Page 167 - Biofuels for a More Sustainable Future

152 Biofuels for a More Sustainable Future

Table 5.6 Summary of scenarios in this case study (all reductions refer to a 2009
baseline year)—cont’d

Scenarios Subscenarios
(including interna- renewables. The mix
tional aviation and in 2070: 50% nuclear
shipping) by 2070 and 50% renewables
• GHG emissions from
electricity are effec-
tively zero by 2050
• Total energy demand
reduces by 30% by
2070, but electricity
demand increases by
60% as transport and
other services switch
to electricity (demand
peaks in 2050 at 78%
higher than 1990, then
declines to 60% with
efficiency
improvements)

implications of falling short of this target, with the 80% scenario matching
the national target and 65% being less ambitious still.
It should be noted that the UK’s emission reduction target refers only to
direct emissions of GHGs rather than life cycle emissions. Therefore the
reduction targets considered in the scenarios also refer to the direct emis-
sions; however, the implications of reaching these targets are estimated
on a life cycle basis.
The narratives for the scenarios are based on work by the Tyndall Centre
(Azapagic et al., 2011) but have been developed further to focus solely on
electricity.
The electricity mixes for each subscenario are shown in Fig. 5.10.As
illustrated, the amount of coal and natural gas diminishes with time to be
replaced by nuclear, wind, solar PV, biomass, and/or coal with carbon cap-
ture and storage (CCS). In the most aggressive scenarios, all fossil fuel (with
and without CCS) is eliminated by 2050.