Development and analysis of a novel liquid ammonia energy storage (LNHES) technology integrated into different energy systems

Project Description

Intermittent power generation sources, namely wind and solar, are safe and viable options for rapidly decarbonizing the power sector and fulfilling obligations in global climate change mitigation agreements such as the 2015 Paris Agreement. However, intermittent sources, on their own, are unable to provide on-demand electricity as their period of maximum generation often coincides with the off-peak electricity demand period. This could greatly impact grid flexibility as the intermittent sources become dominant in the grid. This challenge will become highlighted in the UK with the government’s ambitious target to increase the wind power installed capacity from the current 24 GW to over 50 GW by 2030, which will be enough to power every home in the UK. The challenge can be addressed by implementing energy storage (ES) alongside intermittent generation technologies. Alternative solutions, such as the deployment of peaking power plants fired by fossil fuel, are expensive and negates the objective to cut down emissions using intermittent renewable sources.

This project aims to develop and evaluate a novel liquid ammonia energy storage (LNH3ES) technology integrated into a typical electricity grid with the capacity to store excess generation from intermittent renewable sources during off-peak periods. LNH3ES can flexibly, reliably, economically and sustainably deliver higher roundtrip efficiencies than existing ES technologies. The proposed technology, shown schematically below, combines the principles of established technologies, namely Kalina cycle and ammonia refrigeration: surplus electricity from the grid during the off-peak period is used to compress and store ammonia in the liquid state. When electricity is needed (peak period), the stored high-pressure liquid ammonia (40 bar at about 25oC) is mixed with water to generate a high-pressure ammonia-water gaseous mixture which can be expanded in a turbine to generate electricity. The proposed technology uses the exothermal heat from mixing liquid ammonia and water to generate the high-pressure ammonia-water gaseous mixture. LNH3ES is a first-of-its-kind technology and it is unique as it uses the principles of established technologies – ammonia liquefaction and Kalina cycle – and therefore will reach the market quickly with minimal R&D