Flow Measurement for Ammonia as an Energy Vector

Horizon Scan Report: Flow measurement requirements for using ammonia as an energy vector

Currently, the vast majority of ammonia produced is made from fossil fuel-derived hydrogen. However, with the rise of green hydrogen (produced by wind or solar powered electrolysis) and blue hydrogen (fossil fuel-derived coupled with carbon capture utilisation and storage systems), utilising ammonia as a viable green energy vector is being considered.

Ammonia has also received a significant amount of interest as a means of decarbonising the maritime industry due to it having a higher volumetric energy density than hydrogen, its ease of transportation, and the established trade/transport systems.

Despite this, there are some key challenges that exist in ammonia flow measurement. Under the process conditions typical of the ammonia value chain, ammonia may be present in either its gaseous or liquid phase, and is both corrosive and toxic, making it difficult to establish a safe testing/calibration facility. Although ammonia is typically encountered in its gaseous state under atmospheric conditions, ammonia is more commonly found as a liquid throughout the value chain and is therefore susceptible to phase change. Finally, additional considerations such as solubility in water, and maintaining low water concentrations in nominally anhydrous ammonia are imperative to ensure safety.

There are numerous regulations, and international and national standards that broadly fall under three categories; flow measurement standards that are independent of the fluid being measured; standards relating to the trace measurement of ammonia in both the atmosphere and emissions; and standards relating to the safe handling and use of ammonia. However, there are fewer international standards and regulations relating to the bulk transportation and flow measurement of ammonia.

The predicted increase of demand in this market raises the issue of traceability in flow measurement. At present, a traceability chain for ammonia does not exist anywhere in the world. Nor is there any understanding of the transferability of calibrations between other fluids (e.g. water) and ammonia. To match measurement uncertainties associated with the fuels it is predicted to replace, required uncertainties in the range of 0.25 % to 1 % (at k = 2) are anticipated. This is not currently able to be verified with the existing traceability chain and calibration capabilities. Therefore, research is needed to explore how to best address the absence of traceable measurements in this sector.

This Horizon Scan report outlines observations and key recommendations to enable a smooth transition to utilising ammonia as an energy vector.

This report by TÜV SÜD National Engineering Laboratory was prepared for the Department for Science, Innovation & Technology (DSIT). TÜV SÜD National Engineering Laboratory is the UK’s Designated Institute for Flow Measurement, under contract from DSIT, and part of the UK’s National Measurement System.