The-biogas-handbook-Science-production-and-applications

10
The biogas handbook
the production of heat by burning the gas. This use would only be
reasonable in the long term if the heat is produced by a gas flame such as in
some industrial applications, (e.g. in the glass industry).
Considering the necessity of converting the whole energy supply system
and particularly electricity supply to renewable sources, a main use of biogas
and other renewable gases in the future will be as a source of electric power
at times when other fluctuating renewable energies such as wind or solar are
not available. The available support mechanisms should thus encourage
meeting the demand by renewable electric power. At present, biogas, in
addition to hydroelectric power, is the only renewable energy source that –
given the present state of technology – can supply electric power as and
when needed. In this respect, biogas is a service – and a cost-covering price
must be paid for this service because otherwise it will not be delivered.
In connection with the available gas network, biogas upgraded to
biomethane can deliver this system service well and at short notice because
the gas network, as a rule, has extensive storage capacity. Sterner (2009) has
shown, using the example of Germany, that the storage capacity available in
the gas network is 1000 times larger than that of all available pumpedstorage
power plants together. With this in mind, the biogas industry can
offer ready solutions in today’s international quest for storage possibilities
and the supply of electric power to meet the demand from renewable
sources. The technology of treating and feeding biomethane available today
is a direct and immediately available solution. In the long term, the
combination of biogas upgrading plants in which carbon dioxide is
eliminated from the biogas with plants converting excess electricity into
gas (as described by the Sabatier equation) can offer an additional way out.
In these plants, hydrogen is at first produced by electrolysis and then carbon
dioxide is added to obtain methane (power-to-gas). This is a promising
method of combining the finite biomass resource with the enormous
potential of wind energy in an efficient way (Sterner 2009).
Today, no ready answer can be given to the question of what is the ideal
support mechanism that would enable making the most cost-effective and
efficient use of biogas as a versatile source of source energy. In view of the
key role played by biogas produced by the digestion of biomass, despite the
limited availability of the resource, it is important to ensure continuous
development of the biogas sector through a continuous and clear-cut
support policy. There is no other way in which the industry, by research and
development, can face the challenges for higher efficiency and integration in
energy supply systems of the future.
© Woodhead Publishing Limited, 2013