Capturing C02

While the energy industry is using new technologies such as Integrated Gasification Combined Cycle (IGCC) to reduce its carbon footprint in new power plant construction, Alstom is exploring another path to cut carbon dioxide emission by using CO2 capture and storage (CCS) technology for existing power plants.

Alstom presented its clean power strategy in China with the aim of providing a commercially viable solution for carbon capture by 2015 during the recent Alstom Power Convention 2008 in Beijing.

CCS, also called carbon sequestration, captures carbon dioxide after it is produced and injects it underground.

A power plant in Anhui province.

There are three main technology paths for CO2 capture: pre-combustion, oxy-firing and post-combustion, while CCS refers to post-combustion.

Alstom says that it concentrated its R&D efforts on the latter two as they can be used for both existing and new power plants, while pre-combustion can only be used for new plants.

Alstom, whose equipment is used in more than 25 percent of existing power plants worldwide currently has nine pilot plants in operation around the world and is aiming to market its post-combustion technology by 2015, and its oxy-firing solution by around 2020.

Global power generation accounts for about 40 percent of overall CO2 emissions. It will double by 2030 from today's level, with CO2 emissions increasing by two thirds.

"As we cannot take fossil fuels out of the mix very quickly, but CCS plays as a central role in reducing global emissions so fossil fuel remains an important part of the energy mix," said Philippe Joubert, Alstom executive vice-president and president of Alstom Power Systems. "This is especially the case for China where coal in the overall power generation is expected to remain at its current level of 78 percent by 2030."

This is crucial for China with its need to upgrade its existing power facilities to meet international environmental standards. In order to refine its carbon capture solutions, Alstom is currently testing its post-combustion and oxy-firing technologies at nine pilot plants located in Germany, France, Norway, Sweden, the United States and Canada, Joubert says.

"There is no economic growth without expansion in the power sector, which also means increased emissions," he says. "The good news is that adapting clean power technologies allows countries like China to address environmental challenges without jeopardizing economic growth."

Yet, the case may not be so clear.

Supporters say carbon capture has the potential to reduce more than 90 percent of an individual plant's carbon emissions.

Capturing carbon dioxide from small, mobile sources, such as cars, would be more difficult, says Lynn Orr, director of Global Climate and Energy Project (GCEP), but adds that fossil-fuel power plants would be ideal candidates for the technology.

The greatest concern surrounding carbon dioxide storage is the potential for it to leak, researchers say. "But if you do it right, if you select the site correctly and monitor, it can be near permanent," says Sally Benson, executive director of GCEP.

Skeptics don't agree. "CCS is still at an experimental stage. It is too short to prove the technology is safe and feasilble," said Zhang Jianyu, China program director of US-based Environmental Defense.

"And the process takes energy, adding to inefficiency and meaning more fuel must be burned. Furthermore, as the government hasn't set requirements for reducing CO2 emissions, there are no economic incentives or mandatory policies to promote the use of CCS in China. "

The world's biggest CCS project in the Sleiper field in Norway, is reportedly going well. But oilfields are often a long way from the places where power is produced. Even if carbon can be stored in quantity without leaking, it will have to be transported around the world first, according to the Guardian newspaper.

Yet CCS is an "important solution" to fight global warming, says Rajendra Pachauri, chairman of a United Nations panel of scientists who shared the Nobel Peace Prize with Al Gore. "Although much more effort is needed to get the technology widely adopted, we need to use everything at our disposal to curb global warming."

Joan MacNaughton, senior vice-president general administration, Alstom Power System, urged the Chinese government to deliver regulatory clarity to CCS.

"In addition to the efforts made by enterprises from the technology view, the government should provide support both financially and legally promote the CCS projects," says MacNaughton. "I have been working with government departments for 35 years. My experience is if governments don't pay much attention to environmental related projects and issues, the results will be discounted."

Oil exporter Norway aims to get CCS projects included in the Clean Development Mechanism (CDM), under the Kyoto Protocol which allows developed countries with a CO2-reduction commitment to buy carbon credits from developing countries.

Others argue that renewable energy incentives and subsidies, such as feed-in tariffs, should be adopted for the CCS projects.

Jeff Chapman, chief executive of the Carbon Capture and Storage Association (CCSA) says the current problem of CCS is not the technology but the regulatory policy. He says the best way to promote CCS will be to set a cap on carbon emissions so as to allocate tradable carbon credits for CO2 captured and stored.

(China Daily 06/09/2008 page5)