Ammonia production with offshore wind power has the potential to transform energy and fertilizer markets within the United States. The vast offshore wind resource can be converted directly into liquid ammonia using existing technologies. The liquid ammonia can then be transported around the country via rail, truck, barge or pipeline and used as either a fertilizer or a fuel. This thesis reviews the technologies required for all-electric, wind-powered ammonia production and offers a simple design of such a system. Cost models based on the physical equipment necessary to produce ammonia with wind power are developed; offshore wind farm cost models are also developed for near-shore, shallow, wind farms in the United States. The cost models are capable of calculating the capital costs of small industrial-sized ammonia plants coupled with an offshore wind farm. A case study for a utility-tied, all-electric ammonia plant in the Gulf of Maine is used to assess the lifetime economics of such a system. Actual utility grid prices and offshore wind are incorporated into a systems-level simulation of the ammonia plant. The results show that significant utility grid backup is required for an all-electric ammonia plant built with present-day technologies. The levelized cost of one metric ton of ammonia is high relative to ammonia produced with natural gas or coal, but is not as susceptible to spikes in ammonia feedstock prices. A sensitivity analysis shows that the total levelized cost of ammonia is driven in large part by the cost of producing electricity with offshore wind. Major cost reductions are possible for systems that have long lifetimes, low operations and maintenance costs, or for systems that qualify for Renewable Energy Credits.
Techno-Economic Feasibility Study of Ammonia Plants Powered by Offshore Wind
Eric R. Morgan, University of Massachusetts - Amherst