The Role of Tidal Stream Energy in Green Ammonia and Green Hydrogen Production in The English Channel

Ammonia and hydrogen production are currently dominated by fossil fuels, which is carbon emissions-intensive. Production of ammonia and hydrogen is also possible with renewable energy, generating no direct carbon emissions. Tidal stream energy is a predictable renewable energy source, and utilising the difference in phase of tidal stream currents in close-by locations can provide a more stable power profile. This stable power profile could be useful as ammonia production has limited flexibility, and although hydrogen production is more flexible, hydrogen storage is particularly expensive. This paper explores the effect of tidal stream phasing on both green ammonia and green hydrogen production in the English Channel for the first time. The coefficient of variation (CV) of the power profiles between pairs of locations is used as a metric of tidal phasing, and the minimum is determined from locations in the English Channel appropriate for an Orbital O2 turbine with a similar energy. This minimum CV method is novel and can be applied to other tidal regions. For 66 MW of Orbital O2 turbines with an average capacity factor 20.5%, utilising phasing reduces the levelized cost of ammonia by 5% and the levelized cost of hydrogen by 4%.