China’s Most Advanced Power-Grid Tech Is in Xinjiang, But Good Luck Trying to See It

Chinese authorities want to avoid outside scrutiny of the country’s security crackdown on Uyghur Muslims

Last year I boarded a flight to China on a mission to report on an emerging supergrid whose scale and scope remain unimaginable for grid operators everywhere else. Seeing China’s ultrahigh-voltage transmission power technology up close had been a longstanding dream for this incurable power geek. Energy writers, myself included, had covered China’s UHV program from the outside. This time, I’d been invited by the State Grid Corp. of China—the world’s largest utility by revenue and workforce and China’s UHV leader—to step inside its installations and research labs.

I naturally wanted to see State Grid’s latest and greatest equipment, and that meant going to the Xinjiang Uyghur Autonomous Region—the northwestern territory named for its Turkic Muslim ethnic group. 

Xinjiang was the place to go because its rich coal, wind, and solar resources far exceed its energy needs, and State Grid was building its largest UHV transmission project to date to export those riches. I wanted to see the project’s converter station outside Xinjiang’s capital, Ürümqi, which was designed to take in alternating current from local power plants and spit out direct current at a blistering 1,100 kilovolts—a third higher voltage than China’s previous record-setting 800-kV converters. That DC voltage would enable electricity from Xinjiang to travel as far as Shanghai—nearly 1,000 kilometers farther than any other power line in the world.

You can read all about the technology behind Xinjiang’s 1,100-kV UHV DC project in my recent exclusive report on its subsequent startup. And you can learn about the origins of State Grid’s UHV technology and its struggle to operate the resulting UHV AC-DC power grid in China’s Ambitious Plan to Build the World’s Biggest Supergrid,” my feature in IEEE Spectrum’s March issue. 

Alas, I never did see the groundbreaking infrastructure in Xinjiang myself.

My previous reporting in China had prepared me for the usual language and cultural barriers. But on this trip, I encountered a whole new set of controls on speech and movement that threatened to constrain my work. As I got ready to travel to China last March, government clampdowns against suspected separatists and extremists within the Uyghur community were drawing international criticism. Human rights groups and some Western governments called out a new security regime in Xinjiang that included “widespread use of arbitrary detention, technological surveillance, heavily armed street patrols, security checkpoints and an array of intrusive policies violating human rights,” according to Amnesty International [PDF].

Criticism intensified when Radio Free Asia, a U.S. government–funded media outlet, reported that 120,000 Uyghurs were being held in political re-education camps in one Xinjiang district, and more were being detained elsewhere. The scale reinforced arguments by China’s critics that its police crackdown amounted to discriminatory racial and religious profiling.

The first sign that my visit to Xinjiang might fall through was a mysterious series of hotel cancellations. I’d planned a side trip to see the ancient Silk Road city of Turpan and its archaeological sites and Uyghur culture. One week prior to my flight to Xinjiang, the online travel site notified me that my hotel booking for Turpan had been canceled. When I tried to make other bookings in Turpan, they were similarly reversed.

Any hope of seeing State Grid’s construction in Xinjiang ended two days before my flight to China, when my hosts reported that the territorial government had imposed a 20-day delay to review my admissibility.

I recognized that the “delay” was a de facto rejection. Subsequent restriction and harassment of foreign journalists bound for Xinjiang suggest I got off light. Officially, the only Chinese region that’s off-limits to journalists is Tibet—a policy that recently prompted U.S. travel restrictions on some Chinese officials. But many reporters also experienced “prohibited or restricted” access in Xinjiang and other areas deemed “sensitive,” according to a 2018 survey by the Foreign Correspondents’ Club of China.

To bring home the UHV story, I switched to Plan B and set course for one of State Grid’s newest 800-kV converter stations just southeast of Xinjiang in Gansu province. It was well worth the trip. The Qilian Converter Station is named for the glacier-topped mountains nearby. Since starting up in 2017, it’s been exporting gigawatts of power captured from the strong and steady winds those mountains help create.

Visiting Gansu also gave me a taste of Uyghur life. In the oasis town of Dunhuang (Dukhan in Uyghur), I dined on lamb’s brain–an intensely rich and disconcertingly sticky-smooth pâté served in cranium. I also witnessed the surveillance state that China is building outward from Xinjiang.

The photo at the top, taken in a small alley in Dunhuang, shows one of the security cameras that are now omnipresent in Xinjiang and paired with facial-recognition algorithms. According to the Washington Post’s former China bureau chief Simon Denyer, “Facial-recognition cameras [in Xinjiang] have become ubiquitous at roadblocks, outside gas stations, airports, railway and bus stations, and at residential and university compounds and entrances to Muslim neighborhoods. DNA collection and iris scanning add extra layers of sophistication.”

Since my trip in March 2018, there has been growing recognition of the troubles in Xinjiang. In August an expert panel assembled by the United Nations Human Rights Council, citing “credible sources,” stated that China had interned more than 1 million people, turning Xinjiang into a “no rights zone” where Muslims were treated as “enemies of the State.” Panel member Gay McDougall, distinguished scholar-in-residence at Fordham University’s Leitner Center for International Law and Justice, said authorities had criminalized common cultural practices, including “daily greetings, possession of certain halal products, and growing a full beard.”

Xinjiang is making news again this month ahead of the U.N. group’s next session, where it will take up a report on human rights in China. Earlier this month, Turkey’s foreign ministry condemned what it called “the re-emergence of concentration camps in the 21st century.” Human rights groups and some governments are calling for an international fact-finding mission.

For its part, Xinjiang’s territorial government finally acknowledged the camps’ existence in October, describing them as “professional vocational training institutions.” A Chinese delegate to the U.N. Human Rights Council insisted the camps were needed, “to protect the human rights of the majority of people,” according to Canada’s Globe and Mail. He added that Xinjiang’s detainees have “never thought that life could be so colourful and so meaningful,” before concluding: “Xinjiang is a nice place. Welcome to Xinjiang.”

That is, as long as you’re not a Uyghur—or a journalist.


Alphabet's Wind Energy Kites to Fly Offshore

Airborne wind energy company Makani has graduated from X’s experimental labs and is teaming up with offshore energy giant Shell

Renewable energy technologies seem to fill every nook and cranny of the earth. Turbines generate power on the seafloor and off coastlines. Solar panels carpet desolate deserts and abandoned wastelands. Volcanic aquifers, mountain streams, and urban sewage systems all help to produce electricity. For Makani, an airborne wind energy company, the next place to tap is roughly 300 meters in the air.

The California startup recently spun out of X—Alphabet’s experimental technology lab, or “moon shot factory”—to become an independent business within Google’s parent company. Makani is also partnering with Royal Dutch Shell in a bid to launch the startup’s high-flying kites where they haven’t flown before: offshore.

Starting this year, Makani will begin testing a floating system for one of its kites at the Metcentre, an offshore wind testing facility in southwest Norway. The kite will be tethered to a small spar buoy, which itself will be moored with a synthetic line and a gravity anchor. The goal is to operate where today’s floating wind turbines can’t go, either because it’s too challenging or cost-prohibitive to build supportive platforms.

China Stumbles on Path to Solar Thermal Supremacy

A crash plan to scale up solar thermal power generation struggles amidst overly-ambitious timing and market uncertainty

In the final days of 2018 a 100-megawatt solar thermal generating station capable of running around-the-clock, 365-days-a-year connected to the Northwest China regional power grid. It was a race against time to commission the plant in temperatures as low as -20 celsius—and one that plant designer and builder Beijing Shouhang Resources Saving Co could not afford to lose.

“We must finish on time. Otherwise we may face a heavy financial problem,” says Chen Han, Shouhang’s director for international markets.

Shouhang was racing to beat the Chinese government’s December 31, 2018 deadline to secure a guaranteed price for the plant’s power. The deadline was part of an aggressive demonstration program launched in September 2016 to slash the cost of solar thermal power and catapult Chinese firms to the head of the global packmuch as China did with solar photovoltaics.

Alas, a little more than two years later, China has stumbled on the path to solar thermal supremacy. While Shouhang’s and two more of the program’s 20 approved projects met the deadline, four others were cancelled last year and the remaining 13 projects are in limbo.

Solar thermal plants are a potentially crucial power source for global grids as they add more wind and PV solar. Unlike their weather-dependent cousins, solar thermal plants can efficiently store heat and then raise steam for their turbine-generators at will. They can thus dispatch power when it is needed most, reducing grid reliance on conventional gas, diesel and coal-fired generators.

However, the technology is comparatively costly and thus growing slowly relative to PV and wind. The technology took a public relations hit back in 2014 when birds killed by intense solar flux at the largest U.S. plant sullied solar thermal’s eco-friendly image. China’s program has been viewed as an opportunity to put solar thermal technology back on track, but the delays and cancellations mean it will fall far short.

The government anticipated adding 5.3 gigawatts by 2022—more than has been installed to date worldwide since the technology’s debut in the 1980s. Adding six more facilities that have a shot at starting this year would bring China’s total to just 550 MW, according to the Beijing-based Du Fengli, the Alliance’s secretary general. Two years from approval to completion was too short since most projects targeted high-altitude desert regions in China’s Northwest, a region with fantastic solar resources that also experiences long, punishing winters that limit outdoor construction to as few as  months.

Du adds that many players were trying to jump into solar thermal energy without prior experience building an entire plant, let alone one of commercial scale. The three projects that met the deadline are the exceptions that prove that rule.

SUPCON Solar and nuclear power giant China General Nuclear Power each completed 50-MW plants in Qinghai province late last year, and both had operated pilot plants there since as early as 2009. Their plants use different approaches: CGN’s ‘trough’ plant employs mirrors to concentrate sunlight on glass tubes, while SUPCON’s ‘power tower’ uses heliostat mirrors to focus solar energy on a central receiver.

Shouhang, meanwhile, erected its own ¥3-billion power tower plant on the southwestern edge of the Gobi Desert in Dunhuang, in Gansu province, adjacent to a 10-MW plant that it began building in 2014.

In a bulletin announcing the 100-MW plant’s startup Shouhang likens it to, “a silver sunflower blooming on the Gobi.” A field of 11,935 heliostats—each up to 115.5-square-meters across—illuminate a 260-meter-high tower where the energy heats a mix of molten nitrate salts. Tanks hold enough hot salt to operate the plant’s steam turbine for 11 hours, enabling continuous power output with or without sunlight.

Shouhang’s core business is heat transfer devices, so it was able to develop and manufacture the bulk of the plant’s solar equipment in-house, according to Chen. The firm also learned a lot from operating the pilot plant. “We have very complete experience,” he says.

Chen says the new plant is completing tests mandated by grid operator State Grid Corp. of China before it can enter regular operation. He says that so far no one has observed dead birds around the tower. That’s as expected, he says, since the site is not frequented by many birds and is not along a migratory bird flyway.

Shouhang helped build CGN’s plant and is under contract to build others. It has also taken over another 100-MW power tower project in Gansu whose developer backed out last year. But Chen says those opportunities are on hold because the power price for further plants has not been set. Such uncertainty makes it difficult to secure financing for future projects.

Du at the Alliance says the rates will be less than the ¥1.15 ($0.17) per kilowatt-hour secured by the first three projects. She says officials have indicated they will be ¥1.14 for plants completed this year and ¥1.10 for those starting up in 2020 and 2021, but the government has yet to put those prices in writing.

Much hangs in the balance as China’s solar thermal developers struggle to sustain the anticipated build-out. Recent modeling from Beijing-based Tsinghua University suggests that solar thermal power plants can slash the cost of managing variable wind and solar power. For example, they found that replacing 5-20 percent of Gansu’s planned wind and solar PV generation with solar thermal plants would provide flexibility worth 24-30 cents per kilowatt-hour to China’s State Grid—a benefit well above the tariff that Shouhang raced to secure.

At the same time, some top solar researchers are warning that Chinese developers promising big cost cuts could pose a risk to the sector. Exhibit A, they say, is a record low 7.3 cent/kwh bid for power from a big plant in Dubai to be engineered and built by power equipment giant Shanghai Electric. “Something is nonstandard in that bid,” cautions Johan Lilliestam, a professor of renewable energy policy at the Swiss government laboratory ETH Zürich in a recent publication from the Paris-based International Energy Agency.

Robert Pitz-Paal, who chairs an IEA solar thermal research program, stated in the same report that “unseasoned Chinese firms” will hurt the technology’s global standing if they can not deliver: “If they fail, this may become the coffin nail for the technology as the confidence of clients in CSP and its potential for cost reduction may be damaged strongly by Chinese suppliers.”


Iron-Platinum Catalyst Keeps Fuel Cells Clean, Even in Cold Weather

A novel catalyst protects fuel cells from contaminants, and could help China catch up in battery-free EVs

Batteries are currently outpacing fuel cells in the technological race to power the electric vehicle. Lithium batteries keep getting cheaper, while fuel cells remain hampered by pricey, short-lived platinum catalysts. An advance reported today in Nature by researchers in China suggests that adding a bit more platinum—albeit in a novel form—could help fuel cell cars catch up.

The report from a group at the University of Science and Technology of China (USTC) in Hefei also shows that China is catching up to fuel cell leaders such as Japan and Korea. China’s automakers already make the majority of the world’s battery electrics, and the government is keen to see them dominate in fuel cells, too. Last year Beijing and local governments provided US $12.4 billion in subsidies for fuel cell vehicles, according to the Financial Times.

Platinum catalysts drive the core reaction inside proton-exchange membrane fuel cells (the kind used in cars) that sustains their electric circuit—the same reaction that creates the water that dribbles out of vehicle tailpipes. Junling Lu, a professor with USTC’s Hefei National Laboratory for Physical Sciences at the Microscale, says they have found a way to protect those platinum catalysts from a ubiquitous contaminant: carbon monoxide. It tightly binds to platinum, blocking the catalytic action.

The carbon monoxide is present because most hydrogen fuel is produced from hydrocarbon fuels. Even after costly purification, hydrogen fuel contains up to 0.2 parts-per-million carbon monoxide (CO). Over time, it builds up on the catalyst, slowing the fuel cell reaction, and such ‘poisoning’ snowballs each time a fuel cell vehicle starts up in cold weather. “Even the highest grade hydrogen has trace amounts of CO that can eventually deactivate the fuel cell electrodes,” says Lu.

Lu and his colleagues found a solution by designing a novel catalyst—platinum particles peppered with iron oxide—that can rapidly burn away CO in hydrogen. The catalyst selectively converts CO to harmless CO2 and, critically, it works across a broad temperature range. Their testing confirmed a 200-fold reduction in CO between -75 and 107 degrees C, which he says is a huge improvement over previous CO-selective catalysts. “All the catalysts in the literature were only operating above room temperature,” says Lu.

In the near term, Lu imagines their catalysts extending the operating life of fuel cell vehicles’ costly stacks. Down the road, he says onboard fuel clean-up could allow the use of lower-grade hydrogen fuel with a lower price that “all of the people can bear.”

“They may have a good solution here. It looks like it could work,” says William Goddard, director of the California Institute of Technology’s Materials and Process Simulation Center and a designer of fuel cell catalysts who was not involved in today’s advance.

That said, Goddard notes that the CO problem should eventually go away as hydrogen production shifts from stripping fossil fuels to applying electrolysis to water using renewable or nuclear energy. He adds that what’s really needed to make fuel cell vehicles competitive are cheaper catalysts within the fuel cell stack. The platinum-rich stack contributes to the hefty $85,000 price tag on Toyota Motor’s Mirai fuel cell sedan.

China’s government seems to expect that goal to be reached sometime within the coming decade. By 2030, its plans call for one million fuel cell vehicles to be cruising China’s roads. To get there, it is financing domestic research such as USTC’s and also providing rich subsidies to spur development by Chinese companies—up to $30,000 per vehicle plus additional local subsidies according to the Financial Times report.

Over the past two years, several Chinese firms have bought stakes in foreign fuel cell firms and set up joint ventures to access advanced technology. Most recently, in November 2018, Chinese engine and auto parts manufacturer Weichai Power acquired 20 percent of Canadian fuel cell pioneer Ballard Power Systems. In a separate deal it acquired a 20 percent stake in UK-based fuel cell maker Ceres Power.


China’s State Grid Corp Crushes Power Transmission Records

State Grid’s 1.1 million volt DC line pushes power from Xinjiang to eastern megacities over 3000 kilometers to the east

China’s primary grid operator has energized its biggest and most powerful line yet, a 1.1-million-volt direct current (DC) behemoth that crushes world records for voltage, distance and power.

The new ultra-high voltage DC (UHVDC) line built by Beijing-based State Grid Corporation of China can transmit up to 12 gigawatts. That is enough to power 50 million Chinese households, according to a statement issued in Chinese by State Grid last week, and 50 percent more than most of the 800-kilovolt UHVDC lines that State Grid has built over the past decade.

The new 1100-kv UHVDC line absorbs the grid’s alternating current at an AC/DC converter station near the capitol of Xinjiang—China’s vast northwestern territoryand sends DC power to a second converter station in Anhui province in eastern China. That 3,293 kilometer run extends power transmission’s distance record by over 900 kms.

State Grid dubs it the “Power Silk Road” in its statement because it follows the eponymous ancient route’s path through northwest China’s Hexi Corridor and can replace the equivalent of 25,000 coal trains’ worth of coal-fired generation in China’s heavily polluted eastern cities. In addition to battling air pollution, it could also deliver a hefty reduction in greenhouse gas emissions if State Grid prioritizes export of the northwest’s abundant solar and wind power.

Jin Zhang, a senior engineer and deputy division head in State Grid’s DC transmission project department, told IEEE Spectrum during interviews in Beijing last year that State Grid began developing 1100-kv UHVDC technology more than a decade ago. They recognized, he said, that China would need to transfer power farther over distances that would incur large losses on 800-kv lines.

Early risk-benefit studies identified 1100-kv as the optimal next step, said Zhang, in part because of the big AC transformers that mediate between the converter stations and the surrounding AC grids. Installing a smaller number of large transformers is most cost-effective, he said, but for a 1200-kv converter station such transformers might be impossible to deliver from factories.

The transformers at State Grid’s newly-energized 1100-kv converter stations are movable, but they are hardly small. Zurich-based ABB, which provided some of the new line’s components along with Munich-based Siemens and a number of Chinese suppliers, says transformers it built for State Grid’s project weigh 800 metric tons, and stretch to 32 meters in length. One of State Grid’s domestic suppliers, TBEA, set up UHV transformer manufacturing in Xinjiang to minimize transport costs.

Supersizing was also required for other 1100-kv components, such as power lines and transmission towers, to manage the system’s unprecedented electromagnetic fields. Magnus Callavik, general manager of Beijing-based ABB Sifang Power System Co., a joint venture that provided one set of AC/DC converters for the new line, says the 300-kv jump from 800-kv required a “completely new” design.

“It sounds like you’re only adding an incremental part,” Callavik said. “But it’s very challenging for insulation design, structure and weight of the whole design, [plus] system aspects such as how you integrate with the transformer and other systems.”

Zhang pointed to the bushings that carry DC power between each station’s electronic converters, housed indoors, and the UHVDC transmission lines outside. The bushings keep electricity from flashing over to the converter halls’ walls. With the step up from 800-kV, Zhang said they grew by half a meter to roughly 1.3 meters in diameter and from under 20 meters in length to over 30 meters. “Higher voltage means higher impulse levels, mainly during switching. So we need longer air clearances,” said Zhang.

UHVDC technology is seen by Chinese president Xi Jinping as a key technology for his “Belt and Road” international development program. And at the UN’s 2015 Sustainable Development Summit Xi proposed the construction of intercontinental power links to massively scale-up cross-border sharing of renewable energy.

But UHVDC also has an important role to play domestically, where Xi has promised to turn China’s skies blue again. Specifically, Xi has committed to ending rampant wastage of renewable power generation, whereby wind, solar and hydro power plants are deliberately shut off due to grid capacity and stability limits or to simply make room for coal-fired generation.

State Grid’s new 1100-kv line could help reduce renewable energy curtailment because Xinjiang’s wind and solar power plants are among China’s largest and also the country’s most heavily curtailed. More than one-fifth of Xinjiang’s solar generating potential and one-quarter of its wind power was squandered in 2017, according to Chinese government statistics. Sending that power to eastern China instead of wasting it would help State Grid meet Xi’s promise to shrink curtailment to less than 5 percent in all regions by 2020.

State Grid is working hard to meet that goal, according to Zhang. While 13-gigawatts of new coal power generation was planned along with State Grid’s 1100-kv UHVDC project, Zhang told Spectrum that many of the anticipated plants were cancelled. “At least more than half will be renewable power,” he said of the power exports the new line will carry.

One more question hangs over the impact of State Grid’s 1100-kv technology: whether its massive power flows can be safely integrated with China’s congested eastern grids. Challenges associated with absorbing power injected by big DC lines led to the break-up of China’s southern grid in 2016. State Grid is counting on another major UHV innovation — its growing network of 1000-kv AC lines — to solve that problem.


With Vineyard Wind, the U.S. Finally Goes Big on Offshore Wind Power

The 400-megawatt Vineyard Wind project is the first large offshore wind farm in the U.S. It won’t be the last

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Sometime in 2019, construction on Vineyard Wind, the first major offshore wind farm in the United States, will begin. Workers will start prepping a pair of undersea substations to be installed about 55 kilometers south of the Massachusetts mainland. A specially equipped trawler will lay undersea transmission cable between the site and a landfall on Cape Cod. The cable will connect to the switching station in Barnstable, and from there to the New England power grid.

Meanwhile, the first of 84 wind turbines, 9.5 megawatts each, from MHI Vestas will be shipped to the site and installed in an array that will populate a 650-square-kilometer expanse and generate some 800 MW. The exact timetable for all that work is uncertain, though. The developers—Copenhagen Infrastructure Partners and Avangrid Renewables—declined to be interviewed for this story.

The most remarkable thing about Vineyard Wind isn’t its size or scope or the fact that it’s a first for the United States. It’s the 7.4 U.S. cents per kilowatt-hour price that Vineyard Wind has agreed to charge for the wind farm’s electricity. In the project’s second phase, the price will drop to just 6.5 cents, making it competitive with coal and natural gas, but without the carbon emissions. For comparison, electricity from the tiny five-turbine, 30-MW Block Island wind farm, which became operational in 2016 off the coast of Rhode Island, is priced at 24.4 cents per kilowatt-hour.

“Vineyard Wind’s price is a game changer,” says Bill White, who spoke to IEEE Spectrum in September, when he was senior director of offshore wind development at the Massachusetts Clean Energy Center. (In October White joined the German renewable energy firm EnBW.) “Offshore wind is good for [combatting] climate change. It creates jobs. It meets the need for more electricity as the Northeast’s power-generation fleet ages. Offshore wind has been a no-brainer—except on cost. Now, cost has almost been taken off the table.”

The U.S. offshore wind market has been a long time coming, says Walt Musial, manager of offshore wind at the National Renewable Energy Laboratory (NREL). He’s worked on wind power for 35 years, so he’s intimately familiar with the technical, economic, regulatory, and, above all, political hurdles that have stymied U.S. efforts, even as other countries embraced the technology.

Epitomizing those struggles was Cape Wind, which was to be built off the coast of Cape Cod. Proposed in 2001, it won local, state, and federal approvals and major financial backing. But it also faced years of legal challenges from people concerned about how the turbines, which would be visible from shore, would affect the area’s scenic beauty and wildlife. Finally, in 2017, the developers canceled the project.

“It was death by a thousand cuts,” Musial says. “But in a way Cape Wind was the leader. We learned a lot, and now the industry is on track.”

The Massachusetts Clean Energy Center helped ensure that Vineyard Wind’s fate didn’t mirror Cape Wind’s. “We recognized that offshore wind would come to Massachusetts but that there were obstacles, so…we’ve been doing all this work to get ready,” White says.

That work included environmental surveys, planning for transmission lines, and funding a study of gray whales, which may be affected by wind farm construction. Massachusetts spent $100 million upgrading its New Bedford Marine Commerce Terminal, to allow it to handle massive turbine components. Despite such preparatory efforts, at press time local fishermen were protesting the project, upset over the positioning of the turbines.

Turbine technology has evolved considerably since Cape Wind’s time, Musial notes. “Back in 2003, we couldn’t place turbines south of Martha’s Vineyard. Now we can.” Cape Wind’s turbines were to be 3.6 MW. “Now turbines are more than twice that size, which means you need fewer of them.” Though the turbines are also taller, they’ll be farther from shore.

Vineyard Wind is only the first of a number of large U.S. offshore wind projects in the works. Next to the Vineyard Wind site are several other sites leased to Deepwater Wind (recently purchased by the Danish company Ørsted) and to Bay State Wind (a partnership of Ørsted and the transmission company Eversource).

Meanwhile, New Jersey is soliciting 1,100 MW of offshore wind capacity, the largest ever for a U.S. state, with an eventual 3,500 MW by 2030. New York state has set a goal of 2,400 MW of offshore wind by the same year.

Elsewhere in the world, France, Taiwan, and Vietnam have invested heavily in offshore wind, joining the likes of China, Germany, and the United Kingdom. The total installed capacity of offshore wind is projected to reach 115 gigawatts by 2030, a sixfold increase from 2017, according to Bloomberg New Energy Finance.

And new technologies continue to be deployed, including floating turbines, for use in deeper water where turbines can’t be directly anchored in the ocean floor, and telescopic turbine towers, which can be fully assembled onshore, towed to the site, and then extended.

“We spent years doing site development, industry cultivation, meeting with regulators,” NREL’s Musial says. “It’s finally paying off.”

This article appears in the January 2019 print issue as “The U.S. Finally Goes Big on Offshore Wind.”


This Photocell Generates Both Power and Hydrogen

A novel hybrid photocell could accelerate the transition to carbon-free power

A novel solar cell reported this week by researchers at Lawrence Berkeley National Laboratory (LBL) in California selectively cranks out electricity and hydrogen. Panels of these hybrid cells, a novel integration of photovoltaic and electrochemical devices, could simultaneously meet real-time energy demand while socking away hydrogen to back-up solar, hydro and wind generators and to fuel hard-to-electrify equipment such as airplanes.

Yuriy Pihosh, a University of Tokyo research scientist who was not associated with the reported work, calls LBL’s design “simple and innovative.” Pihosh says it could have “huge impact” on the commercialization of solar hydrogen, which has been one of the holy grails of renewable energy for several decades. In fact, it could be crucial to the transition to carbon-free power that climate scientists say must occur by mid-century to head off the worst impacts of climate change.

What has held solar hydrogen back is the low efficiency of photoelectrochemical (PEC) cells that split water and release hydrogen gas. Most efforts to date focus on tandem designs, in which PEC cells get a boost from an adjacent PV cell connected in series. However, electrical mismatches and contacts between the PV and PEC devices wastes much of the PV cell’s energy, and hydrogen output remains limited. 

LBL’s patent-pending design is a single hybrid photoelectrochemical and voltaic (HPEV) cell. The HPEV makes dual use of its photon-excited electrons and thus maximizes its overall efficiency, much as cogeneration power plants achieve high fuel efficiency by squeezing both heat and power from natural gas or coal. 

The HPEV cell manages its dual function feat by adding a third electrode. The PEC electrode atop the device uses as many electrons as it can to produce hydrogen, while dual PV electrodes allow leftover charges to deliver electricity just as they do in standard solar cells.

Putting dual electrical contacts on the HPEV cell’s back face was the key design advance, according to Gideon Segev, an LBL-based postdoc with the U.S. Department of Energy’s Joint Center for Artificial Photosynthesis and lead author on this week’s report in Nature Materials.

Dual back contacts are already well-honed technology applied in high-performance PV panels by San Jose-based Sunpower, where they eliminate the top-face electrode strips that block some light from penetrating into the cells. “It’s well-known stuff. We’re just putting the puzzle pieces together in a different way,” says Segev.

Segev and colleagues illustrate their design’s energy boost by simulating an HPEV cell using PEC materials that, as Pihosh showed in 2015, can convert 6.8 percent of sunlight to hydrogen. In Segev et al’s simulation the HPEV cell turns out the same amount of hydrogen, but also converts another 13.4 percent of the available solar energy into electricity — essentially tripling the total energy conversion.

The device should also age gracefully according to Segev, which is important because PEC materials are struggling to match the multi-decade robustness of PV materials. (The PEC cells whose efficiency best Pihosh’s rely on short-lived catalysts and fail within a few days.) Segev says that HPEV cells whose hydrogen output fades should simply produce more power, thus cushioning the loss. 

Better still, the HPEV cell can be electrically modulated. “You have a reservoir of charges and you can choose if you want to direct it to hydrogen production or to electricity depending on the cost of electricity right now,” says Segev. That functionality could be crucial for 100-percent renewable power grids such as those that Hawaii’s utilities are mandated to build. When demand surges or wind power falls off, hydrogen cogeneration plants equipped with HPEV cells could boost their power output by half to keep the grid balanced.

The LBL team are now exploring use of the HPEV cell to drive other chemical reactions including applications that could directly reduce carbon dioxide emissions, according to an LBL press release. But Segev says he hopes other teams will extend the hydrogen work. The LBL team created a small, unoptimized HPEV cell to demonstrate hybrid operation with an efficiency of slightly over 1 percent. He says he is looking forward to other teams producing souped-up hydrogen cells “with the efficiency that it deserves.” 


How Solar-Powered, Mobile Water Purifiers Can Help Cities Cope With Bad Water

Quench Water & Solar is selling its solar-powered water purifiers to private owners as U.S. cities wrestle with clean drinking water issues

When WorldWater and Solar Technologies deploys its mobile water purifiers—arrays of solar panels, batteries, and high-pressure pumps—the machines usually wind up in natural disaster zones, off-grid villages, or military operations around the world.

Now the company is expanding within the United States, where cities are grappling with contaminated water supplies and dwindling freshwater reserves. Quench Water & Solar lets entrepreneurs sell clean—and ideally cheap—drinking water to their neighbors, local businesses, and at large events like festivals, where plastic water bottles pour down like rain.

“The water infrastructure throughout most of the U.S., and certainly way beyond, is very old…and municipalities don’t have the wherewithal or the resources to be able to address these things,” says David Hammes, president of Quench and vice president of international development at WorldWater. “We see this as an opportunity to take our technology and really benefit people that are subject to contaminated water.”

The mobile systems range from the size of golf carts to food trucks, depending on their desired output. Solar panels lay on top, generating electricity that charges the GEL-sealed, lead-acid batteries, which in turn run the motor that pumps water through filters. Clean water pours out a hose and, depending on the filtration process, contaminants flow out a discharge stream or remain in mechanical membranes. Internet-connected monitors remotely display the systems’ water quality, output, and equipment performance.

“We can deploy it anywhere and literally take contaminated, poisoned water and turn it into drinking water in minutes,” Hammes says.

If water comes from ponds, lakes, or municipal taps, it passes through four filters to remove microbes, sediment, and other contaminants. An ultraviolet light then sterilizes the filtered water. Brackish or seawater undergo reverse osmosis, in which water is forced through a thick membrane that blocks sodium and chloride ions and lets freshwater pass. The process uses a substantial amount of energy, so those units require more solar panels and batteries and cost thousands of dollars more.

Lead-tainted water also requires reverse osmosis, because of the metal’s low molecular weight, says Ben Switzer, Quench’s director of business development. When we spoke in early October, he was manning a promotional booth at a conference in Flint, Michigan—a city still reeling from a public water crisis.

After Michigan officials switched Flint’s water supply in 2014, foul-smelling water laden with lead and harmful bacteria coursed through kitchen faucets and shower heads for two years. State authorities say Flint’s water is now safe to drink, but many residents say they no longer trust the government’s word, and they continue buying bottled water or installing home filtration systems for drinking, cooking and bathing. Nationwide, some 18 million people were served by water systems with federal lead violations in 2015, according to an analysis of federal data.

Quench’s water purifiers aren’t designed to rival a municipal water supply. Its largest solar-powered units produce an average of 113,500 liters per day for freshwater filtration, and about 11,400 liters per day with reverse osmosis filtration. By contrast, more than 45 million liters of water per day flow through the pipes in Flint, a city of nearly 97,000 people.

But the mobile systems could provide communities an affordable alternative to the bounty of bottled water and home filters. With the Quench units, licensees could provide a gallon of drinking water “at the cost of a fraction of a cent,” Switzer says.

WorldWater, Quench’s parent company, has already delivered its technology to about 30 countries in the last three decades. The Mobile MaxClear systems feature a 900-watt solar array and 5.4 kWh of battery storage, while the Mobile MaxPure system has a 4-kW folding solar array and up to 31 kWh of battery storage. Systems can range from $30,000 to $150,000, depending on the water source and capacity expectations.

A handful of other companies provide mobile, solar-powered water purifiers and pumps worldwide. Tata Group, the Indian conglomerate, is building village-scale desalination systems and solar-driven water pumps in India. PV Pure, a startup founded by MIT researchers, has delivered its small units across Latin America, the Caribbean islands, and the Middle East.

Amy Bilton, who helped develop PV Pure’s technology as an MIT doctoral student, says a key challenge with solar-powered water purifiers is the intermittent nature of solar energy. If a system operates with any fluctuations, it can quickly degrade the equipment. To address this, operators can either use small batteries to maintain steady power flows, or turn the system on and off to match the sunlight.

“In the course of our work, we’ve done a little bit of both,” says Bilton, now director of the Center for Global Engineering and the Water and Energy Research Lab at the University of Toronto. “Even if you include batteries, you’re still going to have to operate the system intermittently. To be able to run a system 24 hours a day, like a traditional desalination plant, is something you can’t cost-effectively do.” Larger batteries can bank power and extend operating times, but they add considerable costs to the overall system.

Purifiers with reverse osmosis face an additional challenge, she says. Intermittent operations can lead to membrane “fouling” if not properly managed. Salts, microbes, and heavy metals can attach to and grow on the membrane, which means it takes even more energy to force water through the filters. To avoid this, operators can run a rinse cycle when shutting down to make sure there’s no stagnant water adjacent to the membrane. Certain chemicals can be added to untreated water to ensure deposits don’t build up.

Bilton noted a growing interest in these types of solar-driven water technologies, not only overseas but also across North America, including in the parched southwestern U.S. and in remote Canadian villages, where water treatment is difficult. “It’s something that’s becoming more common,” she says. “There are certain markets where it makes a lot of sense.”


Stretchy, Solar-Powered Sensor Detects Heartbeats

Researchers have successfully integrated a solar cell and an ultra-flexible biosensor

As electronics decrease in size and increase in flexibility, it’s becoming harder and harder power them. Now, a team in Japan has married a tiny, effective solar cell to a flexible biosensor to create a heartbeat monitor that powers itself.

It’s the latest work from Takao Someya’s team at the RIKEN Center for Emergent Matter Science in Saitama, Japan, building on their library of ultra-flexible, washable, and breathable wearable sensors. As if that were not impressive enough, the sensors are pretty too: Some resemble sleek gold tattoos, others pulse with green and red LED lights.

The new self-powering feature, described last week in the journal Nature, solves a problem the team first confronted years ago: How does one maintain a steady power supply without cords?

“We realized that the unstable output power was a problem if we use only a battery as power source because we cannot avoid the problems of replacement/recharging of batteries,” says Kenjiro Fukuda, a senior research scientist on the Someya team.

So the team spent three years investigating a lightweight self-powering system for their sensors. It took plenty of trials and errors, notes Fukuda, but in the end they integrated an electronic biosensor into a flexible photovoltaic cell the team had previously created for use in textiles.

The solar cell, only about 10 nanometers wide, is made of layers of different materials, including zinc oxide, that improve the efficiency of the cell over similar flexible solar cells. The layers are fabricated in nanometer-sized patterns that improve the cell’s overall efficiency and give it unique rainbow colors.

Once the devices were made, the researchers stuck them onto human skin and rat heart tissue, shined bright light on them, and successfully detected heartbeats. What’s more, the heart-rate signals were three times better than those of similar sensors with external power sources, according to an accompanying editorial in Nature.

The flexible solar cells were able to convert up to 10.5% of the light energy into electricity. That is “among the highest reported values of power-conversion efficiency for ultraflexible devices,” note the authors of the editorial.

That 10.5% was more than enough to power the team’s cardiac biosensor, which requires less than one volt, notes Fukuda. The team tested the device under dimmer lights, mimicking typical room light conditions, and it continued to function well.

Currently, the technology could be used to monitor heartbeats during exercise, Fukuda says. With accuracy improvements, the team hopes it can eventually be used in hospitals to monitor patients.

Next up, they will keep improving the power supply and the device’s ability to withstand air, water, heat and pressure. They’re also exploring how to integrate other types of biosensors and how to best transmit biological signals and data to users, says Fukuda.

“Integration with wires transmission and/or memory devices are important next step,” he notes.


New Device Marries Solar Cells With Flow Batteries

The solar flow battery should be a simple, cheap, and more efficient way to get round-the-clock electricity from the sun

As solar power gets more affordable and installations rise, so does the need for batteries that can store all that energy for 24-hour use. Now researchers report a new device that combines solar cells and batteries into one integrated device, a “solar flow battery.” If it could be made affordable, it could be an ideal way to bring electricity to people in remote, off-grid regions.

It is, of course, possible to just store electricity produced by solar panels in large batteries for electricity when the sun isn’t shining. But combining the two processes and using sunlight to directly charge a battery should in principle be a simpler, more efficient, compact, and cost-effective approach to utilize solar energy, says Song Jin, a professor of chemistry at the University of Wisconsin-Madison. Besides, the device Jin’s team reported in the journal Cell can also behave as a straight-up solar cell or a battery.

Researchers have integrated solar cells with rechargeable batteries before by coupling a light-absorbing semiconductor electrode with a battery electrode. But the 14.1% round-trip efficiency of the new device—calculated as solar energy input to electrical energy output at a different time—is higher than devices made previously.

There are several ways to tap energy from the sun: convert it to electricity with photovoltaics; use its heat to produce steam for turning power plant turbines; and using sunlight, water, and carbon dioxide to directly produce liquid fuels.

Sunlight can also be stored as chemical energy by using it to charge the chemicals in a liquid electrolyte. This is the principle Jin and his colleagues have harnessed for their solar cell/flow battery hybrid.

Touted as ideal for grid storage, flow batteries store energy in tanks of electrolyte solution. The electrolytes, called anolyte and catholyte, serve as the electrodes. Ions move between the electrolytes during charge and discharge.

To make the solar flow battery, the researchers put a highly efficient solar cell on top of a thin reaction chamber, which contains the anolyte and catholyte separated by a thin membrane. The chamber is also connected to a small reservoir each for the anolyte and the catholyte. The chamber is sandwiched between two carbon electrodes.

A control box that is connected to the solar cell and the two carbon electrodes lets the researchers switch the device to one of three modes. In battery mode, the two carbon electrodes are connected, and the device works like a normal flow battery with the electrodes charging and discharging the chemicals in the electrolytes. In solar cell mode, the solar cell is connected to the carbon electrode on top of the reaction chamber, so the chamber is out of the picture. And in solar recharge mode, the solar cell is connected to the bottom carbon electrode. The voltage created in the solar cell causes a reshuffling of electrons that creates ions in the electrolytes, charging the battery.

Jin says there is room for improvement in the device. The high-efficiency solar cell made of expensive III-V semiconductors such as indium gallium arsenide is expensive. And the cell’s voltage does not perfectly match the battery’s working voltage, which hurts efficiency. By using more cost-effective semiconductors, improving the chemistry, and further tweaks to device design, efficiency should go up and cost should go down.

The cost for integrated solar flow battery devices should eventually be lower than individually operated solar photovoltaic devices plus redox flow batteries, he says. “We can see a clear pathway to achieve round-trip efficiency greater than 20 percent [and] believe we could eventually get to 25 percent efficiency using emerging solar materials and new solar cell designs. Then I think commercialization could be possible.”