Technology Energy Efficiency: Changes and Renewable Sources

Although technology change (usually involving an improvement in energy efficiency) is not inherently a geographic process, it does not occur uniformly over geographic space. Consequently, mathematical modeling and behavioral and innovation diffusion studies by geographers have improved our understanding of the pervasive phenomenon of technology energy efficiency change in energy markets. Similarly, creative government policies in Germany since 1990 have led to a faster rate of adoption of renewable energy sources, compared to the United States. (more…)

CO2 Emission Reduction and Fossil Fuels Carbon

Reductions in carbon intensity, C/E, the carbon emitted per unit of energy generated, reflect the degree to which societies decarbonize their energy sources. The long-term trend has been a shift from coal to oil to natural gas––hydrocarbons with decreasing C/H ratios emitting progressively less CO2 per joule. However, the increasing use of clean low-carbon fuels is not sustainable without somehow disposing of excess carbon because it opposes the trend in the abundance of fossil fuels, with coal resources being the most abundant followed by oil and gas. (more…)

Circulating Fluidized Bed Gasification Biomass Feedstock

Air-blown circulating fluidized bed gasifiers are of interest because they produce a good quality, low calorific value (LCV) gas (4–6 MJ/Nm 3 ) and possess a very high carbon conversion efficiency while allowing high capacity, good tolerance to variations in fuel quality, and reliable operation. The high and homogeneously distributed temperatures and the use of particular bed materials, such as dolomite, favor tar cracking. Successful tar cracking can also be achieved using secondary circulating fluidized bed reactors. Also, successful tests on catalytic tar cracking have been performed, for example, by introducing nickel compounds into the gasifier. Sulfur control is made easier because of the significant reduction that can be achieved by adding limestone or dolomite to the gasifier bed. (more…)

Renewable Energy Sources in Europe: Geothermal, Wind Energy, Biomass

In Europe, modern renewable energy sources technologies were explored thoroughly for the first time after the oil embargo/ price crisis of 1973. Notably, market introduction of renewable energy technology started in about 1985, but the renewable energy sources industry has become vital only during the past decade. Accordingly, relevant statistical renewable energy sources data have been systematically compiled only over the past decade, although reliable and consistent statistical renewable energy sources data, collected since 1989, exist for all 15 countries of the European Union and for Western Europe (defined here as the EU-15 plus Switzerland, Norway, and Iceland). (more…)

Biomass Gasification: Electricty Conversion from Feedstock

Biomass Gasification
Gasification is a thermo chemical process that has been exploited for more than a century for converting solid feedstocks to gaseous energy carriers. The first gasifier patent was issued in England at the end of the 18th century and producer gas from coal gasification was mainly used as lighting fuel throughout the 19th century. At the turn of the 20th century, the main use of producer gas, obtained essentially from coal, switched to electricity generation and automotive applications via internal combustion engines. The use of producer gas was gradually supplanted by the use of higher energy density liquid fuels and as a result confined to areas with expensive or unreliable supplies of petroleum fuels. (more…)

Fuel Cycle Analysis of Vehicles and Transportation Fuels

fuel cycle

The fuel cycle for a given transportation fuel includes the following processes: energy feedstock (or primary energy) production; biomass feedstock transportation and storage; fuel production; fuel transportation, storage, and distribution; and vehicle operations that involve fuel combustion air or other chemical energy conversions. The processes that precede vehicle operations are often referred to as the well-to-pump (WTP) stage, the vehicle operations are referred to as the pump-to-wheels (PTW) stage, and the entire fuel cycle is referred to as the well-to-wheels (WTW) cycle. Various models have been developed that allow researchers to conduct fuel cycle analyses of vehicle/fuel systems. The GREET (greenhouse gases, regulated emissions, and energy transportation) model, developed by Argonne National Laboratory, is in the public domain and, so far, more than 1000 users worldwide have used the model to predict the energy use and emissions associated with alternative fuels vehicles. The GREET model and its documents are posted on the Internet at http:// greet.anl.gov. (more…)

Biomass Gasification Process Effect of Feedstock Properties and Operating Parameters

Biomass Gasification Feedstock
Thermo chemical processing of biomass yields gaseous, liquid, and solid products and offers a means of producing useful gaseous and/or liquid fuels. Biomass gasification is a total degradation process consisting of a sequence of thermal and thermo chemical processes that converts practically all the carbon in the biomass to gaseous form, leaving an inert residue. The gas produced consists of carbon monoxide (CO), hydrogen (H2), carbon dioxide (CO2), methane (CH4), and nitrogen (N2) (if air is used as the oxidizing agent) and contains impurities, such as small char particles, ash, tars, and oils. The solid residue will consist of ash (composed principally of the oxides of Ca, K, Na, Mg, and Si) and possibly carbon or char. (more…)

Bioenergy from Dependent Resources (Forestry, Vegetable Oils, Waste)

Agricultural and forestry residues provide the largest proportion of biomass used for the production of biomas bioenergy. Some estimates suggest that globally available biomass role in the form of recoverable residues represents about 40 Ejyr -1, enough to meet 10% of the total present energy use of 406 Ejyr -1 . However, realizing this potential is limited by factors such as ease and cost of recovery and environmental concerns relating to sustainable land use practices. (more…)

Carbon Dynamics in Forest Ecosystems

The accumulation of carbon within a forest growth cycle can be considered in four stages. The initial establishment stage involves low global carbon cycle accumulation and may even experience net carbon loss (particularly from soil) as a result of site preparation and low biomass and bioenergy inputs. A rapid uptake of carbon is then experienced during the second phase, known as the full vigor stage, which subsequently levels off as the stand reaches the mature stage. Finally, the forest reaches old growth and the carbon is in steady state with accumulation associated with new growth balanced by mortality and disturbances. (more…)

Wood Products’ Role as Carbon Sink Sources

To date, most discussion and research relating to the various of biomass role in mitigating CO2 emissions has been focused around its use as a fuel or as a sink. However, full utilization of the potential of biomass products, particularly from woody biomass, may provide significant opportunities. (more…)

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