biofuels, biogas production is a natural process, non-energy intensive, and the raw
materials are mostly renewable resource like agricultural waste, and food scraps,
which are easily available making it a highly viable resource.
In biogas digester, anaerobic digestion-fermentation processes take place, in
which organic waste is digested to produce methane and other gases. Almost any
type of organic waste can be used as initial substrate in the process; however pH and
temperature of the process influence the optimum production of gas. Digester tank
provides a suitable environment for anaerobic microbes to digest the biomass, thus
producing digested solids, slurry, and biogas. The favourable/optimum temperature,
moisture content, oxygen exclusion, pH, and a continuous food (organic waste)
supply are some of the prerequisite conditions required in order to support anaerobic
digestion process. Even though, in most cases, the pH is maintained by itself, the
problem of pH drops by acidophilic bacteria, which grows faster than methanogens,
creating an unfavourable condition (optimum pH range ~6.8–8.5) for methanogens.
To maintain consistent pH, sometimes bicarbonates are also used. Like any other
biogenic processes, biogas plant operators also must be aware of associated potential
hazards such as explosion, suffocation, probable pathogens, or hydrogen sulphide
(H 2 S) poisoning and must take all sorts of preventative safety measure. As per the
energy and climate policies of the European Union, the EU has set some goals for
year 2020, such as at least 20% lesser greenhouse gases emissions and 20%
reduction in utilization of energy by means of better energy efficacy and to cover
20% of requirement by renewable sources. To reach such set targets, Germany uses
~66% biomass as a key contributor to provide energy, and in year 2012, ~50% of
electricity was produced using biogas from biomass. Overall share of biogas was
~15% to generate electricity and ~8% to provide heat supply. Biogas could play a
distinct role among other renewable fuels, as it is suitable for the production of
combined heat and power simultaneously and as a natural gas substitute once
purified. The storage of biogas is relatively easy and it is flexible to use. Currently
biogas plants in Germany are reported to be capable to generate ~420 kW, which
thereby already replaced some of the coal-fired power plants, showing great potential
that even small energy producers can also jointly generate such a significant magnitude of energy (Heffels et al. 2012). Brundtland Report of 1987 (https://mediathek.
fnr.de/media/downloadable/files/samples/b/r/brosch.biogas-2013-en-web-pdf.pdf)
states that sustainability means that “the present generation satisfies its needs without
endangering the ability of future generations to meet their respective needs”. All
three dimensions – environmental, economic, and social – are interconnected in
sustainability. Sustainable resources mean striking a balance between what is essential in terms of economics (such as consistent and high biomass produces) and
practicality (for our expectation from our environs). One of the main research
areas of the Federal Ministry of Food, Agriculture and Consumer Protection
(BMELV) was to assess those methods in various research projects to find proper
approaches for viable energy supply and natural resources management and to
further develop them through appropriate and coordinated research funding. The
strategies being pursued included increasing the biodiversity to cultivate different
energy crops, breeding of new plant varieties, novel cultivation techniques, and
reduce-reuse and recycle (reduced use of chemicals, agricultural lands with perennial
3 Biogas: An Effective and Common Energy Tool – Part I
67
materials are mostly renewable resource like agricultural waste, and food scraps,
which are easily available making it a highly viable resource.
In biogas digester, anaerobic digestion-fermentation processes take place, in
which organic waste is digested to produce methane and other gases. Almost any
type of organic waste can be used as initial substrate in the process; however pH and
temperature of the process influence the optimum production of gas. Digester tank
provides a suitable environment for anaerobic microbes to digest the biomass, thus
producing digested solids, slurry, and biogas. The favourable/optimum temperature,
moisture content, oxygen exclusion, pH, and a continuous food (organic waste)
supply are some of the prerequisite conditions required in order to support anaerobic
digestion process. Even though, in most cases, the pH is maintained by itself, the
problem of pH drops by acidophilic bacteria, which grows faster than methanogens,
creating an unfavourable condition (optimum pH range ~6.8–8.5) for methanogens.
To maintain consistent pH, sometimes bicarbonates are also used. Like any other
biogenic processes, biogas plant operators also must be aware of associated potential
hazards such as explosion, suffocation, probable pathogens, or hydrogen sulphide
(H 2 S) poisoning and must take all sorts of preventative safety measure. As per the
energy and climate policies of the European Union, the EU has set some goals for
year 2020, such as at least 20% lesser greenhouse gases emissions and 20%
reduction in utilization of energy by means of better energy efficacy and to cover
20% of requirement by renewable sources. To reach such set targets, Germany uses
~66% biomass as a key contributor to provide energy, and in year 2012, ~50% of
electricity was produced using biogas from biomass. Overall share of biogas was
~15% to generate electricity and ~8% to provide heat supply. Biogas could play a
distinct role among other renewable fuels, as it is suitable for the production of
combined heat and power simultaneously and as a natural gas substitute once
purified. The storage of biogas is relatively easy and it is flexible to use. Currently
biogas plants in Germany are reported to be capable to generate ~420 kW, which
thereby already replaced some of the coal-fired power plants, showing great potential
that even small energy producers can also jointly generate such a significant magnitude of energy (Heffels et al. 2012). Brundtland Report of 1987 (https://mediathek.
fnr.de/media/downloadable/files/samples/b/r/brosch.biogas-2013-en-web-pdf.pdf)
states that sustainability means that “the present generation satisfies its needs without
endangering the ability of future generations to meet their respective needs”. All
three dimensions – environmental, economic, and social – are interconnected in
sustainability. Sustainable resources mean striking a balance between what is essential in terms of economics (such as consistent and high biomass produces) and
practicality (for our expectation from our environs). One of the main research
areas of the Federal Ministry of Food, Agriculture and Consumer Protection
(BMELV) was to assess those methods in various research projects to find proper
approaches for viable energy supply and natural resources management and to
further develop them through appropriate and coordinated research funding. The
strategies being pursued included increasing the biodiversity to cultivate different
energy crops, breeding of new plant varieties, novel cultivation techniques, and
reduce-reuse and recycle (reduced use of chemicals, agricultural lands with perennial
3 Biogas: An Effective and Common Energy Tool – Part I
67