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its assessment of unconventional resources. Unlike previous
energy systems projections, which have mostly focused on
either specific topics or single objectives, the GEA report at-
tempts to consider the technological feasibility and economic
implications of meeting a range of sustainability goals (Riahi
et al.
2012). The GEA assessment of different pathways sug-
gests that it is technically possible to achieve improved en-
ergy access, air quality, and energy security simultaneously,
while avoiding dangerous climate change.
Within each of the groups analysed, one pathway was se-
lected as “illustrative” in order to represent alternative ways
to move the energy system toward sustainability. Figure 1.5
shows the primary energy mix and carbon dioxide emis-
sions historically, as well as an illustrative GEA pathway
under the assumption of intermediate energy demand. The
modelling results show a significant increase in natural
gas consumption after 2020, with the share of gas in the
primary energy mix reaching almost 50 per cent by 2050.
The largest part of gas extraction shown in the figure re-
sults from the development of unconventional resources.
Figure 1.5 also illustrates the desired carbon dioxide emis-
sions curve, peaking at 10 GtC in 2020 and declining rap-
idly thereafter.
To achieve this pathway, the rapid and simultaneous growth
of many advanced technologies is required. A potentially
important technology is carbon capture and storage. In-
deed, the sustainability target of limiting global tempera-
ture change to less than 2°C over preindustrial levels may
only be achievable with very substantive global efforts to ad-
vance these technologies. In this pathway, the most attrac-
tive option for generating electricity after 2020 is natural
gas combined with carbon capture and storage. This option
provides cleaner fuel supply chains, lower upstream green-
house gas emissions, higher conversion efficiencies, and
significantly lower capital intensity.
Figure 1.4 also shows the historic H/C ratio and projects
the ratio as far as 2050, based on the same GEA scenario as
Figure 1.5. The expansion of natural gas use envisaged by this
scenario (3 per cent annually) results in continuous improve-
ment of the H/C ratio after 2015. We have chosen 2050 as a
reasonable time horizon for discussing the implications of
commercial gas hydrate production. As described in Chap-
ter 3, it is generally accepted that technical barriers to gas
hydrate extraction can be overcome before or by that date,
and that national governments will be in a position to choose
whether and how to exploit the resources at their disposal.
Even as the commercial feasibility of gas hydrate extraction
is demonstrated, technology alone will not determine the
energy future. Economic, social, and environmental consid-
erations, among others, will weigh in the decision. Recent
decisions by Germany and Japan to move away from nuclear
power as an energy source (see IEA 2011a) are examples. The
time horizon of 2050 also provides enough time to consider
alternative future pathways for the external factors that could
have a major impact on how the gas hydrate option is utilized
over the long term.