Siemens pilots the use of ammonia for green energy storage

A chemical compound commonly used to boost crop yields could be the answer to helping the world increase its consumption of renewable energy.

In a world first, Siemens is opening a £1.5m pilot project in Oxfordshire employing ammonia as a new form of energy storage.

The German industrial firm hopes to prove that ammonia can be as useful as more established storage technologies, such as lithium-ion batteries, when it comes to managing the variable output of wind and solar power.

The proof-of-concept facility at Harwell will turn electricity, water and air into ammonia without releasing carbon emissions. The ammonia is stored in a tank and later either burned to generate electricity, sold as a fuel for vehicles or for industrial purposes, such as refrigeration.

Dr Ian Wilkinson, programme manager for Siemens’ green ammonia demonstrator, said: “Storage is recognised as the enabler for intermittent renewable power.

“This is where we’re different from usual storage, we’re not just looking at power. Usually it’s [storage] just filling in the gaps when the sun’s not shining and the wind is not blowing. We’re looking at other uses, mobility and industrial uses.”

Siemens believes ammonia has an advantage other over emerging storage technologies, such as “liquid air” and flow batteries, because it is repurposing existing technology and hardware.

The world produces about 170m tonnes of ammonia a year, the vast majority of which is used by farmers as fertiliser. Most of that is made from natural gas, emitting greenhouse gas in the process, but the Harwell plant does not use fossil fuels.

While the compound was used as a fuel in Nasa hypersonic jets in the 1960s and some cars have been converted to run on it, Siemens does not expect it to be used directly in cars.

The hydrogen in ammonia, however, can be extracted for use. “I see it supporting a hydrogen economy, hydrogen vehicles,” Wilkinson said.

Given the demonstration scheme is relatively small in terms of storage and power generation capacity, Siemens is not expecting to make money from the trial. Instead the hope is to establish that the concept can work and prove useful.

If the technology took off, the German firm stands to benefit as it makes the electrolysers which use electricity to split water into oxygen, and the hydrogen that is a building block of ammonia.

Wilkinson said: “Siemens is looking at a whole range of storage technologies, including batteries and chemical storage [including ammonia].”

The Harwell facility opens on 26 June, and was funded with £500,000 by Siemens and £1m from government innovation agency Innovate UK.

SOURCE: The Guardian