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Natural gas a big GHG contributor

28th November 2014

By: David Oliveira

Creamer Media Staff Writer

  

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As indicated in President Jacob Zuma’s June State of the Nation Address, South Africa is serious about integrating natural gas into the country’s energy mix. This, however, could have unexamined consequences for South Africa’s contribution to global warming, as is the case in the shale gas-prominent US, according to US-based Lewis & Clark Law School associate professor of law Melissa Powers.

While the US promotes a multifaceted energy mix, including coal, nuclear energy, gas, hydropower and renewable energy, Powers, who is also a director at the law school’s Green Energy Institute, warned that the dominance of natural gas, which was receiving significant financial and policy support in the US, could have an adverse impact on global climate change.

Delivering a presentation at the University of the Witswatersrand in September, Powers further noted that natural gas’s contribution to the US’s electricity supply has expanded significantly over the past decade, from about 18% ten years ago to about 30% currently.

She pointed out that, when both are combusted, natural gas produces about half the carbon dioxide (CO2), compared with coal.

However, Powers noted that the life-cycle greenhouse-gas (GHG) emissions associated with natural gas were being investigated, particularly in terms of the emissions of natural gas associated with hydraulic fracturing, commonly known as fracking.

Powers said studies had shown that a 2% leakage rate from natural gas facilities was permissible before it displaced the climate benefits of the resource; however, many wells in the US were far exceeding this rate, with reported natural gas leakages of more than 9%.

The International Energy Agency’s ‘World Energy Outlook 2011’ report presented a scenario, called the 450 Scenario, which aims to limit global temperature increases to 2 ºC and reduce the potential harmful effects of global warming by preventing global GHGs from exceeding 450 parts per million (ppm) of CO2.

Powers pointed out, however, that if current fossil fuel-based infrastructure was not immediately retired, limiting GHG concentrations to 450 ppm would not be attainable by 2017. “In other words, we have built all the possible fossil fuel infrastructure we can possibly build to meet our global carbon emissions goals,” she explained.

“However, methane, like CO2, is a GHG, but has heat-trapping potential 25 times greater than CO2. Therefore, each molecule of methane will trap 25 times more heat than a single molecule of CO2. It follows then that if methane escapes from natural gas facilities it will impact on the climate,” said Powers.

The Natural Gas Promise
Powers noted that, according to the US energy policy, the country viewed natural gas as a backup energy resource in the event of unexpected changes in the availability of other electricity sources and that, when renewable-energy technology developed in terms of storage and power management, natural gas would be displaced.

“This is not very realistic, as gas companies are not going to willingly step back once [the renewable-energy sector is established]. It is also unrealistic based on what has been happening in the US to support natural gas, but not renewable energy to the same extent,” asserted Powers, adding that, while the US did offer subsidies to renewable-energy suppliers, the subsidies were not equal to those offered to fossil fuel providers.

She added that the unbalanced subsidies in the US incentivise more investment in fossil resources than renewables, owing to fossil resources currently being cheaper.

“The US needs to advance its renewable-energy mandates by increasing and expanding them over a longer period to create market demand. Renewables also need a more stable and predictable subsidy system to enable them to remain competitive with natural gas, moving forward,” said Powers.

She noted that the US had been fracking since 2008, but started drilling before it understood the environmental implications and without an environmental legal framework in place.

“Generally, the US does not regulate the disposal of wastewater, the use of water or the air emissions associated with fracking. This means that it is cheaper to engage in this process because gas companies do not face the same environmental controls that other types of activities are subject to,” said Powers.

She cited the example of wind farms being subject to several federal requirements that apply to almost every phase of the operation, making wind energy more expensive than gas.

Powers added that the lack of environmental controls on fracking was reflected in the price of natural gas, which was about $16 per million British thermal units (MMBTu) in 2008, but is currently between $2 MMBTu and $4 MMBTu in different regions of the US.

She suggested that the US needed to strengthen environmental controls associated with natural gas and fracking, as it would “drive natural gas costs up and make producers accountable for the externalities it is imposing on society”.

Edited by Samantha Herbst
Creamer Media Deputy Editor

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