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Unformatted text preview: New coal technologies such as carbon capture and storage (CCS) could theoretically reduce the climate impact of coal, but at a significant economic and energy cost (by one estimate, up to 40 percent of the energy from coal would go toward mitigat- ing climate impact, with the other 60 percent being available for economically useful work; there would also be an environmental cost from damage due to additional mining required to produce the extra coal needed to make up for the energy costs from CCS). 28 Coal prices increased substantially in 2007- 2008 as the global economy heated up, which sug- gests that the existing global coal supply system was then near its limit. Prices have declined sharply since then as a result of the world economic crisis and falling energy demand. However, prices for coal will almost certainly increase in the future, in inflation- or deflation-adjusted terms, as high-qual- ity deposits are exhausted and when energy demand recovers from its lowered level due to the current recession. 3. NATURAL GAS Formed by geological processes similar to those that produced oil, natural gas often occurs together with liquid petroleum. In the early years of the oil industry, gas was simply flared (burned at the well- head); today, it is regarded as a valuable energy resource and is used globally for space heating and cooking;it also has many industrial uses where high temperatures are needed, and it is increasingly burned to generate electricity. Of the world’s total energy, natural gas supplies 25 percent; global reserves amount to about 6300 trillion cubic feet, which represents an amount of energy equivalent to 890 billion barrels of oil. 29 PLUS: Natural gas is the least carbon-intensive of the fossil fuels (about 53 kg CO 2 per GJ). Like oil, natural gas is energy dense (more so by weight than by volume), and is extracted from a small land footprint. It is easily transported through systems of pipelines and pumps, though it cannot be trans- ported by ship as conveniently as oil, as this typically requires pressurization at very low temperatures. MINUS: Natural gas is a hydrocarbon fuel, which means that burning it releases CO 2 even if the amounts are less than would be the case to yield a similar amount of energy from coal or oil. Like oil, natural gas is non-renewable and depleting. Environmental impacts from the production of nat- ural gas are similar to those with oil.Recent disputes between Russia, Ukraine, and Europe over Russian natural gas supplies underscore the increasing geo- political competition for access to this valuable resource. International transport and trade of lique- fied natural gas (LNG) entails siting and building offloading terminals that can be extremely hazardous....
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This note was uploaded on 09/04/2011 for the course CHEM 1B taught by Professor Fossum during the Spring '10 term at Laney College.
- Spring '10