Shale gas and tight gas offer many countries the best chance to move toward an affordable energy supply that promises an alternative to coal-fired power generation and potentially a way to reduce greenhouse gas emissions, said Royal Dutch Shell's executive director, upstream international.
Malcolm Brinded acknowledged mounting "public anxiety" about the safety of developing and producing unconventional oil and natural gas. He spoke late last year to the Foundation for Science and Technology in London.
"Tight gas has already brought tangible environmental and economic benefits to North America," he said. "It now offers the rest of the world the opportunity to cut carbon dioxide emissions in the power sector while meeting surging demand for affordable energy.
"The sheer scale of this opportunity is what makes it so vital that any discussion about these energy sources is underpinned by hard facts and rigorous analysis," he said.
Brinded said industry has been "too hesitant to engage with the public about these matters, leaving the field clear for a number of misconceptions to take root, misconceptions that form a major part of the case against tight gas." Encouraging gas producers to maintain high operational and environmental standards, Brinded recommends governments implement "strict and well-targeted regulation" regarding shale gas and tight gas operations. Many countries are moving to develop their gas resources.
"The tight gas revolution is poised to become a global phenomenon," he said. "China, Latin America, Australia, Eastern Europe, and South Africa all hold significant tight gas deposits. Coupled with the rapid expansion of the global LNG market, this is giving more governments the confidence to back natural gas."
The International Energy Agency estimates the world will need to invest some $38 trillion to meet projected energy demand in the period to 2035 ($9.5 trillion in gas).
Shell's operating principles
Shell established operating principles for its tight gas operations worldwide to protect water, air, wildlife, and the communities in which Shell operates. These principles cover well design, construction, and operation.
"At Shell, we use what is known as a safety-case approach based on North Sea regulation. This requires our staff and contractors to assess closely and mitigate systematically all potential risks before drilling begins," he said.
"I emphasize this because a major public concern is that hydraulic fracturing could lead to the contamination of fresh water supplies, either by the fluid used to fracture the rocks, or by the gas itself."
A 2011 study by the Massachusetts Institute of Technology found that "there is no evidence" that contamination by fracturing fluids is occurring, he said.
MIT researchers noted "evidence of natural gas migration into freshwater zones in some areas, most likely as a result of substandard… practices by a few operators" in designing and constructing wells.
To put that in perspective, Brinded noted industry has used fracing more than 1.1 million times in the US during the past 60 years.
Industry is responsible to demonstrate to the general public that proper well design and construction prevent groundwater contamination.
"At Shell, we only operate wells that can be safely isolated from potable groundwater," he said. "First, where we drill through the aquifer, we line all of our tight gas wells with multiple steel and concrete barriers to prevent gas or liquids from escaping.
"Second, our North American gas formations that require fracturing are typically located a mile or more below the water table, trapped below many layers of impermeable rock. So, it is virtually impossible for gas or liquid to reach drinking water supplies through the localized cracks induced by fracturing the rock, which typically extend no more than 100 m above the well."
Shell supports regulation promoting the publication of fracing fluid chemicals, Brinded said, noting that typically water accounts for 99% of fracing fluid with chemical additives accounting for only 1%.
"Indeed, we would like to see regulations that promote transparency and public engagement by the tight gas industry in relation to all of its activities," Brinded said. "That doesn't just mean how we build and design wells or how we protect water sources, but also what we do to prevent excessive lorry traffic on local roads, to avoid disturbing livestock, or to mitigate light pollution at night."
Water, emissions concerns
He acknowledges the public's concerns about whether fracing involves unsustainable consumption of freshwater volumes.
"Operational practices can keep water consumption to a minimum," he said, adding Shell specifically designs its operations to minimize the use of potable water used in gas operations, sometimes recycling water.
Although shale gas production can require twice the water volume used in conventional gas production, Brinded noted that the production phase accounts for only a small fraction of the total amount of water used to generate electricity.
"The water intensity of conventional gas-fired power is far lower than nuclear and all other fossil fuels. So across the entire lifecycle, from production to use, shale-gas fired-power still uses half the volume of fresh water per megawatt hour consumed by coal and nuclear."
Moreover, the volume water used in the production of US shale gas is "a tiny proportion of overall water consumption," he said.
The US Department of Energy has studied the water use of the Marcellus play, he said. At peak gas production, the maximum water use represented less than 0.8% of the total used in the area overlying the play in New York, Pennsylvania, and West Virginia.
Brinded said another public concern is that GHG emissions from shale gas operations far exceed not only those from conventional gas, but even those from coal. He believes that by displacing coal-fired power, gas is the quickest, cheapest way to cut GHG emissions.
"Now, there's no doubt that the question of emissions is a complex one, and that further research is required," Brinded said.
He noted a Cornell University report sparked controversy, and he said that report "greatly exaggerated the emissions released during the production and distribution of shale gas. For example, it overlooked the steps taken by the industry to contain the amount of methane released during production."
Cornell University researchers also used a 20-year timeframe to study the global warming potential of methane in the atmosphere while scientists commonly consider a 100-year horizon to be more relevant in assessing climate change.
"Other studies take a more measured view," Brinded said. "For example, the IEA found that on a well-to-burner basis, emissions from shale gas exceed those of conventional gas by as little as 3.5% in the best case scenario and by 12% in the worst. At Shell, we manage our operations to keep emissions to the lower number.
"We also measure, catalogue, and report emissions to the relevant authorities. And remember: It's in our economic interest to capture as much gas as possible."
Brinded believes that across the lifecycle, GHG emissions from shale gas-fired power would be around half of the GHG emissions from coal.
"It's true that there are environmental and operational challenges associated with the production of tight gas. And it's imperative that the industry does its utmost to address them," Brinded said. "But, it's also true that the industry has the expertise to manage these risks, especially if governed by well-targeted and strictly implemented regulation."
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