Gravity Batteries, Green Hydrogen, and a Thorium Reactor for China: IEEE Spectrum’s biggest energy stories of 2021

2021 was a big year for energy-related news, what with the ongoing hunt for new forms of energy storage and cleaner if not carbon-free electricity and events and research that spotlighted the weak links in our power grid. As the…

2021 was a big year for energy-related news, what with the ongoing hunt for new forms of energy storage and cleaner if not carbon-free electricity and events and research that spotlighted the weak links in our power grid. As the pandemic continued to grind on, it was actually comforting to know that smart people in the energy sector were working hard to keep the lights on, advance the technology, and improve people’s lives. IEEE Spectrum did its best to cover those developments, and these were the stories that our readers liked best.

Gravity Energy Storage Will Show Its Potential in 2021

Why was this Spectrum’s most popular energy story of the year? Well, let’s think. As power grids everywhere increasingly rely on intermittent renewable energy, batteries and other forms of energy storage that can even out the bumps in supply and demand are taking on a crucial role. No battery is perfect, however, so engineers keep pushing for new and improved ways to store those electrons. The gravity batteries described in this story lift giant weights in the air or up mine shafts to store excess electricity, releasing the weights later on to recover the stored energy. One of the companies featured in the story, Gravitricity, completed its 250-kilowatt gravity battery demonstrator in Edinburgh last April and is now working on a full-scale deployment at a mine in the Czech Republic.Lithium-Ion Battery Recycling Finally Takes Off in North America and EuropeBattery makers around the world are cranking out lithium-ion batteries of various flavors as fast as they can. While lithium isn’t exactly in short supply, extracting it from the ground exacts a huge environmental cost. Thus the recent boom in battery recycling—and readers’ interest in this story on how the industry is expanding beyond China and South Korea and into the United States, Canada, and Western Europe. Last May, one of the story’s featured startups, Canada’s Li-Cycle, announced it would begin recycling the manufacturing scrap from Ultium Cell’s $2.3 billion EV battery plant—that’s GM’s and LG Chem’s new mega-gigafactory in Lordstown, Ohio. Here’s How We Could Brighten Clouds to Cool the EarthGeoengineering—altering the planet to mitigate the worst effects of climate change—is an idea that has taken on new currency of late. As global temperatures rise, greenhouse gases accumulate, and all signs point to Really Bad Things happening in the coming decades, Spectrum readers are clearly looking for a way out of our current climate predicament. This article, by researchers at PARC and the University of Washington, is one possible answer. The basic idea is to add particles of sea salt to the atmosphere to brighten clouds and cool the planet. We’ll still have to do the hard work of cutting carbon emissions, but geoengineering could be a way to buy us some time.Solar-to-Hydrogen Tech Sees “Remarkable” Efficiency JumpAnother big development in the energy sector is the return of the hydrogen economy. This time around, though, the emphasis is on “green hydrogen”—that is, hydrogen produced using clean energy such as solar or wind power. Most of the world’s hydrogen comes from deeply polluting methods. And most green hydrogen production still relies on electrolyzers, which themselves consume lots of electricity. This story looks at promising research out of Japan’s Shinshu University on light-absorbing materials to split water into hydrogen and oxygen directly—cutting the electrolyzer out of the equation. As the story notes, it will take quite a bit more R&D until this method is “ready for prime-time hydrogen production.”China Says It’s Closing in on Thorium Nuclear ReactorAlso getting a second look: nuclear power! While some recent efforts call for radical new reactor designs, this report highlights an old approach with a modern spin. Molten salt nuclear reactors fueled by thorium were first investigated at Oak Ridge National Laboratory in the 1950s. A new molten salt reactor reportedly being built by China follows the Oak Ridge design but also incorporates the same kind of high-temperature salt pumps used in concentrated solar-power plants.What the Texas-Freeze Fiasco Tells Us About The Future of the GridIn this clear-eyed consideration of last winter’s deadly deep-freeze in Texas, Robert Hebner, director of the Center for Electromechanics at the University of Texas at Austin, describes the converging factors and troubled history that contributed to the catastrophic blackout. “[It] seems pretty clear that what happened in Texas was likely preventable with readily accessible and longstanding engineering practices,” Hebner concludes. “But a collective, and likely implicit, judgment was made that the risk to be mitigated was so small that mitigation would not be worth the cost. And nature ‘messed’ with that judgment.”One Atmospheric Nuclear Explosion Could Take Out the Power GridAnother popular story in the “things that are bad for the power grid” category was this piece by national security writer Natasha Bajema. She looked at a recent study out of the U.S. Geological Survey and the University of Colorado on the likely effects of detonating a several-kiloton nuclear weapon in the atmosphere and generating a high-altitude electromagnetic pulse (EMP). (To be fair, Foreign Policy in a similar 2020 examination rated the EMP problem as very much outsized and “the last thing you need to worry about in a nuclear explosion.”) The conductivity of the Earth, the Geological Survey scientists discovered, plays an important role in the outcome, with low-conductivity regions most at risk of suffering a “grid-crippling power surge,” as the electric field travels out through high-voltage power lines. Here’s hoping that doesn’t happen in 2022, or any other year. Off-Grid Solar’s Killer AppSpectrum contributing editor Peter Fairley traveled to Kenya to report on a boom in agriculture driven by off-grid solar power and efficient solar-powered irrigation pumps. The pumps tap into vast stores of groundwater that lie not too far underground and cover much of sub-Saharan Africa. Solar-irrigation technology, combined with micro-lending payment plans, lets small farmers boost crop yields, lengthen growing seasons, and neutralize the effects of drought. It’s a win-win-win for a part of the world that could really use a victory right now.How Much Energy Does It Take to Grow a Tomato?Lastly but never leastly, Spectrum columnist and deep thinker Vaclav Smil contemplated the energy footprint of the tomato. Field tomatoes, unsurprisingly, are the least energy-intensive to produce, while raising hydroponic tomatoes grown in greenhouses can consume 60 times as much energy. Food for thought as we close out 2021. batteries Green hydrogen utilities renewables energy Jean Kumagai Jean Kumagai is a senior editor at IEEE Spectrum, covering the history of technology, green energy, and other topics. She holds a bachelor’s degree in science, technology, and society from Stanford University and a master’s in journalism from Columbia University. Topic Magazine Energy Feature Special reports Type China Will Attempt First Carbon-Neutral Winter Olympics A variety of climate-friendly strategies will be on show, along with the athletes Prachi Patel 29 Dec 2021 4 min read The National Speed Skating Oval (known as “The Ice Ribbon”) in Beijing will host speed skaters during the upcoming games. Ice here is formed using climate-friendly refrigeration. The facility also boasts outside architectural glass that includes photovoltaic elements, allowing the structure to generate electricity during the day. Lintao Zhang/Getty Images About 160 kilometers northwest of Beijing, the city of Zhangjiakou with its rugged terrain boasts some of the richest wind and solar resources in China. Renewables account for nearly half of the city’s electricity output with less than a third of its full solar and wind potential of 70 gigawatts installed so far. That makes it an ideal cohost with Beijing for the 2022 Winter Olympic and Paralympic Games, which China plans to make the greenest yet. The plan is to power all 26 venues fully with renewables, marking a first in the games’ history. The Beijing 2022 Organising Committee aims to make the games carbon neutral, or as close as possible—a benchmark for the International Olympic Committee’s mission to make the Olympics carbon positive by 2024. Besides being a symbol for President Xi Jinping’s ambitious goal of China being carbon neutral by 2060, the 2022 games should drive sustainable development in the region. The event has already helped Beijing clean up its skies and environment, and has fired up local energy-technology markets. It will also be a global stage to showcase new energy-efficiency, alternate-transport, and refrigeration technologies. The Olympics will account for only a small fraction of the country’s annual electricity consumption. Powering them with clean energy sources won’t be difficult given China’s plentiful renewable capacity, says Michael Davidson, an engineering-systems and global-policy expert at the University of California, San Diego. But Davidson also points out that insufficient infrastructure to manage intermittent renewables and electricity-dispatch practices that don’t prioritize them mean that much of China’s green-power capacity is often not put to use. And because the game venues are connected to a grid that is powered by a variety of sources, asserting that all the electricity used at the games is 100 percent from clean energy sources is “complicated,” he says. Nonetheless, the games will be important in raising the profile of green energy. “The hope is that this process will put into place some institutions that could help leverage a much broader-scale move to green.” The Games will offer a global stage to showcase new energy-efficiency, alternate-transport, and refrigeration technologies. Case in point: The flexible DC grid put into place in Zhiangjiakou in 2020 will let 22.5 billion kilowatt-hours of wind and solar energy flow from Zhiangjiakou to Beijing every year. By the time the Paralympics end in March, the game venues are expected to have consumed about 400 million kWh of electricity. If all of it is indeed provided by renewables, that should reduce carbon emissions by 320,000 tonnes, according to sports outlet Inside the Games. After the athletes go home, the flexible DC grid will continue to clean up around 10 percent of the capital’s immense electricity consumption. Green transport infrastructure being built to shuttle athletes and spectators between venues will also be part of the games’ lasting legacy. A clean energy–powered high-speed railway that takes 47 minutes to travel between Beijing and Zhangjiakou was inaugurated in 2019. More than 85 percent of public-transport vehicles at the Olympics will be powered by batteries, hydrogen fuel cells, or natural gas, according to state media. In August, officials at the Chinese capital revealed a five-year hydrogen-energy plan, with goals to build 37 fueling stations and have about 3,000 fuel-cell vehicles on the road by 2023, for which the Olympics should also be a stepping-stone. Already, hydrogen fueling stations built by China’s petrochemical giant Sinopec, Pennsylvania-based Air Products, and French company Air Liquide have cropped up in Beijing, Zhiangjiakou, and the Yanqing competition zone located in between. In Yanqing alone, 212 fuel-cell buses made by Beijing-based Beiqi Foton Motor Co. will shuttle spectators around. Even the iconic Olympic torch will burn hydrogen for its flame. Even the iconic Olympic torch will burn hydrogen for its flame.The 2022 event will also put a limelight on climate-friendly refrigeration. The immense 12,000-square-meter speed-skating oval in downtown Beijing—8 times the size of a hockey rink—will be the first in the world to use carbon dioxide for making ice. “We’ve built skating rinks with carbon dioxide direct cooling but never a speed-skating oval,” says Wayne Dilk of Toronto-based refrigeration company CIMCO Refrigeration, which has built most of the National Hockey League arenas in North America and designed and provided consulting services for the Olympics’ icy venues. Ice-rink technology typically relies on refrigerants siphoning heat away from brine circulated under the floors, Dilk explains. But CO2-based cooling systems, which are getting more popular mainly in Europe and North America for supermarkets, food-manufacturing plants, and ice rinks, use CO2 both as the refrigerant and for transporting heat away from under the floor where it is pumped in liquid form. CO2 is a climate villain, of course, but conventional hydrofluorocarbon refrigerants are worse. The common R-22 form of Freon, for example, is about 1,800 times as potent as a greenhouse gas. CO2 cooling systems are also 30 percent more energy efficient than Freon, says Dilk. Plus, the CO2 system produces higher-temperature waste heat, which can be used for space heating and hot water. And while the system is more expensive to build because it runs at higher pressure, the temperature across the large surface stays within a range of only 0.5 °C, giving more uniform ice. Consistent temperature and ice quality generate better competitive racing times. The Beijing 2022 hockey arenas and sliding center for bobsled and luge use climate-friendly ammonia or Opteon as refrigerants. Besides being a key part of the greenest Winter Olympics, these state-of-the-art ice venues should seal the deal for another goal China has in 2022: to establish itself as a world-class winter sports and tourism destination.This article appears in the January 2022 print issue as “China’s Green Winter Olympics .” Keep Reading ↓ Show less