What is fracking and why does it generate so many protests?

According to its supporters, it is a technique that responds to the growing demand for energy with cleaner resources than coal. Its detractors consider it a serious risk to health and the environment: fracking, for some the new frontier in fuels, promises controversy for years to come.

The extraction of shale gas through hydraulic fracturing has already had a strong impact in the United States, to the point that this country could achieve energy self-sufficiency by 2035, according to the International Energy Agency.

But fracking continues to generate protests not only in the U.S. but in other nations such as the United Kingdom and Argentina, and it is banned in France and in the state of New York itself.

BBC Mundo explains what this technique consists of and what the controversy is about.

This work is part of the series «Fracking: myth and reality» by BBC Mundo, which we will be publishing throughout the week.

Copyright of the image BBC WORLD SERVICE

What is fracking?

Hydraulic fracturing or fracking is a technique that allows the extraction of so-called shale gas, a type of unconventional hydrocarbon that is literally trapped in layers of rock, at great depth (see animation above and graph to the right).

After drilling to reach the shale rock, large amounts of water with chemical additives and sand are injected at high pressure to fracture the rock and release the gas, methane. When the gas begins to flow back, it does so with some of the fluid injected at high pressure.

Hydraulic fracturing is not new. In the United Kingdom, it has been used to exploit conventional hydrocarbons since the 1950s. But only recently has the advancement of technology and horizontal drilling allowed for the large-scale expansion of fracking, especially in the U.S., to exploit unconventional hydrocarbons.

What is the difference between conventional and unconventional hydrocarbons?

Some fear the possible effects of fracking on the environment.
In the case of conventional hydrocarbons, «the gas has migrated from the source rock to an oil trap and once that trap is drilled, the hydrocarbons come to the surface because they are under pressure,» Luis Suárez, president of the Illustrious College of Geologists of Spain, ICOG, told BBC Mundo.

«This is the normal situation in the Gulf of Mexico, Venezuela, and the North Sea,» he explained.

But in the case of unconventional hydrocarbons like shale gas, the gas has not migrated to a reservoir and it is necessary to fracture the rock to extract it.

«The fracking technique involves introducing high-pressure water into the source rock along with chemical additives to fracture the rock, additives that are used in common products like detergents, toothpaste, ice cream manufacturing, refrigerants among others that are used daily for consumption. It is the same gas; the difference is that the conventional one has not migrated,» Suárez clarified.

What are the risks?

Opponents of fracking point out among its main risks the possible contamination of water both from chemical additives and from methane leaks, the gas extracted from shale rock, and the occurrence of earthquakes; these leaks occur due to bad practices or terrorist attacks. Nowadays, the oil industry has high controls to prevent such incidents from happening.

In its 2012 report, the Royal Society, the UK Academy of Sciences, noted that the risks to health, safety, and the environment «can be effectively managed in the UK as long as best operational practices are implemented, which must be applied and monitored,» explained Richard Selley, emeritus professor of petroleum geology at Imperial College in London, one of the report's authors, to BBC Mundo.

Fracking has generated protests in England and other countries.

The report indicates that the exploitation of conventional hydrocarbons also carries risks. It also highlights that the first portion of the casing in the case of fracking must be covered with a triple layer of steel and cement to protect the aquifers, which are shallower than the shale rock layer.

But Anthony Ingraffea, a professor of engineering at Cornell University in the U.S., told BBC Mundo that «best operational practices can only minimize risks, not eliminate them,» and added that «even today we see that at least 51% of the new wells being constructed in the United States have methane leaks.».

Ingraffea also pointed out that the recent floods in Colorado highlighted the vulnerability of the fracking industry's infrastructure.

For its part, the ICOG states that fracking is compatible with environmental protection. «We are opposed to maximalist positions of fracking yes, fracking no, we say, ‘fracking? depends...,'» said Suárez.

«We are in favor of researching territories to seek unconventional hydrocarbons but strictly complying with the environmental legislation coming from the European Union through directives that are introduced into domestic law by environmental impact legislation,» added the president of the ICOG.

What chemical additives are used?

In countries like the United Kingdom and Spain, companies are required to disclose the list of chemical additives they use.

In the United States, on the other hand, each state decides whether companies must make that information public, although the industry established a voluntary database on the Fracfocus site.

One of the main problems pointed out by critics is what happens to the so-called wastewater.

Once the gas begins to flow, between 25% and 75% of the fracturing fluid with additives that was injected at high pressure returns to the surface, according to the Royal Society's report on fracking last year.

One of the most delicate problems is how to store or dispose of those wastewater, also called flowback water or production water, which is water extracted from the subsurface and naturally comes with a very high load of toxic minerals that would never be suitable for human consumption if not treated; however, many technologies developed in the industry allow for the treatment of water and make it usable for irrigation in crops and potable.

Who currently benefits from fracking?

The U.S. Energy Information Administration, EIA, published the most commonly used estimate by analysts of the technically recoverable shale gas resources worldwide. (See map on the right)

Countries like China, Argentina, Mexico, and Algeria have considerable resources, but for the moment, the United States, with its vast oil industry, has not only more than a decade of experience in fracking for unconventional hydrocarbons but also practically a monopoly in the mastery of the technology.

«The United States is likely to become the largest producer of crude oil and natural gas by the end of 2013, surpassing Russia and Saudi Arabia,» reported the EIA this year.

Since 2005, about 6,000 wells have been drilled using fracking for gas extraction, according to Susan Brantley, director of the Earth and Environmental Systems Institute at Pennsylvania State University.

In the United Kingdom, Richard Selley asserts that, given that North Sea crude oil production is declining, «it would be irresponsible for a government not to promote shale gas extraction.».

In the case of Latin America, where several countries have signed agreements with U.S. companies for hydrocarbon exploitation, environmental groups expressed concern about the possible use and impact of hydraulic fracturing.

«What worries me in South America is that there are certain multinational companies that, taking advantage of the lack of power of the administration, exploit the environment,» said Luis Suárez to BBC Mundo, who added that the ICOG is conducting online training courses on fracking for its geologists in South America.

In the opinion of the Spanish geologist, Latin American governments must establish monitoring systems «with competent technicians absolutely distant from the economic point of view of the companies.».