Hydrogen is poised to reduce greenhouse gas emissions and help major economic sectors achieve their net-zero carbon objectives by 2050. That’s the date many countries agreed to during a climate change summit earlier this year, and that the European Union, the UK and other countries have already made legally binding. To meet that goal will require an overhaul of energy use for many industries and the advancement of several emerging technologies, according to the International Energy Agency.
Hydrogen is a significant part of the solution for carbon neutrality. There are synergies among major industries like aerospace, energy and automotive to establish a sustainable infrastructure network for hydrogen. Hydrogen provides many pathways toward sustainability – from energy storage to cleaner energy production and propulsion – while complementing other solutions, such as batteries.
Three major challenges for hydrogen democratisation are cost, infrastructure, and scale. The cost of green hydrogen production is around $5 per kilogram, being less competitive compared to carbon-heavy fuels such as natural gas or kerosene. The high cost is linked to the infrastructure investment and demand, which is now getting a boost because of regulations and proactive actions being taken by governments around the world. Investment in green hydrogen now exceeds $1bn per year. The biggest investment, globally, has come from the European Union, which accounts for more than half of hydrogen-based project investments in the early part of this decade.
Significant design challenges at each stage still exist – from its production to storage and transportation, to its end use. One of the major challenges at all stages is the energy efficiency of the devices involved. Fuel cell efficiency currently ranges between 40% and 60%, while the average electrolyser efficiency is 60%. Significant improvements in efficiency are possible, but time consuming in a traditional build-test-improve design environment. Burning hydrogen in engines poses several technical challenges, including flashback, acoustic instabilities, autoignition and flame holding inside the burner.
Because of its low molecular weight and density, storage of hydrogen in a compact space is also a significant challenge. It needs to be heavily compressed or stored in cryogenic/liquid form. The storage tank design, whether its flying in the sky on a plane or riding in the back of fuel cell vehicle on the ground, requires special consideration for embrittlement, leakage and associated safety risk.
Finally, there are end-use challenges related to scaling hydrogen. The current system size and weight of fuel cells are large, especially for aerospace and automotive applications. Their durability and reliability need to be improved for most transportation applications. Thermal, water and air management are also challenges when attempting to keep the size of the heat exchanger and overall system small. How can simulation enable hydrogen adoption?
Ansys technology overcomes many of the challenges associated with hydrogen by improving performance at every phase of its ecosystem and accelerating new technology development to address the cost and scale conundrum. For example, ENHIGMA a national project that involves different companies, as well as technological and research centres, used Ansys technology to manufacture low-cost, energy-efficient, and durable proton exchange membrane (PEM) based electrolysers and fuel cells. Centro Nacional del Hidrógeno (CNH2) researchers optimised the PEM cell stacks using flow simulations in Ansys Fluent.
Ansys simulation technology is used for individual cell design, cost-effective and lightweight material selection, cell-stack optimization for energy efficiency and thermal management of overall fuel cell and electrolysis system.
Cryogenic storage and transport are at the core of the hydrogen ecosystem. Ansys composites solutions can be used to design cryogenic vessels while closely mimicking its manufacturing process. The composite failure tool in Ansys Mechanical enables designers to evaluate potential failure modes and failure locations in-depth using advanced composite failure criteria such as Tsai-Wu, Puck and LaRC. It can be further be used to understand the effect of embrittlement and crack initiation and propagation.
Hydrogen-powered gas turbine engines provide the most promising path for decarbonization efforts in the energy and aviation sector. The most complex technical challenges of hydrogen combustion – such as flashback, acoustic instabilities and autoignition – can be characterised and addressed with high-fidelity simulations.
Finally, advanced digitalisation technologies, such as digital twins and reduced order models (ROMs), can be used to optimise the operations of hydrogen-based systems. ROMs are simplifications of high-fidelity, complex models. They capture the behaviour of source models so that engineers can quickly study a system’s dominant effects using minimal computational resources.
A typical hydrogen production system or hydrogen-based fuel cell plant contains many components. Most of these can be represented by a simplified model, but most critical parts – such as a fuel cell or PEM-cell stacks – can be represented by a ROM derived from Ansys 3D physics solvers. ROM creation for this digital twin is enabled by Ansys optiSLang, which automates the simulation toolchain and connects to algorithms for robust design optimization (RDO). With connection to live sensor data, this digital twin can monitor and optimize operations while enabling predictive maintenance.
By empowering engineers to explore more hydrogen design options faster and more affordably, simulation will help meet the top challenges related to increased hydrogen adoption. Being able to design and test hydrogen-related technologies in a virtual environment speeds time-to-market, which is critical as governments and industries rush to meet the 2050 net-zero carbon goals.
About the author
Pepi Maksimovic is Director of Applied Engineering at American software company Ansys.