Nuclear hybrid energy systems: imperatives, prospects, and challenges

As global population reaches an expected 8 billion people by 2030, primary energy consumption is expected to increase by almost 40% from approximately 520 exajoules consumed today to almost 740 exajoules. Much of this increase is expected to come from non-Organization for Economic Cooperation and Development (OECD) nations, and Asia specifically. In these economies, energy used for transportation is expected to grow substantially, as is industrial, commercial and to a lesser degree residential energy use, creating considerable pressure on global and local energy markets. The magnitude and timing of growth in energy consumption likely will create a global imperative to deploy energy production technologies that balance the three pillars of energy security: • economic stability – related to the affordability of energy products, stability and predictability in their price, and the efficient and effective deployment of global capital resources in their development; • environmental sustainability – related to minimizing the negative impacts of energy production to air, land, and water systems and advancing the long-term viability of using a particular resource in a way that does not limit future generations ability to prosper; • resource security – related to the ability to access energy resources and products where and whenmore » necessary, in an affordable and predictable manner. One approach to meeting these objectives is hybrid energy systems (HES). Broadly described, HES are energy product production plants that take two or more energy resource inputs (typically includes both carbon and non-carbon based sources) and produce two or more energy products (e.g. electricity, liquid transportation fuels, industrial chemicals) in an integrated plant. Nuclear energy integration into HES offers intriguing potential, particularly if smaller (<300 MWe) reactors are available. Although the concept of using nuclear energy in a variety of non-electrical process applications is certainly not new, renewed interest in more tightly coupled energy product plants (such as HES) that meet the objectives outline above have gained additional interest recently, an interest likely sparked by sharpening energy security concerns. Studies have shown that non-nuclear integrated (hybrid) energy systems can have appealing attributes in terms of overall process efficiency, enhanced electric grid stability, renewable energy integration, and economic performance, and lifecycle greenhouse gas emissions. These attributes seem to be sufficiently compelling that several significant commercial investments in fossil-renewable HES are being made in the United States while the U.S. Defense Advanced Research Projects Agency (DARPA) has openly solicited information regarding nuclear energy integration schemes. The challenges of nuclear energy integration include myriad issues associated with the following RDD • heat / energy management (e.g. advanced heat exchangers, process design); • energy storage (e.g. H2 production, liquid fuels synthesis); • byproduct management (e.g. CO2 recycle approaches); • systems dynamics, integration and control (e.g. process dynamics analyses and optimization, advanced prognostics, diagnostics, variable time scale control and flow sheet optimization).« less