Expanding the Reach of Green Hydrogen with eMethanol

Green hydrogen is poised to play an important role in the global Energy Transition by accelerating decarbonization of industries that are difficult to electrify, including cement, steel, long-haul marine shipping, etc. However, the world currently lacks the requisite transport infrastructure for widespread hydrogen adoption.

Hydrogen, in its pure form, presents transport challenges due to its low volumetric energy density. As a gas, it requires high-pressure storage or cryogenic temperatures, making distribution complex and costly. Especially for long-distance transport, these factors have hindered the integration of hydrogen into existing energy infrastructure – effectively limiting its use as an industrial decarbonization agent.

eMethanol (CH3OH) offers a solution to this problem by serving as stable liquid carrier of green hydrogen (and, in turn, renewable electricity).

Unlike conventional methanol, which is primarily synthesized via natural gas reforming, green eMethanol is derived by chemically combining green hydrogen with CO2 obtained via carbon capture from biogenic sources or through direct air capture (DAC). Methanol can also be produced using CO2 captured from industrial waste streams. In such cases, the methanol is not considered renewable/green; however, it is still carbon neutral.

?One of the primary advantages of methanol as a hydrogen carrier is its high energy density, which at 15.8 MJ/L, is three times greater than compressed gaseous hydrogen at 690 bar and nearly twice that of pure liquid hydrogen. Additionally, an established global infrastructure for methanol transport and utilization already exists, which minimizes the need for new capital investment.

?Methanol also has a strong safety record and is highly versatile as both a fuel and a feedstock. Today, it is being explored for use in a wide range of applications and industries. Some of these include:

• Mobility (e.g., in fuel cells or for conversion to gasoline or kerosene)
• As a replacement for heavy fuel oil in marine shipping
• Power generation
• As a clean feedstock to produce chemicals, plastics, fabrics, fibers, etc.

If required, methanol can also be cracked back into hydrogen gas and carbon dioxide. The hydrogen can then be separated out and used in its pure form.

Compression Solutions for Methanol Applications

Compressors play a key role in eMethanol production. Siemens Energy has extensive experience in methanol-related applications and offers best-in-class compressor solutions for plants and processes across both the conventional methanol and eMethanol value chains.

Our portfolio covers markets for:

Hydrogen – Siemens Energy is a leading provider of reciprocating and turbo-compressors to the hydrogen industry. Currently, we have over 2,500 reciprocating units (more than 2.5 million horsepower) installed worldwide in hydrogen-rich services, including some of the world’s largest green hydrogen plants.

Last year, we announced a significant advancement to our turbo-compressor technology offering with the STC-SVm, which combines the best attributes of our proven DATUM and STC-SV compressor lines. The STC-SVm is the platform which combined with our newly developed advanced rotor technology designed for high impeller tip speeds, which allows for fewer stages and casings, leading to a lighter and more compact solution than legacy machines, making it particularly advantageous for high-flow applications, including hydrogen.

We continue to work with our customers across the industry to improve performance and address evolving process requirements.? ?

One specific example is with hybrid solutions, which combine turbo and reciprocating compressor technology to enable increased turndown and flow flexibility. This type of configuration can be beneficial for electrolyzer plants, where meeting pressure and flow requirements efficiently is challenging due to potential high production variability driven by availability of renewable power supply.

CO2 – Siemens Energy has built and executed multiple CO2 compression units based on integrally geared, single-shaft, and reciprocating compressor technology.

In the case of CO2 needed for eMethanol production, capture from a waste or exhaust stream from an industrial plant is preferable due to the high concentration. Siemens Energy is involved in the development of several eMethanol plants across the globe where this is being done.

?DAC is currently less feasible as a source of carbon due to the low concentration of CO2 in the air, which makes the capture process very energy intensive. While progress is being made to advance industrial large-scale DAC for eMethanol production, the technology is still under development.

?Even with its limitations, eMethanol production is possible using this method, particularly if the Levelized Cost of Energy (LCoE) is low. An example is a project in Chile, where Siemens Energy is providing the electrolyzer technology for green hydrogen production. That project is the world’s first large-scale commercial plant for hydrogen-based eMethanol and eGasoline production.

Another landmark project Siemens Energy is part of is the first large scale DAC plant in Texas’ Permian Basin, where we are supplying two electric motor-driven compressor packages. The equipment will compress the captured CO2 for additional processing and pressurize the final product into a pipeline for injection into underground reservoirs.? Once fully operational, the DAC plant will be able to capture up to 500,000 metric tons of CO2 per year.

Methanol Syngas – We also have several project references in the methanol syngas market. In addition to our greenfield compressor solutions, we offer revamps for our own equipment and that of other OEMs.

Historically, converter changes that typically decrease compressor discharge requirements tend to free up power by creating lower compressor head requirements. Clients in this situation typically push for more production and higher flows, which causes the compressor to run inefficiently. The best way to identify if this condition exists is when there is a visible change in syngas loop converter and resultant pressure reduction. ?

A syngas compressor revamp provides a quick and high ROI by reducing power requirements in syngas trains. EPC/Process licensors can also create schemes to use new high-pressure reformers to remove whole compression bodies.

Waste Heat Recovery (WHR) – In addition to classical WHR technologies, such as high temperature heat pumps (HTHPs) and mechanical vapor recompression (MVR) cycles with steam compression, we are working on novel ways to improve overall system efficiency of carbon capture systems by recovering and reusing waste heat from CO2 compressors.

?Looking Ahead

?With its high hydrogen content and energy density, as well as an established infrastructure, eMethanol presents an exciting opportunity for the hydrogen economy and can address many of the logistical and transport challenges faced by pure hydrogen.

?As technology and research continue to advance, eMethanol can play an important role in the global energy transition by enabling integration of hydrogen into hard-to-abate sectors. However, unlocking its full potential as a decarbonization agent will require continued innovation and collaboration between industries and researchers.

?Government also has an important role to play in helping to create a market for long-term offtake by incentivizing green hydrogen production and adoption, and driving the deployment of supporting technologies like carbon capture.