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Maintaining Stable Energy Supply While Reducing Emission Of Carbon Dioxide At The Same Time

February 12, 2013
Image Caption: Pumpjacks extracting oil from a southern Saskatchewan oilfield in Canada. Credit: Mike Kendall, University of Bristol.

Royal Astronomical Society

Decisions about future energy challenges are too often hindered by propaganda, half-truths and a limited grasp of the science that informs the choice and use of hydrocarbon and other resources, according to delegates at the annual conference of the British Geophysical Association (BGA), to take place in the Geological Society, Burlington House in London on 14 and 15 February.

For example, rather than being a quick fix that helps cut carbon dioxide emissions, poor quality carbon capture and storage may actually make things worse whereas ‘fracking’, the controversial gas and oil extraction technique, may prove to be vital in the years ahead. Leaders from universities and industry will come together to discuss these issues at the BGA meeting, where delegates will discuss the sustainability, security and risks of future energy choices.

Scientists at the conference will argue that evidence from geophysics must be part of the political decision making process, as the UK and other countries consider how to maintain the stable energy supply we depend on while simultaneously reducing the emission of carbon dioxide, one of the key greenhouse gases responsible for global warming.

At first sight, carbon capture and storage (CCS) appears to be a technological fix that allows us to carry on using the fossil fuels oil, gas and coal (hydrocarbons) to generate energy. CCS power stations could pump the resulting greenhouse gases to underground reservoirs rather than releasing them into the atmosphere.

In reality, it is not so simple. Even handling the greenhouse gases emitted by fossil fuel burning means storing something close to 3.5 billion tonnes of carbon dioxide per year, a volume comparable to the 27 billion barrels of oil produced annually. And for the storage to be worthwhile the gases must also be stored in reservoirs that leak at rates of less than 1% per thousand years, at which point their carbon footprint effectively matches that of renewable energy sources. Geophysical modelling and monitoring, to be discussed at the meeting, is needed to ensure reliable storage for the thousands of years required.

A related discussion centers on ‘fracking’, potentially a huge new energy source for the UK, but one that is struggling for public acceptance despite the promise it holds of lower energy prices and better energy security. Until now media coverage of fracking has centered on the perceived environmental risks, such as earthquakes and contamination of groundwater.

In his keynote address to the BGA meeting, Professor Mark Zoback of Stanford University points to the data from the ten years of gas production by fracking at 150,000 sites across the United States. US Geological Survey information demonstrates that earthquakes can result from fracking, but that serious effects can be avoided with careful choice of location. Ironically European countries that have banned fracking are now purchasing US coal for power stations and driving up carbon dioxide emissions as a result.

Intriguingly, Prof. Zoback draws a comparison between fracking and CCS. The techniques are similar — pumping fluid into rocks — and he argues therefore carry the same risks of earthquakes in some rock types and locations. The problem is that these tremors could then release carbon dioxide too quickly, well above the 1% loss per thousand years needed for CCS to be effective. If carbon capture and storage is to have any effect on greenhouse gas emissions, reservoir locations will need to be chosen with care.

Other sessions at the meeting will cover risks associated with nuclear power in the light of Fukushima, renewable energy from wind turbines and criteria for nuclear waste storage sites.

Meeting organizer Prof. Mike Kendall of the University of Bristol commented: “A reliable, affordable and environmentally friendly supply of energy is one of the major challenges facing society. And although there are numerous different options, there is no single silver bullet that will solve this challenge. The issues are clouded by misinformation and a poor public understanding of the underpinning science. Geophysicists have a key role to play in helping clarify these complex issues and can help governments make the right decisions on how we supply energy to homes and businesses in the 21st century.”

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Source: Royal Astronomical Society



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