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In 1995 the USDA released a report stating that the net energy balance of corn ethanol in the United States was an average of 1.24. It was previously considered to have a negative net energy balance. However, due to increases in corn crop yield and more efficient farming practices corn ethanol had gained energy efficiency. [3]
The energy input might be rendered in several different types depending on the type of propulsion, and normally such energy is presented in liquid fuels, electrical energy or food energy. [ 9 ] [ 10 ] The energy efficiency is also occasionally known as energy intensity . [ 11 ]
The Jevons paradox occurs when the effect from increased demand predominates, and the improved efficiency results in a faster rate of resource utilization. [7] Considerable debate exists about the size of the rebound in energy efficiency and the relevance of the Jevons paradox to energy conservation.
The total amount of energy input into the process compared to the energy released by burning the resulting ethanol fuel is known as the energy balance (or "energy returned on energy invested"). Figures compiled in a 2007 report by National Geographic [ 68 ] point to modest results for corn ethanol produced in the US: one unit of fossil-fuel ...
The heating value (or energy value or calorific value) of a substance, usually a fuel or food (see food energy), is the amount of heat released during the combustion of a specified amount of it. The calorific value is the total energy released as heat when a substance undergoes complete combustion with oxygen under standard conditions .
R&D GREET (Research and Development Greenhouse gases, Regulated Emissions, and Energy use in Technologies) is a full life cycle model developed by the Argonne National Laboratory (U.S. Department of Energy's Office of Energy Efficiency and Renewable Energy). [1]
For fossil fuels the free enthalpy of reaction is usually only slightly less than the enthalpy of reaction so from equations and we can see that the energy efficiency will be correspondingly larger than the energy law efficiency. For example, a typical combined cycle power plant burning methane may have an energy efficiency of 55%, while its ...
However, missing life cycle phases [25] exist for a number of energy sources. At times, assessments variably and sometimes inconsistently include the global warming potential that results from decommissioning the energy supplying facility, once it has reached its designed life-span.