The increase of energy demand in recent decades driven in particular by developed countries and countries with economic growth as Colombia, is leading to rapid depletion of nonrenew­able energy resources, increasing pollution and global warming. The alternatives energetics sources emerge as a great option to reduce the adverse effects of this development. The biomass is considered as the alternative energetic source the most potential, according to reports from the World Energy Council [11] it is estimated that energy from biomass will account for 25,4% of global consumption by 2030 and 80% by 2080. Biomass is very varied due to its production and origin, a particular type are the wastes of natural processes, industrial or agroindustrial.

It is estimated that Colombia has an energy potential from residual biomass of 449.485 TJ / year, also has a land area of 114,174,800 hectares, of which 44,77% are engaged to agricultural activities, this places to sector as the main source of wastes (with an energy potential of 331.645 TJ / year, mainly from annual and permanent crops). At the second place are the wastes from livestock activities (with an energy potential of 117.747 TJ / year), then the urban organic wastes (wastes from food and homes with an energy potential of 91 TJ / year) and finally the wastes from agroindustrial activities [12].

Among the methods to profit energetically the residual biomass, the anaerobic fermentation is a way of great interest, with this bioprocess is possible to generate a gas with high energy characteristics such as hydrogen and sludge that could be employed as fertilizer on crop. The generation of biohydrogen by anaerobic fermentation of wastes has generated great interest in the last decades. Hydrogen is a promising option as energy source [13, 14], it is a clean renewable resource because its combustion produces only water as emissions, in addition has the highest energy content per unit mass, with a value of 122 kJ / g [13]. The biological production of hydrogen can be seen as a promising option [15], two types of bacteria are involved in the process: acidogenic bacteria which initially to reduce the substrate in H2 (biohydrogen), acetic acid and CO2 and the methanogenic bacteria that converted these elements in methane gas. If the purpose is to produce biohydrogen, favorable conditions for the growth of the first type of bacteria (acidogenic) should be provided, inhibiting or elimi­nating the population of methanogenic bacteria [16]. Currently there are two methods to inhibit this type of bacteria: thermal shock and acidification [17, 18].

The residual biomass in Colombia has a high potential as alternative energetic source, only in wastes of sugar cane, rice husk, coco fiber, coffee pulp, oil palm, bean seed and barley, the potential is 12.000 MW/year approximately. The wastes are produced in different regions of the country and during all year. The country has a potential for generation of biomass of 331’638.720 ton/year, if all agricultural and urban wastes were treated by fermentation anaerobic, could be generated 28’825.609 m3 of biohydrogen, this might give a energetic potential of 144 GW, upper value to country potential in wind energy (21 GW), tidal energetic potential (30 GW with two coasts) and geothermic energetic potential (1 GW).

In Colombia this quantity of biohydrogen could replace all diesel requested by the diesel electrical plants installed in the country. This has a great important especially in regions without connection to national electrical grid. In the country approximately the 66% of the territory are not connection to national electrical grid, this is 1,4 millions of people, namely the 4% of the population. The country has an installed electric capacity at the region without connection to national electrical grid of 102 MW of which 97 MW are produced by diesel plants, this quantity could be generated, using only the 40% of the urban organic wastes generated at the country. Colombia produces 250.000 tons/year of banana wastes with a potential to generated 100.000 m3 of biohydrogen by anaerobic fermentation, this represent 500 MW of energy per year, quantity enough to supply the electric energy demand of 200.000 people during a year.