(59e) Unlocking the Potential of Open-Ocean Wind Energy Via Green Offshore Ammonia Production

The world is transitioning toward renewable sources of energy, such as solar and wind, at an unprecedented pace. In particular, the offshore wind market grew nearly 30% per year between 2010 and 2018 and is expected to increase 15-fold over the next two decades [1]. There is vast untapped potential in offshore wind, especially at locations far from shore where wind velocities are significantly higher than close to or on shore. However, transmitting electricity generated on the open ocean to onshore demand points is a major challenge since using electrical cables for such long distances can be prohibitively expensive. In this work, we propose to address this challenge with green offshore ammonia, where the idea is to directly produce ammonia offshore using electricity generated from the wind; the ammonia then serves as an energy carrier that can be readily shipped to shore. This is feasible since, besides electricity, the production of green ammonia only requires air and water [2], which are available in abundance on the ocean.

While research has been conducted on ammonia production with offshore resources, most of them only consider transmitting offshore generated electricity to shore for ammonia production on land [3,4]. In this work, we assess the techno-economic viability of wind-powered offshore ammonia production by applying a superstructure-based optimization approach that determines the optimal design and operational schedule of the process. This approach allows a systematic selection among various means of chemical production, storage, and transportation as well as different energy transmission, conversion, and storage technologies. We optimize the design with regard to the levelized cost of ammonia (LCOA) for given demands at locations with different distances to shore, water depths, and wind profiles. Our results show that the LCOA depends heavily on the wind speed and means of chemical transportation or electricity transmission. When the distance to shore is relatively small, it is economically more favorable to transmit the generated electricity to shore and produce ammonia onshore. However, as the distance increases, shipping offshore produced ammonia becomes the better option. Also, as the distance increases, the economics favor transporting ammonia using ships rather than pipelines. Our analysis demonstrates the potential of green offshore ammonia and provides insights that can help identify suitable locations for realizing this new concept.

References:

[1] International Energy Agency (2019). Offshore Wind Outlook 2019.

[2] Palys, M. J., Wang, H., Zhang, Q., & Daoutidis, P. (2021). Renewable ammonia for sustainable energy and agriculture: vision and systems engineering opportunities. Current Opinion in Chemical Engineering, 31, 100667.

[3] Morgan, E. R., Manwell, J. F., & McGowan, J. G. (2017). Sustainable ammonia production from US offshore wind farms: a techno-economic review. ACS Sustainable Chemistry & Engineering, 5(11), 9554-9567.

[4] Serna, Á., & Tadeo, F. (2014). Offshore hydrogen production from wave energy. International journal of hydrogen energy, 39(3), 1549-1557.