.
In 2007, the company began incorporating multijunction solar cell technology originally developed for the space industry into its modular design. The system contains several photovoltaic solar cells which are combined to boost power production even further. Once connected the cells become modules that can be combined into arrays to provide increasing levels of solar power. Amonix has achieved a world record 34.9% outdoor efficiency and 36.2% peak efficiency in its modules.
Amonix opened its headquarters in Seal Beach, Cal., in 2008. In December 2009 the company acquired Sunworks Solar LLC, a solar manufacturing plant developer. Sunworks' co-founder and chief executive officer, Brian Robertson, became Amonix CEO as part of the restructuring.
Funding.
Amonix received $129.4 million in a Series B financing round, which closed in April 2010. Amonix previously raised $25 million in Series A funding, and also received $15.6 million in cost-share grant funding through the DOE's Solar America Initiative to improve the reliability and reduce the cost of solar electricity to meet national goals (measured as the levelized cost of electricity) of 6 cents per kilowatt hour by 2015.
In addition to the DOE, Amonix investors include Kleiner Perkins Caufield & Byers, MissionPoint Capital Partners, Angeleno Group, PCG Clean Energy & Technology Fund, Vendanta Capital, New Silk Route, The Westly Group, Adams Street Partners, and Goldman Sachs.
In 2011, Amonix won a $4.5 million United States Department of Energy SunShot partnership award under Extreme Balance of System Hardware Reduction to develop a new dual axis tracking system specifically for CPV systems.
Technology.
Amonix employs concentrated photovoltaic technology systems which require no water in power production and produce more energy per acre than any other solar technology. CPV technology uses optics to focus large amounts of sunlight onto small photovoltaic surfaces to generate electricity. CPV systems are the most efficient solar energy systems and produce the most energy in dry, sunny climates, where the solar radiation averages 6 kilowatt-hours per square meter per day (6 kW-hr/m2/day) or more. According to the research firm, Global Data, the average cell, module and system efficiencies for CPV systems are expected to reach 50.37 percent, 39.48 percent and 34.03 percent, respectively.
Originally used for space-based applications, the CPV technology was adapted to utility-scale application by Amonix to take advantage of the improved energy efficiencies it offers over the previous silicon-based technology.
The multijunction solar cells used in Amonix CPV systems work by layering semiconductor materials that have different band gaps. Sunlight enters the layer that has the largest band gap and each photon continues to penetrate the solar cell until it reaches the layer that has a smaller band gap than its energy. In this way, multijunction solar cells are more efficient than single layer solar cells because less of the photon's energy is lost to heat when it exceeds the band gap of the absorbing semiconductor material.
Used in conjunction with concentrator optics such as Fresnel lenses, multijunction solar cells are capable of converting sunlight into electricity exceeding 40 percent efficiency. This efficiency rises as the level of concentration increases, but decreases as temperature increases. The Amonix CPV system is designed to keep the cell temperature as low as possible using passive air-cooling.
Amonix CPV systems use refractive Fresnel lenses to focus sunlight 500 times onto multijunction solar cells. The Amonix CPV system is composed of seven proprietary MegaModules™, each with 36 acrylic lenses and multijunction solar cell collector plates. A dual-axis mounting structure tracks the sun throughout the day as the lenses collect sunlight. MegaModules™ are mounted to a patented hydraulic drive tracking structure. The Amonix tracking system follows the sun from dawn to dusk to maintain the sun's focus on the solar cell. This ensures that the system generates close to peak power output throughout the day and produces more energy to better match power demand from utilities.
In February 2013, Amonix signed a Joint Development Agreement (JDA) with solar cell designer and manufacturer Solar Junction for the purpose of continuing to increase CPV performance and drive down cost by combining efforts of the companies.
In April 2013, Amonix broke its own world record for photovoltaic module efficiency at 34.9% (full regression analysis) under nominal operating conditions, verified by the National Renewable Energy Laboratory (NREL). In discussing the result and plans for the future, Amonix Founder and then CTO Vahan Garboushian recently stated that, "plenty of headroom remains for Amonix to confidently achieve a 40 percent module efficiency in the foreseeable future.".
In August 2013, Amonix announced that it had achieved a rating of 35.9% (full regression analysis) under standard concentrator test conditions (CSTC), calculated by NREL. In the press release Amonix comments that the CSTC result is a direct comparison to PV module efficiencies which are often reported under standard test conditions.


Newfoundland and Labrador Hydro

Newfoundland and Labrador Hydro (NL Hydro), commonly known as Hydro, is a provincial Crown corporation that generates and delivers electricity for Newfoundland and Labrador, as well as portions of Quebec and the north-eastern areas of the United States. Since 2007, Hydro has been a subsidiary of the provincial Crown-owned energy holding company Nalcor Energy.
Newfoundland and Labrador Hydro's installed generating capacity, 7289 megawatts (MW), is the fourth largest of all utility companies in Canada. Generating assets consist of 12 hydroelectric plants, including the Churchill Falls hydroelectric plant, which is the second largest underground power station in the world, with a rated capacity of 5,428 MW of power, one oil-fired plant, four gas turbines and 26 diesel plants. Every year, Hydro generates and transmits over 80% of the electrical energy consumed by Newfoundlanders and Labradorians – over 6,487 GWh of energy in 2004. Hydro also distributes power directly to 35,000 customers in rural Newfoundland and Labrador.
In 1975, the Newfoundland and Labrador Power Commission, a crown corporation originally established to assist in rural electrification, was renamed "Newfoundland and Labrador Hydro Corporation".
Newfoundland and Labrador Hydro is the parent company of the Hydro Group of Companies, which comprises
Grid operations, services and connections.
Atlantic power connections.
The Nova Scotia government commissioned (from SNC-Lavalin) a study in 2009 to consider an Atlantic wide regional electricity market operator.
A $6.2 billion deal between Newfoundland and Labrador Hydro's parent company, Nalcor Energy and Halifax-based Emera was announced by premiers Darrell Dexter and Danny Williams on November 18, 2010. Nalcor Energy will spend $2.9 billion to build a power generating facility at Muskrat Falls, while Emera will invest $1.2-billion in the Maritime Transmission Link underwater power connection and $600 million in the Muskrat Falls facility in exchange for 20% of the 800-megawatts of capacity.


EL34

The EL34 is a thermionic valve or vacuum tube of the power pentode type, first made in 1949. It has an international octal base (indicated by the '3' in the part number) and is found mainly in the final output stages of audio amplification circuits; it was also designed to be suitable as a series regulator by virtue of its high permissible voltage between heater and cathode and other parameters. The American RETMA tube designation number for this tube is 6CA7. The USSR analog was 6P27S (Cyrillic: 6П27C).
Specifications.
In common with all 'E' prefix tubes, using the Mullard–Philips tube designation, the EL34 has a heater voltage of 6.3 V. According to the data sheets found in old vacuum tube reference manuals, a pair of EL34s with 800 V plate voltage can produce 90 watts output in class AB1 in push–pull configuration. However, this configuration is rarely found. One application of this type was in "Australian Sound" public address amplifiers commonly used in government schools in Australia in the 1950s, using four EL34s for ≈200 watts. More commonly found is a pair of EL34s running class AB1 in push–pull around 375–450 V plate voltage and producing 50 watts output (if fixed bias is used), while a quad of EL34s running class AB1 in push–pull typically run anywhere from 425 to 500 V plate voltage and produces 100 watts output. This configuration is typically found in guitar amplifiers.
The EL34 is a pentode, while the 6L6, which delivers a similar range of power output, is a beam tetrode which RCA referred to as a "beam power tube". Although power pentodes and beam tetrodes have some differences in their principles of operation (the beam forming plates of the beam tetrode or fifth electrode (3rd grid) of the pentode, both serving to hinder the return of unabsorbed electrons from the anode (or plate) to the 4th electrode (2nd grid)) and have some internal construction differences, they are functionally closely equivalent. Unlike the 6L6, (EIA base 7AC) the EL34 has its grid 3 connection brought out to a separate Pin (Pin 1) (EIA base 8ET) and its heater draws 1.5 Amps compared to the 0.9 Amp heater in the 6L6. However, Sylvania (and possibly GE) marketed a tube as 6CA7 which was not only in a markedly different 'fat boy' envelope, but used a beam forming plate much like a 6L6. Examining the mica spacer on the top of the tube will confirm the lack of a suppressor grid. Although these tubes have similar (but not identical) characteristics, they are made very differently.
The EL34 was introduced in 1949 by Philips, the parent company of Mullard. Although no longer made by them, it is manufactured by JJ Electronic, Shuguang, Svetlana and Reflector (Sovtek, Electro-Harmonix, Tung-Sol and other brands), amongst others. Some firms make a related tube called an E34L which is rated to require a higher grid bias voltage, but which may be interchangeable in some equipment.
Application.
The EL34 was widely used in higher-powered audio amplifiers of the 1960s and 1970s, such as the popular Dynaco Stereo 70 and the Leak TL25 (mono) and Stereo 60, and is also widely used in high-end guitar amplifiers because it is characterized by greater distortion (considered desirable in this application) at lower power than other octal tubes such as 6L6, KT88 or 6550. The EL34 is found in many British guitar amps and is associated with the "British tone" (Vox, Marshall, Hiwatt, Orange) as compared to the 6L6 which is generally associated with the "American tone" (Fender/Mesa Boogie; the earlier classic Marshall "Plexi" amps used the KT66, a beam tetrode similar to the 6L6, as well).


Octode


Genesis Energy Limited

Genesis Energy Limited, formerly Genesis Power Limited, is a New Zealand publicly listed electricity generation and electricity, natural gas and LPG retailing company. It was formed as part of the 1998–99 reform of the New Zealand electricity sector, taking its generation capacity from the breakup of the Electricity Corporation of New Zealand (ECNZ) and taking retail customers from three local power boards in the Lower North Island.
Genesis Energy is the largest electricity and natural gas retailer in New Zealand, with 26% and 39% market share respectively in the 2015–2016 financial year. In 2015, Genesis produced 14% of New Zealand's electricity, and is the third largest electricity generating company in New Zealand in terms of MW capacity, GWh generation and revenue (see comparison table at New Zealand electricity market).
History.
Genesis Energy began business on 1 April 1999, after the reform of the New Zealand electricity market and the breakup of the Electricity Corporation of New Zealand (ECNZ). It took over the Huntly Power Station, Tongariro Power Scheme and Waikaremoana Hydro Scheme from ECNZ, and the Hau Nui Wind Farm and the Kourarau Hydro Scheme from Wairarapa Electricity. It also inherited the retail arms of Powerco, Central Power and Wairarapa Electricity, while Powerco and Central Power concentrated on electricity distribution (the distribution arm of Wairarapa Electricity merged with Powerco on the same day).
During 2000 to 2002 Genesis Energy purchased several electricity and gas retailing entities, following changes to laws governing the electricity industry. These included electricity retail businesses of Todd Energy, and electricity and gas customers from NGC (now Vector Limited) and Energy Online.
In September 2013, the company announced a change of name from Genesis Power Limited to Genesis Energy Limited.
On 17 April 2014, the National Government sold a 49% stake in Genesis Energy through an initial public offering at NZ$1.55 per share.
In February 2018, Genesis Energy announced a pathway to a coal-free electricity future for New Zealand by 2030.
Power stations.
Genesis Energy owns and operates a diverse portfolio of assets that includes hydroelectric, thermal and wind generation.
Genesis Energy operates three hydroelectric generating stations on the (361.8 MW) Tongariro Power Scheme – Rangipo (120 MW) Tokaanu (240 MW) and Mangaio (1.8 MW). The company also operates the (138 MW) Lake Waikaremoana hydro scheme including the Tuai (60 MW), Kaitawa (36 MW) and Piripaua (42 MW) stations.
On 1 June 2011, Genesis Energy purchased Tekapo A (27 MW) and B (160 MW) hydroelectric power stations from Meridian Energy.
Genesis Energy operates the Huntly Power Station, a (953 MW) coal- and gas-fired thermal plant on the Waikato River. In addition to two gas/coal-fired generating units, Huntly has a 50 MW open-cycle gas turbine unit which runs as base load, and a (403 MW) combined cycle gas turbine commissioned in June 2007 as a NZ$500 million project. In addition to these units Huntly also has a third coal unit which can be taken out of storage within 90 days. The coal units are mainly used as hydro firming when NZ is in a dry winter.
The first of the four coal-fired units at the Huntly Power Station was taken out of service in late 2012. A second unit was placed into long-term storage in December 2013 and permanently retired in June 2015.
The company also operates the (7.3 MW) Hau Nui windfarm in the North Island.
Future generation developments.
Castle Hill.
Genesis Energy has resource consents for a wind farm at Castle Hill, 20 km north-east of Masterton in the northern Wairarapa. It is planning up to 286 turbines over a area, with a total installed capacity of up to 860 MW and potentially generating over 2000 GWh per year.
Slopedown Wind Farm.
In 2010, Genesis Energy purchased the Slopedown wind from Wind Prospect CWP Ltd. It is 15 km east of Wyndham. Genesis Energy has not yet applied for resource consents.
Community and environmental investments.
School-gen.
Genesis Energy began its School-gen programme in 2006 to teach students about solar power, renewable energy and energy efficiency. The School-gen program has created extensive teaching resources, including Maker Projects and eBooks that are free for any school in New Zealand. It has also provided 92 New Zealand schools with either a 2, 4 or 6 kilowatt photovoltaic (PV) solar panel system, at no cost to the schools. The largest solar array on a School-gen school is 16 kilowatts on Vauxhall School in Auckland. The PV system allows these schools to generate a portion of their electricity from the sun while also teaching students about solar energy.
Whio Forever Project.
Genesis Energy has partnered with the New Zealand Department of Conservation to help save the endangered native "whio" or blue duck. The Whio Forever Project includes a national recovery plan that will double the number of fully operational secure breeding sites throughout New Zealand and boost pest control efforts.
Curtain Bank.
Genesis Energy is the major sponsor of the Wellington Curtain Bank and the Christchurch Curtain Bank. The curtain banks take donated second-hand curtains or fabric and re-cut and line them for distribution to households in need. This helps households in saving money on their energy bills and to create warmer, healthier homes. Some retailers offer a service in which they take down and donate your old curtains when installing new ones.
Subsidiaries.
Energy Online.
Genesis Energy purchased Energy Online in December 2002 from the Newcall Group Limited. After continued growth Energy Online now services 70,000 customers with a primary focus on retailing energy services to an expanding customer base in the North Island.
Infogen.
Genesis energy retailed internet services to its customers through its Infogen service. The service was outsourced and provided by Orcon until it was purchased by Orcon in 2009.


Tube socket

Tube sockets are electrical sockets into which vacuum tubes (electronic valves) can be plugged, holding them in place and providing terminals, which can be soldered into the circuit, for each of the pins. Sockets are designed to allow tubes to be inserted in only one orientation. They were used in most tube electronic equipment to allow easy removal and replacement. When tube equipment was common, retailers such as drug stores had vacuum tube testers, and sold replacement tubes. Some Nixie tubes were also designed to use sockets.
Throughout the tube era, as technology developed, sometimes differently in different parts of the world, many tube bases and sockets came into use. Sockets are not universal; different tubes may fit mechanically into the same socket, though they may not work properly and possibly become damaged.
Tube sockets were typically mounted in holes on a sheet metal chassis and wires or other components were hand soldered to lugs on the underside of the socket. In the 1950s, printed circuit boards were introduced and tube sockets were developed whose contacts could be soldered directly to the printed wiring tracks. Looking at the bottom of a socket, or, equivalently, a tube from its bottom, the pins were numbered clockwise, starting at an index notch or gap, a convention that has persisted into the integrated circuit era.
In the 1930s, tubes often had the connection to the control grid brought out through a metal top cap on the top of the tube. This was connected by using a clip with an attached wire lead. An example would be the 6A7 pentagrid converter. Later, some tubes, particularly those used as radio frequency (RF) power amplifiers or horizontal deflection amplifiers in TV sets, such as the 6DQ6, had the plate or anode lead protrude through the envelope. In both cases this allowed the tube's output circuitry to be isolated from the input (grid) circuit more effectively. In the case of the tubes with the plate brought out to a cap, this also allowed the plate to run at higher voltages (over 26,000 volts in the case of rectifiers for color television, such as the 3A3, as well as high-voltage regulator tubes.) A few unusual tubes had caps for both grid and plate; the caps were symmetrically placed, with divergent axes.
The first tubes.
The earliest tubes, like the "Deforest Spherical Audion" from c. 1911, used the typical light bulb Edison socket for the heater, and flying leads for the other elements. Other tubes directly used flying leads for all of their contacts, like the "Cunningham AudioTron" from 1915, or the "Deforest Oscillion". Type C6A xenon thyratrons, used in servos for the U.S. Navy Stable Element Mark 6, had a mogul screw base and L-shaped stiff wires at the top for grid and anode connections. Mating connectors were machined pairs of brass blocks with clamping screws, attached to flying leads (free hanging).
Early bases.
When tubes became more widespread, and new electrodes were added, more connections were required. Specially designed bases were created to account for this need. However, as the world was suffering from World War I, and the new electronics technology was just emerging, designs were far from being standardized. Usually, each company had their own tubes and sockets, which were not interchangeable with tubes from other companies. By the early 1920s, this situation was finally changing, and several standard bases were created. They consisted of a base (ceramic, metal, bakelite, etc.) with a number of prongs ranging from three to seven, with either a non-regular distribution or with one or two of the prongs of bigger diameter than the other, so that the tube could only be inserted in a certain position. Sometimes they relied on a bayonet on the side of the base. Examples of these are the very common USA bases UX4, UV4, UY5 and UX6, and the European B5, B6, B7, B8, C7, G8A, etc. Tubes in the USA typically had from four to seven pins in a circular array, with adjacent pairs of larger pins for heater connections.
Before AC line/mains-powered radios were developed, some four-pin tubes (in particular, the very common UX-201A ('01A)) had a bayonet pin on the side of a cylindrical base. The socket used that pin for retaining the tube; insertion finished with a slight clockwise turn. Leaf springs, essentially all in the same plane, pressed upward on the bottoms of the pins, also keeping the bayonet pin engaged.
The first hot-cathode CRT, the Western Electric 224-B, had a standard four-pin bayonet base, and the bayonet pin was a live connection. (Five effective pins: It was an electrostatic-deflection gas-focused type, with a diode gun and single-ended deflection. The anode and the other two plates were common.)
An early exception to these types of bases is the Peanut 215, which instead of using prongs had a tiny bayonet base with four drop-like contacts. Another exception is the European Side Contact series commonly known as P, which instead of using a prong, relied on side contacts at 90 degrees from the tube axis with four to twelve contacts.
Octal.
In 1935, RCA introduced a new type of tube base for their new metal envelope tubes, which they called an "octal base". As the name implies it had eight pins—more than were usually used previously. Octal bases, as defined in IEC 60067, diagram IEC 67-I-5a, have a 45-degree angle between pins, which form a diameter circle around a diameter keyed post (sometimes called a "spigot") in the center. Octal sockets were designed to accept octal tubes, the rib in the keyed post fitting an indexing slot in the socket so the tube could only be inserted in one orientation.
When used on metal tubes, pin 1 was always reserved for a connection to the metal shell, which was usually grounded for shielding purposes. The octal base soon caught on for glass tubes, where the large central post could also house and protect the "evacuation tip" of the glass tube. The eight available pins allowed more complex tubes than before, such as dual triodes, to be constructed. The glass envelope of an octal base tube was cemented into a bakelite or plastic base with a hollow post in the center, surrounded by eight metal pins. The wire leads from the tube were soldered into the pins, and the evacuation tip was protected inside the post.
Matching plugs were also manufactured that let tube sockets be used as eight-pin electrical connectors; penurious experimenters would sometimes salvage the base from a discarded tube for this purpose. Octal sockets were used to mount other components, particularly electrolytic capacitor assemblies and electrical relays; octal-mount relays are still common.
Most octal tubes following the widespread European designation system have penultimate digit "3" as in ECC34 (full details in the Mullard–Philips tube designation article). There is a different, totally obsolete, pre-world-war-II German octal type.
Octal and miniature tubes are still in use in tube-type audio hi-fi and guitar amplifiers. Relays were historically manufactured in a vacuum tube form, and industrial grade relays continue to use the octal base for their pinout.
Loctal.
A variant of the octal base, the B8G loctal base or "lock-in" base (sometimes spelled "loktal" — trademarked by Sylvania), was developed by Sylvania for ruggedized applications such as automobile radios. Along with B8B (a British designation out of date by 1958), these eight-pin locking bases are almost identical and the names usually taken as interchangeable (although there are some minor differences in specifications, such as spigot material and spigot taper, etc.). The pin geometry was the same as for octal, but the pins were thinner (although they will fit into a standard octal socket, they wobble and do not make good contact), the base shell was made of aluminium, and the center hole had an electrical contact that also mechanically locked (hence "loctal") the tube in place. Loctal tubes were only used widely by a few equipment manufacturers, most notably Philco, which used the tubes in many table radios. Loctal tubes have a small indexing mark on the side of the base skirt; they do not release easily from their sockets unless pushed from that side. Because the pins are actually the Fernico or Cunife lead-out wires from the tube, they are prone to intermittent connections caused by the build-up of electrolytic corrosion products due to the pin being of a different metallic composition to the socket contact.
The loctal tube's structure was supported directly by the connecting pins passing through the glass "button" base. Octal tube structures were supported on a glass "pinch", formed by heating the bottom of the envelope to fusing temperature, then squeezing the pinch closed. Sealing the pinch embedded the connecting wires in the pinch's glass and gave a vacuum-tight seal. The connecting wires then passed through the hollow base pins, where they were soldered to make permanent connections.
Loctal tubes had shorter connecting lengths between the socket pins and the internal elements than did their octal counterparts. This allowed them to operate at higher frequencies than octal tubes. The advent of miniature "all-glass" seven- and nine-pin tubes overtook both octals and loctals, so the loctal's higher-frequency potential was never fully exploited.
Loctal tube type numbers in the USA typically begin with "7" (for 6.3-volt types) or "14" for 12.6-volt types. This was fudged by specifying the heater voltage as "nominally" 7 or 14 volts so that the tube nomenclature fitted. Battery types (mostly 1.4-volt) are coded "1Lxn", where "x" is a letter and "n" a number, such as "1LA4". Russian loctals "end" in L, e.g. 6J1L. European designations are ambiguous; all B8G loctals have numbers either in the range:
Miniature tubes.
Efforts to introduce small tubes into the marketplace date from the 1920s, when experimenters and hobbyists made radios with so-called peanut tubes like the Peanut 215 mentioned above. Because of the primitive manufacturing techniques of the time, these tubes were too unreliable for commercial use.
RCA announced in "Electronics" magazine, new miniature tubes, which proved reliable. The first ones, such as the 6J6 ECC91 VHF dual triode, were introduced in 1939. The bases commonly referred to as "miniature" are the 7-pin B7G type, and the slightly later 9-pin B9A (Noval). The pins are arranged evenly in a circle of eight or ten evenly spaced positions, with one pin omitted; this allows the tube to be inserted in only one orientation. Keying by omitting a pin is also used in 8 (subminiature), 10, and 12-pin (Compactron) tubes (a variant 10-pin form, "Noval+1", is basically a 9-pin socket with an added center contact).
As with loctal tubes, the pins of miniature tube are stiff wires protruding through the bottom of the glass envelope which plug directly into the socket. However, unlike all their predecessors, miniature tubes are not fitted with separate bases; the base is an integral part of the glass envelope. The pinched-off air evacuation nub is at the top of the tube, giving it its distinctive appearance. More than one functional section can be included in a single envelope; a dual triode configuration is particularly common. Seven- and nine-pin tubes were common, though miniature tubes with more pins, such as the Compactron series, were later introduced, and could fit up to three amplifying elements. Some miniature tube sockets had a skirt that mated with a cylindrical metal electrostatic shield that surrounded the tube, fitted with a spring to hold the tube in place if the equipment was subject to vibration. Sometimes the shield was also fitted with thermal contacts to transfer heat from the glass envelope to the shield and act as a heat sink, which was considered to improve tube life in higher power applications.
Electrolytic effects from the differing metal alloys used for the miniature tube pins (usually Cunife or Fernico) and the tube base could cause intermittent contact due to local corrosion, especially in relatively low current tubes, such as were used in battery-operated radio sets. Malfunctioning equipment with miniature tubes can sometimes be brought back to life by removing and reinserting the tubes, disturbing the insulating layer of corrosion.
Miniature tubes were widely manufactured for military use during World War II, and also used in consumer equipment. The Sonora Radio and Television Corporation produced the first radio using these miniature tubes, the "Candid", in April 1940. In June 1940 RCA released its battery-operated Model BP-10, the first superheterodyne receiver small enough to fit in a handbag or coat pocket. This model had the following tube lineup: 1R5 — pentagrid converter; 1T4 — I.F. amplifier; 1S5 — Detector/AVC/AF Amplifier; 1S4 — Audio Output. The BP-10 proved so popular that Zenith, Motorola, Emerson, and other radio manufacturers produced similar pocket radios based on RCA's miniature tubes. Several of these pocket radios were introduced in 1941 and sold until the suspension of radio production in April 1942 for the duration of World War II.
After the war miniature tubes continued to be manufactured for civilian use, regardless of any technical advantage, as they were cheaper than octals and loctals.
Miniature 7-pin base.
The B7G (or "small-button" or "heptal") seven-pin miniature tubes are smaller than Noval, with seven pins arranged at 45-degree spacing in a 9.53 mm (3/8th inch) diameter arc, the "missing" pin position being used to position the tube in its socket (unlike octal, loctal and rimlock sockets). Examples include the 6AQ5/EL90 and 6BE6/EK90. European tubes of this type have numbers 90-99, 100-109, 190-199, 900-999. A few in the 100-109 series have unusual, non-B7G bases, "e.g.", Wehrmacht base.
Noval base.
The nine-pin miniature Noval B9A base, sometimes called button 9-pin, B9-1, offered a useful reduction in physical size compared to previous common types, such as octal (especially important in TV receivers where space was limited), while also providing a sufficient number of connections (unlike B7G) to allow effectively unrestricted access to all the electrodes, even of relatively complex tubes such as double triodes and triode-hexodes. It could also provide multiple connections to an electrode of a simpler device where useful, as in the four connections to the grid of a conventional grounded-grid UHF triode, "e.g.", 6AM4, to minimise the deleterious effects of lead inductance on the high-frequency performance.
This base type was used by many of the United States and most of the European tubes, "e.g.", 12AX7-ECC83, EF86 and EL84, produced commercially towards the end of the era before transistors largely displaced their use.
The IEC 67-I-12a specification calls for a 36-degree angle between the nine pins of 1.016 mm thickness, in an arc of diameter 11.89 mm.
European tubes of this type have numbers 80-89, 180-189, 280-289, 800-899, 8000-8999.
Duodecar base.
The Duodecar B12C base (IEC 67-I-17a) has 12 pins in a 19.1 mm diameter circle and dates from 1961. It was also called the Compactron T-9 construction/E12-70 base It is generally similar in form to a Noval socket, but larger. In the center is a clearance hole for a tube evacuation pip, which is typically on the bottom of a Compactron tube. (It should not be confused with the similar-sounding but differently sized Duodecal B12A base.)
Rimlock base.
The Rimlock (B8A) base is an 8-pin design with a pin circle diameter close to Noval, and uses a nub on the side of the envelope to engage with a guide and retaining spring in the socket wall. This provides pin registration (since the pins are equi-spaced) and also a fair degree of retention. Early tubes with this base type typically had a metal skirt around the lower ~15mm of the envelope to match the socket wall, and this offered a degree of built-in screening, but these were fairly soon replaced by "skirtless" versions, which had a characteristic widening in the glass to compensate physically for the absence of the skirt. In the European naming scheme, rimlock tubes are numbered in the ranges 40-49, 110-119 (with exceptions), and 400-499, "e.g.", EF40. Although virtually unknown elsewhere, this was a very common base type in European radios of the late 1940s through the 1950s, but was eventually displaced by the ubiquitous B7G and Noval (B9A) base types.
UHF tubes.
By 1935 new tube technologies were required for the development of radar and telecommunications. UHF requirements severely limited the existing tubes, so radical ideas were implemented which affected how these tubes connected to the host system. Two new bases appeared, the acorn tube and the lighthouse tube, both solving the same problems but with different approaches. Thompson, G.M. Rose, Saltzberg and Burnside from RCA created the acorn tube by using far smaller electrodes, with radial short connections. A different approach was taken by the designers of the lighthouse tube, such as the octal-base 2C43, which relied on using concentric cylindrical metal contacts in connections that minimized inductance, thus allowing a much higher frequency.
Nuvistors were very small, reducing stray capacitances and lead inductances. The base and socket were so compact that they were widely used in UHF TV tuners. They could also be used in small-signal applications at lower frequencies, as in the Ampex MR-70, a costly studio tape recorder whose entire electronics section was based on nuvistors.
Other socket styles.
There are many other socket types, of which a few are:
A remarkably wide variety of tube and similar sockets is listed and described, with some informal application notes, at a commercial site, Pacific T.V., including nuvistor, 8-pin subminiature, vidicon, reflex klystron, nine-pin octal-like, 10-pin miniature (two types), 11-pin sub-magnal, diheptal 14-pin, and many display tubes such as Nixies and vacuum fluorescent types (and even more). As well, each socket has a link to a clear, high-quality picture.
Some subminiature tubes with flexible wire leads all exiting in the same plane were connected by subminiature inline sockets.
Some low-power reflex klystrons such as the 2K25 and 2K45 had small-diameter rigid coaxial outputs parallel to octal base pins. To accommodate the coax, one contact was replaced by a clearance hole.
Vacuum tubes for high-power applications often required custom socket designs. A jumbo four-prong socket was used for various industrial tubes. A specialized 7-pin socket (Septar or B7A), with all pins in a circle with one pin wider than the others, was used for transmitting tubes. Subminiature tubes with long wire leads, introduced in the 1950s, were often soldered directly to printed circuit boards. Sockets were made for early transistors, but quickly fell out of favor as transistor reliability became established. This also happened with early integrated circuits; IC sockets later became used only for devices that may need to be upgraded.


25L6

The 25L6 is an octal-based vacuum tube of the Beam tetrode type. It is the Octal base equivalent to the type '43 power tube which made early AC-powered loudspeaker radios affordable. It found common application in AC/DC radio receivers - such as those of the All American Five type - and was also found in large numbers in early computers, such as the UNIVAC I.
The tube used EIA base 7AC in common with many other power tubes. The tube was identical in design and ratings with the 50L6 with the exception of having a 25 volt 300 mA heater, whereas the 50L6 has a 50 volt 150 mA heater. The 12L6 and identical 12W6 were made with a 12 volt, 600 mA heater, and the 6W6 was made with a 6.3V, 1200mA heater. There was also a 35L6 with a 35V, 150 mA heater. Because of the slightly lower-power heater, the 35L6 has slightly lower output than the rest of the family.
This family is not to be confused with the 6L6, which has the same basing diagram, but has more than twice the power capability of the 25L6.
The 25L6 was introduced as a metal tube on November 4, 1936, but most examples of this family were made of glass. The ST14 glass 25L6G came out on March 30, 1937. The T9 size GT version came out on April 11, 1938. There was also a 25L6G in the smaller ST-12 glass envelope.
Computer equipment used this tube as a relay driver or to run the solenoids in key punch machines. The heater in this case ran off the 24 volt power line in the equipment, resulting in long life and slightly lower power output. The industrial type 6046 is a 25L6GT rated for that application.


Sempra Energy

Sempra Energy is a North American energy infrastructure company based in San Diego, California. Sempra Energy's focus is on electric and natural gas infrastructure. Its operating companies include: Southern California Gas Company (SoCalGas) and San Diego Gas & Electric (SDG&E) in Southern California; Oncor Electric Delivery Company (Oncor) in Texas; Sempra LNG; and IEnova, based in Mexico.
As of August 2020, Sempra Energy reported more than $60 billion in total assets and 18,000 employees, serving more than 35 million customers worldwide. The company is led by chairman and chief executive officer Jeffrey Martin, who assumed that role in May 2018.
History.
Sempra Energy was created through the 1998 merger of Los Angeles-based Pacific Enterprises, the parent company of SoCalGas, and Enova Corporation, the parent company of SDG&E.
In 1999, the company acquired two utilities in South America; Chilquinta Energia in Chile and Luz Del Sur in Peru, which gave Sempra Energy an entry into the expanding Latin American energy market.
In 2003, Sempra Energy Resources, the former power generation subsidiary of Sempra Energy, completed three state-of-the-art power plant projects in Arizona, California and New Mexico.
Sempra was sued over claims it manipulated natural gas supplies and electricity contracts during the 2001 California electricity crisis. In 2006, the company agreed to pay $377 million to settle gas supply claims, and in 2010, it paid another $410 million to settle claims on electricity price gouging, but has never admitted wrongdoing.
In 2007, Sempra created the Sempra Energy Foundation as a 501(c)(3) private foundation. The foundation matches employee's charitable contributions. In 2018, Sempra Energy Foundation matched $1.2 million. Sempra Energy reported giving $13.85 million in COVID-19 response across the Sempra Energy Foundation and operating companies.
On March 8, 2018, regulators in Texas approved Sempra Energy's purchase of a majority stake in Oncor for $9.45 billion.
On January 16, 2019, Sempra Energy was added to the Dow Jones Utility Average, replacing Pacific Gas and Electric.
Sempra Energy and Aramco signed a deal to supply LNG for Saudi Arabia in May 2019.
In April 2020, Sempra Energy announced it had completed the sale of its business in Peru, Luz del Sur, for $3.59 billion. In June 2020, Sempra Energy announced it completed the sell of its Chilean businesses to China’s State Grid International Development Ltd for $2.23 billion in cash. These two sales completed Sempra Energy's exit from South America.
Operating Companies.
Former.
The following subsidiaries have been reformed into Sempra LNG & Midstream and Sempra Renewables:
Awards and recognition.
In 2020, Sempra Energy was named to Fortune Magazine's World's Most Admired Companies list. The company has received numerous recognitions for leadership in diversity and inclusion, including being named to Bloomberg's Gender Equality Index, Forbes Best Employers for Diversity. and the Human Rights Campaign Foundation's Best Place to Work for LGBTQ Equality. The company has also been named to a number of stock market indexes focused on sustainability.


Edison Electric Institute

The Edison Electric Institute (EEI) is an association that represents all U.S. investor-owned electric companies.
Its members provide electricity for 220 million Americans, operate in 50 states and the District of Columbia, and directly employ more than one million workers.
EEI has 70 international electric companies as Affiliate Members, and 250 industry suppliers and related organizations as Associate Members.
Membership.
Members of the Edison Electric Institute are investor-owned utility companies, meaning that they are privately held companies that supply power and electricity to businesses and consumers.
Some of the larger members include:
Issues.
2017 tax cut.
The Tax Cuts and Jobs Act, the largest tax overhaul in 30 years, was passed by Congress and signed by President Trump at the end of 2017. The legislation had several provisions that benefit the electric industry: maintaining the federal income tax deduction for interest expense for regulated electric companies; maintaining the federal income tax deduction for state and local taxes; and providing for the “continuation of normalization, including addressing excess deferred taxes resulting from a reduction in the tax rate.”
Electric vehicles.
On June 8, 2015, U.S. Energy Secretary Ernest Moniz and the Edison Electric Institute signed a memorandum of understanding (MOU) regarding plug-in electric vehicles (PEVs). The MOU sets up a collaboration between the government and EEI to make PEVs, by the year 2022, as affordable as regular gas-powered vehicles were in 2012. The Department of Energy runs an initiative called the "EV Everywhere Grand Challenge", which put forth the 2022 affordability goal. The program coincides with the popularity of electric vehicle sales, which have increased by 128 percent between 2012 and 2014.
EEI runs a program called the Employee PEV Engagement Initiative. The goal is to "increase electric vehicle readiness, especially in the workplace," according to the Department of Energy. According to the Department of Energy, Kate Brandt, Federal Chief Sustainability Officer at the White House Council on Environmental Quality, said, "Today’s Memorandum of Understanding with the nation’s electric power industry allows the Department of Energy to tap into the experience and scale of an industry that is truly leading the way in moving the electric vehicle market forward."
In pursuing the initiative, EEI and the DOE will work with other federal agencies including Department of Transportation (DOT), General Services Administration (GSA), Council on Environmental Quality (CEQ), and the White House.
Grid security.
The energy grid is a complex, interconnected network of generation, transmission, distribution, control, and communication technologies. Any of these can be damaged by either natural events or malicious attacks such as cyber or physical attacks. The electric power industry has engaged with a series of initiatives meant to protect the energy grid from these threats. The industry collaborates with the National Institute of Standards and Technology, the North American Electric Reliability Corporation, and federal intelligence and law enforcement agencies.
On September 20, 2018, EEI announced that it supported the Trump Administration's unveiled National Cyber Strategy. The protection of critical infrastructure such as the electric grid were included in the National Cyber Strategy.
Hurricane Maria.
After Hurricane Maria hit the island of Puerto Rico in 2017, the federal government invested $3.2 billion into restoring the island's power grid. The Edison Electric Institute deployed Carlos D. Torres, a retired vice president at Consolidated Edison, to Puerto Rico to coordinate storm rebuilding of the power grid. Subsequently, Torres was appointed by Gov. Ricardo Rossello as coordinator for storm restoration.
Unmanned aircraft.
EEI supports the use of drones (unmanned aircraft systems, or UAS) by electric power companies to maintain electric grids and restore downed service. In July 2016, Congress passed legislation (H.R. 636) that "includes provisions supporting electric power companies utilizing unmanned aircraft systems (UAS) for energy grid maintenance and service restoration."
Renewable energy.
Partnership with pro-environment group.
In February 2018, EEI and the Natural Resources Defense Council (NRDC), a non-profit international environmental advocacy group, released a joint statement outlining 21 policy priorities on which both organizations would work together to advance clean energy. Both organizations said the recommendations are designed to “accelerate the clean energy transition; promote investment in smarter energy infrastructure, while ensuring affordable and reliable electricity; and facilitate collaboratively developed rate design and regulatory reforms that accommodate rapid technology change and evolving customer expectations.”
Advocacy for changes to homeowner solar panel policies.
Between 2011 and 2017, rooftop solar panel installations had "explosive growth — as much as 900 percent by one estimate." But by 2017, the growth stopped. Saturation in certain markets, such as California, and financial problems at several of the top solar panel makers are the main factors that caused the decline in growth. But, according to the "New York Times", "the decline has also coincided with a concerted and well-funded lobbying campaign by traditional utilities, which have been working in state capitals across the country to reverse incentives for homeowners to install solar panels." EEI has played a central role in a national U.S. campaign to reduce renewable energy incentives. However, the EEI has been successful in rolling back state-level incentives for rooftop solar energy.
Utilities are not opposed to solar panel-produced energy. Rather, they are opposed to state rules, known as net metering, that are connected to homeowner-produced solar energy. Under net metering rules in many states, private solar customers can sell excess power they produce back to the grid at what is known as the "retail price," which is more than the utilities pay for the energy itself from energy producers. Utilities argue that this practice is unfair to homeowners who do not want or can't afford their own solar panels.
ESG reporting template.
In August 2018, EEI announced that it was launching an environmental, social, governance, and sustainability-related (ESG/sustainability) reporting template to help both consumers and the financial sector, the latter with "more uniform and consistent ESG/sustainability data and information." EEI had launched a similar program as a pilot program in 2017. The template is the first of its kind, being "the first and only industry-focused and investor-driven ESG reporting framework."
Foundation.
The Edison Electric Institute runs the Edison Electric Institute for Electric Innovation foundation, a 501(c)(3) charitable organization. The foundation's main activities are research, holding conferences, giving grants, and outreach to outside parties and organizations. The foundation's three main goals are to educate the public about how electric power is produced, delivered, and used; help make the environment clean and safe; and to improve the quality of life for all people. The governing structure of the foundation is a board of directors composed of electric industry CEOs.


Great Belt Power Link

The Great Belt Power Link (Storebælt HVDC) is a high voltage direct current interconnection across the Great Belt between Funen and Zealand connecting two power transmission systems in Denmark.
Background.
Denmark has two separated transmission systems, of which the eastern one is synchronous with Nordic (former NORDEL) and the western one with the synchronous grid of Continental Europe. The phases of the two systems are not synchronized, and can therefore only be connected via transformers and direct current.
There had been several discussions and feasibility studies about possible interconnection between these systems. The Danish system had changed due to closure of older plants and expansion of renewable energy. The purpose of the connection is to improve utilisation of the power system, share power reserves, obtain synergies in a common regulating power market and better market performance. The decision to build the Storebælt HVDC was made in December 2005 and it is based on the feasibility study carried out in 2005.
Construction.
The submarine power cable across the Great Belt was laid in July 2009 by a submarine contractor JD-Contractor A/S using the cable-laying barge C/B Henry P. Lading. The interconnection was commissioned in July 2010 and started commercial operations in August 2010. It was inaugurated on 7 September 2010.
Economy.
In the first months of operation, the connection has transferred power from West to East near full capacity.
Energinet.dk estimates that the connection will save consumers in East Denmark between 150 and 200 million kroner per year, while West Denmark will retain normal prices due to the strong connections with Germany and Norway.
The Power Link has reduced the price variability in both East and West Denmark, and reduced the price in fossil fuel East Denmark. The cable's effect on price change in West Denmark is disputed due to the strong connections with Germany and Norway.
A researcher from Aalborg University claims that the reduced price variability has reduced the incentive for Smart Grids, and proposes that the bottleneck income is diverted from investments in physical grid to Smart Grid.
In 2012, Energinet concluded that a second power cable would not be feasible, but if decided, it could run between Studstrup Power Station, which lies north of the city of Aarhus and the power plant at (Danish:"Kyndbyværket") in Frederikssund Municipality. In 2015, Energinet started considering a second cable again, due to lower expectations for stationary power in East Denmark.
Technical description.
The Storebælt HVDC is a 600 MW Line Commutated Converter (LCC) HVDC at a voltage of 400 kV. It consists of the Fraugde converter station on Funen connected to an existing 400 kV substation and the new Herslev converter station on Zealand connected to an existing 400 kV overhead line. The converter stations are supplied by Siemens Power Transmission and Distribution. The interconnector includes long sea cable, long land cable on Funen and long land cable on Zealand.
Operator.
The Storebælt HVDC is ordered and operated by the Danish transmission system operator Energinet.dk.


Gwyneth Cravens

Gwyneth Cravens is an American novelist and journalist. She has published five novels. Her fiction and nonfiction have appeared in "The New Yorker", where she also worked as a fiction editor, and in "Harper's Magazine", where she was an associate editor. She has contributed articles and editorials on science and other topics to "Harper's Magazine", "The New York Times", and "The Washington Post".
At a September 2007 seminar given by the Long Now Foundation, Cravens outlined the message of her book, "Power to Save the World: The Truth About Nuclear Energy". Released in October 2007, it argued for nuclear power as a safe energy source and an essential preventive of global warming. She appeared in the documentary Pandora's Promise to speak about the merits of nuclear power.
Since then, she has given presentations to members of the technical and academic communities around the U.S., including the Brookings Institution, the Progressive Policy Institute, the University of Hartford, and Sandia National Laboratories. She has often shared the podium with Dr. D. Richard ("Rip") Anderson, a chemist, oceanographer, and international expert in nuclear risk assessment. These talks emphasize the need for the environmental and technical communities to work together to reduce the anthropogenic causes of catastrophic climate change.
Cravens has contributed articles on nuclear power as a low-carbon alternative energy source to "The Huffington Post" and "Discover". In 2002, she wrote "Terrorism and Nuclear Energy: Understanding the Risks" for "The Brookings Review".
Gwyneth Cravens has a daughter, the artist Astrid Cravens (born 1967). In 1974, she started dating the author Henry Beard. While there is some question if they ever married or not, they have continued as a couple.


Trans Bay Cable

The Trans Bay Cable is a high-voltage direct current (HVDC) underwater transmission cable interconnection between San Francisco, California and Pittsburg, California. The cable under San Francisco Bay and through the Carquinez Strait can transmit 400 megawatts of power at a DC voltage of ±200 kV, enough to provide 40% of San Francisco's peak power needs.
The line connects PG&E's Potrero Substation (formerly the switchyard for Potrero Generating Station) to its 230 kV transmission line in Pittsburg. The system was completed in November 2010. The Trans Bay Cable project was the first HVDC system to use the "Modular Multi-Level Converter" (MMC) system.
History.
1998 San Francisco power outage.
Until recently, San Francisco was connected to the rest of California's grid through a single transmission path including the San Mateo Substation near Coyote Point Recreation Area. At the time, in addition to power imported through the grid, there were two remaining power plants within city limits to support local demand: Hunters Point Power Plant and Potrero Generating Station. On December 8, 1998, a disturbance at that substation tripped it offline; the resulting chain reaction also would knock the transmission lines out of service and shut down both Hunters Point and Potrero electric generating stations, causing a power outage covering most of the city for eight hours.
Reliability initiatives.
Following the prolonged outage, the utility (Pacific Gas and Electric), the City and County of San Francisco, and the California Public Utilities Commission formed the San Francisco Stakeholder Study Group (SFSSG) to determine immediate transmission solutions to ensure electric reliability, which led to the upgrading of PG&E transmission lines and towers paralleling Interstate 280 under the Jefferson-Martin transmission line project to diversify the path. After the Jefferson-Martin project was complete, PG&E decommissioned Hunters Point in 2006.
The SFSSG also studied projects to enhance long-term reliability, which included an evaluation of several proposals for transmission lines across San Francisco Bay. In September 2005, the California Independent System Operator (CAISO) identified the Trans Bay Cable (TBC) project as the preferred option over alternatives from PG&E, which had proposed building AC lines to Potrero from East Bay substations in Moraga or Fremont. The capital costs of the alternatives were approximately equal, but the HVDC technology proposed for the TBC project would have reduced transmission losses. The submarine route also avoided siting concerns for high-voltage overhead transmission lines and towers in residential neighborhoods; in addition, adding the new transmission line could obviate the need to build peaking power plants within city limits, including the removal of the Potrero Generating Station.
Babcock & Brown (B&B) executed a development agreement with the City of Pittsburg in January 2004, and introduced the project to CAISO in February. The original intent was for B&B to develop the cable project and finance it, then transfer ownership to the city's municipal utility (Pittsburg Power) and convey transmission rights to CAISO. The San Francisco Board of Supervisors voted 9–2 to approve the TBC project in August 2007 and the final discretionary permit was granted by the San Francisco Bay Conservation and Development Commission on August 16, 2007.
Construction.
Construction on the TBC officially began on December 15, 2007. A joint venture between Siemens Energy and Prysmian Construction Services (formerly Pirelli Cable) were responsible for building the turnkey project; the Siemens/Prysmian joint venture subcontracted electrical equipment installation to Cupertino Electric. After B&B declared bankruptcy in 2009, the management of B&B partnered with John Hancock Life Insurance Company, creating SteelRiver Infrastructure Partners to complete the cable.
Cable laying operations began on October 11, 2009 using the cable vessel "Giulio Verne" and the barge "Manson 73" for the shallower eastern approaches. The starting point for both vessels was just west of the Benicia–Martinez Bridge. By November 6, "Giulio Verne" had laid cable to the north side of the San Francisco–Oakland Bay Bridge and "Manson 73" had completed its segment to Pittsburg; a total of of cable had been placed. Another Manson Construction Company barge, "Hagar", was used to perform post-lay burial activities, including placing flexible concrete mats for protection. The cable was laid, buried, and connected at each end by December 3, 2009, and a preliminary test was conducted on January 15, 2010, successfully transmitting 400 MW to the San Francisco grid. However, during subsequent testing, the converter modules failed at a higher than expected rate. Final testing was completed on November 3, 2010, with substantial completion declared a week later; the Trans Bay Cable entered revenue service on November 23. After the Trans Bay Cable was completed, Potrero (then owned by Mirant) was decommissioned in 2011.
TBC was damaged in September 2014 after dropped anchor after losing power near the Benicia–Martinez bridge; repairs took four months to complete. In 2018, Siemens upgraded the control system, allowing black start capability, which enables the TBC to support critical infrastructure needs in San Francisco as the sole source of power, without relying on the local grid. Under black start conditions, up to 300 MW electric can be supplied through the TBC; normally, the TBC can transmit up to 400 MW, which is approximately 40% of the total load for San Francisco under peak demand. SteelRiver sold its interest in the cable to NextEra Energy Transmission in July 2019 for a reported $1 billion.
Design.
In the original plan, there were five major components in the Trans Bay Cable project:
The original design for the HVDC cable bundle included a 400 kV transmission line (approximately in diameter), a 12 kV metallic return (ground) cable ( diameter), and a fiber optic communication cable ( diameter); the total bundle was in diameter. With the adoption of HVDC Power Link Universal System (PLUS) technology, two cables of identical size were used instead for the transmission line, along with the fiber optic cable. Each cable is energized to 200 kV (one positive, one negative). The HVDC converter for HVDC PLUS uses a half-bridge topology; the system is rated to carry up to 400 MW of electric power in a symmetrical monopole configuration.
Prysmian Group manufactured the HVDC and terrestrial AC cables in its Arco Felice (Naples) factory and laid the submarine HVDC cable using its own ship, the "Giulio Verne" ().
Each converter station consists of a valve hall originally designed to be high, a DC hall, and a control building; the total area for the buildings is ; in addition, a switchyard will handle the connection to the existing grid after conversion. With the update to HVDC PLUS, the building height and size were reduced: height was reduced to and the required footprint is reduced by approximately 25 percent.
The original route for the AC lines connecting the Pittsburg substation with the converter site (near the Delta Energy Center) were mainly underwater, running approximately north from the substation, east around the northern end of Browns Island, southeast along the slough between Browns and Winter islands, east to the southern tip of Winter Island, then south and back on land to the converter site. However, the Pittsburg converter station later was moved to a site near West Tenth Street, just south of the existing PG&E substation, reducing the AC interconnect lines to less than and shortening the HVDC cable bundle to . The San Francisco converter station is near the intersection of 23rd and Illinois, between Piers 70 and 80.
The submarine HVDC cable is buried at a depth of below the floor of the Bay to protect it from anchor strikes. In certain locations, such as where the cable crosses existing utilities, it is unable to be buried, and flexible concrete mats were placed atop the cable for protection.


Rooftop photovoltaic power station

A rooftop photovoltaic power station, or rooftop PV system, is a photovoltaic (PV) system that has its electricity-generating solar panels mounted on the rooftop of a residential or commercial building or structure. The various components of such a system include photovoltaic modules, mounting systems, cables, solar inverters and other electrical accessories.
Rooftop mounted systems are small compared to ground-mounted photovoltaic power stations with capacities in the megawatt range, hence being a form of distributed generation. Most rooftop PV stations in developed countries are Grid-connected photovoltaic power systems. Rooftop PV systems on residential buildings typically feature a capacity of about 5 to 20 kilowatts (kW), while those mounted on commercial buildings often reach 100 kilowatts to 1 Megawatt (MW). Very large roofs can house industrial scale PV systems in the range of 1-10 Megawatts.
Installation.
The urban environment provides a large amount of empty rooftop spaces and can inherently avoid the potential land use and environmental concerns. Estimating rooftop solar insolation is a multi-faceted process, as insolation values in rooftops are impacted by the following:
There are various methods for calculating potential solar rooftop systems including the use of Lidar and orthophotos. Sophisticated models can even determine shading losses over large areas for PV deployment at the municipal level.
Components of a rooftop solar array:
The following section contains the most commonly utilized components of a rooftop solar array. Though designs may vary with roof type (eg. metal vs shingle), roof angle, and shading concerns, most arrays consist of some variation of the following components
Finances.
Installation cost.
Cost trends.
In the mid-2000s, solar companies used various financing plans for customers such as leases and power purchase agreements. Customers could pay for their solar panels over a span of years, and get help with payments from credits from net metering programs. As of May 2017, installation of a rooftop solar system costs an average of $20,000. In the past, it had been more expensive.
Utility Dive wrote, "For most people, adding a solar system on top of other bills and priorities is a luxury" and "rooftop solar companies by and large cater to the wealthier portions of the American population." Most households that get solar arrays are "upper middle-income". The average household salary for solar customers is around $100,000. However, "a surprising number of low-income" customers appeared in a study of income and solar system purchases. "Based on the findings of the study, GTM researchers estimate that the four solar markets include more than 100,000 installations at low-income properties."
A report released in June 2018 by the Consumer Energy Alliance that analyzed U.S. solar incentives showed that a combination of federal, state and local incentives, along with the declining net cost of installing PV systems, has caused a greater usage of rooftop solar across the nation. According to "Daily Energy Insider", "In 2016, residential solar PV capacity grew 20 percent over the prior year, the report said. The average installed cost of residential solar, meanwhile, dropped 21 percent to $2.84 per watt-dc in the first quarter of 2017 versus first quarter 2015." In fact, in eight states the group studied, the total government incentives for installing a rooftop solar PV system actually exceeded the cost of doing so.
In 2019, the national average cost in the United States, after tax credits, for a 6 kW residential system was $2.99/W, with a typical range of $2.58 to $3.38.
Due to economies of scale, industrial-sized ground-mounted solar systems produce power at half the cost (2c/kWh) of small roof-mounted systems (4c/kWh).
Net-metering mechanism.
This is an arrangement for grid connected solar power systems. In this mechanism, the excess solar power generated is exported to the electricity grid. The consumer gets credit for the amount of power exported. At the end of the billing cycle, the consumer is charged for the net or difference of power imported and power exported to the electricity grid. Hence the name, net-metering.
A key point to note here is that there is no sale of solar power in this mechanism. The exported kWh are only used to adjust the imported kWh prior to the bill calculation.
Feed-in tariff mechanism.
In a grid connected rooftop photovoltaic power station, the generated electricity can sometimes be sold to the servicing electric utility for use elsewhere in the grid. This arrangement provides payback for the investment of the installer. Many consumers from across the world are switching to this mechanism owing to the revenue yielded. A public utility commission usually sets the rate that the utility pays for this electricity, which could be at the retail rate or the lower wholesale rate, greatly affecting solar power payback and installation demand.
The FIT as it is commonly known has led to an expansion in the solar PV industry worldwide. Thousands of jobs have been created through this form of subsidy. However it can produce a bubble effect which can burst when the FIT is removed. It has also increased the ability for localised production and embedded generation reducing transmission losses through power lines.
Hybrid systems.
A rooftop photovoltaic power station (either on-grid or off-grid) can be used in conjunction with other power components like diesel generators, wind turbines, batteries etc. These solar hybrid power systems may be capable of providing a continuous source of power.
Advantages.
Installers have the right to feed solar electricity into the public grid and hence receive a reasonable premium tariff per generated kWh reflecting the benefits of solar electricity to compensate for the current extra costs of PV electricity.
Disadvantages.
An electrical power system containing a 10% contribution from PV stations would require a 2.5% increase in load frequency control (LFC) capacity over a conventional system—an issue which may be countered by using synchronverters in the DC/AC-circuit of the PV system. The break-even cost for PV power generation was in 1996 found to be relatively high for contribution levels of less than 10%. While higher proportions of PV power generation give lower break-even costs, economic and LFC considerations impose an upper limit of about 10% on PV contributions to the overall power systems.
Technical Challenges.
There are many technical challenges to integrating large amounts of rooftop PV systems to the power grid.
Future prospects.
The Jawaharlal Nehru National Solar Mission of the Indian government is planning to install utility scale grid-connected solar photovoltaic systems including rooftop photovoltaic systems with the combined capacity of up to 100 gigawatts by 2022.


Pentagrid converter

The pentagrid converter is a type of radio receiving valve (vacuum tube) with five grids used as the frequency mixer stage of a superheterodyne radio receiver.
The pentagrid was part of a line of development of valves that were able to take an incoming RF signal and change its frequency to a fixed intermediate frequency, which was then amplified and detected in the remainder of the receiver circuitry. The device was generically referred to as a "frequency changer" or just "mixer".
Origins.
The first devices designed to change frequency in the manner described above seem to have been developed by the French, who simply put two grids into what would otherwise have been an ordinary triode valve (the bi-grille or bi-grid). Although technically a four electrode device, neither the term tetrode nor the tetrode valve as it is known today had yet appeared. The bi-grid differed from the later tetrode because the second (outer) grid was coarsely wound compared with the tetrode's screen grid which had to be finely wound to provide its screening effect. Each grid was able to accept one of the incoming signals, and the non-linearity of the device produced the sum and difference frequencies. The valve would have been very inefficient, but, most importantly, the capacitive coupling between the two grids would have been very large. It would therefore have been quite impossible to prevent the signal from one grid coupling out of the other. At least one reference claims that the bi-grille was self-oscillating, but this has not been confirmed.
In 1918, Edwin Armstrong used only triodes when he invented the superheterodyne receiver. One triode operated in a conventional oscillator circuit. Another triode acted as a mixer by coupling the oscillator signal into the mixer's cathode and the received signal to the grid. The sum and difference frequencies were then available in the mixer's anode circuit. Once again, the problem of coupling between the circuits would be ever present.
Shortly after Armstrong invented the superheterodyne, a triode mixer stage design was developed that not only mixed the incoming signal with the local oscillator, but the same valve doubled as the oscillator. This was known as the autodyne mixer. Early examples had difficulty oscillating across the frequency range because the oscillator feedback was via the first intermediate frequency transformer primary tuning capacitor, which was too small to give good feedback. Also keeping the oscillator signal out of the antenna circuit was difficult.
The invention of the tetrode demonstrated the idea of screening electrodes from each other by using additional earthed (grounded) grids (at least, as far as the signal was concerned). In 1926, Philips invented a technique of adding yet another grid to combat the secondary emission that the tetrode suffered from. All the ingredients for the pentagrid were now in place.
Pentagrid.
The development of the pentagrid or heptode (seven-electrode) valve was a novel development in the mixer story. The idea was to produce a single valve that not only mixed the oscillator signal and the received signal and produced its own oscillator signal at the same time but, importantly, did the mixing and the oscillating in different parts of the same valve.
The invention of the device at first sight doesn't seem to be obscure, but it would appear that it was developed in both America and the United Kingdom, more or less at the same time. However, the UK device is different from its American counterpart.
It is known that Donald G. Haines of RCA applied for a patent for the pentagrid on 28 March 1933 (subsequently granted on 29 March 1939) under US patent number 2,148,266. The pentagrid also featured in a UK patent (GB426802) granted on 10 April 1935. However, the Ferranti company of Great Britain entered the valve business with the first known UK-produced pentagrid, the VHT4, late in 1933 (though it must have been in development, and would certainly have existed as a prototype well before that time).
The pentagrid proved to be a much better mixer. Since the oscillator circuit was more or less self-contained, good feedback for reliable oscillation across the frequency range was easy to obtain. Some manufacturers that had adopted the autodyne mixer converted some, if not all, of their designs to pentagrid mixers.
What was the goal to develop a reliable self-oscillating mixer? The reasons were to differ from the UK to America. The UK radio manufacturers had to pay a royalty of £1 per valve holder to the British Valve Association to cover use of their members' patent rights. Further, they dictated that not more than one electrode structure could be contained in a single envelope (which would have evaded the royalty - at least in part). The Americans appeared to be driven by the desire to produce a low-cost 'every expense spared' design which was to lead to the All American Five. By making the mixer self-oscillate, the necessity of providing a separate oscillator valve is avoided. The All American Five was to use a pentagrid converter from when it first appeared in 1934, right up until valves became obsolete when transistors took over.
In the UK, the five grids operated thus. Grid 1 acted as the oscillator grid in conjunction with grid 2 which acted as its anode. Grid 4 accepted the incoming signal with the remaining two grids, 3 and 5 connected together (usually internally) which acted as screen grids to screen the anode, grid 4 and grid 2 from each other. Because grid 2 was a 'leaky' anode in that it allowed part of the modulated electron stream through, the oscillator was coupled into the mixing section of the valve. In fact, in some designs, grid 2 consisted of just the support rods, the actual grid wire itself being omitted.
In America, the configuration was different. Grid 1 acted as the oscillator grid as before, but in this case, grids 2 and 4 were connected together (again usually internally). Grid 2 functioned as both a screen and the oscillator anode; in this case the grid wire had to be present to provide the screening. Grid 3 accepted the incoming signal. Grid 4 screened this from the anode, and grid 5 was a suppressor grid to suppress secondary emission. This configuration limited the oscillator design to one where the oscillator 'anode' was operated from the HT+ (B+) rail. This was often accomplished by using a Hartley Oscillator circuit and taking the cathode to the tap on the coil.
The UK version would have had significant secondary emission and would also have had a tetrode kink. This was exploited in providing the non linearity necessary to produce good sum and difference signals. The American devices although having no secondary emission due to the suppressor grid, nevertheless were able to get the required non linearity by biasing the oscillator such that the valve was overdriven. The American version was also a little more sensitive because the grid that accepted the signal was closer to the cathode increasing the amplification factor.
The pentagrid converter in either guise operated extremely well, but it suffered from the limitation that a strong signal was able to 'pull' the oscillator frequency away from a weaker signal. This was not considered a major problem in broadcast receivers where the signals were likely to be strong, but it became a problem when trying to receive weak signals that were close to strong signals. Some short wave radios managed quite satisfactorily with these devices. Special high frequency versions appeared after World War II for the 100 MHz FM bands. Examples are the 6SB7Y (1946) and the 6BA7 (1948). The pulling effect had a beneficial side effect in that it gave a degree of automatic tuning.
Another disadvantage was that in spite of the presence of the screen grids, the electron beam, modulated by the oscillator electrodes, still had to pass through the signal grid, and coupling of the oscillator into the signal circuit was inevitable. The American Federal Communications Commission (FCC) started requiring radio manufacturers to certify that their products avoided this interference under Part 15 of their rules. In the UK, the Postmaster General (who was responsible for radio licensing), laid down a set of stringent rules concerning radio interference.
Hexode.
The hexode (six-electrode) was actually developed after the heptode or pentagrid. It was developed in Germany as a mixer but was designed from the start to be used with a separate triode oscillator. Thus the grid configuration was grid 1, signal input; grids 2 and 4 screen grids (connected together - again, usually internally) and grid 3 was the oscillator input. The device had no suppressor grid. A major advantage was that by using grid 1 as the signal input grid, the device was more sensitive to weak signals.
It was not long before the triode and hexode structures were placed in the same glass envelope - by no means a new idea. The triode grid was usually internally connected to the hexode grid 3, but this practice was dropped in later designs when the mixer section operated as a straight IF amplifier in AM/FM sets when operating on FM, the mixing being carried out in a dedicated FM frequency changing section.
The UK manufacturers were initially unable to use this type of mixer because of the BVA prohibition on multiple structures (and indeed unwilling to use separate valves because of the levy). One UK company, MOV, successfully enforced the cartel rules against the German Lissen company in 1934 when they attempted to market a radio in the UK which had the triode-hexode mixer.
Following pressure from the UK manufacturers, the BVA were compelled to relax the rules and the UK started to adopt triode-hexode mixers. The Mullard ECH35 was a popular choice.
One company, Osram, made an ingenious move. One of their popular pentagrid converter designs was the MX40, initially marketed in 1934. They put on sale in 1936, the X41 triode-hexode frequency changer. The clever bit was that the X41 was a direct plug-in pin-compatible replacement for the MX40. Thus a pentagrid radio could easily be converted to a triode-hexode without any other circuit modifications.
America never really adopted the triode-hexode and it was seldom used, even though the 6K8 triode-hexode was available to manufacturers in 1938.
In some designs, a suppressor grid was added to produce yet another heptode design. Mullard's ECH81 became popular with the move to miniature nine-pin valves.
Octode.
Although not strictly a pentagrid (in that it has more than five grids), the octode (eight-electrode) nevertheless operates on the pentagrid principle. It resulted simply from the addition of an extra screen grid to the UK version of the pentagrid heptode. This was done mainly to improve the antenna/oscillator separation and to reduce the power consumption for use in radio sets operated by dry batteries that were becoming increasingly popular.
In North America, the only octode manufactured was the 7A8. Introduced by Sylvania in 1939 (and used mostly by Philco), this valve was the product of adding a suppressor grid to type 7B8, which was the loctal version of type 6A7. Adding the suppressor allowed Sylvania to lower the current of the 6.3-volt heater from 320 milliamperes to 150 milliamperes while maintaining the same conversion transconductance (550 microsiemens). This allowed Philco to use this valve in every line of radio throughout the 1940s.
The Philips EK3 octode was designated as a "beam octode". The novel part about the design was that grids 2 and 3 were constructed as beam-forming plates. This was done in such a way that Philips claimed that the oscillator electron beam and the mixer electron beams were separated as much as possible and thus the pulling effect was minimised. No information is available as to the degree of success. The manufacturer's information also notes that the valve's high performance comes at a cost of a high heater current of 600 mA – double that of more conventional types.
Pentode.
The use of a pentode would seem an unlikely choice for a frequency converter because it only has one control grid. However, during the Great Depression, many American radio manufacturers used pentode types 6C6, 6D6, 77 and 78 in their lowest priced AC/DC receivers because they were cheaper than pentagrid type 6A7. In these circuits, the suppressor (grid 3) acted as the oscillator grid, and the valve operated in a similar manner to a true pentagrid.
One UK company, Mazda/Ediswan, produced a triode-pentode frequency changer, the AC/TP. Designed for low-cost AC radios, the device was deliberately designed to allow strong signals to pull the oscillator without the risk of radiating the oscillator signal from the aerial. The cathode was common to both sections of the valve. The cathode was connected to a secondary coil on the oscillator coil and thus coupled the oscillator into the pentode mixer section, the signal being applied to grid 1 in the conventional manner. The AC/TP was one of the AC/ range of valves designed for low-cost radios. They were considered durable for their time (even the AC/TP frequency changer, which was normally problematic). Any AC/ valves encountered today are likely to be brand new as service shops stocked up on spares which were seldom required.
Nomenclature.
In order to distinguish between the two versions of the heptode, manufacturers data often describes them as "heptode of the hexode type" for a heptode without a suppressor grid, and a "heptode of the octode type", where a suppressor grid is present.
Examples.
Triode/hexode types (not operating on the pentagrid principle).
This list is by no means exhaustive.