A controversial power station in northern Groningen will not burn coal and instead will be taken ‘carbon-emissions free’, energy company Nuon said.

Nuon has begun a research project with Delft University of Technology to investigate using the plant as a super battery to store energy generated by wind and solar power farms.

Working with the university’s Professor Fokko Mulder, Nuon is looking at storing seasonal surpluses after particularly windy or sunny weather in the form of ammonia. This could then be turned into energy in the plant, without releasing more carbon dioxide.

Alexander van Ofwegen, director of Nuon Heat, said: ‘There are three steps. First, you convert your electricity from wind into liquid ammonia. A chemical process is involved in this, which binds hydrogen to nitrogen to make ammonia. Then you save the ammonia in large tanks, which can be there as long as needed. So you always have a supply of fuel for those times when there is little wind or sun.’

The idea – which is yet to be tested – could be rolled out in around five years. It aims to address an under-reported issue with renewable energy sources: the sun doesn’t always shine, nor is it always windy, but we always want electricity.

According to other reports, this means the end of potential coal burning at the plant, which became operational in 2013. It had been built to run on biomass, gas and also coal, but under pressure from environmental agencies, the coal unit was temporarily suspended in 2011.