Other conversion

Beyond electricity and centralized heat generation there are three further subsectors of the conversion sector represented in MESSAGE, liquid fuel production, gaseous fuel production and hydrogen production. Fig. 11 provides an overview of the investment cost ranges for these conversion technologies. The black bars show historical cost ranges for 2005. Green, blue, and red bars show cost ranges in 2100 for SSP1, SSP2, and SSP3, respectively. Global values are represented by solid ranges. Values in the global South are represented by dashed ranges. The diamonds show the costs in the “North America” region.

Fig. 11 Cost indicators for other conversion technology investment (Fricko et al., 2017 [17]) Abbreviations: CCS – Carbon capture and storage; CTL – Coal to liquids; GTL – Gas to liquids; BTL – Biomass to liquids.

Liquid Fuel Production

Apart from oil refining as predominant supply technology for liquid fuels at present a number of alternative liquid fuel production routes from different feedstocks are represented in MESSAGE (see Table 14). Different processes for coal liquefaction, gas-to-liquids technologiesand biomass-to-liquids technologies both with and without CCS are covered. Some of these technologies include co-generation of electricity, for example, by burning unconverted syngas from a Fischer-Tropsch synthesis in a gas turbine (c.f. Larson et al., 2012 [47]). Technology costs for the synthetic liquid fuel production options are based on Larson et al. (2012) [47].

Table 14 Liquid fuel production technologies in MESSAGE by energy source.

Energy Source	Technology	Electricity cogeneration
biomass	Fischer-Tropsch biomass-to-liquids	yes
	Fischer-Tropsch biomass-to-liquids with CCS	yes
	Gasoline via the Methanol-to-Gasoline (MTG) Process	yes
	Gasoline via the Methanol-to-Gasoline (MTG) Process with CCS	yes
coal	Fischer-Tropsch coal-to-liquids	yes
	Fischer-Tropsch coal-to-liquids with CCS	yes
	coal methanol-to-gasoline	yes
	coal methanol-to-gasoline with CCS	yes
gas	Fischer-Tropsch gas-to-liquids	no
	Fischer-Tropsch gas-to-liquids with CCS	no
oil	simple refinery	no
	complex refinery	no

Gaseous Fuel Production

Gaseous fuel production technologies represented in MESSAGE are gasification of solids including coal and biomass. In both cases carbon capture and storage (CCS) can be combined with the gasification process to capture to a good part the carbon that is not included in the synthetically produced methane. Table 15 provides a listing of all gaseous fuel production technologies.

Table 15 Gaseous fuel production technologies in MESSAGE by energy source.

Energy Source	Technology
biomass	biomass gasification
coal	coal gasification

Hydrogen Production

A number of hydrogen production options are represented in MESSAGE. These include gasification processes for coal and biomass, steam methane reforming from natural gas and hydrogen electrolysis. The fossil fuel and biomass based options can be combined with CCS to reduce carbon emissions. Table 16 provides a full list of hydrogen production technologies.

Table 16 Hydrogen production technologies in MESSAGE by energy source.

Energy source	Technology	Electricity cogeneration
coal	coal gasification	yes
	coal gasification with CCS	yes
biomass	biomass gasification	yes
	biomass gasification with CCS	yes
gas	steam methane reforming	yes
	steam methane reforming with CCS	no
electricity	electrolysis	no