What are power-to-x and e-fuels?

A windfarm across a mountainous landscape

As more businesses focus on reducing their environmental footprint, the interest in alternative fuels, power-to-x, and e-fuels continues to rise. Today, many varieties of e-fuels are used in power generation applications and beyond. 

Let’s start with basics around power-to-x and e-fuels. 

What is power-to-x?

“Power-to-x” refers to a series of techniques and pathways allowing to convert, store and utilize renewable electrical energy. Power-to-x is specifically applicable when there is an excess of renewable electricity produced from solar or wind resources. Rather than be wasted—the specific industry term for this is “curtailed”—the excess electricity is used productively. The “x” can refer to a variety of energy carriers or uses. Power-to-hydrogen is the generation of hydrogen using renewable electricity. Power-to-power refers to storing electricity in batteries. Power-to-heat consists of using electricity to heat a home or a business, typically coupled with a heat accumulator. The meaning of power-to-methane should be easy to guess.

What are e-fuels?

E-fuels are fuels that are synthetized using renewable electricity, often using inorganic feedstock. They’re the “x” of power-to-x when “x” is a fuel. E-fuels include liquid and gaseous hydrocarbons such as methane and various gasoline-like, diesel-like fuels, alcohols such as ethanol and methanol, and non-carbon fuels such as hydrogen and ammonia. 

Green hydrogen is combined with CO2 from a power plant to produce e-methane. The e-methane is then piped to consumers.
Green hydrogen is combined with CO2 from a power plant to produce e-methane. The e-methane is then piped to consumers.

Why do we need e-fuels and power-to-x?

Power-to-x system allow to decouple electricity generation and electricity demand. At each instant, the total amount of electricity generated on an electricity grid must precisely match the total amount of electricity used by consumers. In other words, generation and demand are normally closely coupled. If generation is unable to keep up with demand, for example if too many power-plants trip at the same time, the electric grid can quickly collapse. Counterintuitively, the same is true if generation exceeds demand. When large quantities of variable renewable energy resources such as wind and solar are online, renewable generation can rapidly exceed demand. When this occurs, renewable resources get curtailed to avoid collapsing the system. 

In some markets, the spot price of electricity can, as a result, become negative when renewable generation is high. This means that market participants get paid to use more electricity. 

Power-to-x projects take advantage of excess and off-peak renewable power to produce something useful. It’s a win-win situation—power-to-x producers can buy cheap renewable CO2-free electricity and solar and wind farms get to sell electricity that would otherwise have been lost. 

E-fuels produced at a power-to-x project can be used hours, weeks or months later to produce electricity. 

E-hydrogen, for example, can be used in a business equipped with a fuel cell and solar panels to make electricity during the evening and night. Business can use this setup to reduce demand fees charged by the electric utility to consumers with a high peak demand. 

At the grid level, e-hydrogen can be stored seasonally. The city of Los Angeles, California (U.S.) for example, is sponsoring a large power-to-hydrogen-to-power project in Utah. The project will create hydrogen using electricity from nearby wind and solar resources. During summer, the hydrogen will be stored underground in a geological formation. During winter, the hydrogen will be used to generate electricity, which will then be transported directly to Los Angeles via an existing high voltage transmission line.

For electricity consumers, e-hydrogen are a way to reduce their carbon footprint beyond what can be achieved with solar arrays and wind turbines alone. For utility companies and grid system operators, e-hydrogen is especially valuable, because it is one of the few CO2-free ways to balance out intermittent variable renewable energy resources.

The benefits of using e-fuels are not limited to the power generation application. They can be used in vehicles and other industrial sectors to great advantage. Forklifts running on e-hydrogen are one e-fuel application that has become popular in the logistics sector, and e-hydrogen forklifts check several boxes. They have little downtime. They don’t generate any fumes or exhaust, and in an enclosed environment like a warehouse, this feature is important. And, they’re CO2-free.

Beyond e-hydrogen, liquid e-fuels have a different process to be produced, which is more complicated. These liquid e-fuels are especially useful to power up heavy-duty applications such as marine applications. 

For applications where hydrogen is not a practical option, several alternative e-fuels can be synthesized using hydrogen. Here are some of the main ones:

What is e-methanol?

Methanol is a commodity product used on a large scale in the chemical industry to produce a variety of substances. Methanol is sometimes known as wood alcohol, and has long been used as a fuel in specialty vehicles such as RC aircraft, dirt bikes, and, yes, monster trucks. Several processes have been developed to synthesize methanol using CO2, hydrogen, and renewable electricity. Their product is a clean, carbon-neutral energy carrier—e-methanol. There is growing interest in using methanol as a marine fuel. Methanol and e-methanol could help tugboats, fishing boats, ferries and other vessels using specially modified engines to meet increasingly strict regulations limiting emissions of NOx and sulfur in densely populated coastal areas, and, in the case of e-methanol, also decrease their carbon footprint.

What is e-methane?

Methane, the main constituent of natural gas, is a widely used fossil fuel. In the United States, methane is the number one energy source used in power generation. Methane and natural gas are also increasingly popular fuels for motor vehicles. A power-to-methane system combines an e-hydrogen production process with CO2 to produce carbon-neutral e-methane. Several e-methane production processes are being developed and industrialized. Outside of power generation, the mining sector has shown a great deal of interest in these processes. For mines located in remote areas, the cost of trucking in gasoline or diesel can be prohibitively high. These mines can potentially save a lot of money by fueling their heavy hauler trucks with e-methane on-site, using renewable electricity generated locally.

What is e-diesel?

Companies and research institutions around the world are developing processes to mass produce liquid hydrocarbons from CO2, and water using e-hydrogen. The production of synthetic gasoline, jet fuel and diesel is envisioned. One advantage of these e-fuels is they can be used as a drop-in fuel in standard engines, making CO2-neutral operation possible without needing any modification to the vehicles or fueling infrastructure. 

What is e-ammonia?

Ammonia is another very common chemical. The fertilizer industry uses it in vast quantities, and it has seen occasional use as a fuel in specific situations. Belgium, for example, converted city buses to run on ammonia during World War II (the buses were scrapped as soon as fossil fuels became available again). 

In the 1960s NASA flew the X-15 rocket-powered aircraft using ammonia as fuel. Producing ammonia from hydrogen is a well-established process. Ammonia, or e-ammonia, could thus be produced industrially without any CO2 emissions in a power-to-hydrogen-to-ammonia system. E-ammonia is seen as a potential alternative to hydrogen, being easier to store and transport. Like hydrogen, ammonia can be used in specially designed fuel cells, internal combustion engines and gas turbines without releasing any emissions.

E-fuels show promise, but all must still overcome challenges preventing their widespread adoption. In almost all cases, production costs are the main issue. Outside of certain specific use cases, there are often other low CO2 alternatives available that e-fuels must compete with. Biofuels and electric batteries have a head start in that regard, having been on the market longer. 

Infrastructure costs are another challenge, particularly in the case of the non-hydrocarbon e-fuels. Fewer ships can adopt methanol if methanol is not widely available at ports. Costs, however, will come down as e-fuel technology matures and production scales increase. To make a parallel, the cost of lithium-ion batteries (the type used in electric vehicles and most stationary energy storage) has fallen by 98% in the past 30 years. If e-fuels experience a fraction of that progression, it will not be long before you can find them at your local gas station.

In addition to e-fuels, don’t forget to check out what the low-carbon fuels are, and the benefits of alternative fuels and fuel-flexibility.

Power-to-x, e-fuels, and your business

You are likely already centering your frame of thinking on the needs of your business, and asking yourself how these different alternative fuels can play a role to fulfill your needs.

In addition to the fuel itself, consider taking local availability, regulations, and your use case into account too. These additional factors compliment the unique benefits each alternative fuel offers.

These additional factors are also locally driven. If you are interested in having a discussion specific to your business, we recommend you reach out to a local partner with deeper understanding of your business and needs.

Aytek Yuksel - Cummins Inc

Aytek Yuksel

Aytek Yuksel is the Content Marketing Leader for Cummins Inc., with a focus on Power Systems markets. Aytek joined the Company in 2008. Since then, he has worked in several marketing roles and now brings you the learnings from our key markets ranging from industrial to residential markets. Aytek lives in Minneapolis, Minnesota with his wife and two kids.

Unpacking CARB’s trucking rules, regulations and legal challenges

Semi truck driving

The state of California has positioned itself as a central figure in a revolutionary shift from a 100-year path of internal combustion engines (ICE) used in commercial transportation. Within a three-year span, the state has adopted the world’s most stringent commercial vehicle regulations: Advanced Clean Trucks (ACT), the Heavy-Duty Engine and Vehicle Omnibus Regulation and Advanced Clean Fleets (ACF). The three rules work together to gradually transition commercial trucks, buses and vans to zero emission vehicles (ZEVs).

The stringent regulations have generated plenty of praise, collaboration, concern and even legal challenges. Turning away from familiar and trusted technology will be anything but easy but the industry is proving it is possible.

Questions around ZEV cost and capability relative to ICE are not taken lightly by Cummins nor other players in one of the nation’s most critical industries.

As with prior emissions legislation, amendments will undoubtedly emerge as collaborative efforts between policymakers and industry continue. That is currently the case with the Omnibus regulation as proposed amendments are under review by the Environmental Protection Agency. Some of the amendments in question focus on diesel engine testing, warranty periods and aftertreatment. 

“Omnibus, the amended version, got resubmitted to EPA and is calling for increased legacy allowances,” explained Tom Swenson, Director of Global Regulatory Affairs.

Emission legislation passed by the California Air Resources Board (CARB) requires a Clean Air Act waiver from the EPA when it proves stricter than federal policy. CARB has been receiving federal waivers for its emissions policies since the 1960s given its ongoing battles with air pollution.

Geographical features such as valleys and mountains appearing throughout the state can hinder air circulation to keep pollutants hanging around.

“The San Joaquin Valley in California, for example, is like a little trap of NOx,” Uma Vajapeyazula, North American Market Strategy Director, described.

Eager to overcome its unique air pollution issues, CARB has kept a close eye on ZEV development. Once board members decided the technology was up to the challenge of replacing ICE trucks up to Class 8, CARB adopted the Advanced Clean Trucks (ACT) rule in June of 2020. To date, it’s the only one of the three ZEV polices that has received an EPA waiver.

 The ACT rule requires that manufacturers who certify chassis or complete vehicles with a gross vehicle weight rating (GVWR) greater than 8,500 lbs. sell zero-emission vehicles (ZEV) at an increasing percentage of their annual California sales starting with the 2024 model year. The annual reporting began with the 2021 model year.

 OEMs struggling to sell ZEVs can buy ZEV credits from other manufacturers to unlock sales of their ICE vehicles. However, there’s concern that funds used to purchase ZEV credits could impact their bottom line.

 “One question is, ‘Will ZEV credit trades happen between competitors?’” Swenson said.

In September 2021, CARB adopted the Heavy-Duty Engine and Vehicle Omnibus Regulation to “drastically cut smog-forming nitrogen oxides (NOx) from conventional heavy-duty engines. The Omnibus Regulation will significantly increase the stringency of NOx emissions standards and will also lengthen the useful life and emissions warranty of heavy-duty diesel engines for use in vehicles with a gross vehicle weight rating (GVWR) greater than 10,000 pounds. The more stringent NOx emission standards begin with the 2024 model year engines and become more stringent with 2027 and subsequent model year engines.”

 Extending warranty coverage will necessarily increase the cost of equipment, Swenson noted.

 Advanced Clean Fleet legislation rolled out next in April 2023. ACF requires fleets to gradually replace acquired ZEVs while allowing them to retain ICE vehicles throughout their useful life. Per CARB, useful life is defined “as the later of either: 1) 13 years, beginning with the model year that the engine in the vehicle and was first certified for use by CARB or United States Environmental Protection Agency (U.S. EPA), or 2) the date that the vehicle exceeds 800,000 vehicle miles traveled or 18 years from the model year that the engine in the vehicle was first certified for use by CARB or U.S. EPA (whichever is earlier).”

ACF compliance challenges

In August, EPA held an ACF waiver hearing that included a full day of testimony, comments were also accepted online. One of the companies to participate was Sundance Stage Lines in San Diego. The charter bus company currently uses diesel-powered custom-built buses with a 1,000-mile range and 20-minute refueling time. It has stated opposition to ACF’s zero-emission mandate.

“As BEVs, range is cut to approximately 200 miles (substantially less in cold weather), at which point the vehicle requires a four-hour charge at a dedicated high-voltage charger before it can proceed another 200 miles,” Sundance Stage Lines writes. “Thus, any group attempting to access an area not serviced by either an airport or a nearby charter operator will be forced to make other arrangements. This will have substantial negative effects both on motorcoach operators and the traveling public.”

Among the concerns expressed, Sundance noted that “four major motorcoach manufacturers offer at least one of their models as battery-electric vehicles (BEVs.) In converting the vehicle to run as a BEV, all of the buses have lost over 70% of luggage space because the volume of batteries needed to give the vehicle a reasonable range requires the batteries and the accessories normally driven by the engine be mounted in the underfloor luggage compartments.”

Sundance also pointed out the high cost of ZEVs versus ICE. In the case of motor coaches, the company contends the price “more than doubles, from $650,000 each to over $1,400,000 per bus - a cost per unit over twice as high as any other electric vehicle.”

In its ACF waiver request submitted last November to EPA, CARB writes that “anticipated developments will likely both reduce the costs and increase the number of commercially available ZEVs, including projected decreased costs of batteries and improvements in battery energy density due to economies of scale and increasing pace of technology development and decreased costs of other ZEV components resulting from the projected increased production of ZEVs.” 

Legal battles persist

At least three lawsuits that have emerged to challenge the enforcement of ACF make it California’s most contentious trucking legislation to date. 

The first complaint was filed in October 2023 by the California Trucking Association in the U.S. District Court for the Eastern District of California. The challenge has resulted in the state holding off full enforcement that was originally slated to go into effect on January 1, 2024. CTA’s 32-page complaint argues that the state needs a waiver from the Environmental Protection Agency prior to enforcing ACF since its policies exceed federal mandates.

In response, California put ACF enforcement on hold for most fleets pending receipt of an EPA waiver. CTA noted on its website that waivers typically take 9-12 months to process. The state has been enforcing ACF for public fleets since applying for the waiver in November

“They’re implementing and enforcing ACF for state [California] and local government fleets,” explained Mari Mantle, Cummins Regulatory Affairs Manager. “It's the high priority, federal and then drayage [fleets] that they're waiting on the waiver for.”

CTA’s complaint also highlights concerns of ZEVs relative to internal combustion. Acquisition costs of ZEVs, according to CTA, are “projected to be 2 to 6 times higher than comparable ICE tractors”; ZEV range “is less than half that of an ICE truck”; additional refueling stops needed for ZEVs will require additional time and infrastructure and thus limit more route options historically utilized by ICE trucks.

In April, American Free Enterprise Chamber of Commerce (AmFree Chamber) and Associated Equipment Distributors (AED) filed suit also challenging California’s ACF regulation.

In May, the Nebraska Trucking Association topped a list of plaintiffs that included seventeen states opposing ACF: Alabama, Arizona, Arkansas, Georgia, Idaho, Indiana, Iowa, Kansas, Louisiana, Missouri, Montana, Nebraska, Oklahoma, South Carolina, Utah, West Virginia and Wyoming. Several of these same states joined a suit last year against the Advanced Clean Trucks rule.

Tom Quimby headshot

Tom Quimby

Tom Quimby, On-highway Journalist, has a broad range of experience covering various topics for local and national periodicals. His stories and photos have appeared in The Washington Times and more recently in Commercial Carrier Journal, Overdrive, Hard Working Trucks, Equipment World and Total Landscape Care. Tom has reported on Class 1 – 8 commercial vehicles since 2015. A graduate of the University of Southern California, Tom enjoyed growing up around hot rods, dirt bikes, deserts and beaches near San Diego. He now calls Northwest Florida home.

STEM Project Unites Children in the UK and Uzbekistan

Zoom call with West Park School and the Children's Home

If you ever doubted the ability of young minds to grasp what many adults would consider complex concepts, then you'll be amazed by the achievements of two groups of young children - one in a school in northern England, and the other 4,000 miles away in an orphanage in Uzbekistan.

With the support of Cummins, children ranging from six to twelve years of age have managed to bridge the language, culture, and time divide. They are collaborating with great success on building a basic electric racing car.

The story begins with a visit by Cummins to Rudmash Export Service, which has been representing Cummins in Tashkent, the capital of Uzbekistan, since 2018.

Rudmash has an impressive list of clients in mining, construction, gas, and power generation.

It is also a highly respected supporter of community initiatives, a key focus for Cummins.

During the visit, Amit Kumar, Cummins' Technical Territory Manager for the Commonwealth of Independent States (CIS) region, mentioned the work he was doing with local schools involving the Greenpower Education Trust in the UK.

Amit suggested that Rudmash might consider introducing local children to the fantastic learning opportunity that comes from building an electric car.

The Rudmash executive team loved the idea and reached out to their friends at the local orphanage (Children’s Home 22), about the proposed connection with children from West Park Academy – a primary school near Cummins' manufacturing plant in Darlington, England.

Students at the Children's Home working on the car
The children from Children's Home 22 building the car

Speaking through a translator, Rudmash Sales Manager Mr. Mavlonberdi Akhmedov said there was no hesitation from the orphanage. "Everyone was excited about it," he said. "When we showed them pictures of the car, the children's eyes lit up with interest.

"The only issue we encountered was not being able to involve the older children, but I think Amit has something in his mind for them. It will involve a similar collaboration with a UK school on a larger electric car that they can fit in!"

Over in Darlington, teacher Mr. David Fraser and his group of 9 to 11-year-olds were thrilled at the prospect of working with children from another country.

Students from West Park Academy
The children from West Park Academy

"Before our first session, I showed the children a map of Uzbekistan and explained how the time zones worked," Mr. Fraser said. "Tashkent is four hours ahead of us."

"When they started hearing a different language, they were a little hesitant although still excited. However, towards the end, once they got used to the translation pauses, lots of questions were being asked."

"They adapted very quickly, and every session with the orphanage has become more engaging. The children have greatly benefited from the relationship. It's been a great learning experience."

The car involved in the project is called the Greenpower Goblin G2. It comes as a flat-pack kit including chassis, wheels, steering, disc brakes, a 24V electric motor, and two 12V batteries.

Students at West Park Academy working on the car
The children from West Park Academy building the car

"The project is all about inspiring young children to take an interest in engineering in a fun and innovative way," said Amit Kumar, who earlier this year received special recognition at the North-East England STEM (Science, Technology, Engineering, and Mathematics) Awards for his years of dedication to STEM Education.

"The build introduces children to basic mechanics and electronics and might be the first step on the pathway to a career in engineering or another STEM field.

Mr. Fraser said the children soon started discussing aspects of the car such as frames, brakes, and steering geometry. There was a lively question-and-answer session on different materials that could be used to design and make the car's body. Their last session was about controls and driving.

"There are also other general discussions, as the children are eager to learn more about each other's countries," said Amit, who leads the sessions.

Students at the Children's Home looking at the car drawing
The children from Children's Home 22 talking about a drawing while on a zoom call

Rudmash service engineer Mr. Abdullayev Shakhzod said the children were enjoying the experience of working in teams.

"It's a fantastic new chapter in the history of a place that has a storied past. It was established in 1942 during the Second World War to care for evacuees from all over Eastern Europe. Children of over 40 different nationalities have been cared for by this children's home.

"The home is named Antonina Pavlovna Khlebushkina after the woman who ran it in the early days. She would be so proud of what is happening there today.

"As the summer vacation times differ in the two countries, the West Park school children have already finished building their cars, while the Uzbekistan car is about 40% complete.

"When the children return from their summer camp in September, they will start the rear axle, motor, and electrical components. Then they can take it for a drive," Amit said.

"Just before their summer term ended, the West Park children conducted a demonstration for their new friends in Tashkent. They set up a track and showcased driving the car on it. It was a great success."

Mr. Akhmedov, speaking through a translator, mentioned that the management team at Rudmash was considering how the project could expand beyond the children's home and into schools and youth organizations throughout Uzbekistan.

Mr. Akhmedov praised Cummins for their support of the project. "They have shown great responsibility at every stage and been very proactive, always striving to ensure things are done right.

"This is just the beginning for these children. It's already motivating them to learn more and develop their skills in broader technical applications.

"I would say that this project is not only important for the children's home but also for our city of Tashkent and the Republic of Uzbekistan, as it is nurturing an educational culture that is highly valuable. I can't thank Amit and Cummins enough."

Amit expressed that it's a privilege to help Cummins inspire young people about engineering and science from an early age.

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