by Mark Gillispie and Tom Krisher
Each morning at a transit facility in Canton, Ohio, more than a dozen buses pull up to a fueling station before fanning out to their routes in this city south of Cleveland.
The buses—made by El Dorado National and owned by the Stark Area Regional Transit Authority—look like any others. Yet collectively, they reflect the cutting edge of a technology that could play a key role in producing cleaner inter-city transportation. In place of pollution-belching diesel fuel, one-fourth of the agency's buses run on hydrogen. They emit nothing but harmless water vapor.
Hydrogen, the most abundant element in the universe, is increasingly viewed, along with electric vehicles, as one way to slow the environmentally destructive impact of the planet's 1.2 billion vehicles, most of which burn gasoline and diesel fuel. Manufacturers of large trucks and commercial vehicles are beginning to embrace hydrogen fuel cell technologies as a way forward. So are makers of planes, trains and passenger vehicles.
Transportation is the single biggest U.S. contributor to climate change, which is why hydrogen power, in the long run, is seen as a potentially important way to help reduce carbon emissions.
To be sure, hydrogen remains far from a magic solution. For now, the hydrogen that is produced globally each year, mainly for refineries and fertilizer manufacturing, is made using natural gas or coal. That process pollutes the air, warming the planet rather than saving it. Indeed, a new study by researchers from Cornell and Stanford universities found that most hydrogen production emits carbon dioxide, which means that hydrogen-fueled transportation cannot yet be considered clean energy.
Yet proponents of hydrogen-powered transportation say that in the long run, hydrogen production is destined to become more environmentally safe. They envision a growing use of electricity from wind and solar energy, which can separate hydrogen and oxygen in water. As such renewable forms of energy gain broader use, hydrogen production should become a cleaner and less expensive process.
Within three years, General Motors, Navistar and the trucking firm J.B. Hunt plan to build fueling stations and run hydrogen trucks on several U.S. freeways. Toyota, Kenworth and the Port of Los Angeles have begun testing hydrogen trucks to haul goods from ships to warehouses.
In Germany, a hydrogen-powered train began operating in 2018, and more are coming. French-based Airbus, the world's largest manufacturer of airliners, is considering hydrogen as well.Volvo Trucks, Daimler Trucks AG and other manufacturers have announced partnerships, too. The companies hope to commercialize their research, offering zero-emissions trucks that save money and meet stricter pollution regulations.
"This is about the closest I've seen us get so far to that real turning point," said Shawn Litster, a professor of mechanical engineering at Carnegie Mellon University who has studied hydrogen fuel cells for nearly two decades.
Hydrogen has long been a feedstock for the production of fertilizer, steel, petroleum, concrete and chemicals. It's also been running vehicles for years: Around 35,000 forklifts in the United States, about 4% of the nation's total, are powered by hydrogen. Its eventual use on roadways, to haul heavy loads of cargo, could begin to replace diesel-burning polluters.
No one knows when, or even whether, hydrogen will be adopted for widespread use. Craig Scott, Toyota's head of advanced technology in North America, says the company is perhaps two years from having a hydrogen truck ready for sale. Building more fueling stations will be crucial to widespread adoption.
Kirt Conrad, CEO of Canton's transit authority since 2009, says other transit systems have shown so much interest in the technology that SARTA takes its buses around the country for demonstrations. Canton's system, which bought its first three hydrogen buses in 2016, has since added 11. It's also built a fueling station. Two California transit systems, in Oakland and Riverside County, have hydrogen buses in their fleets.
"We've demonstrated that our buses are reliable and cost-efficient, and as a result, we're breaking down barriers that have slowed wider adoption of the technology," Conrad said.
The test at the Port of Los Angeles started in April, when the first of five semis with Toyota hydrogen powertrains began hauling freight to warehouses in Ontario, California, about 60 miles away. The $82.5 million public-private project eventually will have 10 semis.
Hydrogen fuel is included in President Joe Biden's plans to cut emissions in half by 2030. The infrastructure bill the Senate approved passed this week includes $9 billion for research to reduce the cost of making clean hydrogen, and for regional hydrogen manufacturing hubs.
The long-haul trucking industry appears to be the best bet for early adoption of hydrogen. Fuel cells, which convert hydrogen gas into electricity, provide a longer range than battery-electric trucks, fare better in cold weather and can be refueled much faster than electric batteries can be recharged. Proponents say the short refueling time for hydrogen vehicles gives them an edge over electric vehicles for use in taxis or delivery trucks, which are in constant use.
That advantage was important for London-based Green Tomato Cars, which uses 60 hydrogen fuel cell-powered Toyota Mirai cars in its 500-car zero emission fleet to transport corporate customers. Co-founder Jonny Goldstone said his drivers can travel over 300 miles (500 kilometers) on a tank and refuel in three minutes.
Because drivers' earnings depend on fares, Goldstone said, "if they have to spend 40, 50 minutes, an hour, two hours plugging a car in in in the middle of the working day, that for them is just not acceptable."
For now, Green Tomato is among the largest operators of hydrogen vehicles in what is still a tiny market in Europe, with about 2,000 fuel cell cars, garbage trucks and delivery vans on the roads.
About 7,500 hydrogen fuel cell cars are on the road in the U.S., mostly in California. Toyota, Honda and Hyundai produce the cars, which are priced thousands more than gasoline-powered vehicles. California has 45 public fueling stations, with more planned or under construction.
Unlike with buses and heavy trucks, experts say the future of passenger vehicles in the U.S. lies mainly with electric battery power, not hydrogen. Fully electric vehicles can travel farther than most people need to go on a relatively small battery.
And for now, hydrogen production is adding to rather than reducing pollution. The world produces about 75 million tons a year, most of it in a carbon emission-creating processes involving steam reformation of natural gas. China uses higher-polluting coal.
So-called "blue" hydrogen, made from natural gas, requires an additional step. Carbon dioxide emitted in the process is sent below the earth's surface for storage. The Cornell and Stanford study found that manufacturing blue hydrogen emitted 20% more carbon than burning natural gas or coal for heat.
That's why industry researchers are focused on electrolysis, which uses electricity to separate hydrogen and oxygen in water. Hydrogen mixes with oxygen in a vehicle's fuel cell to produce power. The amount of electricity generated by wind and solar is growing worldwide, making electrolysis cleaner and cheaper, said Joe Cargnelli, director of hydrogen technologies for Cummins, which makes electrolyzers and fuel cell power systems.
Currently, it costs more to make a hydrogen truck and produce the fuel than to put a diesel-powered truck on the road. Hydrogen costs about $13 per kilogram in California, and 1 kilogram can deliver slightly more energy than a gallon of diesel fuel. By contrast, diesel fuel is only about $3.25 per gallon in the U.S.
But experts say that disparity will narrow.
"As they scale up the technology for production, the hydrogen should come down," said Carnegie Mellon's Litster.
While a diesel semi can cost around $150,000 depending on how it's equipped, it's unclear how much fuel cell trucks would cost. Nikola, a startup electric and hydrogen fuel cell truck maker, estimated last year that it would receive about $235,000 for each hydrogen semi it sells.
Clean electricity might eventually be used to make and store hydrogen at a rail yard, where it could refuel locomotives and semis, all with zero emissions.
Cummins foresees the widespread use of hydrogen in the U.S. by 2030, sped by stricter diesel emissions regulations and government zero-emissions vehicle requirements. Already, Europe has set ambitious green hydrogen targets designed to accelerate its use.
"That's just going to blow the market open and kind of drive it," Cargnelli said. "Then you'll see other places like North America kind of follow suit."GM, Wabtec to develop hydrogen powered locomotives
© 2021 The Associated Press. All rights reserved.
Touted as clean, 'blue' hydrogen may be worse than gas, coal
"Blue" hydrogen—an energy source that involves a process for making hydrogen by using methane in natural gas—is being lauded as a clean, green energy to help reduce global warming. But Cornell and Stanford University researchers believe it may harm the climate more than burning fossil fuel.
The carbon footprint to create blue hydrogen is more than 20% greater than using either natural gas or coal directly for heat, or about 60% greater than using diesel oil for heat, according to new research published in Energy Science & Engineering.
Robert Howarth, professor of ecology and environmental biology at Cornell, together with Mark Z. Jacobson, professor of civil and environmental engineering at Stanford, authored the report.
Blue hydrogen starts with converting methane to hydrogen and carbon dioxide by using heat, steam and pressure, or gray hydrogen, but goes further to capture some of the carbon dioxide. Once the byproduct carbon dioxide and the other impurities are sequestered, it becomes blue hydrogen, according to the U.S. Department of Energy.
The process to make blue hydrogen takes a large amount of energy, according to the researchers, which is generally provided by burning more natural gas.
"In the past, no effort was made to capture the carbon dioxide byproduct of gray hydrogen, and the greenhouse gas emissions have been huge," Howarth said. "Now the industry promotes blue hydrogen as a solution, an approach that still uses the methane from natural gas, while attempting to capture the byproduct carbon dioxide. Unfortunately, emissions remain very large."
Methane is a powerful greenhouse gas, Howarth said. It is more than 100 times stronger as an atmospheric warming agent than carbon dioxide when first emitted. The United Nations' Intergovernmental Panel on Climate Change report released on Aug. 9 shows that cumulatively to date over the past century, methane has contributed about two-thirds as much to global warming as carbon dioxide has, he said.
Emissions of blue hydrogen are less than for gray hydrogen, but only by about 9% to 12%.
"Blue hydrogen is hardly emissions free," wrote the researchers. "Blue hydrogen as a strategy only works to the extent it is possible to store carbon dioxide long-term indefinitely into the future without leakage back to the atmosphere."
On Aug. 10, the U.S. Senate passed its version of the $1 trillion Infrastructure Investment and Jobs Act, which includes several billion dollars to develop, subsidize and strengthen hydrogen technology and its industry.
"Political forces may not have caught up with the science yet," Howarth said. "Even progressive politicians may not understand for what they're voting. Blue hydrogen sounds good, sounds modern and sounds like a path to our energy future. It is not."
An ecologically friendly "green" hydrogen does exist, but it remains a small sector and it has not been commercially realized. Green hydrogen is achieved when water goes through electrolysis (with electricity supplied by solar, wind or hydroelectric power) and the water is separated into hydrogen and oxygen.
"The best hydrogen, the green hydrogen derived from electrolysis—if used wisely and efficiently—can be that path to a sustainable future," Howarth said. "Blue hydrogen is totally different."
This research was supported by a grant from the Park Foundation. Howarth is a fellow at the Cornell Atkinson Center for Sustainability.
Effectively removing carbon dioxide from the atmosphere
Researchers at the Paul Scherrer Institute PSI and ETH Zurich have investigated the extent to which direct capture of carbon dioxide (CO2) from the ambient air can help to effectively remove greenhouse gasses from the atmosphere. The result: With careful planning, for example with regard to location and provision of the necessary energy, CO2 can be removed in a climate-effective manner. The researchers have now published their analysis in the journal Environmental Science & Technology.
Direct air carbon capture and storage (DACCS) is a comparatively new technology for removal of carbon dioxide from the atmosphere. Since it would allow large amounts of CO2 to be, in effect, trapped, this technology could also reduce the greenhouse effect. Researchers at the Paul Scherrer Institute PSI and ETH Zurich have now investigated how effectively this could be implemented with different system configurations of a certain process. To do this, they analyzed a total of five different configurations for capturing CO2 from the air and their use at eight different locations around the world. One result: Depending on the combination of technology used and the specific location, CO2 can be removed from the air with an effectiveness of up to 97 percent.
To separate CO2 from the atmosphere, air is first passed over a so-called absorbent with the help of fans. This binds CO2 until its capacity to absorb the greenhouse gas is exhausted. Then, in the second, so-called desorption step, the CO2 is released from the absorbent again. Depending on the absorbent, this happens at comparatively high temperatures of up to 900 degrees Celsius or at rather low temperatures of about 100 degrees Celsius. In addition to the energy required for the production and installation of the equipment, the operation of the fans and generation of the required heat produce greenhouse gas emissions. "The use of this technology only makes sense if these emissions are significantly lower than the amounts of CO2 it helps to store," says Tom Terlouw, who conducts research at PSI's Laboratory for Energy Systems Analysis and is first author of the study.
Efficiency of up to 97 percent
In their study, the researchers focused their examination on a system from the Swiss company Climeworks, which works with the low-temperature process. The PSI researchers analyzed the use of the technology at eight locations worldwide: Chile, Greece, Jordan, Mexico, Spain, Iceland, Norway, and Switzerland. For each location, they calculated the overall greenhouse gas emissions over the entire life cycle of a plant. For example, they compared the efficiency of the process when the required electricity is provided by solar energy or comes from the existing electricity grid. As sources for the necessary thermal energy they assumed, for example, solar thermal plants, waste heat from industrial processes, or heat pumps. For the study, they drew up five different system layouts for atmospheric CO2 capture for each of the eight sites. With respect to efficiency, the results show an enormous range, from 9 to 97 percent, in terms of actual greenhouse-gas removal through the use of DACCS.
No substitute for reducing emissions
"The technologies for CO2 capture are merely complementary to an overall decarbonisation strategy—that is, for the reduction of CO2 emissions—and cannot replace it," stresses Christian Bauer, a scientist at the Laboratory for Energy Systems Analysis and a co-author of the study. "However, they can be helpful in achieving the goals defined in the Paris Agreement on climate change, because certain emissions, for example from agriculture, cannot be avoided." Thus a net-zero emissions target can only be achieved with the help of suitable negative-emissions technologies.Study says 'blue hydrogen' likely bad for climate
More information: Terlouw, Tom et al, Life Cycle Assessment of Direct Air Carbon Capture and Storage with Low-Carbon Energy Sources ,Environmental Science & Technology (2021) DOI: 10.1021/acs.est.1c0326
Journal information: Environmental Science & Technology
Provided by Paul Scherrer Institute
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