http://frack-off.org.uk/press-release-natural-gas-drilling-rig-stormed-by-anti-fracking-protesters/
Il 2 novembre, un gruppo di ecoattivisti è salito su una torre di fracking nel Lancashire per protestare contro un metodo di estrazione di gas metano che reputano idrologicamente e geologicamente insostenibile. Il sito di trivellazione della Cuadrilla Resources a Hesketh Bank è stato così bloccato. L’azione del gruppo Frack Off è la prima ad alto profilo ad avvenire in Europa contro questo controverso metodo di estrazione del metano (in Francia, per esempio vige una moratoria).
Sempre più diffuso negli Stati Uniti, il fracking (hydraulic fracturing) comporta la trivellazione a un profondità di 1,5-6km per crackare con un getto d’acqua ad alta pressione le rocce ricche di metano. Il gas naturale così ricavato viene donominato shale gas, per distinguerlo da quello estratto dai normali giacimenti, da cui viene poi trasportato verso i paesi consumatori via metanodotto o con metaniere previa, sua liquefazione a -160°C (Gas Naturale Liquido, LNG in inglese). Per sapere tutto sul fracking e le sue conseguenze ambientali, soprattutto sulla potabilità dell’acqua intorno agli impianti di trivelazione, c’è un’ottima voce di wikipedia in inglese http://en.wikipedia.org/wiki/Hydraulic_fracturing
Malgrado le proteste ambientaliste anche di gruppi meno radicali di Frack Off, il mercato mondiale del metano è in corso di rivoluzionamento per effetto della disponibilità di shale gas da fracking che stanno rendendo Stati Uniti e altri paesi come la Polonia meno dipendenti dal gas importato, sia esso qatariano o russo. Qui sotto riportiamo alcuni brani (e una mappa) di due articoli che l’Economist ha pubblicato quest’estate in merito al boom del gas da fracking e più in generale dei benefici (per l’aria e anche per il clima, ma più a lungo termine) del metano rispetto al carbone.
The Shale Gas Boom
The US independent companies which embraced horizontal drilling and the use of high-pressure fluids to crack open the otherwise impermeable shales—a process known as “fracking”—have brought about a revolution. Shale now provides 23% of America’s natural gas, up from 4% in 2005. That upheaval in American gas markets has gone on to change the way gas is traded globally. A lot of LNG export capacity created with American markets in mind —global supply increased 58% over the past five years— is looking for new outlets.
To the extent that the shale-gas success is repeated elsewhere, a vital source of energy will become available from an ever more diverse and numerous set of suppliers in increasingly free markets. This means that, unlike the boom in oil in the decades following the second world war, this growth in gas may not hand a powerful political weapon to those countries with the biggest reserves. Shale gas could significantly diminish the political clout that Russia, Venezuela and Iran once saw as part and parcel of their gas revenues.
“The power of the shale-gas revolution has surprised everyone,” says Christof Rühl, chief economist at BP. In 2003 America’s National Petroleum Council estimated that North America (including Canada and Mexico) might have 1.1 trillion cubic metres (tcm) of recoverable shale gas. The shale-gas bounty is not confined to America. The country’s Energy Information Administration released a report in April that looked at 48 shale-gas basins in 32 countries (see map). It puts recoverable reserves at 190tcm.
The development of shale-gas reserves beyond North America is still at an early stage. Although widespread pollution of groundwater by fracking seems unlikely (shales that hold gas typically lie far deeper than groundwater supplies), such risks have raised a great deal of environmental concern about the technology. Coupled with a sensitivity to the rural charms of la France profonde, this has led to a moratorium on shale-gas exploration in France. But in Poland, which may have Europe’s largest reserves, companies are busily sinking test wells to see what is there.
In South Africa, which may have the largest shale-gas reserves on the continent, the shales in the Karoo basin have attracted the attention of Shell, which is increasingly billing itself as a gas-focused company. Shell is also one of the companies looking at shale-gas reserves in China, which may be the largest on the planet. Chinese interest in shale gas is strong, with state companies buying up American expertise as they take stakes in established shale-gas producers. The country might be producing its first shale gas at scale before the current five-year plan is over.
Gas is currently bought and sold in three distinct global markets—North America, Europe and Asia—and prices differ widely between the three. In deregulated North America, with a competitive market and plenty of shale gas to augment conventional supplies, prices are low. In Asia, where gas is largely traded using a system of long-term contracts tied to the price of oil, prices are high. Europe sits in between: prices at the moment are around $4 per million btu in America, $8 in continental Europe and $11 in Asia (1m btu is about 300 kilowatt-hours).
The origins of long-term contracts and oil-linked pricing go back a long way. When gas first began to be used a lot in the 1960s it was a substitute for home heating oil, and so it made sense to tie its price to that of oil. Because big exploration, extraction and infrastructure investments required pots of capital, long-term contracts became an industry norm.
Today oil is generally no substitute for gas. Gas is used not to fill up cars and lorries—though there are gas-fired transport enthusiasts who would like to do something about that—but to fuel power stations and heat homes. Still, many gas producers are happy enough with the archaic pricing structure, particularly when oil prices are high. Customers with limited choices have had to put up with it. According to a recent study from the Massachusetts Institute of Technology, pipelines carry 80% of all gas traded between regions. The firms at the upstream end of those pipelines, such as Russia’s Gazprom, which supplies a quarter of all western Europe’s gas, thus have a strong hand in negotiations. Control of the pipelines meant that when Gazprom turned off the gas (as it did in 2009 in a dispute over trans-shipments through Ukraine), buyers had nowhere to turn for alternatives.
But the new technologies are widening the production base all the time, weakening the strategic importance of conventional reserves and the power of those who, like Gazprom, hold them. Before shale gas, it was thought that Venezuela might soon become an important gas source for America, and that Iran’s vast gas reserves would motivate potential customers to break the sanctions imposed on it as a result of its nuclear programme. Both things are now less likely; the Baker Institute study suggests that while both countries will grow in importance—it foresees 26% of the world’s LNG coming from Venezuela, Iran and Nigeria by 2040—they will do so much more slowly than they would have in a world of constrained supplies.
The growth of the gas market will not be untroubled. America’s shale-gas success —a matter not just of helpful geology and Yankee ingenuity, but also of various legal and regulatory positions such as those of the 1978 Natural Gas Policy Act act— may prove hard to replicate in some other countries. Environmental worries could stop shale gas dead in places. But although the pace may slow and the road may have bumps, for the moment the revolution looks set to roll on.
Natural gas and the environment: So much nicer than coal, but perhaps no cooler
IF THE rise of gas means the decline of coal, the environment is one of the winners. Though more research into the damage shale-gas extraction may do to the environment is needed, there is no doubt that the extraction of coal already harms the environment a lot.
It kills a lot of miners, too. In America, a coalminer’s risk of dying on the job is almost twice that of a worker in the oil industry. In China, the world’s largest coal producer, mining fatalities have been dropping quite quickly, especially when calculated per tonne of coal produced, but official figures still put the 2010 number at 2,433.
The toll gets higher after the stuff is burned. In America it is estimated that in 2010, 23,600 premature deaths, and 20 times that many cases of illness, could be put down to soot from coal-fired power stations. Other pollutants, such as sulphur, increase the burden. A recent analysis by Michael Greenstone and Adam Looney of the Brookings Institution concludes that if the damage to human health and the local environment by such pollution were factored into energy costs, the price of a kilowatt hour from an American coal-fired power station would more than double. For gas such accounting would increase the price by just 4%. In China, where pollution controls (though tightening) are less developed, air pollution may be killing more than 500,000 people a year, and blighting the lives of many millions more: a pressing reason for shifting from coal to gas.
This is all before taking the climate into account. Coal typically produces almost twice as much carbon dioxide per kilowatt-hour as natural gas. Just substituting gas for coal would not solve the world’s climate problems—Europe aspires to emission cuts of 80% or more by 2050, which would require any carbon dioxide from gas plants to be sequestered underground, not emitted to the air. But in terms of long-term climate impact gas is still a much better choice than coal.
However, carbon dioxide is not the only fossil-fuel by-product to affect the climate. Sulphate pollution due to coal cools the planet by shading its surface from sunshine. This effect is taken by climate scientists as explaining a slower rate of global warming over the 20th century than carbon-dioxide levels alone would suggest. The 130% growth in China’s coal use over the past ten years may help explain why temperatures did not rise much over the decade.
The near-term climate benefits of a global dash for sulphur-free gas may thus be smaller than might be expected. Indeed, it is possible that, over the next few decades, the net effect of such a dash could be marginally more warming.
