Although it may be a seemingly unrelated sector of American industry, researchers at Texas A&M have contended that energy production facilities, particularly coal-fired power plants, can benefit from co-firing of animal-wastes based biomass with coal. It can also minimize the CO2

emissions by reducing the amount of fossil fuels used for heat and energy and the resulting emissions from fossil fuel power plants. Nitrogen oxides (NOX), sulfur oxides (SOX), mercury (Hg), and particulates have all been scrutinized emissions from coal-fired power plants, and restrictions on these products of combustion will probably continue to rise. Of course, animal biomass combustion will not solve global climate change alone; however, as discussed by (Pacala et al., 2004), biomass combustion can be one of many wedges of advancement that can create an energy economy capable of sustaining our climate and our way of life. Direct combustion of biomass, combustion basics including stoichiometry, excess air, underfire and over fire air are dealt in Chapter 5 of this book (Desideri and Fantozzi, 2013).

There is also a great potential in the European Union (EU) to use animal waste based biomass to co-fire in existing coal-fired power plants. In 2011, the 27 EU member countries had a total cattle livestock of over 87 million with more than 23 million dairy cows. The animal numbers are projected to shrink because cattle herds are getting more productive. Annual reductions are estimated at 1.1% in 2012 to an 84.4 million head (TX PEER, 1998). The corresponding manure produced by cattle in 2009 was nearly 1300 million tonnes (Osei etal., 2000). Five different paths for energy production from cattle biomass (CB) or any suitable animal wastes are illustrated in Figure 3.5 (Carlin et al, 2007):

• Biological conversion

1. Biogas and bio-liquid fuels

• Thermal conversion

2. Direct slurry combustion (Carlin et al., 2007)

3. Co-firing of dried solids with coal

4. Reburn

5. Gasification.

The utilization of animal manure in combustion/gasification facilities can help ease the impacts large CAFOs, including dairies, have on the environment.