**1. Introduction**

With one of the largest cattle herds in the world, with almost 215.2 million heads1 according to FAO [1] and IBGE data [2], with almost 90% of this being beef cattle (approximately 193.5 million heads of cattle) and almost 22 million head of dairy cattle, in 2015, the production of beef and dairy products, largely based on extensive systems, has a significant environmental impact, including with a large demand for energy resources, most of which is non-renewable and of fossil origin. The **Figure 1** shows countries with the largest cattle herds, 2000-2014.

<sup>1</sup> Emissions generated by other animals will not be analyzed, only those from the raising of cattle. In the case of analyses and the scenarios proposed, the author uses data for the confinement of beef cattle, not considering the herd of dairy cattle which belong to the entirety of the bovine herd.

**Figure 1.**

*Countries with the largest cattle herds, 2000–2014, in millions of heads. Source: Prepared by the authors, based on FAO [1].*

Agriculture is one of the principal GHG emitting activities in Brazil due to, for example, the methane resulting principally from enteric fermentation and the handling of waste, and nitrous oxide from feces and urine deposited by animals [3]. In the last emissions inventory, agriculture was responsible for around 32% of greenhouse gas emissions in the country, without taking into account the emissions created from the use of energy, measured in the part of energy whose contribution is almost 29%, but which includes a part related to the demand of the agricultural sector for energy and energy resources, as well as emissions from the conversion of forests into pasture, calculated in the part related to changes in land use. Agricultural thus contributes, directly or indirectly, to most greenhouse gases produced in the country, as seen in **Figure 2**.

In relation to the demand for energy, the agricultural sector demanded around 14.08% of the total diesel oil used in the country (approximately 7460,000 m3 ) and almost 11.48% of firewood (more than 9000 tons) [4]. In the case of the use of electric energy, the agricultural sector consumed around 5.14% of the final total consumption of electricity in 2015, or 26,870.89 GWh [4].

Despite have a majority renewable energy matrix, as D'Avignon [5] highlights, this does not impede the need for the implementation of complementary renewable energy programs, above all with short-term energy policies, given the environmental limitations on the construction of new hydro-electric power plants with large reservoirs2 , which include the majority of those constructed in Brazil, or the hydric crises which have occurred in recent years, causing serious problems with the supply of electric energy, imposing the need, for example, for rationing and the introduction of non-renewable sources of energy and more sources of GHG emissions, following the insertion of thermoelectric power plants (above all, coal and oil) [6–10]. A way to reduce dependence on hydroelectricity for the generation of electric energy and with a lower environmental impact is a policy of complementarity with new sources of renewable energy generation [5]. One of the possible renewable energy sources is biogas produced through the confinement of cattle.

<sup>2</sup> It should be emphasized the hydroelectricity continues to be the principal source in the Brazilian energy matrix. According to BEN, hydraulic energy was responsible for 64% of the total offer of electric energy in 2015 [6].

*Biogas Generation from Bovine Confinement: An Energy Policy Option for Brazil DOI: http://dx.doi.org/10.5772/intechopen.99828*

**Figure 2.**

*Participation of each sector in the GEE emissions, in CO2e, in 2010. Source: [12], p. 18.*
