Nuclear-renewables energy system for hydrogen and electricity production

Abstract

Climate change concerns and expensive oil call for a different mix of energy technologies. Nuclear and renewables attract attention because of their ability to produce electricity while cutting carbon emissions. However their output does not match demand. This thesis introduces a nuclear-renewables energy system, that would produce electricity and hydrogen on a large scale while meeting the load demand. The system involves efficient high temperature electrolysis (HTE) for hydrogen production, with heat provided by nuclear and electricity by the grid (nuclear and/or renewables). Hydrogen production would be variable, typically at time of low demand for electricity and large power generation from renewables. Hydrogen would be stored underground on site for later shipping to industrial hydrogen users by long-distance pipeline or for peak power production in fuel cells. A hydrogen plant was designed, and the economics of the system were evaluated by simulating the introduction of the system in the Dakotas region of the United States in both a regulated and a deregulated electricity market. The analysis shows that the system is economically competitive for a high price of natural gas ($12-13 MMBtu) and a capital cost reduction (33%) of wind turbines. The hydrogen production is sufficient to supply the current demand of the Great Lakes refineries. With today's electricity prices, a competitive production cost of $1.5 /kg hydrogen is achievable. The analysis indicates large economic incentives to develop HTE systems that operate efficiently in reverse as fuel cells to displace the gas turbines that operate only a few hundred hours per year and thus have high capital cost charges. The capital cost of the HTE system has a significant impact on system economics, with large incentives to develop reversible HTE/ FC systems to reduce those costs. Such a system would expand the use of nuclear beyond electricity generation, and allows a larger penetration of renewables by providing an energy storage media and bringing flexibility to the grid operators.