Energy security: the role of shale technology.

Sustainable energy systems are sensitive to the countries' energy portfolio decisions, shaping geopolitics and contributing to the global energy security (ES). Accordingly, this paper applies the "Markov regime-switching" method to explore the impact of "the North American shale technology" (NAST) on behavioral regimes of the US energy security measurements (ESM), e.g., diversity of primary energy demand ([Formula: see text]), net energy import dependence ([Formula: see text]), non-fossil fuel resource portfolio ([Formula: see text]), and crude oil import dependency ([Formula: see text]). The findings confirm time-varying and asymmetric behavior of the US ESM before and after the NAST. Specifically, the overall interaction of substitution effect and scale effect of NAST strengthens the US energy systems through [Formula: see text], [Formula: see text], and [Formula: see text], while [Formula: see text] leads to higher risks of the US energy supply security. Consequently, the shale reserves development, diversification of primary energy demand and import supply, and advanced energy transport and trading policies, are suggested to overcome the barriers in achieving (i) availability, (ii) accessibility, (iii) affordability, and (iv) acceptability aspects of ES and vulnerability reduction of the US energy systems in respect of risk and resilience.