By: Isabelle Kingsley, Category: Lifelong Learning, Date: 07 Dec 2011
Is pumping carbon dioxide into the ground a novel solution to reducing greenhouse gases leading to climate change or is it just sweeping the problem under the rug?
Australia has the most greenhouse gas emissions per person in the world, mainly because most of the energy we use comes from burning fossil fuels. While renewable forms of energy, such as solar, wind and geothermal energy produce little to no greenhouse gas emissions, they currently cannot keep up with the energy needs of our society or compete with the price of fossil fuel. Is there a way to reduce CO2 emissions while continuing to benefit from burning fossil fuels for energy? Some say geosequestration is the answer.
Simply put, geosequestration is burying our excessive carbon dioxide deep beneath the earth. The process includes capturing carbon dioxide from its source, generally from a power station's chimney flue, then separating, compressing and transporting it to its burial site—often depleted oil or gas wells. The compressed gaseous CO2 is then further compressed into liquid CO2 before it is pumped underground where it is trapped by a thick layer of clay or some other plug to prevent it leaking out.
Geosequestration has the potential to reduce CO2 emissions from power stations and natural gas wells to almost zero; however, one of the concerns is how safe the CO2 is once it's in the ground. Geosequestration experts are confident that the CO2 won't leak out. Others worry about the possibility that it could—either slowly over time, or suddenly if there was seismic activity. Research is needed before it is proven to be safe, secure and affordable.
The Gorgon Project run by Chevron, ExxonMobil and Shell—an LNG (Liquefied Natural Gas) processing and shipping facility located on Barrow Island just off the coast of Karratha in Western Australia—will be the world's largest geosequestration project and is expected to bury an estimated 125 million tonnes of CO2 in a depleted gas well beneath the island.
Critics wonder if geosequestration is really about sustainable development or if it is about sustaining the coal and gas industries by greening their image. Others wonder if the appeal of geosequestration is being used to divert focus and funding away from renewable energy and strengthen our dependency on fossil fuels—a finite resource.
What are your thoughts?