Nuclear-Renewable Hybrid System Economic Basis for Electricity, Fuel, and Hydrogen

摘要

Concerns about climate change and altering the ocean chemistry are likely to limit the use of fossil fuels. That implies a transition to a low-carbon nuclear-renewable electricity grid. Historically variable electricity demand was met using fossil plants with low capital costs, high operating costs, and substantial greenhouse gas emissions. However, the most easily scalable very-low-emissions generating options, nuclear and non-dispatchable renewables (solar and wind), are capital-intensive technologies with low operating costs that should operate at full capacities to minimize costs. No combination of fully-utilized nuclear and renewables can meet the variable electricity demand. This implies large quantities of expensive excess generating capacity much of the time. In a free market this results in near-zero electricity prices at times of high nuclear renewables output and low electricity demand with electricity revenue collapse. Capital deployment efficiency-the economic benefit derived from energy systems capital investment at a societal level-strongly favors high utilization of these capital-intensive systems, especially if low-carbon nuclear renewables are to replace fossil fuels. Hybrid energy systems are one option for better utilization of these systems that consumes excess energy at times of low prices to make some useful product. The economic basis for development of hybrid energy systems is described for a low-carbon nuclear renewable world where much of the time there are massive quantities of excess energy available from the electric sector. Examples include (1) high-temperature electrolysis to generate hydrogen for non-fossil liquid fuels, direct use as a transport fuel, metal reduction, etc. and (2) biorefineries. Nuclear energy with its concentrated constant heat output may become the enabling technology for economically-viable low-carbon electricity grids because hybrid nuclear systems may provide an economic way to produce dispatachable variable electricity with economic base-load operation of the reactor.