Too risky?

Germany's upper house of parliament, the Bundesrat, has struck down a law for testing carbon capture and storage (CCS) technology amid strong resistance from some politicians.

The legislation, which is the German implementation of a European Union regulation, was meant to test the technology until 2017.

CCS refers to capturing carbon dioxide from fumes emitted by coal-fired factories and industrial plants before it escapes into the atmosphere, liquefying the pollutant and pumping it into underground storage sites.

The decision by the Bundesrat, which represents the interests of Germany's 16 states, could also throw into doubt the construction of a 250-megawatt testing plant by Swedish utility giant Vattenfall in the eastern state of Brandenburg.

CCS is seen as a promising technology by several German politicians and researchers who say it could help cut greenhouse gas emissions, fight climate change and help Germany meet ambitious climate protection goals.

The International Energy Agency estimates that the technology, if implemented successfully, could contribute nearly 20 percent to the reductions in CO2 emissions aimed for by 2050. Many companies also hope CCS technology will free them from having to buy expensive emissions certificates.

Residents opposed to technology

But the decision to test CCS technology in Germany remains highly controversial.

Many carbon capture facilities, which are still in the test phase, face strong objections from local citizens' initiatives and some state governments. They argue that the underground sites could pose a threat to human health.

There are fears that cracks or leaks in the underground cavities could lead to dangerous gasses escaping to the surface. That happened in 1986 when a naturally-occurring carbon dioxide leak led to the death of 1,700 people at Lake Nyos in Cameroon.

Transporting CO2 from factories and other facilities to safer storage units would require long pipelines, and residents also fear that faulty pipes could lead to the uncontrolled release of dangerous fumes.

Hans-Georg von der Marwitz, a member of parliament for Chancellor Merkel's conservatives in the eastern state of Brandenburg, is skeptical that CCS will be adopted in Germany.

"That's especially due to the residents here in the region who have made it clear that this risky technology should not and can not have a future here for us," he told Deutsche Welle.

Just a stop-gap measure?

But some environmental groups such as WWF say the technology should be tested so as to cut industrial emissions and push the fight to combat climate change.

Others say the technology is just a stop-gap measure on the way to lasting carbon-free energy production. They argue that investing in CCS could even delay the transition to renewable energies.

"Up until now, the widespread, risk-free implementation of CSS is nothing but a promise," Oliver Krischer, a member of parliament from the Green Party said.

"We should be looking instead at going down the right path and focusing on renewable energies and efficiency," he said.

Complicated technology

But it's not just the heated debate in Germany surrounding CCS that's hindering the technology's acceptance.

Separating out the CO2 from power plant emissions is a complicated process requiring large chemical processors. Future coal power plants would have to be equipped with carbon cleaning and isolation facilities that would take up about half of the space required for the plant. But once in place, they can isolate much of the harmful CO2.

"Carbon dioxide processors can separate over 90 percent of the CO2 released by using a multi-step process - first a pre-cleaning, then compression, then a post-cleaning, then drying, and in the last phase, the CO2 has to be put into liquid form," Uwe Burchhardt, a CCS project head employed by Vattenfall, told Deutsche Welle.

Some firms, including Alstom and Siemens, are trying out other ways of separating CO2. One method is called chilled ammonium technology. It binds CO2 using ammonia and water to produce ammonium carbonate, a commercial salt sometimes used in baking. Ammonium carbonate is also used in agriculture as a nitrate-free fertilizer.

Later in the process, the ammonium carbonate is heated and breaks down. The CO2 is then released in a controlled manner and - just like in other CCS plans - condensed and transported away.

The involved process of separation and disposal in many proposed CCS systems leads critics to another objection - namely that the process of chemically isolating and disposing of CO2 requires a lot of energy.

That's one point where developers agree, and they hope to find ways to make carbon isolation and storage more efficient.

Author: Irene Quaile, Bernd Gräßler / sp
Editor: Nathan Witkop