FROZEN HEAT | Volume 2

1.1 INTRODUCTION

Energy is essential to achieving the economic, social, and en- vironmental goals of sustainable human development. The combination of services that acquires energy and delivers it where it is needed to serve those goals is called an energy sys- tem. That system consists of an energy supply sector and com- mercial, industrial, or household end-use technologies (WEA 2000). The global energy system is currently facing a number of challenges. Some are related to increasing consumption lev- els, limited access, and energy security, while others are envi- ronmental concerns, such as climate change and pollution of air and water resources (surface and groundwater). Gas hydrates, ice-like combinations of water and natural gases (most commonly methane), are a hitherto untapped energy re- source. Recent scientific drilling and evaluation programs sug- gest that gas hydrates occur in abundance, primarily in marine settings, with about 1% of the global gas hydrate distribution occurring in permafrost environments. (See Volume 1 Chapter 1 of this report for a detailed discussion.) Global resources of methane in gas hydrates are enormous. In fact, some estimates suggest that the amount of hydrocarbons bound in the form of gas hydrates may rival the total energy resources contained in other conventional hydrocarbon sources such as coal, natural gas, and oil. Given the advances in scientific knowledge about gas hydrates over the past few decades, as well as continuing innovation in oil and gas recovery techniques, it is likely that large-scale production of natural gas from gas hydrates will be- come viable in the next several decades. This could have pro- found implications for the future global energy system. Energy resources are sometimes measured in joules, an ex- pression of the amount of energy contained in the resource. In terms of electrical generation, one joule produces one watt of power for one second. A decade ago, largely due to lack of field data, estimates of global gas hydrate resources ranged from 0.1 to 300 million exajoules (EJ, with 1 EJ equal to 10 18 ) (Collett and Kuuskraa 1998; Max et al. 1997). As an indica- tion of the scale of these resources, annual global energy con-

sumption is currently about 500 EJ. In recent years, as more information has become available, estimates of the global in- place hydrate resources have tended to fall into a narrower range: between 0.1 and 1.1 million EJ, or 3 000 to 30 000 trillion cubic metres (Tcm) (Boswell and Collett 2011). How much of this resource is suitable for practical and affordable recovery, however, remains uncertain. Chapter 2 of this volume describes the current state of the assessment of gas hydrates from an energy resource perspec- tive. Most of the earlier assessments focused on quantifying in-place resources, with little attention paid to how much methane might ultimately be recoverable. The first efforts to assess the practical resource potential of gas hydrates are now appearing, both at the global scale (Johnson 2011) and as detailed geological assessments of specific, well-character- ized regions (Saeki et al. 2008; Collett et al. 2008; Frye 2008; Frye et al. 2011). While these findings are clearly preliminary and await confirmation from industrial production tests, they are supported by the findings of initial scientific field-testing programs (Yamamoto et al. 2011; Dallimore et al. 2012). The results are consistent with the potential for substantial, wide- spread, recoverable gas resources in gas hydrates. Given the enormous potential methane resource contained in gas hydrates, the lack of any clear technical hurdles (Paull et al. 2010; Moridis et al. 2009), and the need for secure ener- gy in many parts of the world, it is plausible that economical- ly attractive extraction methods will eventually be developed. Preliminary evaluations of gas hydrate potential in the World Energy Assessment report (WEA 2000) and by the Interna- tional Panel on Climate Change (IPCC) (Nakicenovic and Swart 2000) suggested that gas hydrate resources, as part of an expansion in unconventional gas resources, could support a tripling of gas usage globally through 2040. More recently, gas hydrate potential has been considered within the Global Energy Assessment (GEA) (Johnson 2011; GEA 2012). How- ever, gas hydrates have generally been excluded from con-

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