Energian tuotanto, kenttägeneraattorit ja muut

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The 100-metre mirror dishes being tested by Ripasso in the Kalahari desert. Photograph: Jeffrey Barbee

A new solar electricity generation system that developers claim is the most efficient in the world, is being tested in South Africa’s Kalahari desert.

The Swedish company behind the project - which combines military technology with an idea developed by a 19th-century Scottish engineer and clergyman - says it is on the verge of building its first commercial installation.

In the remote Northern Cape province, huge mirrors reflect the sun across the brown Kalahari sand. This is the test site for Swedish company Ripasso, which is using the intense South African sun and local manufacturing know-how to develop their cutting-edge kit.

“Our whole team in South Africa has been hired locally, and our new systems have all been built with local South African labour. It works great,” says CEO Gunnar Larsson.

This is the only working small-scale concentrated solar energy system of its kind in the world. 34% of the sun’s energy hitting the mirrors is converted directly to grid-available electric power, compared to roughly half that for standard solar panels. Traditional photovoltaic panels are able to turn about 23% of the solar energy that strikes them into electricity, but this is cut to around 15% before it is usable by the grid.

http://www.theguardian.com/environm...orlds-most-efficient-solar-electricity-system

 

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Researchers at the U.S. Department of Energy's Princeton Plasma Physics Laboratory (PPPL) have for the first time simulated the formation of structures called "plasmoids" during Coaxial Helicity Injection (CHI), a process that could simplify the design of fusion facilities known as tokamaks.

The findings, reported in the journal Physical Review Letters, involve the formation of plasmoids in the hot, charged plasma gas that fuels fusion reactions. These round structures carry current that could eliminate the need for solenoids - large magnetic coils that wind down the center of today's tokamaks - to initiate the plasma and complete the magnetic field that confines the hot gas.

"Understanding this behavior will help us produce plasmas that undergo fusion reactions indefinitely," said Fatima Ebrahimi, a physicist at both Princeton University and PPPL, and the paper's lead author.

Ebrahimi ran a computer simulation that modeled the behavior of plasma and the formation of plasmoids in three dimensions thoughout a tokamak's vacuum vessel. This marked the first time researchers had modeled plasmoids in conditions that closely mimicked those within an actual tokamak. All previous simulations had modeled only a thin slice of the plasma - a simplified picture that could fail to capture the full range of plasma behavior.

Researchers validated their model by comparing it with fast-camera images of plasma behavior inside the National Spherical Torus Experiment (NSTX), PPPL's major fusion facility. These images also showed plasmoid-like structures, confirming the simulation and giving the research breakthrough significance, since it revealed the existence of plasmoids in an environment in which they had never been seen before.

"These findings are in a whole different league from previous ones," said Roger Raman, leader for the Coaxial Helicity Injection Research program on NSTX and a coauthor of the paper.

The findings may provide theoretical support for the design of a new kind of tokamak with no need for a large solenoid to complete the magnetic field. Solenoids create magnetic fields when electric current courses through them in relatively short pulses. Today's conventional tokamaks, which are shaped like a donut, and spherical tokamaks, which are shaped like a cored apple, both employ solenoids.

But future tokamaks will need to operate in a constant or steady state for weeks or months at a time. Moreover, the space in which the solenoid fits - the hole in the middle of the doughnut-shaped tokamak - is relatively small and limits the size and strength of the solenoid.

A clear understanding of plasmoid formation could thus lead to a more efficient method of creating and maintaining a plasma through transient Coaxial Helicity Injection. This method, originally developed at the University of Washington, could dispense with a solenoid entirely and would work like this:

+ Researchers first inject open magnetic field lines into the vessel from the bottom of the vacuum chamber. As researchers drive electric current along those magnetic lines, the lines snap closed and form the plasmoids, much like soap bubbles being blown out of a sheet of soapy film.

+ The many plasmoids would then merge to form one giant plasmoid that could fill the vacuum chamber.

+ The magnetic field within this giant plasmoid would induce a current in the plasma to keep the gas tightly in place. "In principle, CHI could fundamentally change how tokamaks are built in the future," says Raman.

Understanding how the magnetic lines in plasmoids snap closed could also help solar physicists decode the workings of the sun. Huge magnetic lines regularly loop off the surface of the star, bringing the sun's hot plasma with them. These lines sometimes snap together to form a plasmoid-like mass that can interfere with communications satellites when it collides with the magnetic field that surrounds the Earth.

While Ebrahimi's findings are promising, she stresses that much more is to come. PPPL's National Spherical Torus Experiment-Upgrade (NSTX-U) will provide a more powerful platform for studying plasmoids when it begins operating this year, making Ebrahimi's research "only the beginning of even more exciting work that will be done on PPPL equipment," she said.

http://www.spacedaily.com/reports/G...mplify_the_design_of_future_tokamaks_999.html

 

[miheikki]

Liittyy jotenkuten ketjun aiheeseen.

keskiviikko 3. kesäkuuta 2015 http://murphyssoninlaw.blogspot.fi/2015/06/eun-epaonnistunut-paastovahennys.html
EU:n epäonnistunut päästövähennys

Matti Hukari on kirjoittanut erinomaisen artikkelin Kanava-lehteen otsikolla "Yhdysvaltojen ilmastopolitiikka Kioton sopimuksen vaihtoehtona". Jo sitä seuraava toteamus on paljastava:Yhdysvallat on onnistunut vähentämään päästöjään ja ennen kaikkea taloutensa hiili-intensiteettiä eli bruttokansantuotteeseen suhteutettua hiilidioksidipäästöjen määrää paremmin kuin Kioton sopimuksessa olevat EU-valtiot.Hukari lähtee liikkeelle kirjoituksessaan vuodesta 1982, jolloin Reaganin hallintokäynnisti metaanihydraattien tutkimusohjelman tavoitteena vähentää maansa öljyriippuvuutta Lähi-idän arabimaista. Nyt tuo ohjelma on vihdoin saamassa tuloksia, kun arviolta 2023 Japani aloittaa koeporaukset Nankain allassyvänteessä. Sieltä uskotaan saatavan energiaa Japanin käyttöön seuraavaksi 50 vuodeksi.
/ Seuraava Reaganin hallinnon askel otettiin vuonna 1987, kun USA ja NL sopivat ydinaseiden vähentämisestä ja ydinmateriaalin muuntamisesta hyötykäyttöön kelpaavaksi ns. megatonneista megawateiksi -ohjelmalla. Sen avulla on tuotettu vuosina 1994-2013 noin 16% kaikesta ydinvoimaloiden käyttämästä polttoaineesta tuona ajanjaksona. Venäjällä on nyt varastoituna seitsemän vuoden maailmanlaajuista uraaninlouhintaa vastaava määrä ydinvoimaloiden polttoainetta. Yhdysvalloissa on rakenteilla jalostuslaitos, joka tuottaa kierrätyspolttoainetta ydinvoimaloille vuodesta 2016 alkaen.

UBS-pankin mukaan EU:n päästöoikeudet ovat tulleet maksamaan jo 287 miljardia dollaria, mutta niillä ei ole ollut mitään vaikutusta. Samalla rahalla olisi saatu päästöjä vähennettyä 40%, jos rahat olisi sijoitettu nykyisen energiantuotannon modernisointiin. Näitä ovat mm. liuskekaasun käyttö, vanhojen hiilivoimaloiden sulkeminen, uudempien päivittäminen hiilidioksidin talteenotolla ja uusien kaasuvoimaloiden rakentaminen. Liuskekaasun jälkeen seuraava suuri energiapoliittinen vallankumous voi hyvin olla merenpohjan metaanihydraattien käyttöönotto. Liuskekaasun ja yleensä kaasun poltto päästöjä alle puolet siitä, mitä öljyn ja hiilen suhteessa energiamäärään.

AP-ryhmän jäsenmaat (Kiina, Intia, USA, Japani, Australia, Etelä-Korea ja myöhemmin mukaan tullut Kanada) aloittivat 2005 Bushin johdolla yhteistyön päästöjö vähentävän teknologian kehittämiseksi. USA valitsi - toisin kuin EU - strategiakseen hyödyntää teknologian kehitystä päästöjen vähentämiseksi. Suurimmat vähennykset vuosina 2007-2012 on saavuttanut USA. Tätä nykyä kaikesta maailman hiilidioksidin talteenotosta 75% tehdään Yhdysvalloissa. Toinen merkittävä tapa on ollut ydinvoiman kehittäminen, ja Terra Powerin kehittää kaupalliseen käyttöön torium-käyttöistä voimalaa ja sulasuolareaktorista voimalatyyppiä.

Bushin hallinto ilmoitti noustessaan valtaan vuoden 2001 alussa, että se ei vaaranna kansalaisten taloutta tehottoman ilmastopolitiikan takia. EU-komissiossa tällaisia murheita ei ole kannettu. Bushin ilmastopolitiikkaa johtanut Harlan Watson vaati Kiinaa mukaan sopimukseen, jotta Yhdysvallatkin siihen voisi sitoutua. EU vastusti, ja Kiina livisti pois ja onkin nyt maailman suurin kasvihuonekaasujen tuottaja. Watson varoitti jo tuolloin EU-komissiota, että se ajaa Euroopan jälkiteolliseen talouskurjuuteen. Vartoitus meni kuuroille korville ja EU:n ilmastosankaruuden tavoittelu on johtanut globaalien päästöjen vähentämisen mahdollistavan sopimuksen viivästymiseen jo 10 vuodella. EU:ssa ilmastopolitiikka on antanut poliitikoille mahdollisuuden patsastella linssiluteina maailmanparantajina.

Yhdysvalloissa kongressi on kuunnellut tarkasti Patrick J. Michaelsia, joka on julkaissut kirjan Climate Coup vuonna 2011. Michaels kirjoittaa, miten IPCC:n toiminta on johtanut tieteellisesti ajatellen paluun keskiaikaan. Montrealin yliopiston professori Daniele Fanelli ja Stanfordissa tutkiva John Ionniadis ovat selvittäneet, että IPCC on klassinen esimerkki yhteisöstä, joka suosii haluttuihin johtopäätöksiin johtavia tutkimusmenetelmiä. Michaelsin mukaan IPCC on niin ylimielinen ja tottunut valtionpäämiesten pokkurointiin ympärillään, että sen johto on läpeensä korruptoitunut.

Edullisen energian vaikutus teollisuuden investointeihin on merkittävä. Vanha Saksan ja koko Euroopan teollisuuden tukipilari, kemianteollisuus, investoi Yhdysvaltoihin 10 miljardia dollaria vuonna 2015. Saksaan se ei ole tehnyt uusinvestointeja enää vuoden 2011 jälkeen. Alabamassa Outokumpu on saanut kannattavaksi kuumavalssattua terästä tuottavan tehtaansa, joka käyttää raaka-aineena paikallista romurautaa ja Torniosta tuotavaa kromia. Sähkön hinta on Alabamassa vain 60% Suomen hinnasta. Vuonna 2014 Iowassa avattiin ensimmäinen selluloosaetanolia tuottava laitos. Se tekee etanolia maissijätteistä eikä sen "ilmastoystävällisyys" ole selvä asia, mutta ainakaan se ei tarvitse tukiaisia toisin kuin eurooppalaiset vastineensa.

"EU:ssa keskitytään miettimään, kuinka paljon tukimiljardeja voitaisiin ohjata veronmaksajilta itseään vihreäksi kutsuvalle teollisuudenalalle. Yhdysvalloissa on oivallettu, että vain kilpailukykyiset kustannukset luovat ympäristöalalle kasvua ja kannattavia työpaikkoja", päättää Hukari kirjoituksensa.

 

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Photo: Joe Turner Lin

Evaporating water can generate electricity, a clean renewable energy source that could help power robots, sensors, and vehicles, researchers say.

Biology regularly uses evaporation as a source of energy. For instance, redwood trees rely on evaporation to pull water from the ground to their crowns. Now scientists at Columbia University and their colleagues have developed two new engines that generate power from evaporation.

The researchers previously found that when bacterial spores expand and shrink with changing humidity, they can push and pull other objects very forcefully, packing more energy gram for gram than many other materials.

http://spectrum.ieee.org/energywise...on-can-drive-engines-and-generate-electricity

The researchers suggest HYDRAs could not only help power a variety of machines, but larger versions of the evaporation-driven rotary engines sitting on or above large bodies of water could steadily produce even more power per unit area than wind farms.

 

[BlackFox]

Nyt olisi myynnissä käytettynä, 0h käytettyjä generaattoreja. 25kw
http://army-uk.info/equip.php?ID=697

 

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Photo: FCGEN Project

Although several options to store hydrogen as a fuel for cars have been investigated, a practical and affordable way to store and distribute hydrogen is still the biggest hurdle to the wide deployment of green, CO2-emission-free cars. Now researchers in Europe have built a demonstration system that might be a first step in circumventing the limitations on hydrogen distribution and storage; they simply extract hydrogen from diesel fuel on the go.

The research group, "Fuel Cell Based Power Generation (FCGEN)," which includes researchers from Volvo Technology (Sweden), Johnson-Matthey (United Kingdom), Modelon AB (Sweden), PowerCell AB (Sweden), Jožef Stefan Institute (Ljubljana, Slovenia), Forschungszentrum Jülich (Germany) and Fraunhofer ICT-IMM (Mainz, Germany) announced in a recent press release the creation of a prototype 3-kilowatt, diesel-fueled fuel cell system that has operated flawlessly for 10,000 hours.

http://spectrum.ieee.org/energywise...lpowered-fuel-cell-produces-green-electricity

 

[hessukessu]

Photo: FCGEN Project
http://spectrum.ieee.org/energywise...lpowered-fuel-cell-produces-green-electricity

Jättävät sopivasti kertomatta, paljonko tuosta irtoaa energiaa versus mitä saataisiin polttamalla se diesel sopivassa pienessä polttomoottorissa...

 

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Photo: FirstEnergy
A New Life: Electricians work to turn a generator into a synchronous condenser. This conversion, at a decades-old coal plant in Ohio, is likely one of many to come.

Environmental regulations and competition from gas-fired turbines and renewable energy sources are shutting down dozens of older coal-fired power plants across North America and Europe. But some of these aging plants’ induction generators will go on spinning for years after their furnaces and turbines are scrapped. That’s because operators need new ways to stabilize grids deprived of big power plants, and huge, free-spinning generators synced to a grid’s AC frequency—synchronous condensers—are becoming an increasingly popular option.

The most recent such conversion is under way at the 62-year-old Eastlake coal-fired power plant near Cleveland. Here, Akron, Ohio–based utility FirstEnergy has repurposed three large generators and has two more conversions in process, due to start operating by June 2016. Several other conversions have recently been completed in California and Germany, and newly built synchronous condensers are now appearing on power grids, too.

Synchronous condensers are dynamic controllers of reactive power—AC whose current wave leads or lags the voltage wave and whose presence determines local grid voltage. Adding current to the spinning condenser’s coils produces reactive power—measured in volt-amperes reactive, or VARs—and boosts grid voltage. Reduce the current and the machine absorbs VARs, depressing voltage.

http://spectrum.ieee.org/energy/the-smarter-grid/zombie-coal-plants-reanimated-to-stabilize-the-grid

 

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The 1-square-centimeter prototype shown in the video operated at above 10 percent efficiency for 40 hours straight, producing about 0.8 microliters of hydrogen per second. It's all one piece, there's no wiring, and the active electrocatalysts are all “earth abundant” (another way of saying affordable).

It's obviously nowhere near ready for production, although the Caltech team is already working on methods for cost-effectively manufacturing full systems. But watching it effortlessly produce fuel from water and sunlight is pretty awesome.

Having said that, it's important to note that right now, you can get significantly more energy from sunlight (about 20 percent efficiency) by using a conventional solar cell to convert it into electricity rather than hydrogen. It's also way cheaper to do this, since solar cells are an established industry. But, using that electricity to make hydrogen through electrolysis isn't particularly efficient: with a non-concentrator silicon photovoltaic cell and a commercial electrolyzer, you're looking at a complex system that can convert sunlight into hydrogen with an efficiency of about 12 percent. An artificial leaf that could approach the efficiency of existing sunlight-to-hydrogen converters in a much simpler (and eventually cheaper) way is appealing. But if it does so at something like half the energy efficiency of just using existing technology to make electricity directly, why bother with the hydrogen at all?

In a bunch of important ways, hydrogen is a much better medium for energy storage than batteries. As an inert chemical fuel, hydrogen can store energy for decades without degrading, and offers high energy density, especially in compressed or solid form (bound up in a metallic lattice or powder). For electric vehicles, for example, hydrogen could offer much more range than several tons of lithium ion batteries currently do. And refueling hydrogen is much more like putting gasoline in your car than sitting at a rest stop while your car sips from a charger.

http://spectrum.ieee.org/energywise...s-better-at-generating-hydrogen-from-sunlight

Jos vetymoottorit ja vety-pohjaiset energiavarastot rupeavat yleistymään, niin niillä voisi ruveta korvaamaan bensakoneita ja muita varavoimakeskuksia.

 

[koss]

Varusmiesaikana leireillä paukuteltiin voimakoneella virtaa viestiasemalle, meillä oli tapana käyttää voimakonetta pätkissä ja päästiin aika hyvin 50/50 käyttösuhteeseen koneella ja akuilla. Vähennettiin ilman mitään erityisiä toimenpiteitä huollon kuormaa 50% kun bensaa meni tasan puolet muihin verrattuna ja genujen huoltoväli tuplaantui. Ainakin tuohon aikaan voimakoneet huusivat muilla asemilla 24/7, meillä ei.

 

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Generating and storing renewable energy, such as solar or wind power, is a key barrier to a clean-energy economy. When the Joint Center for Artificial Photosynthesis (JCAP) was established at Caltech and its partnering institutions in 2010, the U.S. Department of Energy (DOE) Energy Innovation Hub had one main goal: a cost-effective method of producing fuels using only sunlight, water, and carbon dioxide, mimicking the natural process of photosynthesis in plants and storing energy in the form of chemical fuels for use on demand. Over the past five years, researchers at JCAP have made major advances toward this goal, and they now report the development of the first complete, efficient, safe, integrated solar-driven system for splitting water to create hydrogen fuels.

http://www.caltech.edu/news/artificial-leaf-harnesses-sunlight-efficient-fuel-production-47635

 

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Kyocera Corp. has come up with a smart way to build and deploy solar power plants without gobbling up precious agricultural land in space-challenged Japan: build the plants on freshwater dams and lakes.

The concept isn’t exactly new. Ciel et Terre, based in Lille, France, began pioneering the idea there in 2006. And in 2007, Far Niente, a Napa Valley wine producer, began operating a small floating solar-power generation system installed on a pond to cut energy costs and to avoid destroying valuable vine acreage.

Kyocera TCL Solar and joint-venture partner Century Tokyo Leasing Corp. (working together with Ciel et Terre) already have three sizable water-based installations in operation near the city of Kobe, in the island of Honshu’s Hyogo Prefecture. Now they’ve begun constructing what they claim is the world’s largest floating solar plant, in Chiba, near Tokyo.

The 13.7-megawatt power station, being built for Chiba Prefecture’s Public Enterprise Agency, is located on the Yamakura Dam reservoir, 75 kilometers east of the capital. It will consist of some 51,000 Kyocera solar modules covering an area of 180,000 square meters, and will generate an estimated 16,170 megawatt-hours annually. That is “enough electricity to power approximately 4,970 typical households,” says Kyocera. That capacity is sufficient to offset 8,170 tons of carbon dioxide emissions a year, the amount put into the atmosphere by consuming 19,000 barrels of oil.

http://spectrum.ieee.org/energywise...ing-worlds-largest-floating-solar-power-plant

 

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Boeing has announced that, after 16 months of development, it has delivered a "reversible" fuel cell for the U.S. Navy that stores energy from renewable sources and generates zero-emissions electricity.

The Solid Oxide Fuel Cell (SOFC) system, which can generate 50 kilowatts (KW) of power, is the largest of its kind and can use electricity from wind or solar power to generate hydrogen gas, which it then compresses and stores.

http://www.computerworld.com/articl...le-clean-energy-fuel-cell-storage-system.html

 

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Olen yrittänyt pähkäillä miten tälläinen voitaisiin ottaa käyttöön Suomessa, mutta tulin tulokseen että ei voi, koska meillä ei ole tarpeeksi mäkiä, taikka isoja kukkuloita. Mutta kriisitilanteessa tälläinen energiavarastointi voi olla hyvinkin hyödyllinen.

he newest entrant into the energy storage market bears a passing resemblance to cutting edge 19th century technology.

It is a rail car with no passengers or freight that goes nowhere. But if the California company working on this technology is right, its rail cars could make big inroads in the energy storage market.

At heart, though, the concept is simple. Electricity powers an electric motor in a locomotive that hauls a heavy load up hill. Sitting at the top of the hill, the rail cars store energy. When the energy is needed, the cars are released to roll down hill and the electric motor runs in reverse to generate electricity.

The company, ARES, is a start-up based in Santa Barbara that is named after its technology, Advanced Rail Energy Storage.

Any resemblance to 19th century rail technology belies the high tech workings of the system and the fact that ARES holds three patents for its technology.

The same electro-mechanical principle that powers the ARES system supplies the regenerative braking power in electric vehicles like a Toyota Prius or in wayside regenerative braking systems such as the one being installed on the metropolitan Philadelphia commuter rail line: When an induction motor that powers a train or car is reversed, it produces electricity.

ARES now hopes to put those principles to work in Nevada where it just won approval from the Bureau of Land Management for its first commercial project.

ARES wants to lay a nearly 5.5 mile track up an 8 degree slope, gaining about 2,000 feet top to bottom. ARES would then put up to seven 8,600-ton trains on the track with each train comprising two locomotives and four rail cars. The entire system, including substation and control systems, would occupy about 43 acres of public land near Pahrump in Clark and Nye Counties.

http://www.utilitydive.com/news/fir...project-targets-role-in-caiso-ancilla/417817/

 

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A new approach to the design of a liquid battery, using a passive, gravity-fed arrangement similar to an old-fashioned hourglass, could offer great advantages due to the system’s low cost and the simplicity of its design and operation, says a team of MIT researchers who have made a demonstration version of the new battery.


Liquid flow batteries — in which the positive and negative electrodes are each in liquid form and separated by a membrane — are not a new concept, and some members of this research team unveiled an earlier concept three years ago. The basic technology can use a variety of chemical formulations, including the same chemical compounds found in today’s lithium-ion batteries. In this case, key components are not solid slabs that remain in place for the life of the battery, but rather tiny particles that can be carried along in a liquid slurry. Increasing storage capacity simply requires bigger tanks to hold the slurry.

But all previous versions of liquid batteries have relied on complex systems of tanks, valves, and pumps, adding to the cost and providing multiple opportunities for possible leaks and failures.

The new version, which substitutes a simple gravity feed for the pump system, eliminates that complexity. The rate of energy production can be adjusted simply by changing the angle of the device, thus speeding up or slowing down the rate of flow.

http://news.mit.edu/2016/new-concept-turns-battery-technology-upside-down-0525

 

[ctg]

From the outside, Elidir Mountain looks like an old industrial site that has returned to nature. The slopes facing the Llyn Peris reservoir have been hacked into terraces by slate quarrying – this was once the second-biggest quarry in the world, with 3,000 workers – but they are now peaceful.

Only a few buildings at ground level and a road leading into the mountain provide a clue that there is still something going on.

A longer look would reveal that Llyn Peris has a habit of rising all day, then falling back overnight. The smaller and higher Marchlyn Mawr reservoir up in the hills does the reverse, dropping as much as 121ft (37 metres) during the day.

This is because the two reservoirs are linked by one of Britain’s biggest post-war industrial projects: the Dinorwig pumped storage power station, hidden within this mountain. It is effectively a monster battery: energy is stored by pumping water from Llyn Peris to Marchlyn Mawr at night, then generated by letting it flow back down at times of peak demand.

Dinorwig is designed to supplement Britain’s national grid, but on its own, it could power Wales for five-and-a-half hours. The station, run by First Hydro Company (jointly owned by Engie and Mitsui), can go from stand-by to 1.32 gigawatts in 12 seconds, making it one of the fastest installations of its kind, with a peak output of 1.728GW.

This is a part of Wales that keeps a power station in the hillsides, a massive industrial equivalent to an uninterruptible power supply. And it is open to the public – although, unsurprisingly, tours are tightly organised.

Visitors get access to Dinorwig through a dedicated visitor centre, Electric Mountain, located in Llanberis on the other side of the valley. 70-minute tours take place at set times each day from Easter until the end of October, and are popular with school groups.

This is where I am and, on arriving, I’m told I will be accompanying a group of French students, one of the least impressible entities known to humanity

http://www.theregister.co.uk/2016/05/16/geeks_guide_electric_mountain/

Tea, or to be more precise the domestic production of Britain’s signature hot beverage, is one of reasons for Dinorwig’s existence. Staff at National Grid, the company that now runs Britain’s power supply, analyse television schedules for breaks in popular television programmes, the Pavlovian signal for millions of Brits to flick on their kettles causing a “TV pick-up” in power demand.

Most power stations take many minutes or hours to increase output – and with solar, tidal and wind power, you get whatever Mother Nature is giving. Pumped storage stations like Dinorwig are designed specifically to cope with spikes in demand. It tells you how much Britain loves tea: we built a power station that power-flushes a lake through a Welsh mountain, just so we can all make a brew at the same time.

The idea of making millions of cuppas simultaneously doesn’t seem to have fired the imagination of the French teenagers in my tour group, but things are about to get less theoretical. We troop down a ramp, putting on the cloth hairnets that are issued by reception and stowing bags and cameras into lockers, to meet our guide, Dave from Bradford. He has worked here for 13 years, after nearly three decades as a British Gas technician.

There is loud humming noise from the water slides, in reality the main inlet valves for Dinorwig’s six turbine units – essentially, giant taps. Water from the upper reservoir flows along a gently sloping tunnel, then falls 450 metres (1,476ft) vertically, then goes into another sloping tunnel which narrows from 10 metres (32ft) to just 2.5m (8.2ft), speeding it up. It then splits into a manifold of six pipes, one for each turbine, regulated by the kit in front of us. They are opened and closed using two 16 tonne yellow counterweights: two are open when we visit.

The nearest, unit one, is closed but leaking a bit. Anything to worry about, someone asks? If it really failed, we’d be fast learning to swim uphill, says Dave, says sort of reassuringly. He adds that staff activate them without warning. Once, a group of more mature ladies were standing by unit one when this happened. Amazing how fast they went round the rest of the tour, he adds.

We then climb a metal staircase to the turbine hall, the heart of the power station. In front of us is a line of Francis reversible fixed-speed turbines, a bit bigger than those Dave showed in the bus: each is four metres wide and 24 tonnes (24,000kg) in weight. They are embedded within casings, but a naked turbine is on display for us to see, made by Markhams of Chesterfield. “It’s a housing estate now,” says Dave of that particular piece of British industry.

After gawping for a bit we get back on the bus and travel to a viewing platform near the top of the turbine hall, which provides a full sense of its vast scale. We can only see the top 30 per cent of its 51m (167ft) height as there are internal floors, but the 180m length (590ft) and 23m (75ft) width are impressive enough. Dave points out the fossilised dragons’ tails in the walls – actually metal bolts which help secure them. Then there’s another video focusing on the history of Dinorwig, with entertainment value provided by footage of a youthful Prince Charles opening the station in May 1984.

Questions are welcomed throughout the tour – for those who have wondered, Dinorwig recovers 76 per cent of the energy it uses to pump the water up the pipes at night – and are likely to be answered in depth by expert guides such as Dave.

 

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31 prosentin teho aurinko kennoissa! Uskomaton tehon nousu!

The rise of the crystal perovskite as a potential replacement for silicon in photovoltaics has been impressive over the last decade, with its conversion efficiency improving from 3.8 to 22.1 percent over that time period. Nonetheless, there has been a vague sense that this rise is beginning to peter out of late, largely because when a solar cell made from perovskite gets larger than 1 square centimeter the best conversion efficiency had been around 15.6 percent. This figure has been improved recently in the work of Michael Grätzel to an average of 19.6 percent. However, the bright prospects for perovskite have dimmed in eyes of some.

Now researchers at the Department of Energy’s Lawrence Berkeley National Laboratory (Berkeley Lab) may have discovered something hidden in perovskite crystals that could boost the conversion efficiency of this material to as high as 31 percent.

In research described in the journal Nature Energy, the researchers peered into the nanoscale structure of these crystals with atomic force microcscopy. At that scale they found that each facet of each grain of the crystal performed differently in terms of conversion efficiency. Some facets of the crystal would have the theoretical conversion limit of 31 percent and these would be adjacent to facets with poor conversion efficiency.

Each facet of the perovskite acts as an individual solar cells and all of them are connected in parallel. In this arrangement, the current flows towards those cells that have the worst performance, leading to a lowering of the overall performance of the solar cell.

The researchers hit upon the idea of making all the facets of the crystal reach the goal of 31-percent conversion efficiency.

“If the material can be synthesized so that only very efficient facets develop, then we could see a big jump in the efficiency of perovskite solar cells, possibly approaching 31 percent,” said Sibel Leblebici, a postdoctoral researcher at the Molecular Foundry at Berkeley Lab,

http://spectrum.ieee.org/nanoclast/...ains-of-perovskite-could-boost-its-efficiency

 

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Harvard University researchers reckon they can make flow batteries cheaper using an electrolyte based on vitamin B2.

Flow batteries function much like lead-acid batteries, with a fluid that reacts with electrodes to store charge. However, the liquid is cycled through an external tank in the charge/discharge cycle.

The external “refresh” of a flow battery's fluid means it can handle very deep discharges, while lead acid batteries have to be kept above 50 per cent charge. For a static application like storage from solar power, that makes flow batteries an attractive third alternative to both lead acid and lithium batteries.

Harvard's research is on improving the electrolyte, so the external tanks can store more energy per unit of volume, and that's where the vitamin B2 molecule comes in.

The university had previously worked on naturally-occurring quinones in the electrolyte; B2 is similar, they say, but uses nitrogen as the electron carrier. The important molecule in B2 is alloxazine, which forms the backbone of how the vitamin stores energy in human bodies.

The solution the researchers produced achieved “open-circuit voltage approaching 1.2 V and current efficiency and capacity retention exceeding 99.7% and 99.98% per cycle”, they write in their paper at Nature Energy.

Since the vitamin is already produced at an industrial scale, the researchers reckon the electrolyte can similarly be manufactured at large scale, and at very low cost.

http://www.theregister.co.uk/2016/07/19/harvard_gives_solar_batteries_performanceenhancing_vitamins/