A proof of concept project by German technology conglomerate Siemens aims to show how ammonia can unlock the future of large-scale storage to deliver seasonal shifts of power on the grid and power electric vehicles.
The 30kW generator and 13kW electrolyser might be small, but the world’s first demonstrator of its type aims to disrupt the energy storage industry by proving it can close the cycle of renewable power using carbon free ammonia (NH3).
Siemens has developed the system, which uses readily available components, in conjunction with the Science and Technology Facilities Council, the University of Oxford and Cardiff University.
It works by using a wind turbine to power an electrolysis machine to split water into hydrogen oxide and an air separation unit to remove nitrogen from the atmosphere. The two elements are then combined to make ammonia.
The ammonia can then be used to run gas turbine engines to generate power, or by cracking it back into nitrogen and hydrogen for use in fuel cells to power electric vehicles.
Ian Wilkinson, programme manager, Siemens Corporate Technologies, told ESJ: “The way to think about it is the fuels we use today are really hydrogen stores and its much easier to store the hydrogen if you hang it off a carbon atom first or a chain of carbon atoms and you get hydro-carbon fuels.
“What I’m doing here is using nitrogen instead of carbon. The objective of the demonstrator is to show that this can be done and then begin to learn about operating the various technology components as a system.”
One of the system challenges is the operation of the ammonia synthesis intermittently, which is key if it is to be run from renewable generated power.
“Existing ammonia plants are designed to run 24/7 to make them efficient,” says Wilkinson, “but here I have a need to run intermittently because of my energy source.
“So when do I charge, when do I discharge, what impact does that have of the synthesis step, how can I manage those challenges, how can I optimize the decision around charging and discharging to make the most money?” he said.
Ammonia is already produced in vast quantities, mostly for agricultural fertilisers, but use natural gas or other fossil feedstocks to power the synthesis process, and as a source of hydrogen.
Another benefit is that ammonia can be transported over long distances by sea or land to efficiently shift the energy in bulk from distant centres of production to centres of consumption.
“The UK is a net energy importer for electric generation, we can look at domestic generation but we are going to be unable to meet UK energy needs with domestic renewables energy generation alone and we will still need to import,” he said.
“And that’s where ammonia has a role to play because the infrastructure for storing and transporting ammonia already exists, something like 180 million tonnes a year is produced world wide already, the tankers to ship it around exist, the terminals to store it and pump it exist, the safe handling procedures, road transportation of ammonia happens.
“So all that exists and we can piggy back all that, and that’s what makes it exciting.”
The next edition of ESJB will have an in depth interview with Wilkinson discussing the technology’s impact on battery ESS, the need for policy changes and its importance in a de-carbonized future.