Gas-turbine power plants offer the most efficient and flexible back-up capacity when the wind isn’t blowing or the sun isn’t shining, but they are currently few and far between. Yet Nuon sees a future for these plants. Wind and solar energy still cannot be stored to any significant capacity. That means that this sustainable energy is often wasted when there is plenty of wind or sun. Together with TU Delft and the University of Twente, Nuon is therefore investigating the options for storing this so-called seasonal oversupply at Magnum in the shape of ammonia. This can then be used as a fuel in the gas-turbine power plant, free of CO2 emissions. Delft is studying the ammonia production – Jim Kok (Mechanical Engineering) of the University of Twente is looking at the options for reburning the ammonia in de NUON gas turbine for clean electricity generation.
Alexander van Ofwegen, Managing Director at Nuon Warmte, explains: “This idea is made up of three steps. Firstly, you convert the wind-generated electricity into liquid ammonia. This involves a chemical process, with the hydrogen bonding with nitrogen to make ammonia. You then store the ammonia in large tanks – you can then keep it as long as you need. This means you always have a reserve of fuel for those moments when there is not enough wind or sun. The ammonia can then be used in the third step as a carbon-neutral fuel in the gas-fired power plant, as it releases only nitrogen and hydrogen, and not CO2. The other great thing about this concept is that it should be possible to convert sustainable energy into ammonia anywhere on earth. This allows you to basically recycle wind or solar energy – you use wind or solar energy to produce ammonia, turning your gas-fired power plant into a super battery at the same time!”
MAGNUM PLANT LEADING THE WAY IN ENERGY TRANSITION
In 2013, Nuon’s Magnum plant in Eemshaven was officially opened. The original concept was to build a power plant that could run on different fuels, such as biomass, gas and coal. In consultation with nature and environmental organisations, the decision was made in 2011 that Magnum would remain as a gas-fired plant until at least 2020. In light of the study by Nuon, Delft and the UT, Nuon has made the definitive decision not to use coal in this power plant. The aim now is to work towards a CO2-emissions-free future for Magnum.
Although Delft, the UT and Nuon are still at the drawing board and a great deal of research is yet required, the parties agree that storing energy in ammonia is a promising technique which, with the necessary research and additional funding, could be used on a large scale within ten years or so. This research naturally places a high priority on safety and the environment.
Alexander van Ofwegen: “Ammonia has already been used for 100-odd years in various ways – it is the main raw ingredient in artificial fertiliser, but it is also deployed in large cooling plants used, for example, for ice rinks. What’s more, the Netherlands has a great deal of experience in the large-scale storage of ammonia. But of course, as with any other concentrated chemical substance, we must take account of the necessary safety measures. We hope to be able to provide a demonstration at a relevant scale within five years.”
POWER TO AMMONIA
Nuon’s study is part of the ‘Power to Ammonia’ project, for which the Institute for Sustainable Process Technology (ISPT) has brought together various parties to share their expertise and carry out affiliated research. Power to Ammonia is a joint venture of ISPT, Stedin Infradiensten, Nuon, ECN, Delft University of Technology, The University of Twente, Proton Ventures, OCI Nitrogen, CE Delft and AkzoNobel.
You can find further information about Power to Ammonia online at: http://www.ispt.eu/
Nuon is an energy concern with 4,400 employees who serve around two million consumers, businesses and organisations in the Netherlands. Its core focus is a reliable and affordable energy supply that is as sustainable as possible. Nuon produces and supplies gas, electricity, energy-related products and geothermal energy and helps its clients to reduce their energy consumption. In the Netherlands, Nuon has 2000 kilometres of heat-distribution pipelines, 251 wind turbines, 2 hydropower plants, 1 biomass plant, 9 high-efficiency gas-fired power plants and 1 coal-fired power plant. Nuon is part of Vattenfall.