Assessment of a hybrid system that uses small modular reactors (SMRs) to back up intermittent renewables and desalinate water

Abstract

Because water is easier to store in substantial quantity than electricity, this paper examines the possibility that a U.S. domestic market for factory-manufactured small modular nuclear reactors (SMRs) might be developed to use the constant output of an SMR to perform water desalination when wind or solar power are producing high output and generate electricity for the grid when wind or solar power output is low. In the first part of the paper, we compare powering desalination systems with electricity from SMRs and from natural gas plants that are equipped with a system that performs carbon capture and geological sequestration (NG CCS). We show that mass-produced SMRs could have costs that are comparable to, but probably somewhat higher than those of systems based on NG CCS. We find that the cost of CO2 emissions would have to rise to roughly 200 $/ton for the SMR solution to be clearly dominant. In the second part of the paper, we examine the uneven water supply situation across the U.S, focusing on the southwestern and western regions, and conclude that over the next several decades serious shortages are likely to develop only in a few local markets, such as West Texas and the Monterey Peninsula. Even if factory mass production of SMR's were more successful in reducing costs than experts have estimated, and costs could be reduced to that of NG CCS systems, the commercial risks and siting difficulties likely to accompany SMRs would probably preclude their wide adoption in the U.S. over the next few decades. Globally there are regions where a significant market for desalination supported by nuclear power might develop. However, aggressive changes in U.S. regulatory and export policy will be needed if U.S. SMR manufacturers are to play a role in those or similar markets in the face of aggressive Chinese, South Korean, and Russian programs of reactor exports.