Combined-cycle gas turbines, which use hot exhaust gases from one turbine to generate steam to turn a second one, can transform 6, 800 Btu of gas into a kilowatt-hour of electricity, enough to light one lightbulb for ten hours.
To supply the extra juice, utilities turn on inefficient single-cycle gas turbines, which turn 25% of the fuel's energy into electricity, as opposed to 45% for combined-cycle plants that use turbine exhaust to make steam to run a second generator.
It says that Xcel is reluctant, and would prefer to invest more in combined cycle natural gas plants.
That will result in the closing of a cadre of coal plants and the construction of numerous combined-cycle natural gas facilities.
Meantime, the oldest coal units built in the middle 1900s are being forced to retire and they are getting replaced with combined-cycle natural gas plants that are both more efficient and cleaner.
CO2 life-cycle emissions for natural gas are higher than coal after taking into account leakage during transport through old Russian pipelines.
But natural gas combined cycle is not a system of emission reduction.
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The EPA is saying with a straight face that natural gas combined cycle is an emission reduction system that has been adequately demonstrated for coal power plants.
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The proposal lumps gas turbines and coal boilers into the same source category, and it holds coal power plants to a CO2 performance standard that nearly all natural gas combined cycle plants and exactly zero commercial coal power plants can meet.
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The device looks a bit like a massively overgrown telephone headset, with overtones of a cycle helmet and maybe a gas mask thrown in.
When life-cycle costs are compared, natural gas is currently a more economical decision than flex-fuel powered vehicles, although both are more expensive than gasoline at current figures (keep in mind that these dynamics could change due to oil shocks or increased demand for traditional fuels both real risks).
Greenpeace asks companies to measure and reduce their greenhouse gas emissions throughout the life cycle of their products: supply chain, manufacturing, distribution, customer use, and end-of-life, using a combination of energy efficiency, renewable energy, and energy policy advocacy.
As environmentalist Bjorn Lomborg notes, manufacturing and charging electric cars over their life cycle can produce more carbon than small, gas-powered vehicles.
For bestselling products like the iPhone 5, the manufacturing process is the source of 76 percent of the 75kg of greenhouse gas emissions associated with the life cycle of one unit.
The Stirling cycle describes a phenomenon where a confined volume of gas expands at high pressure and contracts at low pressure.
Moreover, although controversial, life-cycle analysis indicates that fugitive methane emissions make shale gas obtained by hydraulic fracturing as carbon-intensive as coal.
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During a short cycle the solar wind (a breeze of electrically charged gas blowing off the sun's surface) is stronger than normal.
Icy water from a nearby river then cools the gas back to liquid form, to start the cycle again.
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That will help those who seek to understand the carbon cycle and with it, the consequences of greenhouse-gas-induced climate change.
The vibe in the Fusion Hybrid is one of abiding integration: the subtle slurring of ratios in the continuously variable transmission, the share-the-load cooperation between electric and gas engine (2.0-liter, 141-hp Atkinson-cycle four-cylinder), a sort of light, transparent flickering of power sources.
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We are the only company to comprehensively report greenhouse gas emissions for every product we make, taking into account the entire product life cycle.
The core reason was depressed US gas prices - that have become low margin at best - negative plays over full cycle economics at worst.
Both Otto cycle(spark ignition) and Diesel cycle engines(compression ignition) engines can be made to run on multiple fuels(petroleum, ethanol, natural gas) The cost is only nominally more than single fuel engines.
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