Natural gas: fossil fuel of the XXIst century?

natural gaz, coal, energy efficiency, fossil fuel, European commission Coal fuelled the industrial revolution in the XIXth century and petrol drove world growth during the XXth. Gas is now the third most used electricity-generating source (equal to hydroelectricity) worldwide and its global consumption has been steadily rising (7% in 2010). Although not renewable, there are still large gas reserves across the globe today, partly due to their late exploitation. This resource could be tapped much longer than petrol, pointing to significant developments in exploitation and electricity-generating methods.

Energy efficiency strongly depends on technology

There are two main sorts of gas power plants. First generation gas power plants operate the same way as conventional thermal plants. Gas is used to boil water and turn it into steam, which drives turbines whose rotational movement then generates electricity. This inefficient technology is still marginally used in gas-producing countries but tends to disappear.

More efficient second-generation gas power plants directly produce electricity from burning natural gas. The early technology (also known as “simple cycle”) uses gas combustion to drive turbines. Such gas power plants are increasingly replaced by so-called combined cycle systems, which gain all the benefits of the two latter types: they generate electricity from burning natural gas while simultaneously using gas combustion to generate steam to drive turbines. This ingenious method pools the energy generated through natural gas combustion and offers two different ways to drive the turbines.

There are two kinds of gas: conventional gas, which is easily accessible and requires little processing, and non-conventional gas, whose extraction costs were long deemed too high. Non-conventional sources must be treated before gas can be used; besides, there has been a great deal of political as well as technical discussion about how drilling may impact the environment, as is especially the case with shale gas. In the United States, non-conventional gas drilling has experienced an unprecedented expansion, whereas in July 2011 France was one of the first countries to ban shale gas drilling through hydraulic fracturing, basing its decision on concerns that this technology may pose a serious risk to the environment.

A relatively cheap, little polluting fossil fuel with abundant reserves available… outside the European Union

All things – including electricity generation – being equal, gas power stations emit five times less carbon dioxide than oil power plants. Gas is also a cheap energy source since it costs between 60 to 80 euros per kWh, compared with respectively 50 to 100 euros and 150 to 300 euros for coal and oil.

Although natural gas drilling is accelerating worldwide, Europe can rely only on scant reserves of conventional gas. However, gas consumption across Europe – mainly supplied by Russian pipelines – is expected to rise from 526 to 622 billion cubic metres by 2030, according to the European Commission. Finally, the fact that the state-of-the-art infrastructure required for gas exploitation – specific ports and pipelines – is both costly and politically controversial makes natural gas more expensive and questions the capacity and willingness of Europe to enter a potential “golden age of gas” (La Tribune, 07/01/2012).

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