Preparing to Capture Carbon

Carbon sequestration from large sources of fossil fuel combustion, particularly coal, is an essential component of any serious plan to avoid catastrophic impacts of human-induced climate change. Scientific and economic challenges still exist, but none are serious enough to suggest that carbon capture and storage will not work at the scale required to offset trillions of tons of carbon dioxide (COR) emissions over the next century. The challenge is whether the technology will be ready when society decides that it is time to get going. Strategies to lower CO2 emissions to mitigate climate change come in three flavors: reducing the amount of energy the world uses, either through more efficient technology or through changes in lifestyles and behaviors; expanding the use of energy sources that do not add to the atmosphere; and capturing the CO2 from places where we do use fossil fuels and then storing it in geologic repositories, a process known as carbon sequestration. A survey of energy options makes clear that none of these is a silver bullet. The world's energy system is too immense, the thirst for more and more energy around the world too deep, and our dependence on fossil fuels too strong. All three strategies are essential, but the one we are furthest from realizing is carbon sequestration. The crucial need for carbon sequestration can be explained with one word: coal. Coal produces the most CO2 per unit energy of all fossil fuels, nearly twice as much as natural gas. And unlike petroleum and natural gas, which are predicted to decline in total production well before the middle of the century, there is enough coal to last for centuries, at least at current rates of use, and that makes it cheap relative to almost every other source of energy (Table r). Today, coal and petroleum each account for roughly 40% of global CO2 emissions. But by the end of the century, coal could account for more than 80%. Even with huge improvements in efficiency and phenomenal rates of growth in nuclear, solar, wind, and biomass energy sources, the world will still rely heavily on coal, especially the five countries that hold 75% of world reserves (see (6)): the United States, Russia, China, India, and Australia (1). As a technological strategy, carbon sequestration need not apply only to coal plants; indeed, any point source of CO2 can be sequestered, including biomass combustion, which would result in negative emissions. latest tech fresh news Carbon sequestration uptake through reforestation or fertilization of marine photo plankton. But the potential to enhance bio-logical uptake of carbon pales in comparison to coal emissions, ever more so as India, China, and the United States expand their stock of coal-fired power plants. So developing and deploying the technologies to use coal without releasing CO2 to the atmosphere may well be the most critical challenge we face, at least for the next too years, until the possibility of an affordable and completely non—fossil energy system can be realized.