So CCS isn't perfect either?!

Like many things in life, a world of safe CCS may be too good to be true.

Carbon capture specialist Udayan Singh highlights the key problem areas for CCS: the safe transportation of CO₂ and precise and secure injections of CO₂ into geological formations. If this method is to be introduced there will be great pressure on the quality and constant maintenance of carbon pipelines and injection, as leaks could cause vast environmental damage and would prove very costly.

The devastation of the Lake Nyos disaster
http://www.emigennis.com/2014/04/06/lake-nyos-disaster-reference-photos/

Forgarty & McCally state that if CO₂ concentrations were to reach 7%, enough carbon would be present in the blood of humans to cause narcosis and eventually asphyxiation. To support their points, they offer the Lake Nyos, Cameroon 1986 case study. 100,000 tonnes of CO₂ was released as an overturn of a volcanic lake (near Lake Nyo, as described by Damel et al) as the bottom part became over saturated with CO­₂, Holloway importantly claimed that this was due to a slow leak of CO₂ from magmatic sources into the lake. The leak resulted in  carbon concentrations of up to 10% in surrounding areas and consequentially over 1700 people died whilst hundreds contracted skin conditions or suffered from memory loss. This volume of CO₂ equates to seven days of CO₂ emissions from a single coal-fired power plant, and shows just how catastrophically dangerous this technique may have the potential to be. Pro-CCS scientists argue that this singular event cannot form the basis for summarising the risks associated with CO₂ leakage from a geological formation, however, as CO₂ is heavier than surrounding air it accumulates readily in depressions such as lakes. Therefore I believe that this case study does provide strong and accountable evidence for the dangers faced by carbon capture, and it insists that serious considerations need to be introduced before CCS is implemented worldwide.

Additionally, another potentially severe environmental risk caused by CCS is the potential for ocean acidification caused by leaked CO­₂. Ocean acidification is caused by carbon dioxide reacting with the ocean to create carbonic acid (CO₂ + H₂O à H₂CO₃). The ocean represents the planets largest carbon sink, an increase in carbonic acid severely threatens carbonate secreting organisms in the ocean and in doing so reduces the oceans capacity for carbon storage and so more CO₂ is released into the atmosphere and in doing so worsening the greenhouse effect. 

Moreover, Forgarty & McCally point out that ocean acidification can cause an increase of contaminant (e.g. Arsenic and lead) leaching which would endanger the lives of countless species. Furthermore, Holloway (1996) argues that as well as oceans, groundwater located (100-200m below the surface) may be contaminated from CO_2­ leakage. CO₂ groundwater contamination may cause increases in water hardness as well as transforming the concentrations of trace elements present in the water and therefore has seriously negative effects on our drinking water aquifers.

Finally, there is much discussion within the scientific regarding induced seismicity caused by the injection of CO₂ into the ground. Environmental scientists Verdon & Stork state that large volumes of CO₂ injected into a geological reservoir increases the pore pressure of the reservoir rock, which increases the chance of rock failure. Holloway importantly argues that this could result in micro-seismicity or activating previous faults which may trigger earth tremors. Seismic events within reservoirs could damage cap rocks, natural springs or open up faults allowing for CO₂ leakage further damages to other parts of the environment, environmental effects described above can impact the plant. 

Through my research into the risks associated with CCS, it is absolutely clear that this climate mitigation method is not perfect, and requires serious evaluation as to whether these risks can be limited or if the method is even viable at all in sight of these concerns. Luckily for you, I’ll be doing this in my next blog post!