By Stephen Whitfield, Associate Editor
The diesel engines that power drilling rigs have long been seen as a primary target in the industry’s carbon reduction efforts, as drilling contractors seek to replace them with hybrid or natural gas generators. In the near future, a new replacement option could become available, thanks to a collaborative project aimed at using hydrogen fuel cells to enable a zero-emission power-generation solution.
“We’ve been adding software and battery systems to the rig to help hybridize them and reduce fuel consumption, which reduces the carbon dioxide produced,” said Brian Winter, Project Manager for Rig Equipment at Schlumberger. “That is helping our customers take a big chunk out of their emissions, but how do we get to zero emissions? We think hydrogen is the answer.”
The project, announced in June, will see Ensign Energy Services and Schlumberger partner with hydrogen fuel cells manufacturer Hyzon Motors to develop and deploy an integrated hydrogen/battery storage system. Plans are to pilot test the system on a US land rig next year.
While hydrogen fuel cells are a proven zero-emission solution for powering cars and trucks, this project will mark the first attempt to create a system capable of generating sufficient power for a drilling rig. It’s envisioned that the integrated system will serve as a direct replacement for the diesel generators that typically power the rig, meeting the same horsepower and footprint specifications of a diesel generator on a high-spec North American land rig.
This could have a significant impact on emissions. Hyzon has said it believes a drilling rig completely fueled by hydrogen fuel cell systems could eliminate 10,000 tons/yr of CO2 compared with a diesel-fueled rig.
Hyzon’s hydrogen fuel cells generate electricity through a chemical reaction between hydrogen gas and oxygen from the air within a membrane electrode assembly, an assembled stack of proton-exchange membranes, cathode catalysts and flat plate electrodes.
The byproduct of this chemical reaction is pure water vapor, as opposed to the CO2 generated from diesel or natural gas systems. Multiple fuel cells can be configured in a system to achieve a desired electrical output, which would then be directed to the rig’s power distribution system.
The company’s fuel cells were commercially launched last year and are already in use in other industries. In November, Hyzon delivered 29 fuel cell-powered commercial trucks to China. The trucks, which utilize a 170-kW fuel cell stack, are each expected to eliminate 140 tons of CO2 emissions over the course of the vehicles’ expected seven-year life span. Because these fuel cells were developed for use in long-haul trucking industries, they are easily transportable and, therefore, considered to be especially suitable for powering drilling rigs.
“When you think about a power system for these rigs, you’re drilling on one wellsite, and a few weeks later that rig is completely dismantled, put on trailers and set up on another site. So, the fuel cells that we’re going to use, they have to be transportable,” Mr Winter said.
One of the biggest challenges that remains to be overcome is to ensure the system can meet the extensive power needs of a high-spec land rig, which typically runs a few 1-MW diesel generators. To achieve this, the companies plan to combine several 120-kW fuel cell stacks into a 40-sq ft container, creating a system capable of generating just over 1 MW.
The container will be installed on the rig, along with an energy storage system, to approximate the power generation from diesel engines. The fuel cells will also be integrated into Intelligent Power Management, Schlumberger’s automated software that optimizes fuel consumption and engine run time on the rig. When the power demand is low, the system diverts excess energy generated from the engine to the battery system. When the power demand is high, it draws from the battery reserve, leading to an optimal load on the engine.
Hyzon and Schlumberger plan to conduct an initial six-month laboratory test on the fuel cell system in Q2 2023, during which simulations of various field conditions will be run to ensure the system can always generate enough power for the rig.
After that, field testing will take place on an Ensign US land rig, likely in the second half of 2023. This will essentially serve as a stress test for the system – making sure it can withstand the wear and tear of a drilling environment. Schlumberger said it hopes to have a commercial solution available by early 2024.
While the field trial is still some time away, Ensign said it is already making plans to ensure a seamless installation. This includes confirming the containers will fit within the rig’s space confines and that both the electrical components of the fuel cell system and the Intelligent Power Management system can integrate with the rig, said Mark Anderson, VP of Drilling Solutions at Ensign.
Mr Winter added that making the installation affordable is also a key priority for Schlumberger. “We want to be able to slide the diesel generator out and plug the fuel cell system in the same slot. Obviously, we don’t want our customers to incur a big expense in adopting the technology through heavy modifications on the rig. It’s important for us to make this as problem-free as possible.”
Challenges with hydrogen
While the ultimate goal is to have a hydrogen-fueled system that can be widely deployed, there are major challenges to achieving scalability, including being able to consistently source enough affordable hydrogen to use in the fuel cells. Hydrogen is abundant in the atmosphere, as it’s stored in water, hydrocarbons and other organic matter, but the cost of hydrogen storage systems is much greater than the cost of storage systems for petroleum fuels, primarily because hydrogen storage systems require more expensive materials.
Hydrogen is also typically transported in liquid form, which is easier to transfer over long distances than hydrogen gas. This means that the drilling contractor will likely need additional equipment at the rig site to convert it back to a gaseous form, Mr Anderson explained. “Moreover, we’re not a big enough market to expand the hydrogen market on our own, so that means we’re going to have to locate our rigs in proximity to a hydrogen source.”
Indeed, having hydrogen hubs in close proximity to drilling sites will be key to the success of the hydrogen economy, Mr Winter said.
The US produces more than 10 million tonnes of hydrogen annually, according to the US Department of Energy (DOE), and recent government action could boost that further. Last year, the US government committed $8 billion toward the development of regional hydrogen hubs, which could shorten the distance and time needed to deliver hydrogen from the source to the wellsite.
Also, last year the DOE announced its Energy Earthshot Initiative, which aims to reduce the cost of hydrogen in the US by 80%, to $1/kg, by 2030 through investment in hydrogen production and transport infrastructure.
“There are good sources of hydrogen in the US, and that’s primarily why we’re trialing here, just because of the proximity to hydrogen fuel sources,” Mr Winter said. “The one thing that our customers don’t want to see is downtime on the rig, and we don’t want to have that downtime because the hydrogen fuel didn’t show up on time for the rig. However, the amount of investments in hydrogen hubs is substantial and still growing.”
Mr Winter also noted that deploying fuel cells does not require an all-or-nothing approach. Companies can begin by taking an initial approach of using both fuel cells and diesel generators, which would lower the amount of hydrogen that would need to be sourced.
“The technologies are only getting better. With this solution, even though right now it might only be economic in a few small pockets where we can get hydrogen, there’s going to be a lot of interest. In a few years, we might have the infrastructure to support this on many more drilling rigs,” said Nicole Romanow, Investor Relations and Team Lead, Sustainability Strategy at Ensign Energy Services. “There are some traditional oil and gas players that have expanded into hydrogen projects themselves, so there are going to be more opportunities.” DC