Lo schema della batteria sodio-zolfo secondo Wikipedia. Si tratta di un concetto semplice: la reazione del sodio metallico con lo zolfo a formare solfuro di sodio. L’elemento critico è la membrana che separa il sodio metallico fuso dallo zolfo, che costringe ad utilizzare temperature elevate per ottenere una velocità di reazione sufficiente.

Arriva in questo placido Agosto una notizia che potrebbe essere  una delle tante bufale del periodo. Perlomeno, lo sembrerebbe dal tono trionfalistico della notizia dove si proclama di aver salvato il mondo con queste nuove batterie. Considerate anche  che la notizia arriva da quello stesso Daniel Nocera che aveva già salvato il mondo l’anno scorso con i suoi meravigliosi catalizzatori per pile a combustibile – come si può ben vedere sia avvenuto.

Purtroppo, i comunicati stampa degli scienziati che lavorano sull’energia sembrano sempre di più quelli che arrivavano in Italia dalla Russia nel 1942 – quelli, per intenderci – “le nostre truppe si ritirano vittoriosamente secondo i piani prestabiliti”. Veramente a leggere questa roba viene voglia di tirargli dietro qualcosa.

Tuttavia, stavolta sembrerebbe che qualcosina di buono, sotto tutta la fanfara trionfale, ci potrebbe anche essere. Si dice che una ditta chiamata”Ceramatex” è in grado di produrre batterie sodio-zolfo che funzionano a 90 C, invece che ai 350 che sono lo standard.

Queste batterie sono molto interessanti, durano a lungo, costano relativamente poco, e non usano elementi rari. Il loro problema sta nella temperatura elevata che porta a delle notevoli perdite per mantenerle calde tutto il tempo. Se veramente questi di Ceramatec hanno potuto abbassare la temperatura come dicono, si aprono nuove possibilità sia per i veicoli come per l’energia rinnovabile.

Strano che qui si concentrino tutti sul discorso dello stoccaggio domestico, quando queste batterie sembrerebbero utilissime per i veicoli. Ma, alla fine dei conti, a parte i trionfi di carta e di parole, tutto il discorso rimane concentrato sulla semplice domanda: funziona oppure no? Tutto da dimostrare, ma il concetto è da seguire. Potrebbe non essere la solita bufala estiva.

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http://www.heraldextra.com/news/article_b0372fd8-3f3c-11de-ac77-001cc4c002e0.html

New battery could change world, one house at a time

Randy Wright – Daily Herald | Posted: Saturday, April 4, 2009 2:30 pm 

ASHLEY FRANSCELL/Daily Herald Ceramatec President Ashok V. Joshi and his team John Gordon (from left to right), John Watkins, Grover Coors and Anthony Nickens at Ceramatec in Salt Lake City. The team has been working on developing a storage battery for homes and businesses.

In a modest building on the west side of Salt Lake City, a team of specialists in advanced materials and electrochemistry has produced what could be the single most important breakthrough for clean, alternative energy since Socrates first noted solar heating 2,400 years ago.

The prize is the culmination of 10 years of research and testing — a new generation of deep-storage battery that’s small enough, and safe enough, to sit in your basement and power your home.

It promises to nudge the world to a paradigm shift as big as the switch from centralized mainframe computers in the 1980s to personal laptops. But this time the mainframe is America’s antiquated electrical grid; and the switch is to personal power stations in millions of individual homes.

Former energy secretary Bill Richardson once disparaged the U.S. electrical grid as “third world,” and he was painfully close to the mark. It’s an inefficient, aging relic of a century-old approach to energy and a weak link in national security in an age of terrorism.

Taking a load off the grid through electricity production and storage at home would extend the life of the system and avoid the expenditure of tens, or even hundreds, of billions to make it “smart.”

The battery breakthrough comes from a Salt Lake company called Ceramatec, the R&D arm of CoorsTek, a world leader in advanced materials and electrochemical devices. It promises to reduce dependence on the dinosaur by hooking up with the latest generation of personalized power plants that draw from the sun.

Solar energy has been around, of course, but it’s been prohibitively expensive. Now the cost is tumbling, driven by new thin-film chemistry and manufacturing techniques. Leaders in the field include companies like Arizona-based First Solar, which can paint solar cells onto glass; and Konarka, an upstart that purchased a defunct Polaroid film factory in New Bedford, Mass., and now plans to print cells onto rolls of flexible plastic.

The convergence of these two key technologies — solar power and deep-storage batteries — has profound implications for oil-strapped America.

“These batteries switch the whole dialogue to renewables,” said Daniel Nocera, a noted chemist and professor of energy at the Massachusetts Institute of Technology who sits on Ceramatec’s science advisory board. “They will turn us away from dumb technology, circa 1900 — a 110-year-old approach — and turn us forward.”

Why not just upgrade to a so-called “smart grid” as President Obama has proposed in his economic stimulus package? There are complications, Nocera said.

“First you have to rebuild the grid because the one we have now is a creaky machine from the 1920s, and we keep trying to retrofit it,” he said. “Then you’re going to have computers trying to manage the energy, which brings up issues like security. You have to make it really secure so you don’t have people hacking into things. And then politics. Just wait until you try to run power lines through someone’s backyard.

“I can’t imagine anything more secure than generating my own energy with the sun at my house, and now I’ll have a way to store it. It’s the ultimate in security, and the ultimate in control.”

With small-scale electrical generation taking place at millions of individual homes — as opposed to today’s large-scale power generation from a handful of giant power plants — there would be less worry about what’s called “point failure” on the grid. That’s when a single component gets knocked out and shuts off power to a whole region. California-style rolling blackouts would be history.

The threat of terrorism has heightened the worry. But wide distribution of batteries in homes would virtually eliminate it.

***

Inside Ceramatec’s wonder battery is a chunk of solid sodium metal mated to a sulphur compound by an extraordinary, paper-thin ceramic membrane. The membrane conducts ions — electrically charged particles — back and forth to generate a current. The company calculates that the battery will cram 20 to 40 kilowatt hours of energy into a package about the size of a refrigerator, and operate below 90 degrees C.

This may not startle you, but it should. It’s amazing. The most energy-dense batteries available today are huge bottles of super-hot molten sodium, swirling around at 600 degrees or so. At that temperature the material is highly conductive of electricity but it’s both toxic and corrosive. You wouldn’t want your kids around one of these.

The essence of Ceramatec’s breakthrough is that high energy density (a lot of juice) can be achieved safely at normal temperatures and with solid components, not hot liquid.

Ceramatec says its new generation of battery would deliver a continuous flow of 5 kilowatts of electricity over four hours, with 3,650 daily discharge/recharge cycles over 10 years. With the batteries expected to sell in the neighborhood of $2,000, that translates to less than 3 cents per kilowatt hour over the battery’s life. Conventional power from the grid typically costs in the neighborhood of 8 cents per kilowatt hour.

Re-read that last paragraph and let the information really sink in. Five kilowatts over four hours — how much is that? Imagine your trash compactor, food processor, vacuum cleaner, stereo, sewing machine, one surface unit of an electric range and thirty-three 60-watt light bulbs all running nonstop for four hours each day before the house battery runs out. That’s a pretty exciting place to live.

And then you recharge. With a projected 3,650 discharge/recharge cycles — one per day for a decade — you leave the next-best battery in the dust. Deep-cycling lead/acid batteries like the ones used in RVs are only good for a few hundred cycles, so they’re kaput in a year or so.

How do you recharge? By tapping your solar panels or windmills. It’s just like plugging in your cell phone or iPod, only you plug in your house.

A small three-bedroom home in Provo might average, say, 18 kWh of electric consumption per day in the summer — that’s 1,000 watts for 18 hours. A much larger home, say five bedrooms in the Grandview area, might average 80 kWh, according to Provo Power.;Either way, a supplement of 20 to 40 kWh per day is substantial. If you could produce that much power in a day — for example through solar cells on the roof — your power bills would plummet.

Ceramatec’s battery breakthrough now makes that possible.

Clyde Shepherd of Alpine is floored by the prospect. He recently installed the second of two windmills on his property that are each rated at 2.4 kilowatts continuous output. He’s searching for a battery system that can capture and store some of that for later use when it’s calm outside, but he hasn’t found a good solution.

“This changes the whole scope of things and would have a major impact on what we’re trying to do,” Shepherd said. “Something that would provide 20 kilowatts would put us near 100 percent of what we would need to be completely independent. It would save literally thousands of dollars a year.”

Shepherd is connected to the grid through Rocky Mountain Power, which charges a variable rate for power depending on demand during a given 24-hour period. With his windmill setup, Shepherd has what’s called “net metering” — an electric meter that spins both ways. He pays for electricity coming in, but gets a credit from Rocky Mountain for any excess power generated by his windmills that flows back onto the grid. Already, he’s cut his power bills in half, and with good storage batteries he thinks he could reduce the bill to zero.

While Shepherd opted for windmills over solar at the time he was planning his alternative energy installation, he said he would reconsider that decision today as the bottom continues to fall out of the cost of solar cells.

“Batteries and PV are about to merge,” said MIT’s Nocera, using the shorthand for “photovoltaics” or solar power. “First Solar is now saying that it takes $1 a peak watt to manufacture, and another 80 cents for installation. So they’re saying that you can get PV for under $2 a watt. That’s a reduction of cost by a factor of four. Only a few years ago, it was $8. If CoorsTek and Ceramatec come up with a good battery, the market will develop quickly.”

The long-term impact of home electric generation for a power company’s business model could be huge. After all, you can’t stay in business if nobody’s paying for power. Exactly how that will play out remains to be seen.

***

Fifty miles south of Ceramatec’s laboratories, Chris Cannon, the former congressman from Utah County, is on a crusade to transform the world through technology. He currently sits on Ceramatec’s advisory board with Nocera. No longer burdened by the pressures of Washington, he’s using his experience in energy, manufacturing and government to carry the message of innovation and help move research to reality.

“What I choose to concentrate on now are things that will make the world a better place,” Cannon said, “and Utah is an incredibly good place to do that.”

Approached by Ceramatec after he left Congress, Cannon fills a complementary role in a group of smart engineers and academic types. With extensive Washington contacts and an understanding of the inner workings of power generation, he hopes to be able to make connections that will push the new battery technology forward for the benefit of the country.

“I have an energy and manufacturing background, so I understand the process,” he said. “Ceramatec had a gap in their experience which I think I filled pretty well.” On top of that, there was “good chemistry” from the start.

While Cannon’s six terms in Congress representing what is arguably the most conservative district in America means keeping a somewhat jaundiced eye on the Obama administration, he’s far from negative. He thinks of himself as a “post-partisan Republican” willing to run with good ideas regardless of their source. And when it comes to energy policy, he’s anything but discouraged.

“If you look at the president, he inherited some really difficult things,” Cannon said. “But he hired a guy to be the secretary of energy who is a scientist. And we are on the verge of so many scientific breakthroughs that no matter what the president’s ideology is, if we do the right thing scientifically, America is going to do well. Many of the innovations that are coming out of Utah that I’m involved with are likely to be really important, regardless of the leadership.”

Last month, Obama introduced a raft of broad energy proposals that were sharply criticized by conservatives as economic back-breakers. Proponents hailed the plans as progressive. Either way the administration appears to be on a path that could soon drive the cost of conventional energy higher — some say as much as double. Electrical generation at home using solar panels, coupled with storage in effective batteries, could soften the financial impact on many homeowners’ utility costs.

The new Ceramatec battery could also change the way private enterprises invest in energy, Cannon said. Instead of building another power plant, for example, maybe they buy 100,000 or a million batteries and distribute those around the service area of a utility to reduce loads and eliminate expensive “spinning reserve,” the supplementary power generation that’s fired up in response to daily spikes in electric demand.

“The technology could mean a lot of things,” Cannon said, “but it certainly means that we change the way we invest. It also means that we shift our expenditures on terrorism, because our infrastructure for power transmission is probably the weakest link in America today. If you have local batteries with local control, that gives terrorists a more difficult target. And local control systems are much simpler than a vast national transmission grid.”

***

CoorsTek’s manufacturing roots go back to the early 20th century, when Adolph Coors diversified his beer brewing empire based in Golden, Colo. He set up a ceramic manufacturing business called the Herold China and Pottery Company, whose early product line included dinnerware and utensils but later moved to high-tech industrial products made of ceramics. With World Wars I and II, the company stepped up to provide needed ceramics for industry and the military, including materials used in the production of the atom bomb.

“To most Americans, the word ‘Coors’ means beer,” wrote Business Wire on the ceramic maker’s 75th birthday. “But to scientists and industrialists throughout the world, the word ‘Coors’ means technical ceramics of extraordinary quality.”

That hasn’t changed. Cellular telephones, car engines, computer chips, soda dispensers, semiconductor casings, blood processing pumps, bulletproof vests and armor for military vehicles, to name just a few items in a dizzying high-tech product array, all use ceramic components produced by Coors enterprises. And so it was natural in 2008 for CoorsTek to purchase the hottest ceramics R&D firm going — Ceramatec, with its 165 employees in Salt Lake City.

Ceramatec was founded in 1976 by a group of University of Utah professors who made important contributions to the sodium-sulphur battery technology being pursued by Ford Motor Company for vehicles at the time. Those early liquid-core batteries didn’t pan out well for transportation, though, because of their size and weight, and because of the extremely harsh internal chemical conditions required for them to work.

In the years since, electric cars have remained on the sexy-tech list, with substantial industry efforts aimed at developing various flavors of zippy batteries to power them. Ceramatec had other ideas, recognizing a vast potential market for a different sort of power — for homes.

“With a house, you don’t need to get energy in and out instantaneously. You need huge amounts of storage capacity,” says MIT’s Nocera. “That suggests a different commercial market and different technical restraints and opportunities.”

***

In 2000 Ashok Joshi, a native of India, took the helm at Ceramatec. His international reputation in ion technology and fuel cells kept the company among the first rank of innovators.

Joshi (he prefers A.J.) looked to the potent combination of sodium and sulphur for the basic components of a new battery. That was known chemistry. But while he wanted to achieve a high energy density offered by those elements, he also wanted to get rid of the extreme heat, corrosion and toxicity of liquid sodium batteries.

The key would be found in a paper-thin, yet strong and highly conductive, electrolyte material — an advanced ceramic — to serve as the barrier between the battery’s sodium and sulphur. The thinner the barrier, the cooler the battery can operate. If you can get below the melting point of 98 C, sodium stays in its solid state, and you’ve got enough energy to run a house with safety.

Charged particles of sodium and sulphur — ions — now scoot so effortlessly through the new ceramic wafer that the sodium doesn’t even approach 98 C, let alone 350.

The ceramic that made this possible was dubbed NaSICON by chemists. That stands for “sodium super ion conductor” — “Na” being the code name for sodium in chemistry’s periodic table.

Ceramatec’s formulation is a trade secret. With trademark modesty, A.J. observes, “We feel confident it’s a good material.”

“It’s a miracle material,” corrects Grover Coors. He’s the great-grandson of Adolph Coors, the brewmaster-industrialist who started all this. Grover has a Ph.D and specializes in solid-state ionics and advanced materials. He’s working with Ceramatec as a sort of research fellow to evaluate technologies and advise senior management. A.J. stayed on as president after the sale to CoorsTek.

“There are two classes of ceramic materials that are good conductors,” Coors explained. “One is what developed here in the early days — beta-alumina solid electrolyte, or BASE. It’s temperamental, brittle. A.J. thought of a better material. It’s a better conductor, easier to manipulate and process, and lower cost.”

This is where the earth moves for renewable energy. The new electrolyte enables the development of an energy-dense, inexpensive and safe storage battery for use at home. Combined with the rapidly emerging thin-film solar cells, it presents an unparalleled business opportunity.

***

Grover’s brother, John K. Coors, is CEO of CoorsTek, the manufacturing company that applies what the scientists at Ceramatec dream up. Their nephew, Doug Coors, oversees R&D.

With some 21 plants producing advanced ceramic products worldwide, the expectation is that full-scale production of ceramic sheets for the new batteries could be tooled up in short order. In fact, only a handful of CoorsTek facilities would likely be employed.

The order of magnitude pencils out along these lines: a target of 20 gigawatt hours of storage in 20 kilowatt-hour battery increments equals 1 million batteries. Or using a different metric, 1 million square meters of thin ceramic electrolyte would yield 20 gigawatt hours of batteries, equal to California’s entire spinning reserve.

Nobody at CoorsTek even blinks at such figures. The company already produces 3 million pounds of ceramic material per month. “Once we have a working prototype battery with all the standards and cost requirements met, it will come up quickly,” said Grover Coors. “It would scare people to know how quickly we can bring this up.”

They’re about about six months away from initial scale-up toward a commercial product, he said.

Lots of sodium will be needed to make the new batteries, and Ceramatec proposes a symbiotic relationship with the federal government to get it. Enormous quantities of sodium metals, the byproducts of nuclear weapons manufacturing, just happen be available for cleanup at Hanford nuclear reservation near Richland, Wash. It’s a ready-made source of material that CoorsTek can recycle.

***

In a laboratory at Ceramatec, a small battery — a NaSICON sandwich in silver foil — has been cycling up and down since October to prove out the electrochemistry. Engineers are confident the tests will support a projected useful life of 3,650 cycles, which meet the standard of one discharge/recharge cycle per day for 10 years. It’s a tall challenge, according to Coors, but doable. “It’s very efficient in terms of watt-hours per kilogram,” he said. “We’re now in excess of 200, which puts us in the sweet spot for all the applications we’ve been talking about.”

There are a handful of small hurdles yet to cross in the science, but nobody seems terribly concerned. One is the fact that when two solids are joined along flat surfaces, there will always be at least a 1-micron gap between them. That needs to be closed somehow. Nocera is making some suggestions for suitable fillers, but neither he nor Ceramatec developmental scientist John Watkins feel that the problem will be a difficult one.

“I want to say, this is no big deal,” Nocera said. “But sometimes little things can bite you in the butt. So we’ll just work it out.”

***

Meanwhile, heavyweight liquid sodium-sulphur batteries from Japan are making an inroad into the United States at Luverne, Minn. They’re part of a demonstration project by Xcel Energy, an eight-state power utility. In February, Xcel began testing a 1-megawatt battery installation intended to capture power from a giant 11-megawatt wind farm owned by Minwind Energy, LLC. It’s said to be the first attempt to store wind-generated power at a large-scale.

Contrasting with Ceramatec’s vision of many small home-based power centers with refrigerator-size batteries, this project is another mainframe — albeit fueled by wind. Hot liquid sodium-sulphur batteries from NGK are intended to move a lot of energy to the grid. The 50-kilowatt battery modules — 20 cylindrical cells — are roughly the size of two semi-trailers and weigh 80 tons. They’ll store about 7.2 megawatt hours of electricity, enough to power 500 homes for seven hours, according to company data. The test is intended to validate greater penetration of wind energy on the Xcel Energy system.

It’s one of many efforts by industry to cut down carbon dioxide emissions and move to a more sustainable energy model, but it’s not without hurdles.

“One of the big problems with the NGK system is that it’s megawatt-scale storage,” said Ceramatec’s Coors. “It has to be on top of the 10 kilowatt side of the utility transformer, meaning that there’s a lot of step-down transformers and whatnot involved in hooking those things up — a lot more system complication.

“If you go with a smaller system like the 5 kilowatts for four hours system that we’re contemplating, that’s all done on the 110-volt side of the transformer, and so all the switching can be done with solid-state relays very inexpensively.”

Such comparisons are batted around frequently by Ceramatec insiders as they seek to optimize the science and develop business models. A recent Sunday dinner with several board members was a popcorn machine of problem-solving and technical musings.

Over dessert, Cannon suggested a new angle: Was it possible to use the thin ceramic membrane developed at Ceramatec to reduce the production costs and improve efficiency of NGK’s existing hot liquid batteries — replacing the old beta-alumina electrolyte currently used in those devices? After all, the new ceramic membrane is cheaper and a better conductor. That got Nocera’s attention, and the idea then bounced to A.J., whose mental wheels were rolling.

The exchange was typical of the collegial atmosphere and dynamic thinking processes that characterize Ceramatec.

***

Joe Hunter envisions applications for a new generation of batteries in his specialty of hydroelectric power — not massive banks of batteries at dam sites, but maybe something along the lines of the 1 megawatt battery array at Minwind’s Minnesota wind farm. Alternatively, many small batteries could be distributed throughout a community.

Hunter is a former deputy assistant secretary in the Department of the Interior and was Cannon’s chief of staff.

In Hunter’s world, large dams typically don’t employ batteries on-site because the torrent of juice a hydroelectric plant generates is overwhelming. Glen Canyon Dam, for example, produces close to 1,000 megawatts, which is comparable to a big coal-fired power plant. In eastern Utah, Flaming Gorge churns out 150 megawatts.

The advantage of a dam over a wind farm, however, is predictability. Water must be released continuously to support fisheries and other environmental systems downstream. That’s essentially wasted power. If small energy generation and battery storage could piggyback on such flows, the community could benefit at low cost. Inexpensive batteries could be used economically in areas serviced by many dams, Hunter suggested.

Take Deer Creek at the head of Provo Canyon, for instance. Generators at the dam can produce up to 5 megawatts, but they run mainly in the irrigation season. But water to sustain the Provo River has to be released all the time, and local residences, with batteries trickle-charging continuously, could benefit.

It’s another value proposition added to others, like the net metering enjoyed by the Shepherds in Alpine. The idea in all this is to ease pressure on the grid while moving people toward greater energy independence.

“What we’re talking about is the ability to take the edges off,” Hunter said. “We’re at a tipping point for alternative energy.”

In Salt Lake City, Grover Coors agrees: “This will be the largest industry of all time,” he said. “But it’s all about cost and reliability.”