Why Burying CO2 Gets Wide Interest
Much Is Riding on Pilot Project That Puts Clean-Coal Technology to Test
By LEILA ABBOUD April 26, 2007; Page B3
Swedish power company Vattenfall AB is trying to rehabilitate one of the world's dirtiest yet most-used forms of energy -- coal. At a pilot project in Schwarze Pumpe in eastern Germany, the company is building one of the first coal-fired power plants that will attempt to bury the thousands of tons of carbon dioxide it emits into natural caverns deep beneath the Earth's surface instead of into the atmosphere. Governments, industry and other groups trying to reduce emissions generally accepted as causing global warming have a lot riding on the outcome. Many climate-change scientists estimate it will be very difficult to achieve significant reductions in carbon emissions if this technology, known as carbon capture, isn't applied on a wide scale. "Carbon capture has the potential to help us realize the huge reductions in emissions that we'll need to hold global warming in check," said Bert Metz, author of a report on carbon capture and storage for the Intergovernmental Panel on Climate Change, a United Nations group of climate-change scientists. However, while oil and gas companies such as France's Total SA and utilities such as Germany's RWE AG have also been experimenting with carbon-capture technology, only about a dozen pilot projects are expected to be built over the next five years. Only when these projects have been thoroughly tested for safety, and the technology has been fine-tuned, will it become clear whether carbon capture can achieve its promise of becoming a major weapon in the fight against global warming. Burning coal produces nearly one-quarter of the world's energy, according to the International Energy Agency, and it is one of the major contributors of carbon dioxide into the atmosphere. Coal use is expected to increase 32% by 2015 and 59% by 2030 as China and India, two of the three biggest coal consumers, experience breakneck economic growth. Gas-fired power plants, while cleaner than coal, also emit carbon dioxide. The European Union has been one of the most enthusiastic advocates of carbon capture. In its Technology Platform for Zero Emission Fossil Fuel Power Plants, or ZEP, project, the EU set a target date of 2020 for achieving the capability to build coal-fired power plants with zero carbon-dioxide emissions. The project calls for "urgently implementing" 10 to 12 large-scale carbon-dioxide-storage demonstration projects by 2015. The goals: Test various combustion techniques, amass safety data and refine methods of transporting carbon dioxide from where it is produced to underground storage. Gardiner Hill, BP PLC's director for carbon-capture and storage technology who works on the ZEP project's strategy committee, acknowledges that the EU's timetable is aggressive. "We're sort of on track," he said. "Industry is working hard to meet the goals."
For decades, oil companies have injected carbon dioxide underground as a means to increase pressure and maximize yields from petroleum fields. A few years ago, BP also started to experiment with storing excess carbon dioxide underground at its Salah natural-gas field in Algeria. When natural gas is removed from the ground, it is mixed with carbon dioxide, which must be stripped out before the gas can be sold. So natural-gas extraction plants typically expel the excess carbon dioxide into the air, something BP is trying to change. The process will have a significant impact on reducing emissions only if it can be used to effectively capture and store carbon dioxide produced at power plants that burn coal or natural gas. That is significantly trickier. Unlike oil or gas fields, power plants aren't always conveniently located near geological formations where carbon dioxide can be stored. In many cases, pipelines will be needed to transport carbon dioxide over great distances to underground storage areas. There are safety risks. Carbon dioxide could seep out of geological formations where it is warehoused and affect the surrounding environment. And even proponents of the approach acknowledge that it could be as long as 20 years before carbon-capture technology could be applicable on a wide scale. Vattenfall broke ground in Germany on its 30-megawatt pilot plant in May 2006. It is being built next to an existing 1,600-megawatt coal plant, will cost about €50 million (about $68 million) and is slated to start operating in 2008. About 100 scientists are working in the company's labs to perfect the combustion technique that Vattenfall has chosen, known as oxyfuel combustion. In this approach, coal is burned in the presence of pure oxygen at very high temperatures to generate electricity and pure carbon dioxide that can be stored. To be compressed and stored, carbon dioxide must be pure, with no excess water or gases mixed in with it. Oxyfuel is newer and less proven than others, but Vattenfall believes that in the long run it will be the most cost-effective. Vattenfall has yet to figure out how it will effectively transport and store the carbon dioxide from the plant. At Lacq, in southwestern France, Total plans to complete its own €60 million pilot project in 2008. That project will refurbish a 50-year-old natural-gas boiler so it can produce oxyfuel combustion. The project will then transport the excess carbon dioxide to a nearby depleted natural-gas field via a pipeline and pump it into a rock formation more than 11,500 feet underground. Jean-Michel Gires, Total's executive vice president for sustainable development and environment, said it was important to have all of these components tested on one site to get a true measure of the technology's strengths and weaknesses. "We want to prove it's possible to reduce the cost of carbon-capture technology," he said. "Large demonstration projects like this can convince stakeholders that these schemes are reliable and cost effective enough to be put in place on a much larger scale later on."