The growing demand for food and therefore fertilisers means that ammonia production needs to increase by 3% each year. Ammonia is made using the Haber-Bosch process, converting hydrogen and nitrogen using high temperature and a catalyst. Ammonia production therefore relies on fossil fuels such as natural gas. Together with the fossil hydrogen feedstock, current ammonia production accounts for almost 1.5% of global CO2 emissions.
So how can we reduce CO2 emissions but still meet the need for ammonia? By switching to “green” ammonia which is ammonia (NH3) produced using only renewable electricity, water and air we could save over 40 million tonnes of CO2 each year in Europe alone, or over 360 million tonnes worldwide. This switch would also enable load balancing for electricity grids and allow the use of green ammonia to fertilise crops or to burn and generate electricity when the wind is not blowing.
The Green Ammonia demonstration programme
The Siemens demonstrator, which was launched in June 2018 at the Science and Technology Facilities Council’s (STFC) Rutherford Appleton Laboratory and shows the complete cycle of renewable power stored as ammonia and converted back to electricity. This project was executed in collaboration with STFC, the University of Oxford, Cardiff University and Innovate UK.
The Siemens demonstrator uses water electrolysis to provide a hydrogen supply and extracts nitrogen from the air. The system combines the two elements in the well-established Haber-Bosch process to make ammonia. The power for the all steps is driven by renewable electricity, specifically wind at the site in Oxfordshire, UK. Liquid ammonia is stored in a tank and then combusted in an engine to produce renewable electricity on demand. When burned, ammonia turns back into nitrogen and water, and does not produce the CO2 emissions associated with fossil fuels.
The Clean, Green Hydrogen Fuel Cell System
Hydrogen (H2) is a non-toxic, clear gas that is the most abundant element in the universe – when used as a fuel, its only by-product is water. It does not create fumes or carbon dioxide which pollute the atmosphere. ‘Green’ hydrogen, such as the hydrogen in the fuel cell system we have created in partnership with GeoPura, is made from water in an electrolyser, powered by 100% renewable energy (from a wind farm or solar panels for example). Fuel cells sytems combine hydrogen with oxygen from the air. This chemical reaction releases electrical energy which then powers the cars.
We’re transitioning to Electric Vehicles faster than originally predicted and we need to considerably increase our renewable energy generation capacity if we are going to power our increasing number of EVs and reduce carbon emissions.
In Summer 2019, we created the fuel cell system for Goodwood Festival of Speed - this produced 150kW of electricity to provide fast charging for the EV cars in the First Glance Paddock. This amount of electricity would usually be allocated to 75 households. Current distribution networks aren’t designed to support the mass electrification of personal transport and 40% of UK households do not have access to private parking. The Siemens GeoPura solution can support a network of fast public charging points in our cities that are emissions-free and without limits.
Future applications of this technology could be a substitute for natural gas by feeding hydrogen into existing pipelines, as fuel for fuel-cell vehicles or power plants, or as feedstock for the hydrogen processing industry. This not only opens the possibility to connect energy generation with the industry and mobility sectors but gives us the ability to deliver scalable and carbon-free energy.