Hydrogen fuel cells are a green, carbon-free method of producing electricity. The way in which companies obtain hydrogen, however, is not. Current methods of hydrogen extraction are reliant on fossil fuels, emitting high levels of CO2. Renewable energy company Siemens Gamesa believes this dilemma can be solved by 2030 by reducing the costs of green hydrogen - hydrogen extracted using renewable energy from wind farms.
Hydrogen fuel cells make use of the chemical reaction that occurs when hydrogen interacts with oxygen, releasing energy and water:
A hydrogen fuel cell makes use of this reaction by using an electrolyte membrane to separate the hydrogen (in the cell’s anode) from the oxygen (in the cell’s cathode). A catalyst at the anode separates the hydrogen into protons and electrons.
This electrolyte membrane only allows positively charged particles to travel through it, meaning the protons can now move to the cathode, but the electrons must take a different route. The electrons travel across a circuit around the catalyst to reform the hydrogen at the cathode. Electrical current, by definition, is the flow of electrons. The electrons flowing around the catalyst create the fuel cell’s electrical output.
As a fuel source, hydrogen is highly desirable from an environmental standpoint. Where most other conventional methods of electricity generation have negative products such as CO, hydrogen fuel cells only have one product, as shown in the equation above: water.
In addition to the environmental benefit, hydrogen fuel cells also have a competitive efficiency compared to other conventional methods. Combustion-based power stations operate at around 25-30% efficiency (MEED, 2019).A Hydrogen fuel cell can operate at up to 60% efficiency. With current technology, however, the hydrogen fuel cell is less efficient than standard electrical batteries, which have an efficiency closer to 80% (Volkswagen, 2019).
As hydrogen cells only produce heat and water as a byproduct of their electricity, the only carbon emissions produced by them are in the manufacture of the materials to create the cell. If the hydrogen can be extracted using a carbon-neutral method, the fuel cell can produce electricity with zero CO emission.
The main source of hydrogen is currently extracted using a steam methane reforming (SMR) method. This process currently accounts for more than 95% of the hydrogen produced worldwide (Rapier, 2020). This conventional method reacts methane with high-temperature steam (around 1,300 ⁰F to 1800 ⁰F (EIA,2021)) in the presence of a catalyst. This reaction creates hydrogen and carbon monoxide. The carbon monoxide can be used in an additional reaction with the steam- called a water-gas shift (WGS) reaction - to create additional hydrogen and carbon dioxide.
Due to this extraction method, current hydrogen fuel cells are not as environmentally friendly as they have the potential to be. Current extraction methods produce large amounts of CO, use the potent greenhouse gas methane for extraction, and typically rely on fossil fuels such as coal to power the SMR and WGS reactions.
The more promising route for environmentally friendly hydrogen production is through the electrolysis of water. This method uses electricity to deconstruct water into hydrogen and oxygen gas. The carbon emissions produced by this method are entirely reliant on how the electricity is created. If the electricity used in the electrolysis process is sourced from a renewable energy source, carbon emissions can be minimized dramatically. This is the premise of green hydrogen.
The main issue of green hydrogen is its cost-effectiveness. With the current infrastructure in place, using renewable energy sources is much more expensive and complex than the conventional SMR method.
Renewable energy company Siemens Gamesa believes the challenge of green hydrogen must be addressed as quickly as possible to meet the net-zero emissions goal by 2050. In its recently published white paper on the subject, CEO Andread Naunen writes that green hydrogen is a “key building block for reducing emissions” from “hard-to-electrify” industries such as “shipping, aviation, and heavy-duty trucks.”
“By 2050, it’s expected that demand for hydrogen will reach 500 million tonnes” the paper continues. To meet this increase in demand, from around 70 MtH2/yr in 2019 (IEA, 2021), Siemens Gamesa have outlined four key areas that must be met:
Firstly, the capacity and scale of manufacture in renewable energy such as wind power must be addressed. If governments are willing to invest more money in upscaling the capacity of wind farms, the demand for hydrogen can be supplied solely from renewable energy sources, and green hydrogen will become more cost-effective. Considering the current decrease in CO emissions due to the COVID-19 pandemic, it would be beneficial to begin this step as soon as possible.
The first step leads into the second and is also the reason why most renewable energy resources find it so hard to take off. As the technology is new, mass production of components is less accessible, meaning expenses and investments are higher. If governments upscale wind turbine production, the market size will increase, lowering the costs of manufacture. A large investment early will lead to greater cost-effectiveness for green hydrogen in the near future.
The paper’s third step goes on to suggest an investment in the individual component manufacturers is required, such as the companies responsible for the windfarms, hydrogen storage, and water treatment.
The fourth and final step then points out that the power infrastructure of cities will need to change to make use of this newly produced green hydrogen.
The most useful part of Siemens Gamesa’s plan is that already existing windfarms can be retrofitted with hydrogen storage and electrolyzers to begin the electrolysis process now. This would reduce the initial costs of the green hydrogen industry and accelerate its market growth.
The company is committed to this effort, stating it will “accelerate its efforts”to increase the green hydrogen market. If its targets are met, hydrogen extracted using onshore wind turbines will match cost-effectiveness as SMR extraction. Offshore wind turbines (which are more complicated to manufacture) are expected to reach this cost parity in 2035.
Siemens Gamesa’s white paper, which outlines the need for green hydrogen, the steps governments must take to reach cost parity with SMR, and its own plans to contribute to the green hydrogen industry is publicly available on its website.
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Reuters (2021). Wind could produce affordable green hydrogen by 2030, Siemens Gamesa says. [online] Available at: https://www.reuters.com/business/energy/wind-could-produce-affordable-green-hydrogen-by-2030-siemens-gamesa-says-2021-06-09/ (Accessed 13 June 2021).
Siemensgamesa.com (2021). Unlocking the Green Hydrogen Revolution. [online] Available at: https://www.siemensgamesa.com/en-int/-/media/whitepaper-unlocking-green-hydrogen-revolution.pdf (Accessed 14 June 2021).
Volkswagenag.com. (2019). What’s more efficient? Hydrogen or battery powered? [online] Available at: https://www.volkswagenag.com/en/news/stories/2019/08/hydrogen-or-battery--that-is-the-question.html (Accessed 16 June 2021).
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