Saturday, October 21, 2023

Hydrogen and Natural Gas Blending: Challenges, Pilots, and Optimization



     In the fall of 2020, Mitsubishi began offering its Hydaptive Standard Flexibility Package for green hydrogen which includes an electrolyser and a hydrogen storage tank to be stored on-site at a natural gas power plant with the hydrogen to be blended up to 30% (by 2025) and burned with natural gas in Mitsubishi’s JAC natural gas turbines. Future planned capabilities include the ability to burn up to 100% hydrogen (by 2045). It makes a lot of sense to make hydrogen right where it is to be used since storing and transporting hydrogen can be costly and logistically challenging. These systems can be used with combined cycle natural gas plants as well as single-cycle combustion turbine peaking plants. They can also be retrofitted to existing plants. Power plant functions and H2 blending are integrated into their TOMINI digital AI software control system that offers rapid response. Their power plant project in Utah is expected to be burning 30% hydrogen in 2025.  



Source: Mitsubishi Heavy Industries

 

Co-Combustion: Burning Hydrogen with Natural Gas in Turbines and Engines

     New large-sized gas turbines are able to burn up to 30% or 50% hydrogen and models able to burn 100% hydrogen are expected by 2025-2030. Hydrogen burns differently than natural gas. Low-NOx requirements resulted in retrofitting older gas plants with low-NOx burners that utilized water or steam injection. Modern plants utilize staged or lean premix combustion techniques and burners that do not require water known as Dry Low Emissions, or DLE burners. DLE limits water costs and problems and reduces wear and tear due to water on turbine blades. Some smaller gas turbines in the 25-57MW range can be powered by 60% hydrogen. Manufacturers are working on both DLE combustion and steam injection combustion versions to burn higher percentages of hydrogen. Some small aero-derivative turbines can already burn up to 100% hydrogen. Combustion arrangements for burning natural gas, hydrogen, and other fuels to run turbines include the simple cycle, Rankine cycle, Brayton cycle, Allam cycle and combined cycle. The market is tight for large turbines with about four companies: Siemens, GE, Mitsubishi-Hitachi, and Ansaldo Energia. The pivot toward renewables and less deployment of large gas plants in some areas keeps the market tight. They are also competing for the high-volume hydrogen turbine market share and are expected to possibly expand the turbine market a bit in the future.

     A consortium led by Siemens Energy very recently (October 2023) tested successfully a large gas turbine powered by 100% hydrogen. The HYFLEXPOWER project in France utilizes a Siemens Energy SGT-400 industrial gas turbine, modified to operate with up to 100% hydrogen. This is a DLE burner turbine. It was tested successfully in 2022 with 30% hydrogen/70% natural gas.






Technips Energies’ Large Scale Vortex Burner (LSV) for 100% Hydrogen

     Technips Energies announced in August 2021 a successful test of its Large-Scale Vortex Burner (LSV) to accommodate 100% hydrogen. They tout it as a cost-effective low-NOx decarbonization solution. The technology has been deployed successfully over the past 15 years in cracking furnace and hydrogen reformer installations. “The burner can now be applied to different process heating applications and combustion air supply modes and also is suitable for a wide range of fuel gas compositions and firing configurations.” Stan Knez, Chief Technology Officer, Technip Energies, stated: "We are very excited with the outcome of the LSV® burner technology testing on 100% hydrogen firing. This is another example of how we can advance the energy transition by testing new ways to reduce CO2 emissions, improve energy efficiency and set the stage for wide-application across many industries to replace hydrocarbon-based feedstock with clean-burning hydrogen."

 

Other H2 Blending Project Tests and Challenges

     In March 2023 a demo project by EPRI, WEC Energy Group, engine manufacturer Wärtsilä, and other partners achieved 25% hydrogen blending with natural gas in a 20MW engine. It did not achieve maximum output but did achieve 95% efficiency without hardware modifications, which was better than expected. NOx emissions were less than expected and CO2 emissions were reduced by 10% to 12%. Burning hydrogen produces more NOx than burning natural gas. (This is perhaps one of several reasons we may never use hydrogen at high levels in home appliances). The system used green hydrogen so using blue hydrogen the CO2 emissions reduction would have been much more modest at just a few percent at a 25% H2 blend. Wartsila expects to have an engine capable of burning 100% hydrogen on the market in 2025. They point out that engines are more flexible than larger turbines and ramp up and down faster in response to variable power loads. Engines are also more fuel-flexible and can accommodate other liquid or gaseous fuels such as liquid ammonia which can be stored on-site in sufficient quantities for backup.

     Hydrogen carries less energy than natural gas (60% of the energy that comes from CH4 is hydrogen, but hydrogen has only 30% the energy content of natural gas so 1 cf of methane = 3.3 cf of H2 in energy content) so the emissions reduction will not be one to one, rather they will be closer to requiring 75% hydrogen in the system to drop emissions by 50%. Since the best efficiency of hydrogen via electrolysis is about 80% it would take about 100BCF per day of hydrogen to replace the 30BCF per day of natural gas that produces electricity in the US. This would require about 3100GW of (capacity-weighted) additional solar power to run the electrolysers. Thus, to replace all U.S. natural gas used for electricity with green hydrogen would take at least 15 times the currently installed solar energy in the world. This is daunting and very impossible in a reasonable time frame or any time frame at current costs. Thus, while green hydrogen via electrolysis will no doubt increase from its current 0.1-0.3% contribution it probably won’t really begin to get any meaningful market share for decades, if ever. The price of H2 via electrolysis needs to drop by 80% or to ¼ of what it is now in order to compete with wellhead prices with incentives. Blue hydrogen will be the preferred H2 to blend in due to cost and this will decrease the emissions reduction advantages compared to green hydrogen. Thus, H2 blending will likely be more modest than the hype suggests in reducing emissions.

     In May 2023 Constellation Energy announced a record hydrogen blending rate of 38% retrofitted for a large 753 MW combined cycle natural gas plant in Alabama that is over a decade old. This is an important test because major modifications of the plant were not required as had in the past been assumed would be required beyond about 15% H2 and because NOx emissions did not increase. More tests such as these will no doubt be occurring, probably with variable results as each power plant is different.

     In October 2023 NiSource announced plans to test a specialized blending skid to control the mix of hydrogen and natural gas to fine-tune the fuel blending process. The initial test is a skid-mounted blend control system responding to H2/natural gas blend use in a model home. The goal is to keep the blend at up to 20% H2 regardless of fluctuations in gas appliance use. They will keep the blend between 2 and 20%. The project will likely be scaled up in the future. According to Utility Dive: “The goal, he said, is to evaluate how the blended fuel performs in common gas appliances, and to determine how the mixed fuel impacts maintenance procedures like leak detection and repair. Future phases of the project will also test the use of hydrogen blending in environments such as factories and power plants, according to the company announcement.”

 

Evans noted that the trial is not using clean or electrolytic hydrogen made from renewable energy because NiSource was unable to find a suitable supplier.” The goal of the current phase of the project is to evaluate hydrogen’s effect on the natural gas, equipment, piping, and the net change in carbon emissions from blending. Hydrogen is well-known to have a corrosive effect on metals so testing and quantifying its effects on equipment even in blends is very important. The mention of leak detection and repair is important as well since H2 is the smallest molecule in the universe and thus is more likely to leak than the CH4 that makes up natural gas.  

 

 

References:

NiSource hydrogen, gas blending project to test specialty skid to optimize mix. Emma Penrod. Utility Dive. October 10, 2023. NiSource hydrogen, gas blending project to test specialty skid to optimize mix | Utility Dive

Constellation sets hydrogen-gas plant blending record, but more advances needed for utility-scale use: experts. Emma Penrod. June 5, 2023. Constellation sets hydrogen-gas plant blending record, but more advances needed for utility-scale use: experts | Utility Dive

Hydrogen blending exceeds expectations in WEC Energy Group test of Wärtsilä gas-fired engine. Emma Penrod. March 23, 2023. Hydrogen blending exceeds expectations in WEC Energy Group test of Wärtsilä gas-fired engine | Utility Dive

Mitsubishi Power Cuts Through the Complexity of Decarbonization: Offers the World’s First Green Hydrogen Standard Packages for Power Balancing and Energy Storage. Mitsubishi Power Americas, Inc. | Mitsubishi Power Cuts Through the Complexity of Decarbonization: Offers the World’s First Green Hydrogen Standard Packages for Power Balancing and Energy Storage (mhi.com)

Mitsubishi Power delivers Hydrogen-Ready Gas Turbines to “IPP Renewed” Project in Utah to meet Decarbonization Goals in the Western US. July 28, 2023. Mitsubishi Power Americas, Inc. | Mitsubishi Power delivers Hydrogen-Ready Gas Turbines to “IPP Renewed” Project in Utah to meet Decarbonization Goals in the Western US (mhi.com)

Hydrogen Gas Turbine: All You Need to Know. Linquip. August 9, 2021. Hydrogen Gas Turbine: Working Principles and Function | Linquip

World first: Gas turbine successfully operates with 100% green hydrogen. Pamela Largue. Oct 13, 2023. Power Engineering International. World first: Gas turbine successfully operates with 100% green hydrogen - Power Engineering International

ISTJ Investor, December 2. 2020. Hydrogen Vs. Natural Gas for Electric Power Generation. Seeking Alpha. Hydrogen Vs. Natural Gas For Electric Power Generation | Seeking Alpha

NiSource reaffirms commitment to a diverse energy future with launch of multi-phase hydrogen blending project. NiSource. October 5, 2023. Article - NiSource

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