The development of a thermochemical energy storage system based on ammonia, for use with concentrating solar power is discussed in this paper. This is one of a number of storage options for concentrating solar power, including molten-salt storage, which is already operating commercially. The ammonia storage development has involved prototype solar receiver/reactors operated in conjunction with a 20-m 2 dish concentrator, as well as closed-loop storage demonstrations. An ongoing computational study deals with the performance of an ammonia receiver for a 489-m 2 dish concentrator. The ammonia storage system could employ industry-standard ammonia synthesis converters for superheated steam production. A standard 1500 t/day ammonia synthesis reactor would suffice for a 10-MWe baseload plant with 330 large 489-m2 dishes. At this stage, an updated economic assessment of the system would be valuable.