Centralised hydrogen production

Both the production of hydrogen from coal and the production of oil from unconventional resources (oil sands, oil shale, CTL, GTL) result in high C02 emissions and substantially increase the carbon footprint of fuel supply, unless the C02 is captured and stored. While the capture of C02 at a central point source is equally possible for unconventionals and centralised hydrogen production, in the case of hydrogen, a C02-free fuel results, unlike in the case of liquid hydrocarbon fuels. This is all the more important, as around 80% of the WTW C02 emissions result from the fuel use in the vehicles. If CCS were applied to hydrogen production from biomass, a net C02 removal from the atmosphere would even be achievable. 

Large-scale centralised hydrogen production based on natural gas, with further options for C02 sequestration. 

Hydrogen can be produced from most fossil fuels (e.g. coal, natural gas, oil, etc.). The complexity of the processes varies. Since carbon dioxide is produced as a byproduct, C02 should be captured and stored to ensure a sustainable (zero-emission) process. The feasibility and viability of the processes will vary with respect to a centralised or distributed hydrogen production plant. 

Figure 5.82. Hydrogen production in the centralised Danish 2050 scenario (Sorensen et al, 2001).

Figure 5.98. Hourly level of hydrogen stored in the two central underground facilities (top) and hydrogen production (lower part of figure) in the centralised 2050 renewable energy scenario for Denmark (Sorensen et ah, 2004).

As a result of these assumptions, the required energy production is less in the decentralised scenario as compared with the centralised one, allowing wind power production to be reduced to 106 PJ y and therefore occupying fewer of the designated off-shore sites around Denmark, as shown in Fig. 5.99. The hydrogen production sites are now all buildings, as shown in Fig. 5.101, in contrast to the limited number of sites used in the centralised scenario (Fig. 5.82). 

Hydrogen production from coal was considered in the US Future Gen Program as co-production in ICCC power plants as illustrated in Figure 2.3 (Section 2.6.4). Carbon dioxide is removed by sequestration (refer to Section 1.4.2). This is feasible only in large centralised plants. 

Plants supplying hydrogen for the build-up of a future hydrogen infrastructure are faced with a dilemma when based on fossil fuels [418]. Centralised large-scale hydrogen production is penalised by significant costs for compression and transportation. 

How do different geographical demand scenarios and hydrogen introduction strategies affect the choice of production technology, production structure (centralised vs. decentralised production) and means of transportation (trailer or pipeline) ... 

The use of hydrogen for electric energy production from fossil fuels in large centralised plants will contribute positively to achieve important reductions of C02... 

Synthetic liquid fuels is stand-alone and only requires the large-scale centralised production of hydrogen from any of the available technologies, plus the development and application of methanol technologies, including DMFCs. 

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