Hydrogen and Digital Twins for an Improved Energy Future
Hydrogen is an ideal clean energy source offering a high calorific value and energy density, and multiple transport and storage methods, but most importantly it produces virtually no greenhouse emissions when combusted. Hydrogen can help meet 14% of US final energy demand by 2050 1. Yet, new infrastructure is required to meet this increased demand, including large-scale production plants.
Today, the most common method for producing hydrogen is steam-methane reforming. This process is currently the least expensive way to produce hydrogen, but is mainly produced by reforming natural gas and therefore is CO2-intensive. For hydrogen to become a low-carbon energy carrier, it must be produced through electrolysis – an emissions-free process that splits hydrogen from water using an electric current. When the source of energy for water splitting is renewable or low carbon, the hydrogen produced is known as green hydrogen. There are two established industrialised electrolysis production technologies – alkaline water electrolysis and Proton Exchange Membrane (PEM) electrolysis. High-temperature solid oxide electrolysis, also known as steam electrolysis, presents an interesting alternative, but has yet to be demonstrated at scale.
Scaling up to Drive Costs Down
To meet the market demand, providers of electrolysis technology are looking at ways to scale up and improve their designs. For example, the Green Hydrogen Catapult initiative intends to scale up production 50-fold in the next six years with the aim to reduce costs to below $2 per kilogram. Plant designs will need to handle higher current density and provide high efficiency over a longer lifetime.
Technology providers also need to make their design ready for production-chain manufacturing, which will also lower the cost of hydrogen. There also needs to be a greater use of recycled materials to replace the rare and expensive materials traditionally used in PEM systems, while still guaranteeing system integrity. The control and operational strategies for plants are very important. Operational setpoints need to be established and balance-of-plant (BoP) components and sub-systems must be developed, integrated and optimised.
Potential efficiency improvements of 3-5% in both water purification efficiency and hydrogen purification are possible. Ever larger projects are underway to validate how to achieve higher efficiencies, with a 20 MW PEM electrolysis hydrogen production facility, the largest in the world, soon to become operational in Quebec, Canada. Many of these large-scale hydrogen plants will be built within existing industrial clusters such as refineries, ammonia plants, harbour/ports or even offshore – safety is therefore paramount.
Digital Twin Technology
To this end, one solution that is proving to be a game-changer across many industries is digital twin technology. A digital twin is a software-based virtual replica of the complete physical assets of a production facility, including its process equipment, instrumentation and controls, as well as the production processes. Through this replica, the operation of these assets is modelled and simulated through their lifecycles.
A digital twin converts process design information, including piping and instrumentation diagrams, process flow diagrams and other data governing the process, into a software-based representation of the process using simulation software. The digital twin becomes an invaluable tool to analyse various `what if’ design scenarios, such as different rectifiers or water purification systems, different BoP design improvement ideas and others.
Digital twin technology can also prove essential in regulatory compliance and safety validation where the electrolysis facility will be integrated within existing industrial plants. Fundamentally, it enables cost-effective compliance and validation of the process control system, as well as operating procedures. When the plant is operational, the digital twin can provide data and insight into equipment and system health, helping plant management to optimise preventative maintenance practices and avoid costly unscheduled downtime. With many H2 electrolysis projects to be built in phases, the digital twin can facilitate the seamless integration of each phase.
Digital twins provide a platform to enable faster operator training and competency assessment. Running an exact digital replica of the live plant also makes it possible to train control room operators and technicians, in an offline and risk-free environment, thus making them better equipped to successfully control any process upsets or abnormal situations.
By providing a virtual environment where process control and operational solutions are designed and tested before being applied, a digital twin reduces risk when upscaling electrolysis plant design. Digital twin technology can also help across the plant’s lifecycle, helping to bring it online quicker and safer, upskilling operators in a safe environment, and helping to maximise operational efficiencies for increased plant productivity and profitability.
- “Road Map to a US Hydrogen Economy.” Fuel Cell and Hydrogen Energy Association, https://www.fchea.org/us-hydrogen-study