Energy Conversion Engineering Towards Low CO2 Power and Fuels

Until the mid-1800s, when fossil fuels became the major source of energy for heating, electricity production, and transportation, biomass derived from plants and animal products was the primary source of energy (heating and lighting by fires and candles). The explosive growth in the use of fossil fuels powered the Industrial Revolution and provided enormous improvements in the standards of living wherever it became the dominant source of primary energy. However, biomass still supplies nearly 10% of the primary energy worldwide, and is a major source in rural communities. Although only a small percentage of available biomass resources are used for energy production, the total potential exceeds 4.5 EJ (exajoules; 10 joules). Early use of biomass was likely to have been for fires. More recently, it has been for heating by combustion for domestic use; electricity production by combustion in power plants; and for the production of biofuels such as ethanol and biodiesel by bioconversion or thermochemically. The contribution of biomass to primary energy consumption, both in quantity and form and as a fraction or absolute amount, depends strongly on the level of economic development and geographic location. In 2003, it was 26% of the total consumption in the developing world, but only 4% in the developed world. During 2010–2012, the US consumed 62 terawatt-hour/year (TWh/y) of bio-energy, followed by Germany, which consumed 37 TWh/y. During the same period, China and India consumed 27 and 3.4 TWh/y, respectively. The majority of bio-energy, close to 90% of the total, is produced using solid feedstock in the form of energy crops like sugar and corn, or lignocellulosic material, with the rest in the form of gaseous fuels produced from landfills and bio-digesters.