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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]
In 2004, a USDA report found that co-products accounting made the difference between energy ratios of 1.06 and 1.67. [9] [10] In 2006, MIT researcher Tiffany Groode came to similar conclusions about the co-product issue. [11] In Brazil where sugar cane is used, the yield is higher, and conversion to ethanol is more energy efficient than corn.
The raw energy-per-volume numbers produce misleading fuel consumption numbers, however, because alcohol-fueled engines can be made substantially more energy-efficient. A larger percentage of the energy released by combustion of a liter of alcohol fuel can be converted to useful work. This difference in efficiency can partially or totally ...
Methanol may be made from fossil fuels or renewable resources, in particular natural gas and coal, or biomass respectively. In the case of the latter, it can be synthesized from CO 2 (carbon dioxide) and hydrogen. [3] The vast majority of methanol produced globally is currently made with gas and coal. [4]
Fossil fuel phase-out is the gradual reduction of the use and production of fossil fuels to zero, to reduce air pollution, limit climate change, and strengthen energy independence. It is part of the ongoing renewable energy transition , but is being hindered by fossil fuel subsidies .
Energy efficiency was a lower priority when energy was cheap and awareness of its environmental impact was low. In 1975 the average fuel economy of a car in the US was under 15 miles per gallon [6] Incandescent light bulbs, which were the most common type until the late 20th century, waste 90% of their energy as heat, with only 10% converted to ...
The U.S. Department of Energy's Fuel Cell Technology Program states that, as of 2011, fuel cells achieved 53–59% efficiency at one-quarter power and 42–53% vehicle efficiency at full power, [106] and a durability of over 120,000 km (75,000 miles) with less than 10% degradation. [107]
The use of fossil fuels in the 18th and 19th century set the stage for the Industrial Revolution. Fossil fuels make up the bulk of the world's current primary energy sources. In 2005, 81% of the world's energy needs was met from fossil sources. [3] The technology and infrastructure for the use of fossil fuels already exist.