Green energy and other climate change mitigation measures are part of national, regional, and international efforts to address food security, the dietary needs of local communities and the economic development needs of rural communities.  New agricultural market opportunities and associated increases in income and employment can be achieved through the creation and use of biofuels, biogas, and other renewable energy sources.  Cost savings to agriculture can also result from the use of these new fuel sources. 

Energy-efficiency measures in agricultural production, processing, and marketing offer the possibility of higher revenues, expanded employment and both increased output and availability of food and animal feed.  Furthermore, higher crop yields may also be associated with lower energy use per unit of output. 
Unfortunately, not all of the implications of green energy and other climate change mitigation measures are necessarily positive for food security initiatives. Some measures (e.g., expansion of biofuels, reforestation, and afforestation) could increase competition for land and other inputs and resources used by subsistence farmers and food crop producers, potentially reducing farmer income, subsistence agriculture, and food crop output, and raising food prices to consumers.   Therefore aligning the interest of local agriculturalists with the commercial interests of investors and the economic development interests of government and the sustainability requirements of society is a complex management issue.
The following websites can provide useful information on the green-energy needs and uses in agriculture and animal husbandry:
The Union of Concerned Scientists have created four colorful and easy-to-read fact sheets on renewable energy and agriculture are now available for farmers and clean energy advocates, giving valuable information on renewable energy technologies and the rural economic development opportunities they could create.
The Food and Agricultural Organization (FAO) focuses on the potential of bioenergy to contribute to poverty alleviation, food security, rural development as well as climate change mitigation and adaptation. The Climate, Energy and Tenure Division of FAO serves as focal point for organizing and facilitating a multidisciplinary and global approach to bioenergy. With an emphasis on bioenergy, services provided by FAO include:
Development of analytical tools related to the resource assessment and use, and to how to make sound decisions on bioenergy, strategies, program and investments
Generation of data and knowledge tools
See this site for information on bioenergy and energy agriculture, including anaerobic digestion to carbon sequestration, and from liquid biofuels to energy crops.
Livestock manure is composed primarily of organic material and water. When manure decomposes in an anaerobic environment (i.e., in the absence of oxygen), methane is produced along with carbon dioxide and stabilized organic material.  Major sources of manure methane are large dairy and cattle operations, hog farms and poultry production.  This site contains a vast amount of information on animal waste to energy.