Energy management system expanded with electrolyser
Develop a mathematical model of a complete electrolyser including peripheral devices to simulate the amount of hydrogen and heat it produces under intermittent electricity supply conditions. That is what Mechanical Engineering student Ivo van der Peet managed to do within a mere 14 weeks of internship at TIBO Energy. His work has resulted in a new module for the company’s Energy Management System.
‘When I started my master’s degree, I launched a new student team called Team SHIFT,’ Van der Peet starts telling the story of how he ended up at TIBO Energy. ‘With this student team, we want to develop a fully integrated energy system for the decentralized production of hydrogen. At that time TIBO Energy wanted to start an energy hub at TU/e campus, involving the student teams that are working on energy-related topics. That is how I first came into contact with the company.’
TIBO Energy offers an Energy Management System based on digital twins that enables users to manage network congestion, contract limits, CO2 emissions and reduce energy costs by simulating the impact of adding, changing or removing different energy assets. ‘I told them that I was interested in developing a model to simulate the behavior of a hydrogen electrolyser when powered by an intermittent energy supply, such as solar power. They thought that would be an interesting additional asset for their model.’ With this internship, Van der Peet hoped to kill two birds with one stone. ‘Besides its value for TIBO Energy, such a model would also be very relevant in the context of our student team.’
Delving into details
During his internship, Van der Peet had to gain a lot of new knowledge about the inner workings of an electrolyser, he says. ‘For example, I had to delve into the details of the electrochemistry to be able to model how parameters like pressure and temperature influence the amount of hydrogen that will be produced.’ The fact that Van der Peet explicitly aimed for a model that could deal with the intermittent supply of electricity from solar panels significantly increased the complexity of the simulations. ‘Since at times when there is less or no solar power available you will have to scale down or even completely shut down the electrolyser, fairly often, the reactor will not operate at its optimal temperature.’
‘My model is based on realistic estimates, for example about stack dimensions, cell voltage, and optimal operating temperatures’
He modelled not only the electrolyser itself, but also the peripheral devices such as the heat exchangers used to cool the electrolyser, Van der Peet explains. ‘My model essentially is composed of two parts: one being the electrochemical model, which leads to estimates of the amount of hydrogen and heat that is produced under certain process conditions, and the other is a thermodynamical model, which is able to predict the heating and cooling behavior of the entire system as a result of the intermittent operation.’
Realistic model
His model is based on an alkaline electrolyser, which is one of the most commonly used in commercial applications. Also for the other components, the ambitious student went for the most commonly available alternatives, to make his model as realistic as possible. ‘My model is based on certain estimates from literature, for example about stack dimensions, cell voltage, and optimal operating temperatures. Through contacts I had with people like Thijs de Groot from TU/e’s Department of Chemical Engineering and Chemistry, and companies like Prodrive Technologies, I was able to make these assumptions as realistic as possible. But of course, they still need to be validated in dedicated experiments to further improve the model.’
This validation step is something Van der Peet envisions Team SHIFT could be instrumental in. ‘We have made a technology roadmap and are planning to develop a 10 kW system to demonstrate the potential of the technology. After that, we might want to turn into a start-up to build larger systems, towards the 100-200 kW which would be needed for a typical Dutch farm.’ Him mentioning a farm is no coincidence, since after extensive conversations and market research, the student team aims for farmers as launching customers of their small-scale electrolysers. ‘Over the past decade, many farmers have covered their barns with solar panels. But where it used to be profitable to deliver energy to the grid, now they are often told to switch off their panels because of grid congestion problems. With our small scale electrolysers, we think we can offer them new sustainable business opportunities. Hydrogen can be a great way of storing excess electricity, but society is still hesitant towards installing hydrogen storage tanks in residential areas. We think that farmers can install them on their land, away from people, to demonstrate that this is a safe and attractive option to save excess energy for later use.’
Towards energy cooperative
The students are currently teaming up with Metalot to see if they could extend their proposed business case with an additional element, the enthusiastic master student explains: ‘in that vision, farmers would use an electrolyser to convert the excess solar energy they produce into hydrogen, which is then on the spot used to reduce the iron oxide that results from burning metal fuels. That way, you could establish an energy cooperative where farmers produce iron powder as energy carriers that can be supplied to end users as metal fuels.’
