Pioneering engineering project to power rigs with hydrogen
As the oil and gas industry continues to balance global energy demands with looming net zero goals, there is increased pressure to decarbonize existing oil and gas operations to support environmental objectives. The use of hybrid power on drilling rigs can deliver significant emissions reductions. However, this relatively new concept of applying low-carbon energy carriers, such as hydrogen, on drilling assets, requires expert guidance and verification, if it is to prosper as part of the energy transition.
DNV, a global energy expert and assurance provider, has been engaged by Brazilian upstream service provider Ocyan, as an independent third party in the qualification process of a system injecting hydrogen as an additive in the internal combustion engines of drilling rigs, to reduce diesel consumption and greenhouse gas (GHG) emissions from operations. In conjunction with technology partner LZ Energia, and supported by Shell Brazil through the RD&I investment clause of the National Petroleum Agency (ANP), the partner organizations will ensure that these new technologies function reliably within specified limits.
The project started from an initial development by LZ for the application in the automotive sector, for truck engines, and is now being adapted for use in the large engines of offshore rigs. By using hydrogen together with diesel and optimizing combustion, there is a fuel-saving, and less pollutants are emitted.
After carrying out a pilot test on one of Ocyan’s rigs last year to validate the concept, the group is still in the first phase of the project, which includes delivery of the functional prototype of the product. Having overcome all the challenges of this phase, Ocyan and LZ will start planning a second stage, where efforts will be based on tests in a relevant environment and the commercialization of the product.
IMPLEMENTING QUALITY PROCESSES
Using DNV process (DNV-RP-A203), which provides the industry with a systematic approach to technology qualification, will ensure that the technology achieves the expected degree of maturity, Fig. 1. Going forward, this gives confidence to stakeholders that the technology can be sensibly scaled in support of the global decarbonization of the drilling industry.
The recommended practice (RP) discusses the technology concept, the requirements, the intended use, expected performance, and qualification targets. It assesses the technology composition, its systems, subsystems, components and functions, in order to identify the main challenges, uncertainties and potential gaps. The entire process is designed to focus not only on demonstrating technology performance reliability, but also to comprehensively address the operational risk to ensure safety while assessing classification society requirements.
There are no specific criteria to be met in DNV-RP-A203. The qualification is a process, a systematic approach to be performed according to the objectives of each qualification process. Therefore, based on the qualification targets, the course of action to be taken and criteria to be considered are defined. The important point is to ensure that all relevant aspects are identified and properly addressed to ensure demonstration that the technology can consistently deliver the expected performance.
Of course, it will be done safely, reliably and in accordance with project requirements. In the specific case of this project, safety and performance are key aspects. The RP has been adopted globally by oil majors and independents and has been used to qualify more than 120 technologies, ranging from downhole safety valves to tidal energy systems.
The oil and gas industry is one of the largest contributors to GHG emissions globally, and reducing operator’s carbon output is crucial for mitigating climate change. DNV is proposing a three-tier approach to decarbonization in the sector:
- Reduce overall energy use.
- Seek to remove environmental losses.
- And replace energy supply with low carbon alternatives.
Reduce. The initial step has a low barrier to entry and is easily accessible for companies. A reduction in energy use can be achieved by straightforward design or behavioral changes and does not require significant capex or novel technology. These can include behavioral energy management. Through organized and structured use of organizational management, operations management and technology, the energy performance of an asset can be improved. Efficient energy design and a combination of quality, detailed engineering, assessment, selection and specification of systems, products and equipment can provide the same functions but utilize less energy.
Remove. The second tier seeks to remove direct gaseous losses to the environment by ensuring robust maintenance regimes are in place to maintain hydrocarbon containment and minimize flaring. Carbon reduction can also be expanded to consider methane-related emissions, which are smaller in volume than CO2, but have a greater effect on global warming per unit, as it is more efficient at trapping radiation.
The removal tier can be applied to green field newbuilds and brownfield modifications, with measures including, but not limited to, flaring, fugitive emissions, reduction in venting, and carbon capture utilization and storage.
Replace. In terms of replacing, which is particularly crucial in the case of the Ocyan project, a swapping of conventional hydrocarbon-driven power generation for low-carbon alternatives is undertaken, and existing design assumptions are challenged. There are challenges, such as these technologies may not be robustly proven in service with additional small-scale demonstration projects required to facilitate wider market penetration. For greenfield sites, early technology integration and engineering analysis is key, while for brownfield modifications, there are significant engineering demands and barriers that make the application technologies challenging.
For operators, there are several options available. Power from shore, with subsea distribution, considers the replacement of offshore power generation and offshore gas-fired compression locally onboard the installation, with electrification from a secure and robust supply. The power, itself, can be generated onshore from a combination of renewable sources, nuclear and/or gas-fired onshore plants, but the building of infrastructure and the overall increase in electrical demand would need significant onshore investment to ensure that the existing grid can support such a demand.
Alternative power sources. Another source is power from offshore wind or a renewable energy island or hub. Most offshore renewable energy comes from floating and fixed offshore wind, and in some instances, the wind farms are then interconnected to generate HVDC and transmitted to a HVDC gathering platform. It is possible that this HVDC gathering platform could form the offshore energy hub providing a central HVDC distribution network of subsea HVDC connection(s) between this energy hub and the O&G production assets. A challenge of the sole reliance on offshore wind as the source of electricity production is that the reliability, availability and uptime of the turbine and the electricity production will have a direct impact on the production of the asset.
Hydrogen injection on a drilling rig. In this instance, using hydrogen as a fuel source offshore is not entirely replacing traditional electricity production methods, such as a gas turbine, it is instead replacing the fuel stock that is used to generate this electricity. The challenge is achieving a reliable H2 source to supply the chosen electricity generating method. By implementing technologies like hydrogen injection, the industry can significantly reduce its environmental impact and helps achieve GHG reduction and fosters sustainability. As the world moves toward renewable energy sources like wind and solar, the oil and gas industry must adapt and find ways to reduce its environmental impact, Fig. 2.
Projects like this can help the industry meet regulatory requirements for emissions reduction. Many countries and regions have introduced regulations aimed at reducing emissions from the oil and gas sector, and companies that fail to comply with these regulations may face fines or other penalties. Implementing such technologies can help companies meet these requirements and avoid penalties.
Essentially, this can improve the efficiency of oil and gas operations, which can result in significant cost-savings. By reducing fuel consumption and increasing energy efficiency, companies can improve their bottom line and remain competitive in the industry. The project is important for the energy industry, because it demonstrates the potential of hydrogen technology to reduce emissions, improve efficiency and support the transition to a low-carbon energy system. By investing in this project, the industry can play a leading role in addressing climate change and contributing to a sustainable future.
Third-party qualification. DNV is involved as a third party supporting the technology qualification process to ensure that all necessary aspects will be addressed, so that the technology can demonstrate the expected degree of maturity. DNV involvement in this qualification program will be based on a strong technical involvement.
This is designed to ensure that there is a systematic approach to the qualification process, allowing the expected results to be achieved with the required reliability. DNV will perform an independent assessment of the technology, helping to identify possible aspects not considered during development. Support will also be given to the systematic identification of failure modes and definition of an action plan during the definition of the technology qualification program and qualification plan activities. Throughout the process, it will be ensured that the qualification process is properly documented to evaluate and attest that the qualification process was performed in accordance with the applicable standards.
A comprehensive threat assessment will be undertaken, addressing the potential failure modes and failure mechanisms (with focus on the system performance) and the operational risks (with focus on the safety). This will be done in parallel with the class requirements to enable an “Approval in Principle” to be issued for the system.
Discussions will take place to identify adequate qualification methods, including: 1) numerical analysis; 2) simulation; 3) system test; 4) subsystem test; 5) component test; and 6) integrated test. DNV will then be Involved during execution of the qualification plan activities, to confirm that the qualification activities have been performed properly. The results will then be assessed to confirm that the expected performance and acceptance criteria have been met. They also will be examined to assess the confidence that has been instilled into the qualification evidence through qualification activities, and to assess the system’s maturity to confirm whether the expected technology readiness level was demonstrated.
DNV’s comprehensive approach involves three fully integrated fronts:
- The technology’s qualification process – demonstrating the performance and reliability of the system.
- The assessment of operational risks – with focus on the safety of the new system and of the drilling rig.
- The assessment of class requirements – evaluating the requirements of the Classification Society for the issue of an “Approval in Principle” for the system.
The goal of this strategy is to ensure the technology demonstrates it can safely operate in offshore units and that the technology complies with class requirements. It also ensures it delivers the expected performance. Each one of these aspects will be addressed in parallel by different teams at specific development stages along the qualification process. A cross-disciplinary approach ensures that all technological, safety and regulatory aspects are fulfilled prior to deploying the technology, providing transparency and trust for the different stakeholders.
The process involves retrofitting a diesel engine with a hydrogen injection system, using hydrogen produced by demand through electrolysis and a control system. During operation, the diesel engine operates as usual, but the hydrogen delivery system injects a small amount of hydrogen produced by demand into the engine's intake air. The hydrogen mixes with the air and fuel mixture, improving the combustion process and reducing emissions. The hydrogen also helps to reduce the ignition delay of the fuel, allowing for more complete combustion and reducing the formation of particulate matter.
The hydrogen injection system is controlled by an electronic control unit (ECU), which adjusts the amount of hydrogen injected, based on engine load and other operating conditions, Fig. 3. The ECU also monitors the engine's performance and adjusts the injection rate to ensure optimal performance and emissions reduction.
The emissions reductions will depend on several factors, including the engine size, load, operating conditions, and the amount of hydrogen injected. The pilot conducted on a drilling rig last year (2022) has shown some excellent results leading to up to 6% improvement in fuel efficiency and CO2 emissions reductions, up to 31% reduction in carbon monoxide emissions and up to 34% reduction in hydrocarbon emissions. These results are aligned with studies that have shown that hydrogen injection can lead to significant reductions in GHG emissions and other pollutants. During the research and development phase ongoing now, the plan is to execute more specific emissions and comparison tests to ensure these reductions.
As is inevitable in the energy transition, there are hurdles that stand in the way of success. Unsurprisingly, there are a number of challenges in this instance, included in the following list.
Technical feasibility. The project requires the installation of an electrolyzer to produce hydrogen by demand, an injection and control system on the diesel engine of a drilling rig. This system must be designed to withstand the harsh operating conditions of offshore drilling and ensure that the hydrogen is delivered at the correct concentration and pressure to optimize combustion. Timely and proper supply for the prototype and tests must be overcome.
Safety. The use of hydrogen as an additive can represent safety challenges, particularly in offshore drilling, where the risks of fire and explosion are high. The project must ensure that the hydrogen production, handling, and injection systems are designed and operated safely to minimize the risk of accidents.
Cost-effectiveness. The project must demonstrate that the use of hydrogen as an additive in diesel engines is cost-effective, compared to other options for reducing GHG emissions, such as the use of renewable energy sources or carbon capture and storage.
Regulatory and policy environment. The project must comply with relevant regulations and standards, including those related to safety, emissions, and the use of alternative fuels. Addressing these challenges requires a multi-disciplinary approach, involving expertise in engineering, safety, economics, policy, and environmental sciences. The successful implementation of the project could contribute to the development of a new technology pathway for reducing GHG emissions in the oil and gas industry, while also improving the efficiency and sustainability of offshore drilling operations
FUTURE HYDROGEN-POWERED RIG
While the use of hydrogen as an additive in diesel engines is not a new concept, and it has been explored in various applications, including transportation and power generation, its use for powering oil rigs is still in its infancy. LZ Energia has previously developed a product on a smaller scale for application in the automotive sector but the application of hydrogen as an additive produced by demand in drilling rig diesel engines is still in the early stages of development and implementation, and, therefore, this project can be considered as pioneering.
Furthermore, the project can also serve as a pilot for other applications of hydrogen in the energy industry, and the knowledge gained from this project can be applied to other sectors. The project is a pioneering initiative that can contribute to the development of a more sustainable and low-carbon energy system.
Following qualification, the plan is to upscale for additional rigs and other offshore operations. If the project is successful, it could be implemented in other offshore operations as well, such as support vessels. This could contribute to the industry's efforts to reduce its environmental impact and support the shift toward an energy system that is more eco-friendly.
This application is not limited to offshore drilling operations. It also could be applied to onshore oil and gas operations, such as compressors, and generators. This could provide another pathway for reducing GHG emissions and improving efficiency in the industry.
Hydrogen is already being explored as a fuel for transportation, including cars, trucks and buses. The knowledge gained from the project could be applied to the development of alternative technologies for transportation, which could further reduce GHG emissions and support the transition to a low-carbon transportation system.
Lastly, hydrogen also can be used as a fuel for power generation, either through hydrogen-fueled turbines or fuel cells. The project could lead to the development of new technologies for using hydrogen as a fuel source for power generation, which could contribute to the decarbonization of the electricity sector.
Overall, this project can outline a safe, efficient and accelerated path for further innovation and new developments in the decarbonization of the oil and gas sector. According to DNV’s Energy Transition Outlook 2022, fossils fuels currently supply more than 80% of global energy, a figure that is expected to decline below 50% by 2050. In the coming years, as the energy transition accelerates, this type of enterprise will be key to ensuring that net zero targets are met.
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