IEEE 802.11B Principales
2.4 Topologías de las WLAN
2.4.1 WLAN tipo infraestructura.
Risk Scores:
2012 Energy Security Risk Score 973 2012 Large Energy User Group Rank 4
Score in Previous Year 1,044
Rank in Previous Year 4
Score in 1980 836
Average Score: 1980-2012 755
Best Energy Security Risk Score (1997)633 Worst Energy Security Risk Score (2011)1,044
Risk Scores Relative to OECD Average:
Average Annual Difference 1980-2012 -14%
Best Relative Score (1989)-18%
Worst Relative Score (2011)-7%
1980 1985 1990 1995 2000 2005 2010 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 109 8 7 6 5 4 3 2 1
United Kingdom: Risk Ranking
-20 -15 -10 -5 0 5 1980 1985 1990 1995 2000 2005 2010 United Kingdom OECD Average Per cent
United Kingdom: Risk Variance from oECD
500 600 700 800 900 1000 1100 1200 United Kingdom OECD Average 1980 1985 1990 1995 2000 2005 2010 Risk Inde x Scor e
United Kingdom vs. oECD: Risk Index scores
Since the 1980s, the United Kingdom has scored consistently in the top five most energy secure countries in the large energy user group, and it risk scores have trended well below the OECD average. Since the late 1990s, however, this advantage has been shrinking, from 18% below the OECD average in 1997 to just 7% in 2012. Nevertheless, UK’s score of 972 earned it a number four ranking overall. Only Norway, like the UK a large energy producer, had a better score among European countries. The UK has significant reserves of oil, gas, and coal. It is the second largest producer of crude oil in Europe after Norway and is Europe’s third largest producer of natural gas after Norway and the Netherlands. The United Kingdom also was at one time a major coal producer (it is still the second largest in Western Europe after Germany). Most of the United Kingdom’s oil and natural gas reserves are in the North Sea. From 245,000 barrels per day in 1976, oil production peaked at nearly 2.6 million barrels per day in 1999. From 1981 to 2005, the United Kingdom was self-sufficient in petroleum, but beginning in 2006, the United Kingdom became a net importer of oil
because of declining North Sea output, which in 2010 was less than half its peak. A net exporter of natural gas from 1997 to 2003, the United Kingdom has since then been importing steadily larger amounts of natural gas. While the risks to the United Kingdom from both oil and natural gas imports are better than the OECD average, the spread has been shrinking in recent years. Indeed, over the last three years, the UK’s oil, natural gas, and coal imports risks have been no better or worse than the OECD baseline. The Looking to the future, the application of new drilling techniques, such as hydraulic fracturing, horizontal drilling, and new deep-water technologies could help the United Kingdom maintain if not increase its domestic production of oil and natural gas.
For example, EIA estimates UK shale formations may also hold as much as 700 million barrels of technically recoverable oil and 26 trillion cubic feet of natural gas, which is nearly three times the estimated current proved figure of 9 trillion cubic feet. Some other shale gas estimates are considerably higher. The British Geological Survey recently provided a central estimate of 1,329 trillion cubic feet of natural gas resources in
central Britain. Around 40 exploratory wells could be drilled over the next couple of years to find out if these resources can be extracted economically.
One reason for the country’s recent flip to a net
importer of natural gas has been the United Kingdom’s policy to convert a large portion of the power sector’s capacity to natural gas from coal. From virtually none in the mid 1980s, natural gas now produces about 40% of the UK’s electric power, while the share for coal has slipped from roughly 70% to 30%. Coal production in 2010 was just 14% the level in 1980, so to meet demand, the United Kingdom imports large quantities of coal and has been doing so since 1984, the year United Kingdom coal miners went out on strike. (United Kingdom coal production from 1983 to 1984 dropped 57%—which shows up as a large upward spike in the United Kingdom’s risk index in 1984—and production since has never reached pre-strike levels.) In addition to natural gas and coal, the United Kingdom has 22 megawatts of nuclear capacity in the power sector, and in 2008 the U.K. government announced it would support additional nuclear power builds. Mandates also require the use of renewables. The United Kingdom is situated such that is has a rich wind resource, and wind accounts for most of the renewable capacity.
A growing concern is the shrinking of capacity margins, especially during the winter months when the electricity system is expected to reach 95% capacity, a situation that has raised could lead to blackouts. Recent closures of large coal and older natural gas plants have added to this concern. These developments have contributed to the country’s very high electricity rates, which is another area where the UK is seeing its advantage slip away relative to the OECD baseline. UK power rates are among the highest in the International Index. This may become an even larger concern in the future as more and more affordable baseload capacity is retired and more expensive power generation sources, such as offshore wind, are added to the system.
The United Kingdom is fairly energy efficient economy. Its trends in the intensity and per capita aspects of overall energy use, transportation energy use, petroleum (intensity only) and carbon dioxide emissions have moved largely in line with the OECD average.