What is a dual fuel engine, and its benefits for oil and gas applications?

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The stone age did not end because the world ran out of stones, and the oil age will not end because we run out of oil1. Instead the oil age will end as we (communities, companies, and governments) speed up the energy transition towards our final destination: 100% renewable energy. 

In this energy transition journey there are giant steps we all celebrate, such as the increased use of green hydrogen in rail applications. There are also incremental steps – those that are towards the right direction, those that challenge the status-quo and those that bring us closer to our end goal. 

The oil and gas industry is taking incremental steps to reduce its environmental footprint and improve its financial performance. One of these steps is the use of dual fuel engines, which is seen as the right immediate next step. The industry is already utilizing technologies ranging from microgrids to ultra-low emission engines in this journey. Duel fuel engines are the right addition to this portfolio.

Dual fuel engine technology has proven itself over the years in drilling and well servicing applications. Given the increased interest in these dual fuel solutions, this article outlines what dual fuel engines are and their benefits in oil and gas applications. 

What is a dual fuel engine and how does it work?

Engines that can operate using a mixture of two different fuels are called dual fuel engines. Frequently, diesel and natural gas fuels are used together within dual fuel engines. Often, dual fuel engines that mix diesel and natural gas can also operate using diesel fuel only if the natural gas is temporarily unavailable. 

Beyond natural gas and diesel, some dual fuel engines can also use varying mixtures of biodiesel, landfill gas, bio-gas and other fuels. 

Are all dual fuel engines the same? 

They are not; the differences among duel fuel engines are far beyond "tomayto" and "tomahto"

While the working principles of dual fuel engines are the same, those that operate dual fuel engines experience remarkable differences in total cost of ownership (TCO) and uptime. Things like natural gas substitution rate, quality of the natural gas, emissions produced, and equipment reliability can all effect operational efficiency.

Substitution rate is a key word associated with dual fuel engines. Substitution rate is the portion of fuel energy provided by natural gas. When comparing dual fuel engines, there are two important considerations regarding substitution rates:

  1. Load factor: It is important to compare substitution rates of different engines at the same load factor, which is where your engines usually operate. Strictly comparing ‘maximum’ substitution rates of different engines could mislead you, and prevent you from maximizing the benefits of dual fuel engines.
  2. Diesel fuel consumption: Consider evaluating the diesel fuel consumption rates of the engines while comparing substitution rates. If an engine delivers better diesel fuel economy, then that engine starts the substitution rate comparison with an important advantage. 

Check out how dual fuel engines work to learn more.

Benefits of dual fuel engines in oil and gas applications

Within oil and gas applications, drilling and well-servicing operations are where you could commonly see dual fuel engines powering equipment. This is due to the financial and environmental benefits drilling and well-servicing contractors experience with dual fuel engines. Let’s look at these benefits of dual fuel engines in oil and gas applications.

Dual fuel engines reduce the environmental impact of oil and gas operation

Natural gas is often dubbed as ‘the bridge to the renewable future’ in electricity generation markets. In fact, 40% of utility-scale electricity generated in the U.S. comes from natural gas. The rest is evenly distributed among coal, nuclear power and renewables. 

"Environmental considerations are a key reason many businesses, including drilling and well-servicing operators, choose natural gas over other fossil fuels,” said Patricio Escobar, Cummins' Oil and Gas Market Segment General Manager. “Those that choose to replace diesel with natural gas experience several critical environmental and operational benefits.", he also said.

Here are three of these environmental considerations.

  • Reduced diesel fuel refining and transportation: Diesel fuel goes through a long journey to get from the wellhead to your fuel tank. By using the available on-site gas in your dual fuel engines, you also reduce the need for those operations to process and deliver diesel fuel to your site. This, in turn, reduces the associated environmental impacts of transportation and refining.
  • Reduced flaring: Another key environmental advantage achieved through the use of on-site natural gas, is the reduction of flaring. The excess natural gas burned through flaring can be redeployed to power the dual fuel engines on a well site. 

Dual fuel engines deliver financial savings through reduced diesel fuel consumption

Fuel cost is one of the primary expense line items for drilling and well-servicing operations. Dual fuel engines bring financial savings in the form of reduced operating expenses (OpEx). 

Here is how reduced operating expenses come to life. 

  • Substituting the diesel fuel with natural gas fuel: As mentioned previously, diesel fuel goes through a longer journey in reaching the engines on a well site. This journey includes oil production, oil transportation, diesel production at a refinery, storage, transportation, and delivery to the pump truck. All these steps within diesel’s journey come with additional costs. Meanwhile, natural gas produced at the wellhead can be processed on location and delivered to the engines. Using available on-site natural gas instead of diesel, results in operational savings for drilling and well-servicing contractors.
Benefits of dual fuel engines in oil and gas applications

Dual fuel engines operate with diesel-like performance

Historically, one key reason diesel engines have been the top choice among oil and gas applications has been their solid performance. Diesel engines are known for their longevity and diesel fuel offers very high power density. These are still very much accurate. Meanwhile, natural gas engines have changed over the years too. Let’s look at engine performance from three aspects: 

  • Power density: Power density is an engine’s power output per unit of engine volume. For example, for large displacement engines, you would often see larger natural gas engines deliver power output comparable to smaller diesel engines. In other words, diesel engines have higher power density than natural-gas only engines. Meanwhile, there are also diesel engines upfitted for dual fuel applications. This combined with the electronic controls within the engine allows a dual fuel engine to feature diesel-like power density while operating in dual fuel model.
  • Transient response: Transient response performance is an engine’s ability to respond to varying power demands of the operation. Many oil and gas applications require transient response capabilities that 100% natural gas engines often have trouble accommodating. Meanwhile, selected dual fuel engines can offer comparable transient performance with their diesel-only alternatives.
  • Optimized operating range: Engines often run at a standard duty cycle per the application they are used in. Applying a new technology, like dual fuel, can sometimes require changes to that operating pattern to achieve the maximum fuel savings. The dual fuel engine's optimization resolves this issue by ensuring the maximum substitution rate of natural gas in the ideal operating range required by oil and gas applications. This maximizes the portion of fuel energy provided by natural gas, leading to improved performance in oil and gas applications.

If you already have engines ready to be upfitted, dual fuel kits will save you money

Many oil and gas applications already use engines that are ready to be upfitted using dual fuel kits. This is a great starting point, because you can now save money and help the environment by choosing a dual fuel kit over a new dual fuel engine.

  • Financial benefits: The dual fuel kit costs less than buying a new engine and requires minimal changes to the existing engine, resulting in reduced equipment integration efforts. This reduces the total capital required to upgrade your fleet and achieve operating and sustainability goals.

Interested in more oil and gas perspectives? You might also like: 

To learn more about oil and gas power solutions, visit our webpage.


References: 
1The Economist (Jul 24, 1999). Fuel cells meet big business [Article]. Retrieved from https://www.economist.com/

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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