Harwin’s Interconnect Guru caught up with the team from RWTH Aachen University as they prepared to embark on a journey across the globe, travelling from North West Germany to Darwin Australia for the Bridgestone World Solar Challenge.
What is their motivation and what lessons they’ve learnt from last year that will help them to gain a pole position?
“Climate change and resource depletion are threatening our civilization and emphasize the importance of developing renewable energy alternatives. Our intention with Sonnenwagen is not only to bring these two issues to light, but also show the potential of efficient solar technology. If you speak to any team member, they’ll say they want to be a part of a real-world application that promotes an environmentally-friendly renewable approach.
All of us are looking to make the most of our time in university and being involved in a project combating climate change and helping protect the planet is very rewarding.”
“The aerodynamics are vital. We spent 18 months performing computational fluid dynamics simulations and carried out multiple wind tunnel tests to determine the optimal design, while still considering chassis structure. Simulations were also done on various carbon fiber-reinforced composites and geometries. Data from all of these activities was then compiled to create a final digital prototype.”
The coronavirus outbreak has sent the global economy reeling as businesses shutter and billions of people hunker down. Air travel, vehicle traffic, and industrial production have swiftly declined in recent weeks, with much of the world frozen in place until the virus—which has killed more than 39,000 people globally—can be safely contained. One consequence of the crisis may be a sizable, if temporary, decline in heat-trapping emissions this year.
Global carbon dioxide emissions could fall by 0.3 percent to 1.2 percent in 2020,says Glen Peters, research director of the Center for International Climate Research in Norway. He based his estimates on new projections for slower economic growth in 2020. In Europe, CO2 emissions from large sources could plunge by more than 24 percent this year. That’s according to an early assessment of the Emissions Trading Scheme, which sets a cap on the European Union’s emissions. In Italy, France, and other nations under quarantine, power demand has dropped considerably since early March.
As experts look to the future, Lauri Myllyvirta is tracking how the new coronavirus is already affecting China—the world’s largest carbon emitter, where more than a dozen cities were on lockdown for nearly two months. Myllyvirta is an analyst at the Centre for Research on Energy and Clean Air, an independent organization. Previously based in Beijing, he now lives in Helsinki, where I recently reached him by phone. Our conversation is edited and condensed for clarity.
Renewables are poised to expand by 50 percent in the next five years, according to the International Energy Agency. Much of that wind and solar power will need to be stored. But a growing electric-vehicle market might not leave enough lithium and cobalt for lithium-ion grid batteries.
Some battery researchers are taking a fresh look at lithium’s long-ignored cousin, potassium, for grid storage. Potassium is abundant, inexpensive, and could in theory enable a higher-power battery. However, efforts have lagged behind research on lithium and sodium batteries.
But potassium could catch up quickly, says Shinichi Komaba, who leads potassium-ion battery research at the Tokyo University of Science: “Although potassium-battery development has just been going on for five years, I believe that it is already competitive with sodium-ion batteries and expect it to be comparable and superior to lithium-ion.”
People have historically shied away from potassium because the metal is highly reactive and dangerous to handle. What’s more, finding electrode materials to hold the much heftier potassium ions is difficult.
Yet a flurry of reports in the past five years detail promising candidates for the cathode. Among the leaders are iron-based compounds with a crystalline structure similar to Prussian blue particles, which have wide open spaces for potassium ions to fill. A group from the University of Texas at Austin led by John Goodenough, coinventor of the lithium-ion battery and a winner of the 2019 Nobel Prize in Chemistry, has reported Prussian blue cathodes with an exceptionally high energy density of 510 watt-hours per kilogram, comparable to that of today’s lithium batteries.
But Prussian blue isn’t perfect. “The problem is, we don’t know how water content in the material affects energy density,” says Haegyeom Kim, a materials scientist at Lawrence Berkeley National Laboratory. “Another issue is that it’s difficult to control its chemical composition.”
Kim is placing bets on polyanionic compounds, which are made by combining potassium with any number of elements plucked from the periodic table. Potassium vanadium fluorophosphate seems to hold special promise. Kim and his colleagues have developed a cathode with the compounds that has an energy density of 450 Wh/kg.
Other researchers are looking at organic compounds for cathodes. These cost less than inorganic compounds, and their chemical bonds can stretch to take up potassium ions more easily.
While Goodenough is giving potassium a chance, his fellow lithium-battery inventor and Nobel Prize winner M. Stanley Whittingham, professor of chemistry at Binghamton University, in New York, isn’t sold. “It’s a scientific curiosity,” he says. “There’s no startup looking at potassium batteries.”
Potassium, says Whittingham, is not a practical technology because of its heft and volatility. Potassium also melts at a lower temperature than lithium or sodium, which can trigger reactions that lead to thermal runaway.
Those are valid concerns, says Vilas Pol, a professor of chemical engineering at Purdue University, in West Lafayette, Ind. But he points out that in a battery, potassium ions shuttle back and forth, not reactive potassium metal. Special binders on the electrode can tame the heat-producing reactions.
Developing the right electrolyte will be key to battery life and safety, says Komaba, of the Tokyo University of Science. Conventional electrolytes contain flammable solvents that, when combined with potassium’s reactivity, could be dangerous. Selecting the right solvents, potassium salts, salt concentration, and additives can prevent fires.
Komaba’s group has made electrolytes using potassium-fluoride salts, superconcentrated electrolytes that have fewer solvents than traditional mixes, and ionic liquid electrolytes that don’t use solvents. In January, materials scientist Zaiping Guo and her team from the University of Wollongong, Australia, reported a nonflammable electrolyte for potassium batteries. They added a flame retardant to the solvent.
Potassium enthusiasts point out that the technology is still at an early stage. It’s never going to match the high energy density of lithium, or be suitable for electric cars. Yet for immense grid batteries, cheap potassium might have an upper hand. “Potassium-ion [batteries] could have worked earlier, but there was no need for [them],” says Pol. “Lithium isn’t enough now.”
In the end, the sum will have to be as good as its parts. Most research has focused on the materials that go into the electrodes and the electrolyte. Put it all together in a battery cell and the energy density drops after just 100 charging cycles or so; practical batteries will need to withstand several hundred.
“It will take time to figure out the exact combination of electrolyte, cathode, and anode,” Pol says. “It might take another 15 years from now to get to the market.”
This article appears in the March 2020 print issue as “Potassium Batteries Show Promise.”
A series of earthquakes left Puerto Rico in the dark this week as power outages swept nearly the entire island. About 80 percent of utility customers had power restored by Friday afternoon, yet authorities warned it could take weeks to stabilize the overall system.
A 6.4-magnitude earthquake rocked the U.S. territory on 7 January following days of seismic activity. Temblors and aftershocks leveled buildings, split streets, and severely damaged the island’s largest power plant, Costa Sur. The blackouts hit a system still reeling from 2017’s Hurricane Maria—which knocked out the entire grid and required $3.2 billion in repairs.
Inside a row of nondescript buildings in the small town of Albany, in northeast Indiana—approximately 1,000 kilometers from the nearest coast—Atlantic salmon are sloshing around in fiberglass tanks.
Only in the past five years has it become possible to raise thousands of healthy fish so far from the shoreline without contaminating millions of gallons of fresh water. A technology called recirculating aquaculture systems (RAS) now allows indoor aquaculture farms to recycle up to 99 percent of the water they use. And the newest generation of these systems will help one biotech company bring its unusual fish to U.S. customers for the first time this year.
For AquaBounty Technologies, which owns and operates the Indiana facility, this technology couldn’t have come at a better time. The company has for decades tried to introduce a transgenic salmon it sells under the brand name AquAdvantage to the U.S. market. In this quest, AquaBounty has lost between US $100 million and $115 million (so far).
In June, the company will harvest its first salmon raised in the United States and intended for sale there. Thanks to modifications that involved splicing genetic material into its salmon from two other species of fish, these salmon grow twice as fast and need 25 percent less food to reach the same weight as salmon raised on other fish farms.
Since AquAdvantage salmon are genetically modified, the company has taken special precautions to reduce the odds that these fish could reproduce in the wild. Raising all the salmon indoors, far away from wild populations, is key to that equation. And that strategy wouldn’t be possible without modern recirculating systems.
But it’s not yet clear whether U.S. consumers will buy AquaBounty’s salmon, or even if stores will sell it. Already Costco, Target, Trader Joe’s, Walmart, Whole Foods, and roughly 80 other North American grocery store chains have said they don’t plan to carry it. As of December, AquaBounty was unable to name any restaurants or stores where customers would be able to buy its salmon.
A 2018 report by Diamond Equity Research, paid for by AquaBounty, estimated potential annual sales of $10 million in the United States. Meanwhile, sales in Canada—where AquAdvantage salmon has been sold since 2017—brought in just $140,371 in the first nine months of 2019.
In late October, the biotech firm Intrexon Corp., which held 38.1 percent of AquaBounty’s shares, sold its entire stake to Virginia-based TS AquaCulture for $21.6 million. Both firms are owned by billionaire biotech investor Randal Kirk.
Eric Hallerman, a fisheries scientist at Virginia Tech who served on the U.S. Food and Drug Administration panel that reviewed AquAdvantage salmon, thinks it deserves a place on the table. “People want to eat more meat. We have to do it efficiently,” Hallerman says. “So, I think this has to be part of that.”
The first generation of recirculating systems, which rolled out in the 1980s and 1990s, largely failed. The filters involved couldn’t remove enough waste to maintain water quality at the indoor aquaculture farms that installed them. “Few [of these systems], if any, are still around,” says Brian Vinci, director of the Freshwater Institute, a program sponsored by a nonprofit called the Conservation Fund that has developed recirculation technology. “The ones that [still exist] grow tilapia—a very hardy species that’s able to handle ‘just okay’ water quality.”
These systems use a series of mechanical and biological filters to remove solid waste, ammonia, and carbon dioxide—all produced by the fish—from the water used on the farm. Sensors monitor temperature, pH, and water levels in every tank and track the oxygen content of the water, which must be replenished before it cycles back through. Alarms alert staff to potential problems.
Like all salmon, AquAdvantage fish begin life as fertilized eggs. In AquaBounty’s case, salmon start out at a hatchery on Prince Edward Island, in Canada, where the company keeps a small breeding stock. Technicians there gently massage female fish to extract eggs and prompt males to expel milt, or semen, which the staff mix together to produce fertilized eggs. Aside from the fish used in breeding, all the other salmon the company produces are sterile females, which cannot reproduce with one another or with wild salmon.
When these eggs become “eyed eggs”—so named because two little black eyes suddenly become visible inside each gelatinous orange blob—the eggs are considered stable enough to transport. At this point, they’re moved from the Prince Edward hatchery to AquaBounty’s Indiana farm, where the company had about 150,000 eyed eggs on site in November.
When the eyed eggs arrive, they’re put onto large trays that hold as many as 10,000 at a time. Then they’re placed into one of two incubation units until they hatch (typically within two weeks) and absorb their yolk sac—at which point the fry are said to be “buttoned up.”
The buttoned-up fry then slide into one of 12 small tanks in a nursery, where they begin eating commercial feed (the same kind used on other fish farms) until they weigh about 5 grams. Then they’re transferred into one of 24 tanks—still in the nursery—until they hit 40 to 50 grams.
At that point, the fish are moved from the nursery to a set of “pre–grow out” tanks, which can hold up to 20,000 fish at a time. Once they reach 300 grams, they’re switched over to a set of six tanks where they grow to about 4.5 kilograms.
Right before harvest, the fish must spend about six days being purged in specially-designed tanks that pump in fresh water. Here the fish are rinsed of any compounds that may have built up in the recirculation system and could spoil the salmon’s flavor.
Then, it’s harvest time. Common methods include electrocution or percussive stunning; AquaBounty isn’t yet sure which technique it will use. AquaBounty’s salmon are ready to harvest just 18 months after they hatch. It can take up to three years for wild salmon to reach market weight of 4.5 kg.
AquaBounty’s recirculating system cleans and recycles water and monitors conditions throughout every stage of a salmon’s life. Mechanical filters, such as the Hydrotech drum filters, capture fish waste. Biological filters containing bacteria convert ammonia to nitrite, and then change nitrite into nitrate. Water temperature is kept to between 13 and 15 °C.
One advance developed at Cornell, adopted by the Freshwater Institute and installed at AquaBounty’s facility, is a “self-cleaning” circular fish tank fitted with strategically placed nozzles, which create a whirlpool effect to mechanically separate waste such as uneaten food. “We get the tank to operate like a teacup or coffee cup, so when you swirl the water, the grounds go to the bottom,” Vinci says.
With its recirculating tech, AquaBounty aims to recycle 95 percent of the water used at its Indiana facility. Any water that can’t be recycled will pass through an on-site water treatment plant and then go into wetlands, according to Dave Conley, AquaBounty’s director of communications.
Even with the newest recirculating tech, Vinci at the Freshwater Institute says there’s still room for improvement. “We do use a lot of sensors, and that is one of the weakest parts of the RAS industry, in my opinion,” Vinci says. “I can’t tell you how many different probes we’ve tried.”
He hopes that the machine-vision technology developed by Aquabyte to count sea lice in coastal fish farms will someday be able to recognize individual fish in indoor aquaculture facilities and monitor their health and well-being. Compared with traditional fish farms, AquaBounty’s salmon live in close quarters—there are more than three times as many fish per cubic meter of water at the Indiana facility as there are in traditional fish farms.
Even so, the AquaBounty farm uses no vaccines, antibiotics, or chemical treatments, Conley says. Eyed eggs are disinfected with iodine upon arrival, and technicians clean and disinfect the tanks and incubator trays between each batch (about every three months). Before a fish leaves the nursery, it’s screened for eight different bacterial, parasitic, and viral diseases.
Rosalind Leggatt, a postdoctoral researcher at Fisheries and Oceans Canada who contributed to the agency’s environmental assessment of AquAdvantage salmon, says the development of recirculating technology has dovetailed nicely with AquaBounty’s plans. “The recirculating systems are advancing every six months,” she says. “They might go hand in hand together.”
Now, AquaBounty must try to win over retailers, restaurateurs, and consumers who have plenty of wild-caught and farm-raised salmon from which to choose. AquaBounty plans to produce about 1,200 metric tons of salmon a year. That’s a tiny fraction of the 351,136 metric tons of salmon imported in 2018 to the United States.
To entice customers, AquaBounty is touting the environmental benefits of its salmon. The company’s website even declares it to be “The World’s Most Sustainable Salmon.” The fact that this fish consumes far less feed to reach market weight is part of that story, as is the notion that eating farm-raised salmon preserves wild stocks. Decades of overfishing have landed U.S. wild Atlantic salmon populations on the endangered species list, making it illegal to catch them.
AquaBounty also points out that, for U.S. customers, the carbon emissions generated by the transportation of its salmon will be a fraction (1/25, according to the company) of the emissions produced by transporting Atlantic salmon raised on farms in Norway and Chile to the United States. All wild Atlantic salmon and the vast majority of farm-raised Atlantic salmon consumed in the United States are imported—a condition AquaBounty refers to as the “national salmon deficit.”
However, there’s a smattering of U.S. and Canadian fish farms that raise Atlantic salmon either indoors or along the coasts, and it’s not clear how AquaBounty’s sustainability claims would stack up against these homegrown options—or against wild Alaskan stocks that are sustainably caught, says Bruce Bugbee, a crop physiologist at Utah State University. “The question here is not whether it’s good to eat, and not whether it’s profitable. It’s [whether] they should be using the word ‘sustainable’ on their website.” he says. “And that’s a key question.”
Some North American fish farms even tout their products as not genetically modified—possibly to differentiate themselves from AquaBounty’s offering. Scientific reviews have repeatedly found that genetically modified (GM) crops are as safe to eat as non-GM crops. And reviews by the FDA and Environment and Climate Change Canada concluded that the environmental risks of AquAdvantage salmon were extremely low or negligible thanks to the containment measures that AquaBounty has put in place.
Starting this month, companies that produce bioengineered food—defined as food containing genetic material that does not occur naturally and which could not have resulted from conventional breeding—are required by the United States Department of Agriculture to apply a new label to their products. At press time, AquaBounty could not confirm whether its fish would carry the labels or not.
Undeterred, AquaBounty is already moving forward with its second product—gene-edited tilapia cleared for sale in Argentina. These fish grow faster, consume less food, and produce bigger fillets than conventional tilapia do.
With its progress in Argentina, Canada, and the United States, AquaBounty is finally nearing the end of its protracted push to bring bioengineered fish to consumers. But being first brings no guarantees—and for AquaBounty, it’s time to sink or swim.
This article appears in the January 2020 print issue as “Transgenic Salmon Hits U.S. Shelves.”
IBM lifted the veil this week on a new battery for EVs, consumer devices, and electric grid storage that it says could be built from minerals and compounds found in seawater. (By contrast, many present-day batteries must source precious minerals like cobalt from dangerous and exploitative political regimes.) The battery is also touted as being non-flammable and able to recharge 80 percent of its capacity in five minutes.
The battery’s specs are, says Donald Sadoway, MIT professor of materials chemistry, “staggering.” Some details are available in a Dec. 18 blog posted to IBM’s website. Yet, Sadoway adds, lacking any substantive data on the device, he has “no basis with which to be able to confirm or deny” the company’s claims.
A team of European scientists proposes using mountains to build a new type of battery for long-term energy storage.
The intermittent nature of energy sources such as solar and wind has made it difficult to incorporate them into grids, which require a steady power supply. To provide uninterrupted power, grid operators must store extra energy harnessed when the sun is shining or the wind is blowing, so that power can be distributed when there’s no sun or wind.
Lithium-ion batteries currently dominate the energy storage market, but these are better suited for short-term storage, says Hunt, because the charge they hold dissipates over time. To store sufficient energy for months or years would require many batteries, which is too expensive to be a feasible option.
You could say that farming is in my blood: My grandparents on both sides ran large, prosperous farms in Iowa. One of my fondest childhood memories is of visiting my maternal grandparents’ farm and watching the intricate moving mechanisms of the threshing machine. I guess it’s not surprising that I eventually decided to study mechanical engineering at MIT. I never really considered a career in farming.
Shortly after I graduated in 1957 and took a job with the California Institute of Technology’s Jet Propulsion Lab, the Soviets launched Sputnik. I was at the right place at the right time. JPL was soon transferred to the newly formed NASA. And for more than 50 years, I worked with some of the brightest engineers in the world to send unmanned spacecraft—including Mariner, Viking, and Voyager—to all the other planets in the solar system.
But my love of farms and farming never went away, and in 1999, I purchased my paternal grandfather’s 130-hectare (320-acre) property, Pinehurst Farm, which had been out of the family for 55 years. I wasn’t exactly sure what I’d do with the place, but by the time I retired in 2007, there was more and more talk about climate change due to human-caused carbon emissions. I knew that agriculture has a large carbon footprint, and I wondered if there was a way to make farming more sustainable. After all, the most recent numbers are alarming: The World Meteorological Organization reports that the planet is on course for a rise in temperature of 3 to 5 °C by 2100. The U.S. Environmental Protection Agency estimates that agriculture and forestry accounted for almost 10 percent of greenhouse gas emissions in 2016. While a significant share of those are livestock emissions (that is, belches and flatulence), much of it comes from burning fuel to grow, harvest, and transport food, as well as fertilizer production.
I recalled a conversation I’d had with my dad and his friend, Roy McAlister, right after I acquired the farm. Roy was the president of the American Hydrogen Association, and he owned a hydrogen-powered Nissan pickup truck. Both men were vocal advocates for replacing fossil fuels with hydrogen to reduce the United States’ dependence on oil imports. The same transition would also have a big impact on carbon emissions.
And so, in 2008, I decided to create a solar-hydrogen system for Pinehurst Farm as a memorial to my father. I’d use solar power to run the equipment that would generate fuel for a hydrogen-burning tractor. Several years into the project, I decided to also make ammonia (nitrogen trihydride, or NH3) to use as tractor fuel and crop fertilizer.
My aim is to make the public—especially farmers—aware that we will need to develop such alternative fuels and fertilizers as fossil fuels become depleted and more expensive, and as climate change worsens. Developing local manufacturing processes to generate carbon-free fuel and fertilizer and powering those processes with renewable energy sources like solar and wind will eliminate farmers’ reliance on fossil fuels. And doing this all locally will remove much of the cost of transporting large amounts of fuel and fertilizers as well. At our demonstration project at Pinehurst, my colleague David Toyne, an engineer based in Tujunga, Calif., and I have shown that sustainable farming is possible. But much like designing spacecraft, the effort has taken a little longer and presented many more challenges than we initially expected.
The system that we now have in place includes several main components: a retrofitted tractor that can use either hydrogen or ammonia as fuel; generators to create pure hydrogen and pure nitrogen, plus a reactor to combine the two into ammonia; tanks to store the various gases; and a grid-tied solar array to power the equipment. When I started, there were no other solar-hydrogen farms on which I could model my farm, so every aspect had to be painstakingly engineered from scratch, with plenty of revisions, mishaps, and discoveries along the way.
The work began in earnest in 2009. Before actually starting to build anything, I crunched the numbers to see what would be needed to pull off the project. I found that a 112-kilowatt (150-horsepower) tractor burns about 47 liters per hectare (5 gallons per acre) if you’re raising corn and about two-thirds that amount for soybeans. The same area would require 5 kilograms of hydrogen fuel. That meant we needed roughly 1,400 kg of hydrogen to fuel the tractor and other farm vehicles from planting to harvest. Dennis Crow, who farms the Pinehurst land, told me about half the fuel would go toward spring planting and half for fall harvesting. The growing season in Iowa is about 150 days, so we’d need to make about 4.5 kg of hydrogen per day to have 700 kg of hydrogen for the harvest. Spring planting would be easier—we would have 215 days of the year to make the remaining fuel.
To generate the hydrogen, we would split water into hydrogen and oxygen. By my calculations, running the hydrogen generator and related equipment would require about 80 kW of solar power. I decided to use two-axis solar arrays, which track the sun to boost the collection capacity by 30 percent. Based on the efficiency of commodity photovoltaic panels in 2008, we’d need 30 solar arrays, with each array holding 12 solar panels.
That’s a lot of solar panels to install, operate, and maintain, and a lot of hydrogen to generate and store. I soon realized I could not afford to build a complete operational system. Instead, I focused on creating a demonstration system at one-tenth scale, with three solar arrays instead of 30. While the tractor would be full size, we would make only 10 percent of the hydrogen needed to fuel it. I decided that even a limited demonstration would be a worthwhile proof of concept. Now we had to figure out how to make it happen, starting with the tractor.
As it turns out, I wasn’t the first to think of using hydrogen as a tractor fuel. Back in 1959, machinery manufacturer Allis-Chalmers demonstrated a tractor powered by hydrogen fuel cells. Fifty-two years later, New Holland Agriculture did the same. Unfortunately, neither company produced a commercial model. After some further research, I decided that fuel cells were (and still are) far too expensive. Instead, I would have to buy a regular diesel tractor and convert it to run on hydrogen.
Tom Hurd, an architect in Mason City, Iowa, who specializes in renewable-energy installations, assisted with the farm’s overall design. At his suggestion, I contacted the Hydrogen Engine Center in nearby Algona, Iowa. The company’s specialty was modifying internal combustion engines to burn hydrogen, natural gas, or propane. Ted Hollinger, the center’s president, agreed to provide a hydrogen-fueled engine for the tractor.
Hollinger’s design started with a gasoline-fueled Ford 460 V-8 engine block. He suggested that we include a small propane tank as backup in case the tractor ran out of hydrogen out in the field. Several months later, though, he recommended that we use ammonia instead of propane, to avoid fossil fuels completely. Since the idea was to reduce the farm’s carbon footprint, I liked the ammonia idea.
Scott McMains, who looks after the old cars that I store on the farm, located a used 7810 John Deere tractor as well as a Ford 460 engine. The work of installing the Ford engine into the tractor was done by Russ Hughes, who lives in Monticello, Iowa, and was already restoring my 1947 Buick Roadmaster sedan.
The tractor would need to carry several large, heavy fuel tanks for the hydrogen and ammonia. Bob Bamford, a retired JPL structural-design analyst, took a look at my plans for the fuel tanks’ support structure and redesigned it. In my original design, the support structure was bolted together, but Bamford’s design used welds for increased strength. I had the new and improved design fabricated in California.
The completed tractor was delivered to the farm in late 2014. With the flick of a switch in the cab, our tractor can toggle between burning pure hydrogen and burning a mixture of hydrogen and ammonia gas. Pure ammonia won’t burn in an internal combustion engine; you first need to mix it with about 10 percent hydrogen. The energy content of a gallon of ammonia is about 35 percent that of diesel. The fuel is then mixed with the intake air and injected into the tractor’s computer-controlled, spark-ignited engine cylinders. The tractor can run for 6 hours at full power before it needs to be refueled.
While work on the tractor proceeded, we were also figuring out how to generate the hydrogen and ammonia it would burn.
Ramsey Creek Woodworks of Kalona, Iowa, modified the farm’s old hog shed to house the hydrogen generators, control equipment, and the tractor itself. The company also installed the solar trackers and the solar arrays.
We constructed a smaller building to house the pumps that would compress the hydrogen for high-pressure storage. Hydrogen is of course incredibly flammable. For safety, I designed low slots in the walls on two sides so that air could enter and vent out the top, taking with it any leaked hydrogen.
So how does the system actually produce hydrogen? The generator I purchased, from a Connecticut company called Proton OnSite, creates hydrogen and oxygen by splitting water that we pipe in from an on-site well. It is rated to make 90 grams (3 ounces) of hydrogen per hour. With the amount of sunlight Iowa receives, I can make an average of 450 grams of hydrogen per day. We can make more on a summer day, when we have more daylight, than we can in winter.
The generator was designed to operate continuously. But we’d be relying on solar power, which is intermittent, so David Toyne, who specializes in factory automation and customized systems, worked with Proton to modify it. Now the generator makes less hydrogen on overcast days and enters standby when the solar arrays’ output is too low. At the end of each day, the generator automatically turns off after being on standby for 20 minutes.
Generating ammonia posed some other challenges. I wanted to make the ammonia on-site, so that I could show it was possible for a farm to produce its fuel and fertilizer with no carbon emissions.
A substantial percentage of the world’s population depends on food grown using nitrogen-based fertilizers, including ammonia. It’s hard to beat for boosting crop yields. For example, Adam Sylvester, Pinehurst’s farm manager, told me that if we did not use nitrogen-based fertilizers on our cornfields, the yield would be about 250 bushels per hectare (100 bushels per acre), instead of the 500 bushels we get now. Clearly, the advantages to producing ammonia on location extend beyond just fuel.
But ammonia production also accounts for about 1 percent of all greenhouse emissions, largely from the fossil fuels powering most reactors. And just like hydrogen, ammonia comes with safety concerns. Ammonia is an irritant to the eyes, respiratory tract, mucus membranes, and skin.
Even so, ammonia has been used for years in refrigeration as well as fertilizer. It’s also an attractive carbon-free fuel. A ruptured ammonia tank won’t explode or catch fire as a propane tank will, and the liquid is stored at a much lower pressure than is hydrogen gas (1 megapascal for ammonia versus 70 MPa for hydrogen).
While attending the NH3 Fuel Conference in Sacramento in 2013, I had dinner with Bill Ayres, a director for the NH3 Fuel Association, and we discussed my interest in making ammonia in a self-contained system. Ayres pointed me to Doug Carpenter, who had developed a way to make ammonia on a small scale—provided you already have the hydrogen. Which I did. Carpenter delivered the reactor in 2016, several months before his untimely passing.
We turned again to Ramsey Creek to construct the ammonia-generation building. The 9-square-meter building, similar in design to the hydrogen shed, houses the pumps, valves, controls, ammonia reactor, collector tanks, and 10 high-pressure storage tanks. We make nitrogen by flowing compressed air through a nitrogen generator and removing the atmospheric oxygen. Before entering the reactor, the hydrogen and nitrogen are compressed to 24 MPa (3,500 pounds per square inch).
It’s been a process of trial and error to get the system right. When we first started making ammonia, we found it took too long for the reactor’s preheater to heat the hydrogen and nitrogen, so we added electrical band heaters around the outside of the unit. Unfortunately, the additional heat weakened the outer steel shell, and the next time we attempted to make ammonia, the outer shell split open. The mixed gases, which were under pressure at 24 MPa, caught fire. Toyne was in the equipment room at the time and noticed the pressure dropping. He made it out to the ammonia building in time to take pictures of the flames. After a few minutes, the gas had all vented through the top of the building. Luckily, only the reactor was damaged, and no one was hurt.
After that incident, we redesigned the ammonia reactor to add internal electrical heaters, which warm the apparatus before the gases are introduced. We also insulated the outer pressure shell from the heated inside components. Once started, the reaction forming the ammonia needs no additional heat.
Our ammonia system, like our hydrogen and nitrogen systems, is hooked up to the solar panels, so we cannot run it round the clock. Also, because of the limited amount of solar power we have, we can make either hydrogen or nitrogen on any given day. Once we have enough of both, we can produce a batch of ammonia. At first, we had difficulty producing nitrogen pure enough for ammonia production, but we solved that problem by mixing in a bit of hydrogen. The hydrogen bonds with the oxygen to create water vapor, which is far easier to remove than atmospheric oxygen.
We’ve estimated that our system uses a total of 14 kilowatt-hours to make a liter of ammonia, which contains 3.8 kWh of energy. This may seem inefficient, but it’s comparable to the amount of usable energy we could get from a diesel-powered tractor. About two-thirds of the electrical energy is used to make the hydrogen, one-quarter is used to make the nitrogen, and the remainder is for the ammonia.
Each batch of ammonia is about 38 liters (10 gallons). It takes 10 batches to make enough ammonia to fertilize 1.2 hectares of the farm’s nearly 61 hectares (3 of 150 acres) of corn. Thankfully, we can use the same ammonia for either application—it has to be liquid regardless of whether we’re using it for fertilizer or fuel.
We now have the basis of an on-site carbon-emission-free system for fueling a tractor and generating fertilizer, but there’s still plenty to improve. The solar arrays were sized to generate only hydrogen. We need additional solar panels or perhaps wind turbines to make more hydrogen, nitrogen, and ammonia. In order to make these improvements, we’ve created the Schmuecker Renewable Energy System, a nonprofit organization that accepts donations.
Toyne compares our system to the Wright brothers’ airplane: It is the initial demonstration of what is possible. Hydrogen and ammonia fuels will become more viable as the equipment costs decrease and more people gain experience working with them. I’ve spent more than US $2 million of my retirement savings on the effort. But much of the expense was due to the custom nature of the work: We estimate that to replicate the farm’s current setup would cost a third to half as much and would be more efficient with today’s improved equipment.
We’ve gotten a lot of interest about what we’ve installed so far. Our tractor has drawn attention from other farmers in Iowa. We’ve received inquiries from Europe, South Africa, Saudi Arabia, and Australia about making ammonia with no carbon emissions. In May 2018, we were showing our system to two employees of the U.S. Department of Energy, and they were so intrigued they invited us to present at an Advanced Research Projects Agency–Energy (ARPA-E) program on renewable, carbon-free energy generation that July.
Humankind needs to develop renewable, carbon-emission-free systems like the one we’ve demonstrated. If we do not harness other energy sources to address climate change and replace fossil fuels, future farmers will find it harder and harder to feed everyone. Our warming world will become one in which famine is an everyday occurrence.
This article appears in the November 2019 print issue as “The Carbon-Free Farm.”
About the Author
Jay Schmuecker worked for more than 50 years building planetary spacecraft at NASA’s Jet Propulsion Laboratory. Since retiring, he has been developing a solar-powered hydrogen fueling and fertilization system at Pinehurst Farm in eastern Iowa.
Lucas Joppa thinks big. Even while gazing down into his cup of tea in his modest office on Microsoft’s campus in Redmond, Washington, he seems to see the entire planet bobbing in there like a spherical tea bag.
As Microsoft’s first chief environmental officer, Joppa came up with the company’s AI for Earth program, a five-year effort that’s spending US $50 million on AI-powered solutions to global environmental challenges.
The program is not just about specific deliverables, though. It’s also about mindset, Joppa told IEEE Spectrum in an interview in July. “It’s a plea for people to think about the Earth in the same way they think about the technologies they’re developing,” he says. “You start with an objective. So what’s our objective function for Earth?” (In computer science, an objective function describes the parameter or parameters you are trying to maximize or minimize for optimal results.)
AI for Earth launched in December 2017, and Joppa’s team has since given grants to more than 400 organizations around the world. In addition to receiving funding, some grantees get help from Microsoft’s data scientists and access to the company’s computing resources.
In a wide-ranging interview about the program, Joppa described his vision of the “ultimate optimization problem”—figuring out which parts of the planet should be used for farming, cities, wilderness reserves, energy production, and so on.
Every square meter of land and water on Earth has an infinite number of possible utility functions. It’s the job of Homo sapiens to describe our overall objective for the Earth. Then it’s the job of computers to produce optimization results that are aligned with the human-defined objective.
I don’t think we’re close at all to being able to do this. I think we’re closer from a technology perspective—being able to run the model—than we are from a social perspective—being able to make decisions about what the objective should be. What do we want to do with the Earth’s surface?
Buildings use more than one-third of the world’s energy, most of it for heating spaces and water. Most of this heat is generated by burning natural gas, oil, or propane. And where these fossil fuels are consumed, greenhouse gas emissions are a given.
Electric heat pumps, first widely used in the 1970s in Europe, could be the best solution to cut that fossil fuel use. They could slash the carbon emissions of buildings by half. And if powered by renewables, emissions can potentially go down to zero.
However there are at least two reasons why data centers will likely play a key role in any attempt to curb global emissions. First, as cloud computing becomes more energy-efficient and increasingly relies on renewable sources, other sectors such as manufacturing, transportation, and buildings could turn to green data centers to reduce their own emissions. For example—a car manufacturer might outsource all of its in-house computing to zero-emission data centers.
Even without such partnerships, though, data centers will likely play an important part in the climate’s future. The rise of AI, machine learning, big data, and the Internet of Things mean that data centers’ global electricity consumption will continue to increase. By one estimate, consumption could jump to as much as 13 percent of the world’s total electricity demand by 2030.
For these reasons, says Johan Falk, senior innovation fellow at the Stockholm Resilience Center in Sweden, data centers will have outsized importance in climate change mitigation efforts. And the more progress society makes in the near term, the sooner the benefits will begin to multiply.
A material called ZIF-8 swells up when carbon dioxide molecules are trapped inside, new images reveal
A new kind of molecular-scale microscope has been trained for the first time on a promising wonder material for carbon capture and storage. The results, researchers say, suggest a few tweaks to this material could further enhance its ability to scrub greenhouse gases from emissions produced by traditional power plants.
The announcement comes in the wake of a separate study concerning carbon capture published in the journal Nature. The researchers involved in that study found that keeping the average global temperature change to below 1.5 degrees C (the goal of the Paris climate accords) may require more aggressive action than previously anticipated. It will not be enough, they calculated, to stop building new greenhouse-gas-emitting power stations and allow existing plants to age out of existence. Some existing plants will also need to be shuttered or retrofitted with carbon capture and sequestration technology.
Säntis Tower in the Swiss Alps is struck by lightning more than 100 times a year
Atop a rocky peak in the Swiss Alps sits a telecommunications tower that gets struck by lightning more than 100 times a year, making it perhaps the world’s most frequently struck object. Taking note of the remarkable consistency with which lightning hits this 124-meter structure, researchers have adorned it with instruments for a front-row view of these violent electric discharges.
On Wednesday, a small team installed a new gadget near Säntis Tower in their years-long quest to better understand how lightning forms and why it behaves the way it does. About two kilometers from the tower, they set up a broadband interferometer that one member, Mark Stanley of New Mexico Tech, had built back in his lab near Jemez, New Mexico.
“You can’t really go to a company and find an instrument that’s built just for studying lightning,” says Bill Rison, Stanley’s collaborator who teaches electrical engineering at New Mexico Tech. “You have to build your own.”
The one Stanley built has three antennas with bandwidth from 20 to 80 megahertz (MHz) to record powerful electromagnetic pulses in the very high-frequency range that lightning is known to produce. The device also has a fourth antenna to measure sferics, which are low-frequency signals that result from the movement of charge that occurs with a strike or from storm activity within clouds. “Basically, lightning is a giant spark,” Rison explains. “Sparks give off radio waves and the interferometer detects the radio waves.”
To anyone who has witnessed a lightning strike, everything seems to happen all at once. But Stanley’s sensor captures several gigabytes of data about the many separate pulses that occur within each flash. Those data can be made into a video that replays, microsecond by microsecond, how “channels” of lightning form in the clouds.
By mapping lightning in this way, the Säntis team, which hired Stanley and Rison to haul their interferometer to Switzerland, hopes to better understand what prompts lightning’s “initiation”—that mysterious moment when it cracks into existence.
So far, measurements have raised more questions than they’ve answered. One sticking point is, in order for a thunderstorm to emit a lightning strike, the electric field within it must build to an intensity on the order of several megavolts per meter. But while researchers have sent balloons into thunderstorms, no one has measured a field beyond 200 kilovolts per meter, or one-tenth of the required value, says Farhad Rachidi of the Swiss Federal Institute of Technology (EPFL), who co-leads the Säntis research team.
“The conditions required for lightning to be started within the clouds never seem to exist based on the measurements made in the clouds,” says Marcos Rubinstein, a telecommunications professor at Switzerland’s School of Business and Engineering Vaud and co-leader of the Säntis team with Rachidi. “This is a big, big question.”
In his own research at New Mexico Tech, Rison has laid some groundwork that could explain how small electric fields can produce such big sparks. In 2016, he and his colleagues published a paper in NatureCommunications that described experimental evidence showing that a process known as fast positive breakdown can create a series of streamers, or tiny sparks, and may arise from much stronger local electric fields that occur in small pockets within a storm.
If enough streamers occur in quick succession and within close vicinity to one another, they make more streamers, adding up to a streamer “avalanche” that turns into positive leaders, or mini-bolts that branch toward clouds or the ground.
“We haven’t hit any roadblocks yet to say, this is something that isn’t the process for the initiation of lightning,” Rison says. With his evidence in hand, theorists are now trying to explain exactly how and why these fast positive breakdowns occur in the first place.
Meanwhile, the Säntis team wants to adapt a mathematical technique called time-reversal, which was originally pioneered for acoustics, to better understand lightning’s initiation. With this method, they intend to use data gathered by the tower’s many instruments (which include a collection of six antennas called a lightning mapping array, two Rogowski coils to measure current, two B-Dot sensors to measure the current time-derivative, broadband electric and magnetic field sensors, and a high-speed camera) to reconstruct the total path of strikes soon after they happen, tracing the electromagnetic radiation all the way back to its original source.
As has been true of past lightning research, their findings may someday inform the design of airplanes or electric grids, and help protect people and equipment against lightning strikes and other sudden power surges. The Säntis team’s work has held particular relevance for wind farm operators. That’s because most strikes recorded at the tower are examples of upward lightning—which travels from ground-to-cloud instead of cloud-to-ground.
Upward lightning often originates from tall buildings and structures, which can actually create a lightning bolt that shoots skyward, and this process can damage wind turbines. In 2013, the team published one of the most extensive descriptions to date of this type of flash.
More recently, their work has raised questions about why industry safety certifications for aircraft are based on data about downward strikes, instead of upward ones, which commonly occur with aircraft and cause particular kinds of damage that look more like lightning damage reported by pilots and mechanics.
By the end of this year, the Säntis team expects to record its 1,000th lightning strike at the tower. And there’s one more elusive scientific matter with massive practical implications they hope to someday resolve. “If we understand how lightning is initiated, we could take a big step forward on one of the other questions we’ve been trying to solve for a long time, and that’s to be able to predict lightning before it happens,” says Rubinstein.
Ebook: How to Determine Oscilloscope Signal Integrity
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A prototype solid-state battery based on lithium and glass faces criticism over claims that its capacity increases over time
Is there such a thing as a battery whose capacity to store energy increases with age? One respected team of researchers say they have developed just such a technology. Controversy surrounds their claims, however, in part because thermodynamics might seem to demand that a battery only deteriorates over many charge-discharge cycles.
The researchers have a response for that critique and continue to publish peer-reviewed papers about this work. If such claims came from almost any other lab, they might be ignored and shunned by the broader community of battery researchers, the same way physicists turn their noses up at anything that smacks of a perpetual motion machine.
But this lab belongs to one of the most celebrated battery pioneers today—and one of the inventors of the lithium-ion battery itself. John Goodenough, who at 96 continues to research and publish like scientists one-third his age, last year joined with three co-authors in publishing a paper that grabbed headlines. (Spectrum had profiled him and his battery technology the year before, following an initial announcement about his group’s new glass battery.)
An Australian research team is using tech to monitor global climate change’s assault on the world’s largest living organism
The stats are daunting. The Great Barrier Reef is 2,300 kilometers long, comprises 2,900 individual coral reefs, and covers an area greater than 344,000 square kilometers, making it the world’s largest living organism and a UNESCO World Heritage Site.
A team of researchers from Queensland University of Technology (QUT) in Brisbane, is monitoring the reef, located off the coast of northeastern Australia, for signs of degradation such as the bleaching caused by a variety of environmental pressures including industrial activity and global warming.
The team, led by Felipe Gonzalez, an associate professor at QUT, is collaborating with the Australian Institute of Marine Science (AIMS), an organization that has been monitoring the health of the reef for many years. AIMS employs aircraft, in-water surveys, and NASA satellite imagery to collect data on a particular reef’s condition. But these methods have drawbacks, including the relatively low resolution of satellite images and high cost of operating fixed-wing aircraft and helicopters.
So Gonzalez is using an off-the-shelf drone modified to carry both a high-resolution digital camera and a hyperspectral camera. The monitoring is conducted from a boat patrolling the waters 15 to 70 km from the coast. The drone flies 60 meters above the reef, and the hyperspectral camera captures reef data up to three meters below the water’s surface. This has greatly expanded the area of coverage and is helping to verify AIMS’s findings.
The digital camera is used to build up a conventional 3D model of an individual reef under study, explains Gonzalez. But this conventional camera is capable of capturing light only from three spectral channels: the red, green, and blue covering the 380-to-740-nanometer portion of the electromagnetic spectrum. The hyperspectral camera, by contrast, collects the reflected light of 270 spectral bands.
“Hyperspectral imaging greatly improves our ability to monitor the reef’s condition based on its spectral properties,” says Gonzalez. “That’s because each component making up a reef’s environment—water, sand, algae, etc.—has its own spectral signature, as do bleached and unbleached coral.”
But this expansion in reef coverage and richness of gathered data presented the team with a new challenge. Whereas AIMS divers can gather information on 40 distinct points on a reef in an underwater session, just one hyperspectral image presents more than 4,000 data points. Consequently, a single drone flight can amass a thousand gigabytes of raw data that has to be processed and analyzed.
In processing the data initially, the team used a PC, custom software tools, and QUT’s high-performance computer, a process that took weeks and drew heavily on the machine’s run time.
So the team applied for and received a Microsoft AI for Earth grant, which makes software tools, cloud computing services, and AI deep learning resources available to researchers working on global environmental challenges.
“Now we can use Microsoft’s AI tools in the cloud to supplement our own tools and quickly label the different spectral signatures,” says Gonzalez. “So, where processing previous drone sweeps used to take three or four weeks, depending on the data, it now takes two or three days.”
This speedup in data processing is critical. If it took a year or more before the team were able to tell AIMS that a certain part of the reef is degrading rapidly, it might be too late to save it.
“And by being informed early, the government can then take quicker action to protect an endangered area of the reef,” Gonzalez adds.
He notes that the use of hyperspectral imaging is now a growing area of remote sensing in a variety of fields, including agriculture, mineral surveying, mapping, and location of water resources.
For example, he and colleagues at QUT are also using the technology to monitor forests, wheat crops, and vineyards that can be affected by pathogens, fungi, or aphids.
Meanwhile, over the next two months, Gonzalez will continue processing the spectral data collected from the reef so far; and then in September, he will start a second round of drone flights.
“We aim to return to the four reefs AIMS has already studied to monitor any changes,” he says, “then extend the monitoring to new reefs.”
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