Page 53 - European Energy Innovation - spring 2019 publication
P. 53
Spring 2019 European Energy Innovation 53
ZERO CARBON HYDROGEN
will prevent this since the fuel cell atmosphere and the use of this SNG
reactions produce none of the typical will not contribute to greenhouse
atmospheric pollutants. Most fuel gas (GHG) emissions. This would
cells in use today – typically the ones be completely ‘green’ fuel gas
employed in vehicles, the Polymer compatible with today’s gas supply
Electrolyte type, PEFC – require infrastructure and not requiring any
very pure hydrogen and will not be additional investment in transport,
happy with the natural gas-hydrogen handling, and at point-of-use. Using
mixture mentioned above. the SNG in high temperature fuel
cells, such as Solid Oxide type
On the other hand typical gas (SOFC), is possible and results in
appliances such as boilers do a release of water and CO2, which
not condone high hydrogen are then both recycled through the
concentrations in the fuel gas mixture. atmosphere.
Therefore all gas appliances would
need to be switched over in the case CO2 can of course also be obtained
of more than about 20% or even 100% from any industrial process or power
hydrogen replacement of natural gas plant running on coal, oil or fossil
in the gas grids. This is a difficult and gases. In this case the carbon would
logistically challenging task. be captured and recycled, making
the product SNG ‘grey’. No new CO2
There is one other option to would be emitted when the SNG is
produce a zero-carbon gas, which is used, but still, there would be an
synthesising methane from hydrogen effective release of fossil carbon,
and carbon dioxide. This ‘Sabatier’ therefore only part-addressing the
process has a high efficiency. CO2 issue of GHG emissions and not
is captured from the atmosphere, qualifying for zero-carbon methane.
reacted with hydrogen, and injected
into the gas grids as 100% compatible Green hydrogen and green SNG
substitute for natural gas, even are the two components of a true
producing a higher quality gas than ‘Hydrogen Economy’ based on
the variable fossil resource. hydrogen as the main component of
an emission-free energy economy.
This gas is often labelled ‘synthetic SNG offers more versatility in
natural gas’ (SNG) although it is just combination with the existing gas
methane and has nothing to do with grid transition to an emission-free
natural gas itself. Since capturing CO2 future, whereas hydrogen offers
from the air is energy intensive, we more advantages for transport and
can pull the trick of using biomass vehicle fuels. The combination of
to do the job for us. CO2 from biogas carbon-free production and gas
could be used for the synthesis use in fuel cells will deliver both a
and thus delivers fully ‘carbon free’ zero-emission energy system with a
methane – which admittedly sounds dramatic reduction in point-of-use
odd, but emphasises the fact that emissions, for example a substantial
no fossil carbon is released to the improvement of air quality in cities. l
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Figure 2 Scenario Analysis Results for CCUS (carbon capture, usage, storage)
