Cost-effective,
low-carbon ammonia production is necessary for
decarbonizing its existing uses but could also enable decarbonization
of other difficult to electrify end uses such as shipping, where the
energy density is a key criterion. Here, we assess the levelized cost
of ammonia production (95% availability) at industrial-scale quantities
(250 tonnes/day) in 2030 from integrating commercial technologies
for renewable electricity generation, electrolysis, ammonia synthesis,
and energy storage. Our analysis accounts for the spatial and temporal
variability in cost and emissions attributes of the electricity supply
from variable renewable energy (VRE) sources and the grid and its
implications on plant design, operations, cost, and emissions. On
the basis of 2030 technology cost and grid projections, we find that
grid-connected ammonia in midcontinental U.S. costs 0.54–0.64
$/kg, in comparison to 0.3–0.4 $/kg for natural-gas-based ammonia
and, depending on the generation mix of the grid, may have higher
or lower CO2 emissions. Fully VRE based ammonia production,
even with simultaneous wind and PV utilization, is more expensive
than grid-connected outcomes, due to the need for storage to manage
VRE intermittency and continuous ammonia production. Using a combination
of VRE and grid electricity at locations of existing ammonia facilities
in the midcontinental U.S. can achieve 2–80% CO2 emissions reduction per tonne of ammonia in comparison to natural
gas routes and corresponds to a levelized cost range of 0.57–0.85
$/kg NH3. Further cost reductions are shown to be possible
if the ammonia synthesis loop can be made more flexible, which reduces
the need for a round-the-clock electricity supply and substitutes
use of battery storage with ammonia storage.